In the Hollywood blockbuster "Inception" (2010), a dedicated team of "dream extractors" is hired to alter a CEO's decision-making by manipulating his dreams. In the movie, this feat involves a private jet and liters of sedative gas — but a new study suggests they could have achieved a similar effect with only some steel-drum jingles and a comfy bed in a research lab.

The new work shows that audio cues played to sleeping volunteers during rapid-eye-movement (REM) sleep, the stage of sleep when most dreaming occurs, can manipulate dream content.

In some cases, this manipulation improved the volunteers' ability to solve puzzles they had first encountered the day before.

The work was published Feb. 5 in the journal Neuroscience of Consciousness.

'Sleep on it'

If you are stuck on a problem, people often advise you to "sleep on it." And there's some scientific evidence to back this up, said study co-author Ken Paller, a cognitive neuroscientist at Northwestern University. For example, in one 2012 study, volunteers asked to solve association-based problems performed better after sleeping than did another group that stayed awake.

But how sleep might achieve this was unclear.

"The motivation for this study was to see if dreaming has something to do with the benefits of sleep we get for problem solving," Paller told Live Science.

Paller's team recruited 20 participants who reported having a history of or interest in lucid dreaming, a dream state in which the sleeper becomes aware that they are dreaming and can manipulate their dream to some degree.

Before taking a snooze in the research lab, these participants were tasked with solving puzzles that tested creative cognition within a certain time limit. These included tasks in which volunteers had to alter matchstick diagrams to make certain shapes by moving a limited number of sticks.

As the volunteers considered each puzzle, a short soundtrack played; the tune was unique to each conundrum. These themes included guitar riffs, whistling tunes and steel-drum songs. The puzzles were difficult enough that each participant was left with several unsolved puzzles by the time the testing concluded.

Lead study author Karen Konkoly, who worked on the project while studying dreams in Paller's lab, also taught the volunteers specific eye movements, with the idea that, if the participants were experiencing lucid dreaming, they could attempt to communicate that to the researchers by moving their eyes.

Then, the researchers fitted the participants' scalps with electrodes to measure their brain activity and eye movements while they slept. The participants were allowed to watch "Inception" or "Waking Life" (2001), another film about lucid dreaming, while the electrodes were applied.

Hours later, as the volunteers entered REM sleep, the research team, led by Konkoly, began playing soundtracks associated with puzzles they had failed to solve. Immediately afterward, they woke up the participants to record any dreams they'd had in diaries. The participants recorded their dreams over the next two weeks and spent one more night in the lab solving puzzles.

Three-quarters of the volunteers reported having dreams that related to the unsolved puzzles, and the data suggested they were more likely to dream about the puzzles the researchers had cued up with audio. Six dreamers, upon hearing the puzzle soundtracks, signaled to Konkoly they were lucid by moving their eyes or changing their breathing in preset patterns.

The next day, all of the volunteers attempted the puzzles again. The results were mixed.

If certain unsolved puzzles had appeared in the volunteers' dreams, the volunteers were more likely to solve those puzzles the next day, compared with puzzles they had not dreamed about. The volunteers solved 42% of the puzzles they dreamed about and only 17% of those that didn't appear in their dreams.

Does lucid dreaming help or hinder?

This finding doesn't definitively prove that dreams help us solve puzzles, though. It's possible that the volunteers simply dreamed about the puzzles they were most curious about and were more likely to solve at baseline.

To the authors' surprise, the volunteers whose eye movements suggested they had lucidly dreamed were less likely to solve the puzzles than those who'd had non-lucid dreams about the puzzles. Paller said the study's small sample size may have produced this effect.

"I think we didn't have enough lucid dreams to really be sure about that," he said.

Emma Peters, a dream engineer at the University of Bern in Switzerland who was not involved in the study, said a major talking point in the field had been whether lucid dreaming might actually impair creative thinking, compared to non-lucid dreaming.

"The idea is, you can do creative problem-solving in dreams because your dreams are so bizarre," she said, "and they make associations that you would normally not do if you were consciously there."

For Paller, interpretations of dream research face another important limitation: the other parts of the sleep cycle in which dreams don't occur as often. At present, it's impossible to rule out the possibility that brain activity in these stages could be a driving force in creative thinking; the downstream results of that thinking may then emerge in remembered dreams.

But the field is gradually building a picture of what goes on in the sleeping brain. For Paller, these unresolved mysteries are what keeps dream science exciting.

"I think science is fun when there's still things you need to understand," he said, "and you haven't got there."

You may assume that children have nightmares about monsters under the bed, while adults dream about stressful events like deadlines. But is there any scientific evidence showing that dreams change as we age?

Although there are plausible mechanisms for how aging could cause dreams to change over time, very little research has explored the topic.

"Dreaming depends on neural systems involved in imagination, memory and emotion, all of which develop and reorganize with age," Dr. Giulio Bernardi, head of the Sleep, Plasticity, and Conscious Experience (SPACE) research group at the IMT School for Advanced Studies Lucca in Italy, told Live Science. However, "surprisingly few studies have systematically examined how dreams change across the lifespan."

The studies that have investigated this idea have shown that people tend to report their dreams differently at various stages of their lives. While younger dreamers tend to see and feel more vividly, older people recall more complicated and less-emotional situations.

One of the simplest, and perhaps most common, explanations for the way our dreams adapt and evolve is called the "continuity hypothesis," first put forward in 1971.

According to that theory, our dreams tend to mirror what we're experiencing in our waking lives — if we're lounging on vacation, we may see sun and sand when we fall asleep, but if we're anxious about work, we may be transported to the office. But ultimately, the parallels between sleep and reality reveal very little about why our dreams might change as we grow up.

"Changes in dreaming across life reflect the complex interaction between brain development, sleep architecture, and cognitive-emotional maturation," Bernardi said. Everything from memory to sleep quality can influence how we experience both dreams and their aftermath: "These factors determine not only how vividly dreams are produced during sleep but also how likely they are to be remembered upon awakening."

How dreams change with age

The foundational research on how children dream was done by sleep researcher David Foulkes from the 1970s to the 1990s. According to his research, young people's dreams tend to be relatively straightforward — they feature animals, static objects and simple interactions. (However, research on children's dreams involves complications because the results depend on each child's ability to understand what dreams are and how to relay them to others.)

In adolescence, dreams tend to become more frequent and more vivid than they were in childhood, reflecting the many changes we're experiencing in our waking lives. While younger adolescents report dreaming about falling, being chased, and confronting monsters or animals, older teens reexperience the stresses of school and new relationships.

In adult life, dreams usually become a bit more mundane. One study found that adults and older adults dream about arriving somewhere late and "trying again and again to do something" more often than other age groups. Odd dreams and nightmares still occur, but the aggression of adolescence starts to fade and the complexity of dreams starts to reflect our waking life even more.

Studies show that in old age, people don't tend to report having as many dreams. Many also experience "white dreams," in which they recall having a dream but aren't quite sure what happened during it. While some of this can be explained by the lower quality of sleep that older adults tend to experience, much of this change — as is the case with dreams at all ages — has to do with the ability to accurately and descriptively remember what we saw in our sleep.

"Dreaming is defined as subjective experiences that occur during sleep," Michael Schredl, head of the sleep laboratory at the Central Institute of Mental Health in Germany, told Live Science. "What we get is only the dream or dream report, the recollection of those experiences that occurred during sleep."

At the end of life, and during the dying process, people often report seeing departed loved ones and recall visions of packing and preparing to go on a trip in their dreams. Studies of hospice patients have found that these dreams are often comforting and put people at ease, mirroring the reflection that often occurs at the end of life.

Sleep quiz: How much do you know about sleep and dreams?

We dream every night, but we often can't remember those dreams. Some mornings, we recall vivid details, and other days, we piece together hazy outlines. But what about color? Do most people dream in color or in black and white?

Some people may be surprised to learn that this has proved a divisive question. Modern research has indicated that television and films have a lot to do with how we experience dreaming and what we can remember when we wake up.

"Since we're used to colored media, we think dreams must be kind of like watching a movie or watching something on YouTube," Eric Schwitzgebel, a professor of philosophy at the University of California, Riverside, told Live Science. "Those things are colored, so we tend to assume that dreams are too."

But that hasn't always been the case. Up until the 1960s, researchers thought people largely dreamed in black and white, and surveys have backed this hypothesis. A small study of 277 people published in 1942 found that 70.7% of the college sophomores surveyed rarely or never saw colors in their dreams. Nearly 60 years later, Schwitzgebel asked a group of 124 college students the same questions — and the results had shifted drastically. In the more recent survey, less than 20% of the students surveyed reported rarely or never seeing colors in their dreams.

Other recent studies have produced similar results. Researchers have discovered a pattern: People born before the advent of color television and movies were much more likely to report having monochromatic dreams than people born after. This suggests that the way we interpret our dreams is affected by the types of media we consume.

Entertainment isn't the only factor. Much of what we take away from our nightly dreams has to do with how accurately we remember them and which details stick with us the most.

"Dreams are defined as subjective experiences during sleep, and the only way we can get to them is if the person is remembering them after waking up," Michael Schredl, head of the sleep laboratory at the Central Institute of Mental Health in Germany, told Live Science. "The main problem is, 'how good are you at recalling?'"

Just as in waking life, the colors of objects can be quite forgettable if they match what we expect to see. For example, a yellow banana in a dream probably wouldn't leave a lasting impression.

"You don't think about it, and it's difficult to remember," Schredl said. But if a neon-pink banana appears in a dream, it might make more of an impact.

What's more, if a particular color is significant to a person, they may be more likely to remember it.

"If the color has a specific meaning for the person in her or his waking life, then it might be that the color might point to something," Schredl said. "It's not about the color itself but how the color is affecting the person."

But Schwitzgebel argues that the question of whether we dream in black and white or color could be a bit misguided in the first place. When we imagine a scene in which the colors aren't important, our mental image may not be in black and white or in color; it may just be a fuzzy, "indeterminate" image. Or perhaps what we remember in the morning is slightly different from the mental image we had while dreaming, informed more by assumptions than memory. Dreams might be less of a visual, movie-like experience than we tend to assume, he said. Rather, it's possible our media consumption affects how we remember our dreams.

"A lot of people can't really quite get their minds around what it would mean for a dream experience to be neither colored nor black and white," he said.

Sleep quiz: How much do you know about sleep and dreams?

Both Salvador Dalí and Thomas Edison are said to have used dreams to stoke their creative process. To spark new ideas, the men would let themselves drift off to sleep for just a few moments, and then wake up and note the dreamlike visions they had on the brink of unconsciousness.

But you may have heard that dreams happen only in a stage called rapid-eye-movement (REM) sleep. So is it possible to dream during other stages of sleep, as Dali and Edison supposedly did??

Although dreams in different sleep stages can take on different forms, REM sleep is definitely not the only time we dream, experts told Live Science.

"The belief that dreams are only associated with REM sleep comes from people who are not familiar with the subject in detail, or who have somewhat outdated knowledge," Isabelle Arnulf, a sleep neurologist at Sorbonne University in Paris, told Live Science in an email.

When REM sleep was first described in the 1950s, it had a couple of easily observable characteristics that prompted scientists to link the sleep stage to dreams. REM sleep, which makes up about 25% of our total time asleep, is characterized by brain waves that resemble electrical activity during wakefulness, fast eye movements and full-body paralysis. Scientists theorized that these rapid eye movements reflected people "watching" their dreams and that the body was paralyzed to prevent them from acting out those dreams in real life. While these theories about REM sleep still hold, scientists now know that these outward physical characteristics aren't necessarily required for dreams to take place.

It is true that when people are awoken during REM sleep, they often report remembering vivid dreams with a strong narrative thread. But since the discovery of REM sleep, further research has shown that people dream during non-REM (NREM) sleep, too.

Related: What happens in your brain while you sleep?

In one study, Arnulf used a drug to suppress REM sleep in a small group of participants and then regularly woke them up throughout the night to see if they'd had any dreams. Many participants reported remembering dream-like mental content upon waking up, even though they had never entered REM sleep. Based on their reports, the structure and content of those dreams was a little different, though.

"NREM dreams are less frequent, shorter, less vivid, more conceptual or thought-like, and often lack a clear narrative," Francesca Siclari, a sleep researcher at the Netherlands Institute for Neuroscience, told Live Science in an email. "In contrast, REM dreams are almost always story-like, vivid, and rich in sensory detail. That said, there's a lot of variability. Sometimes NREM dreams are very minimal in content, and other times they can be remarkably similar to REM dreams."

Siclari has used electroencephalography (EEG) — a technique that measures electrical activity in the brain — to learn more about dreams during different sleep stages. She's found that both REM and non-REM dreams share some similarities in EEG signatures, even though REM and non-REM sleep stages generally look quite different on an EEG scan. She also discovered that when people's brain activity is slower, they're less likely to report a dream when woken up.

Although these results shed light on the mechanics behind dreaming in REM and non-REM sleep, many questions remain. Scientists still don't understand exactly how the brain generates dreams, why we have such a hard time remembering them, and why we even dream at all. They hope if they can learn more about dreams — and the different sleep stages in which they occur — it could reveal deeper truths about how the human brain works.

"[Dreaming is] much more frequent and varied than most people realize — we typically remember only a tiny fraction of our dreams," Siclari said. "Studying them gives us a unique perspective on how the mind works when it’s decoupled from the outside world."

Sleep quiz: How much do you know about sleep and dreams?

We spend a large portion of our lives sleeping. That might seem like an evolutionary disadvantage, given sleep leaves us immobile and potentially vulnerable to attacks for hours on end — but evidence suggests we have many key physiological functions tied to sleep, and disruptions in sleep are linked to a wide range of health problems, including a higher risk of death.

What's more, as we sleep, we often dream. In this way, sleep unlocks an experience that we can't access during our waking hours.

In the quiz below, test your knowledge of the science of sleeping, as well as the dreams that unfold during sleep. Remember to log in to put your name on the leaderboard; hints are available if you click the yellow button, and let us know your score in the comments.

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Why does it seem like the same dreams keep following us? Maybe you've dreamed of soaring like a bird since childhood, or you've recently started revisiting a particular place or time while asleep. Perhaps a bad day at work still stirs exam nightmares, even if you haven't been a student for decades.

If so, you're far from alone. Recurring dreams are a surprisingly common phenomenon: research shows that up to 75 percent of adults experience at least one during their lifetime. These dreams exist on a spectrum: sometimes they're nearly identical each time they occur, but they may also have recurring themes, locations or characters set against different backdrops. This fluctuation sets recurring dreams apart from bad dreams triggered by post-traumatic stress disorder, a psychological condition in which people relive specific memories from their waking life with far less variation while asleep. Experts are still uncertain about why we experience recurring dreams at all, but new research is helping better identify patterns in their frequency and content, as well as in the scenarios that provoke them.

Recent studies have bolstered the long-held idea that recurring dreams are often — but not always — bad ones. In a 2022 survey by Michael Schredl, head of the sleep laboratory at the Central Institute of Mental Health in Germany, and his colleagues, adults flagged recurring dreams as "negatively toned" two thirds of the time; these dreams often touched on themes such as being chased or attacked, arriving somewhere late or failing at something. The participants' positive recurring dreams, by contrast, involved themes such as flying or discovering a new room in their house.

The reasons why we might have a greater propensity for negative dreams are not fully understood, but Schredl says dreams typically overdramatize something in our waking life — even a small feeling or minor situation we feel powerless to change. "In the dream, it becomes a much bigger emotion, although the connection isn't always straightforward or obvious," he explains.

Psychology and neuroscience offer additional clues. For example, we are prone to what's known as negativity bias: a tendency to fixate more upon unpleasant thoughts, emotions or social interactions than on positive ones. This behavior is rooted in our subconscious need to resolve negative situations that threaten our survival. Negativity bias may be compounded in sleep because our dreaming brain dampens the areas associated with linear logic and activates portions associated with emotion, weakening the filter between our thoughts and our feelings.

Related: Do blind people 'see' images in their dreams?

Understanding the psychological underpinnings of recurrent dreams has been challenging to study because it's difficult to control dreams in an experimental context. But events like the 9/11 terrorist attacks or the COVID pandemic, those in which many people experience a shared trauma, have allowed scientists to investigate certain dream-related patterns in more detail.

People who live through regional or global catastrophes often experience a "striking" increase in negatively-toned recurring dreams afterward, says Deirdre Leigh Barrett, a dream researcher and author of the 2020 book Pandemic Dreams. During the pandemic, Barrett amassed more than 15,000 dream reports, and in twin publications — a book chapter and a study — she showed that repeated themes involving fear, illness and death were then two to four times more common in peoples' dreams than they were before the pandemic began. Common narratives included watching loved ones die, seeing swarms of insects (perhaps stemming from the description of COVID as a "bug," Barrett says) and experiencing disasters, such as tidal waves, that are emblematic of something all-consuming.

Barrett found that dreams early in the pandemic tended to be more literal and induced more fear and anxiety. Over time, they shifted toward less terrifying but still unpleasant situations related to social embarrassment, such as being the only person in public not wearing a face mask. "They're clearly somewhat linked to what's going on in our daily lives," Barrett says, referring to what is known as the "continuity hypothesis." "If you're not processing the emotions during the day, your nocturnal consciousness will attempt to process them at night," she explains.

Barrett and other experts emphasize that negative recurring dreams are common and normal and that there are actionable steps to control them. Some people have found success in a practice called imagery rehearsal therapy, in which they repeatedly reimagine their nightmares with happier endings before going to sleep. Nirit Soffer-Dudek, a consciousness researcher and clinical psychologist at Ben-Gurion University of the Negev in Israel, also recommends cultivating good "sleep hygiene." By setting a consistent sleep schedule, limiting screen use and avoiding caffeine or alcohol before bed, "you're less likely to fall asleep while still in a heightened emotional state," she says. "The best advice I can give is to try to enforce strong boundaries between your waking time and sleep to avoid bringing anxiety into your dreams."

This article was first published at Scientific American. © ScientificAmerican.com. All rights reserved. Follow on TikTok and Instagram, X and Facebook.

It's well known that the sleep-promoting hormone melatonin plays a key role in sleep. But other hormones, including the reproductive hormones estrogen and progesterone, can also affect our sleep — and potentially even our dreams. 

In particular, people may notice differences in the quality of their sleep and the way they dream at different stages of their menstrual cycle, experts told Live Science. Here's how the menstrual cycle might affect sleep and dreaming.  

Related: Does melatonin work? 

How the menstrual cycle affects sleep and dreams 

Sleep is broken down into stages, broadly known as non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. People dream during REM sleep, which usually begins about 90 minutes after a person falls asleep, said Dr. Tania Adib, a consultant gynecologist at The Lister Hospital in the U.K. 

NREM sleep is broken up into four stages: easily disturbed light sleep, a deeper intermediate sleep, and two stages of deep sleep, which occurs just before REM sleep, according to the Mayo Clinic. Deep sleep is the most restorative and where the body and brain have time to repair.

Estrogen and progesterone can affect how much time people spend in REM and NREM sleep and whether they wake up often while dreaming.

"There are lots of estrogen and progesterone receptors in the parts of the brain that regulate sleep, and because the levels of these hormones change during the menstrual cycle, it means our sleep also varies across the month," said Dr. Zoe Schaedel, co-founder of Myla Health, a private clinic for women experiencing menopause, perimenopause and reproductive health issues in England. 

The menstrual cycle has four stages: menses (when the period occurs), the follicular phase, ovulation, and the luteal phase, according to the Cleveland Clinic. The menstrual cycle "begins" on the first day of a period. Prior to ovulation, which occurs roughly around day 14, estrogen levels rise, Schaedel told Live Science. "Sleep tends to be better-quality in this phase, known as the follicular or proliferative phase."  

After ovulation, progesterone levels then begin to rise and eventually overtake estrogen; if a pregnancy doesn't occur, the levels of both hormones drop in the lead-up to menstration. "This is known as the 'luteal phase' and is where we see changes in the structure of sleep," Schaedel said.

Shifting progesterone levels during the luteal phase may partly cause disturbed sleep in the lead-up to a person's period, Schaedel said. 

Compared to estrogen, progesterone is thought to be more strongly tied to premenstrual symptoms (PMS), which occur during the luteal phase and commonly include insomnia or oversleeping, according to Mount Sinai. These sleep changes aren't fully understood, but rising progesterone in the luteal phase is linked to increased body temperatures and sweating, which may interfere with sleep because normally, body temperatures decline before and during sleep. The overall ratio of REM to NREM sleep may also decrease during this phase, according to a 2021 review in the journal Frontiers in Neuroscience. 

Progesterone and estrogen help modulate chemical messengers in the brain — namely, serotonin and gamma-aminobutyric acid (GABA) — which regulate mood and stress levels, according to Mount Sinai. Anxiousness and depressed mood due to PMS may undermine people's attempts to fall asleep, and physical symptoms, like body aches and nausea, may also help explain why people experiencing PMS are prone to sleep disruptions, per the Frontiers in Neuroscience review. 

Melatonin production and sensitivity may also change during the luteal phase, some studies hint, but the research is "not sufficient" to draw strong conclusions.

Sleep disturbances in the luteal phase may increase the likelihood that individuals remember their vivid dreams, Schaedel said. 

"If sleep fragments REM, or you wake up shortly after the REM stage, you are far more likely to remember your dreams," Adib told Live Science.

One 2019 study hinted that hormones may also affect the types of dreams a person has. The study asked hundreds of women to recall the previous night's dreams. Of the women who could remember, those in the luteal phase more often reported their dreams as being "pleasant," while those in other parts of the menstrual cycle were more likely to report their dreams being "unpleasant." 

However, it's unclear whether this result would carry over to other, larger groups of people.

Lucid dreaming, in which people are partially aware and can control their dreams during sleep, could explain so-called alien abduction stories, a study suggests.

Claims of such abductions date to the 19th century; the circumstances of the kidnappings often sound dreamlike and trigger feelings of terror and paralysis. Certain dream states are also known to produce such feelings, leading Russian researchers to wonder if dream experiments could provide clues about alleged extraterrestrial experiences. The scientists prompted lucid dreamers to dream about encounters with aliens or unidentified flying objects (UFOs), and found that a number of sleepers reported dreams that resembled actual descriptions of alleged alien abductions. 

Related: 7 mind-bending facts about dreams 

During lucid dreams, sleepers are aware they are dreaming and can then use that awareness to manipulate what happens in the dream. About 55% of people experience lucid dreaming once or more in their lifetimes, and 23% have lucid dreams at least once a month, according to a 2016 study in the journal Consciousness and Cognition that analyzed five decades' worth of sleep research. 

Recently, researchers with the Phase Research Center (PRC), a private facility in Moscow that researches lucid dreaming, conducted experiments with 152 adults who self-identified as lucid dreamers, instructing them to "find or summon aliens or UFOs" during a lucid dream, the scientists reported July 2 in the International Journal of Dream Research.

The researchers found that 114 of the participants reported dreaming about having some type of successful interaction with an extraterrestrial. Of those, about 61% described meeting "aliens" that resembled extraterrestrials from science-fiction novels and films, while 19% met aliens that "looked like ordinary people," according to the study. 

Little blue men

One female participant spoke of seeing "little men" with blue skin, oversize heads "and huge, bulging eyes," the study authors reported. When the aliens invited her onto their spaceship, "I was blinded by a very bright light, like from a searchlight," she said. "My vision was gone, and I felt dizzy and light." 

Another participant said that he dreamed he was lying in his bed when he felt as though he were being "dragged somewhere," ending up in a room with a white silhouette that reached into his chest and started "doing something inside with tools," the researchers wrote.

Conversations with dream aliens took place in 26% of the encounters, and 12% of the participants spoke with aliens in their dreams and interacted with them physically. UFOs showed up in 28% of the meetings, and 10% of the dreamers who saw UFOs described being brought inside an extraterrestrial spacecraft.

Of those who described their encounters as "realistic," 24% also experienced sleep paralysis and intense fear. Such emotions often accompany reports of supposed alien abductions, and though individuals who describe being kidnapped by aliens might truly believe that what they experienced was real, these people were likely experiencing an extraterrestrial meeting while in a lucid dream, the study authors reported.

Feelings of paralysis, fear and helplessness in vivid dreams can be so powerful that they blur the line between dreams and reality, so it's no wonder that people who may have unknowingly been dreaming instead insist that they actually met with aliens who stole them away and transported them to UFOs, said PRC head researcher and founder Michael Raduga.

For these unknowing dreamers, "abductions are real," Raduga told Live Science in an email. "They just don't know how to explain it." 

Originally published on Live Science.

MIT scientists have figured out how to manipulate your dreams by combining an app with a sleep-tracking device called Dormio. In their new study, the researchers were able to insert certain topics into a person's dreams, with some pretty bizarre outcomes.

To do so, the researchers at MIT Media Lab's Fluid Interfaces — a group that develops wearable systems and interfaces to enhance cognitive skills — used a technique called targeted dream incubation (TDI). 

Prior studies have shown that during a rare dream state known lucid dreaming, in which a sleeper is aware that a dream is taking place, dreamers can use that awareness to consciously shape aspects of their dreams. TDI takes advantage of an early sleep stage, known as hypnagogia, to achieve a similar result (though not quite "controlling" dreams outright), researchers told Live Science.

Related: 7 mind-bending facts about dreams

During hypnagogia — a semi-lucid dream state that occurs during the onset of sleep — TDI introduced "targeted information" to a sleeper, "enabling direct incorporation of this information into dream content," the scientists wrote in a new study, published in the August issue of the journal Consciousness and Cognition. They conducted dream experiments by performing "serial awakenings" during daytime napping sessions in 25 participants.

Subjects first recorded audio prompts in an app, such as, "remember to think of a tree" and "remember to observe your thoughts," and then prepared for sleep, according to the study. 

A hand-worn sleep tracker monitored the subject's heart rate, electrical changes on the skin surface, and the amount their fingers were bent or relaxed, to detect when a sleeper entered hypnagogia and was therefore "open to influence from outside audio cues," said lead study author Adam Haar Horowitz, a doctoral candidate in MIT Media Lab's Fluid Interfaces Group. The Dormio sleep tracker communicated with the app, "which delivers audio at the correct times, and records audio of dream reports" when the subject is awake, Haar Horowitz told Live Science in an email. 

Just as a subject drifted off to sleep and entered hypnagogia, Dormio would coordinate with the app to wake them up with the pre-recorded prompts. This cycle repeated several times, with the sleeper also recording a brief "dream journal" entry into the app when they were awakened.

"Simply put, people tell us whether the prompts appear in their dream," Haar Horowitz said. "Often, they are transformed — a 'tree' prompt becomes a tree-shaped car — but direct incorporation is easily identified."

The scientists found that 67% of the subjects' dream reports mentioned dreams that incorporated a tree. "I was following the roots with someone and the roots were transporting me to different locations," one participant recalled. Another mentioned "a tree from my childhood, from my backyard. It never asked for anything." The same subject, in later awakenings, described "trees splitting into infinite pieces" and "a shaman, sitting under the tree with me, he tells me to go to South America." 

"Dream reports increased in bizarreness and immersion with each awakening," but the scientists did not develop a universal rating system for the bizarreness of the dreams, the study authors reported.

Dream on

Though some dreaming takes place during hypnagogia, most dreaming happens during rapid eye movement (REM) sleep. Before the brain achieves REM sleep, it passes through three stages of non-REM sleep. First is the transition from wakefulness into sleep, when hypnagogia takes place. This is followed by light sleep, and then, finally, deep sleep, according to the National Institutes of Health (NIH). Throughout the night, a sleeper will cycle through REM and non-REM sleep several times, the NIH says.

Dreams during REM sleep can be vivid, bizarre or intense, and most of the time, the dreamer will experience them passively. However, sometimes a dreamer may find themselves in a lucid dream, in which they recognize that they're dreaming. In this unusual state of awareness, the sleeper might be able to manipulate events in their dream, according to the Encyclopedia of Neuroscience (Elsevier Ltd., 2009).

Related: Daydreaming again? 5 facts about the wandering mind

Such experiences are rare. In a given population, only about half of the people will have ever experienced lucid dreaming, according to the book "Principles and Practice of Sleep Medicine" (Sixth Edition, 2017). Of those individuals, approximately 20% have lucid dreams on a monthly basis, and around 1% have lucid dreams several times a week.

But by interrupting hypnagogia, the study authors found an alternate route for providing sleepers with the ability to shape their dream content, said Tomás Vega, a former graduate student researcher with MIT's Fluid Interfaces Group. Vega is the co-founder at Augmental Tech, a company building technologies that integrate with the human body, and he created the circuit board and software that TDI uses to record different biosignals.

Though Vega initially thought that sleep studies could be conducted only with expensive, bulky equipment in a lab setting, "I realized that we can use really cool devices that are almost off the shelf," he told Live Science.

In your wildest dreams

Vega had tested Dormio on his own dreaming brain, using the tech to plant a suggestion about a favorite movie, "Willie Wonka and the Chocolate Factory," with an audio prompt of the film's chocolate factory workers, the Oompa Loompas, singing their signature song. 

Singing Oompa Loompas did indeed appear in Vega's dream — but with a twist.

"I started dreaming about being in a chocolate waterfall, surrounded by Oompa Loompas singing 'Oompa Loompa, doopity doo,'" he said. However, Vega, who is lactose intolerant, also noted that the waterfall was made of dark chocolate.

"It was a lactose-free waterfall," he said. "So, is my lactose-intolerance knowledge in my consciousness or in my subconscious? I induced this dream content, but there were still some constraints, like, 'You cannot just dream about milk chocolate because that's going to harm you,'" he said.

Creative brainstorming would likely be the most immediate application for targeted dreaming, Haar Horowitz said. But as many of the mechanisms that control sleep and dreaming are not well understood, it's too soon to say precisely how nudging a dream's content or achieving a state of awareness while dreaming could directly benefit a sleeper in other ways, he added. 

"Every benefit shown to be correlated to dreaming deserves an experiment on whether it can be causally shown to come from dreaming," Haar Horowitz said. "This ranges from past work on nightmares and PTSD to current work on language learning in sleep, or creativity and eureka moments in dreams." 

Originally published on Live Science.

The sheets are damp with sweat. You're cold, but your heart is racing as if an assailant just chased you down a dark street. It was just a nightmare, you tell yourself; there's nothing to be afraid of. But you're still filled with dread.

Given how unsettling and haunting nightmares can be, is there a way for dreamers to avoid, or even turn off, these bad dreams as they happen?

Research is limited, but some studies suggest that people who can master lucid dreaming — that is, the ability to be aware that a nightmare is happening and possibly even control it without waking up — may hold the answer.

Related: Why can't we remember our dreams?

Nightmares are part of the human experience, especially for kids. Doctors typically don't consider occasional nightmares a problem, but there are options for people whose nightmares occur frequently and negatively affect their lives during the day. These can be symptoms of nightmare disorder, a sleep disorder that can stem from trauma, stress and certain drugs. 

To treat nightmare disorder, there are a number of medications and therapies that are backed by rigorous research, according to the American Academy of Sleep Medicine, which analyzed the available research on the treatment of nightmare disorder in a 2010 review published in the Journal of Clinical Sleep Medicine. 

However, nightmares are complicated, and researchers are still struggling to understand them, said Dr. Rachel Salas, an expert on sleep disorders and an associate professor of neurology at Johns Hopkins Medicine in Baltimore. What we do know is that people tend to have different kinds of nightmares at different points during the sleep cycle.

Many dreams happen in the sleep phase called rapid eye movement (REM) sleep. This phase is the most likely to produce dreams in which we do things "we don't normally do," like flying, Salas told Live Science. Scans show that the brains of people in REM sleep look similar to the brains of people who are awake.

People typically start REM sleep about 90 minutes after falling asleep, and in some ways, a body entering REM sleep appears to be waking up; you start breathing faster and more irregularly, your heart rate increases and your blood pressure rises. It might sound like the body is getting ready to move, but humans have evolved a clever mechanism to protect dreamers from themselves.

"When we go into REM sleep, our muscle activity decreases," Salas said. "Otherwise, we'd act out our dreams." 

Switching off nightmares

It's possible to achieve lucid dreaming, but there haven't been enough trials to establish lucid dreaming therapy as an accepted medical practice. That said, research published in the past decade has kept alive the possibility that such therapy might help people who suffer from persistent nightmares, according to a 2019 review published in the journal Frontiers in Psychology. 

If you're interested in trying lucid dreaming, you can try the following strategy, known as "wake back to bed," according to Dr. Sérgio Arthuro Mota-Rolim, a postdoctoral researcher at Federal University of Rio Grande do Norte in Natal, Brazil.

First, set an alarm 30 minutes before the time you normally wake up. But when the alarm goes off, don't get up. Instead, think about having a lucid dream as you fall back to sleep. 

It's no guarantee, but doing this raises the odds that you'll have a lucid dream, Arthuro said. It's also a good idea to think or talk about it the day before, as dreams are very suggestible, he said. 

If you can realize you're in a nightmare, the simplest way to stop it is to make yourself wake up, Arthuro said. But some evidence suggests that it's possible to stay in the nightmare but eliminate your fear by knowing you aren't in physical danger, according to Arthuro. Some study participants have even reported turning a nightmare into a more pleasant dream.

An obvious barrier to lucid dreaming is that lucid dreams aren't common. While most people have had a lucid dream at some point, the average person will have fewer than 10 in their lifetime, Arthuro said. One of the reasons so little research has been done on lucid dream therapy is that researchers are still exploring the most effective ways to induce lucid dreams. For instance, researchers reported in 2014 that  using certain frequencies of electrical stimulation can increase the likelihood of a dreamer becoming aware that they're dreaming.

And although lucid dreaming is one way to address nightmares, there are other options. 

If nightmares are "disrupting your sleep or if you've injured yourself [during a nightmare], you should seek medical help," Salas said. Your primary care physician is likely to refer you to a sleep specialist for further evaluation. 

• Can I control my dreams?
• What do babies dream about?
• Do dreams really reveal our deepest secrets?

Originally published on Live Science.

You jolt awake in the middle of the night, your heart pounding. It takes you a moment to realize that, no, you didn't just rush out for a job interview wearing nothing but a bath towel. 

Depending on which dream interpretation dictionary you consult, you might find that your dream reveals anxiety about work, a sense of shame or embarrassment, or perhaps even a deeply repressed inner exhibitionist. 

Given all these possibilities, is it true that dreams can reveal our deepest secrets?

Dreams can provide useful insights on our lives, but despite what Hollywood or your favorite novel might have you believe, there aren't any studies showing that dreams can lay bare our inner workings. 

"There's really no research that supports that point of view," said Deirdre Barrett, a psychologist and dream researcher at Harvard Medical School. Dreams don't contain symbols. No dictionary or dream interpreter can tell you what a dream really "means," she said. 

Humans have long sought meaning in dreams. Ancient Mesopotamians and Egyptians saw them as messages from the gods. Greeks and Romans used them to predict the future. But the belief that symbols in dreams harbor secret truths about ourselves originates with 19th-century psychologist Sigmund Freud. He proposed that dreams functioned as a kind of wish fulfillment, revealing our deeply repressed desires. 

Related: Why Can't We Remember Our Dreams?

Since Freud, the science on dreaming has moved on — and it suggests a reality that's a little more mundane than the one Freud proposed. Dreams aren’t cryptic or fantastical. In fact, dreaming is a lot more like your daytime thinking than you might realize.

But that doesn't mean dreams are meaningless. Research suggests that while we're dreaming, we're really just processing the same interests, memories and concerns that would normally occupy us during the day. 

"We're having wishful fantasies, we're thinking about threats and fears, we're thinking about our social lives and loved ones," Barrett told Live Science. 

Therefore, dreams have psychological meaning as extensions of our waking thoughts and concerns, explained G. William Domhoff, a dream researcher at the University of California, Santa Cruz, in a paper published in The Scientific Review of Mental Health Practice. Studies suggest that dreams are more often plausible narratives of our day-to-day lives than trippy action movies. Except, that is, when something really strange happens, like your mom transforming into Oprah without an explanation.

Although dreams are more similar to waking thoughts than we might assume, our brain functions very differently while we're asleep. 

"Our mind is just operating in a very different biochemical chemical state," Barrett said. That means that during sleep, the cocktail of chemicals in our brains change. Some portions of our brain become far less active; others become far more active. For example, the secondary visual cortex — the part of our brain that forms images — becomes far more active, helping us produce the vivid images we "see" during sleep. Meanwhile, the prefrontal cortex, which normally filters our thoughts, gets tamped down. 

Some psychologists see that as a valuable tool. While psychologist and psychoanalyst Karl Stukenberg of Xavier University in Cincinnati is skeptical that dreams contain intrinsically meaningful symbols or channel repressed desires, he uses dream interpretation with both his students and his patients. 

"A dialogue emerges between the parts of the mind that are functioning in a more symbolic sense and the parts of the mind that's functioning in a logical sense," he told Live Science.

There's no formula for interpreting dreams, Barrett said. Dreams aren't a cache of Easter eggs, waiting to be discovered. But they do offer insight into how we process the world during the third or so of our life that we spend asleep.

And for that, at least, Freud was right, Barrett said. "He introduced the idea that dreams are meaningful. That they can tell us about ourselves," she said.

A woman's engagement ring was lost and found ... in her intestine, according to the woman's viral Facebook post.

Jenna Evans of San Diego wrote on Facebook that she swallowed the ring in her sleep. She said she had a vivid dream in which her fiancé told her to swallow the ring to protect it from "bad guys," and she apparently went through with this while she was half-awake.

"I popped that sucker off, put it in my mouth and swallowed it with a glass of water riiiight about the time I realized what I was doing," Evans wrote in the post. "I assumed this too was a dream, because WHO ACTUALLY SWALLOWS THEIR ENGAGEMENT RING, so I went back to sleep."

However, when she woke up the next day, she realized her ring really wasn't on her hand and that she had indeed swallowed the piece of jewelry. 

Related: 11 Weird Things People Have Swallowed

At urgent care, she had a hard time explaining what happened because she was "laughing/crying so hard," she said.

An X-ray showed that the ring truly was in the woman's stomach. Doctors decided it was best to get the ring out as soon as possible and not let it pass through her digestive system.

Evans underwent a procedure called an upper endoscopy, in which doctors use a thin, flexible tube with a camera to look at the esophagus, stomach and part of the small intestine. Doctors successfully retrieved the ring, which they found in Evans' intestine just beyond her stomach.

"I promised not to swallow it again, we're still getting married and all is right in the world," Evans wrote.

Evans' doctor also recommended that she see a sleep specialist. People usually experience temporary muscle paralysis during the stage of sleep in which dreams occur, known as REM sleep, according to the Mayo Clinic. However, people with a sleep disorder known as REM sleep behavior disorder can physically act out their dreams by talking and moving in their sleep. (It's unclear if Evans has this sleep condition.)

•  27 Oddest Medical Case Reports 
•  12 Amazing Images in Medicine 
•  Top 11 Spooky Sleep Disorders 

Originally published on Live Science. 

How were your dreams last night? By analyzing brain activity, scientists may be able to answer that question for you — especially if you had an angry dream.

New research finds that a signature pattern of brain activity can reveal whether there was anger in a person's dreams. In particular, asymmetry in the activity of the frontal lobes of the brain during sleep — as well as in the evening before bed — can indicate that a person is raging mad in his or her sleep.

Indeed, "There seem to be shared processes for emotions across wakefulness and dreaming," said study author Pilleriin Sikka, a lecturer in cognitive neuroscience at the University of Skövde in Sweden. [7 Mind-Bending Facts About Dreams]

The study was published today (April 15) in JNeurosci: The Journal of Neuroscience.

Alpha and anger

Dreams are emotional experiences, Sikka told Live Science, but there hasn't been much research on the neural basis of these nighttime emotions. She and her team homed in on a brain pattern called frontal alpha asymmetry, which has already been shown to be involved in anger and emotion regulation during wakefulness.

Alpha brain waves oscillate between 8 hertz and 12 hertz, and are common during relaxation, Sikka said. The more alpha activity in a brain area, the less busy that brain region. In wakefulness, a mismatch in alpha activity between the frontal lobes of the brain, the seats of cognition behind the forehead, indicates that someone is experiencing or trying to control anger.

To find out if the same asymmetry that indicates anger when a person is awake also indicates angry dreams, Sikka and her team asked 17 participants to spend two nights, a week apart, in a sleep laboratory. The participants slumbered while wearing a cap of electrodes called an electroencephalogram (EEG) cap, which measures the electrical activity on the surface of the brain.

After taking baseline waking measurements of the participants' brainwaves, the researchers had them settle down to sleep. They watched the slumberers' brain activity on the EEG readout until the participants settled into Rapid Eye Movement (REM) sleep, the phase of sleep when most dreaming happens. After five minutes of REM sleep, they woke the participants and asked them to report what they'd been dreaming and how they'd felt in those dreams. They repeated this sleep-wake-report process all night.

Emotional dreams

Despite the repeated wakeups, the participants had a healthy mix of pleasant and unpleasant dreams. The researchers found that 88% of reported dreams involved feelings of interest. In 41% of reported dreams, participants said they had felt angry. Their brain activity said the same.

"We found that, similarly to prior studies conducted in the waking state, individuals with greater frontal alpha asymmetry during REM sleep experienced more anger in their dreams," Sikka said.

People with greater alpha activity in the right frontal lobe compared with the left frontal lobe experienced more anger, the researchers reported. And people with the same frontal alpha asymmetry in the evening before they fell asleep were also more likely than those with more balanced brain activity before bed to experience angry dreams, hinting at links between the emotions of the real and dream worlds.

"This seems to suggest that some individuals may be more likely than others to experience anger both in their waking life and in their dreams," Sikka said.

The results need to be replicated on a larger, more diverse sample, Sikka said, and the researchers would like to measure frontal alpha asymmetry throughout the day and throughout all stages of sleep to see if the connection remains consistent. Finally, she said, it would be interesting to see if it would be possible to use brain stimulation to change people's frontal alpha asymmetry during sleep and see if that changes the emotions of their dreams.

• Top 11 Spooky Sleep Disorders
• 5 Surprising Sleep Discoveries
• 10 Things You Didn't Know About the Brain

Originally published on Live Science.

The fractured logic and mystifying images that appear in dreams can be downright bizarre for anyone. But one of the hallmarks of pregnancy seems to be the onset of dreams that are unnervingly intense or that seem stranger than usual.

Back in May, pop singer Cardi B, who welcomed her first baby last Tuesday (July 10) — tweeted about experiencing "weird, crazy, spooky dreams," writing in a second tweet that all of her dreams were "too vivid." And she's not alone. Studies have found that pregnant women reported more nightmares and more intense dreams than nonpregnant women, and that women in the last trimester of their pregnancies described more frequent nightmares during that stage than during the earlier trimesters.

What is it about pregnancy that causes troubled dreaming? Turns out, it has to do with troubled sleeping. [7 Mind-Bending Facts About Dreams]

Bring me a dream

The human sleep cycle has five stages, one of which — rapid eye movement, or REM — makes up about 25 percent of sleeping and is the stage when most dreaming occurs, according to the National Institutes of Health. When you fall asleep, you enter the first REM stage after about 70 to 90 minutes, and REM sleep occurs several times during the night as your sleep cycle repeats.

As you dream, your brain is actively sorting through recent experiences and emotions, and dreaming is thought to play a role in memory consolidation and processing new information, Dr. Ryan Donald, a physician and assistant professor of sleep medicine at The Ohio State University Wexner Medical Center, told Live Science.

But if a person's sleep cycle is broken and they wake up during a REM stage, they would be more likely to vividly recall what they're dreaming — and pregnant women often experience disturbed sleep at different pregnancy stages, according to Dr. Julie Levitt, an OB-GYN and clinical instructor at Northwestern Medicine in Chicago.

"Rising progesterone levels in the first trimester can trigger insomnia — that's fairly common," Levitt told Live Science. That usually abates at 12 to 16 weeks into the pregnancy, but the onset of the third trimester, about 28 weeks and beyond, brings increasing physical discomfort that can disrupt nighttime rest, she explained.

"Quality of sleep is the poorest right before you're about to deliver the baby," Levitt said. "You have to get up to pee at night, or you might snore, or have sleep apnea." (People with sleep apnea experience very shallow breathing or pauses in breathing while they're asleep.)

Restless legs syndrome, a disorder that causes an intense urge to move the legs, can also manifest during pregnancy and interrupt much-needed sleep, Donald added. Frequent sleep disruption increases the likelihood of waking up during the REM stage of the sleep cycle, which makes dreams seem more immediate, intense and memorable, Donald said.

"Lower sleep quality, shorter sleep duration, more interruptions during sleep: These all can increase the likelihood of remembering dreams," he said. [Is 'Pregnancy Brain' Real?]

A dream to some, a nightmare to others

Pregnant women also report more frequent nightmares, many of which have to do with childbirth or danger to the newborn baby, according to a study published in November 2016 in the journal BMC Pregnancy and Childbirth. Researchers surveyed 406 pregnant women, ages 17 to 44, and found that they reported nightmares more than twice as often as women who were not pregnant, and that those nightmares were often baby-related.

Pregnancy, particularly the third trimester, is a period of heightened stress; perhaps increased daytime stress for pregnant women could explain why nightmares are more frequent during pregnancy, the scientists wrote.

Another study, published in June 2014 in the journal Sleep Medicine, surveyed 57 pregnant women who were in the last trimester of their pregnancies; 32 percent described having weekly nightmares, and 21 percent reported more than one nightmare per week.

Levitt experienced nightmarish dreaming firsthand during her own pregnancy, when she dreamed that she gave birth to a litter of puppies, she told Live Science.

"You have these dreams, and you're like, 'What in the world? Where did that come from?'" Levitt said. "I think it's based on things people might worry about on a day-to-day basis. A lot of the daytime fears that we walk around with tend to reveal themselves in dreams at night."

Original article on Live Science.

You spend a third of your life asleep, a good chunk of which involves dreaming. But most often, you don't remember any of your dreams. And even on those lucky days when you wake up with a memory of the dream still floating in your mind, there's a good chance that in just a minute the memory will vanish into thin air and back to dreamland.

In waking life, such a case of quickly forgetting recent experiences would surely land you in a doctor's office. With dreams, however, forgetting is normal. Why?

"We have a tendency to immediately forget dreams, and it's likely that people who rarely report dreams are just forgetting them more easily," said Thomas Andrillon, a neuroscientist at Monash University in Melbourne, Australia. It might be hard to believe that you had a dream if you don't remember anything, but studies consistently show that even people who haven't recalled a single dream in decades or even their entire lifetime, do, in fact, recall them if they are awakened at the right moment, Andrillon said. [Can I Control My Dreams?] 

While the exact reason is not fully known, scientists have gained some insight into memory processes during sleep, leading to several ideas that may explain our peculiar forgetfulness.

You are awake, but is your hippocampus?

When we fall asleep, not all the brain's regions go offline at the same time, according to a 2011 study in the journal Neuron. Researchers have found one of the last regions to go to sleep is the hippocampus, a curved structure that sits inside each brain hemisphere and is critical for moving information from short-term memory into long-term memory.

If the hippocampus is the last to go to sleep, it could very well be the last to wake up, Andrillon said. "So, you could have this window where you wake up with a dream in your short-term memory, but since the hippocampus is not fully awake yet, your brain is not able to keep that memory," Andrillon told Live Science.

While this might explain why dream memories are so fleeting, it doesn't mean that your hippocampus has been inactive throughout the night. In fact, this region is quite active during sleep, and appears to be storing and caring for existing memories to consolidate them, instead of listening for incoming new experiences.

"Some data shows that [during some sleep stages] the hippocampus is sending information to the cortex, but not receiving any," Andrillon said. "This unidirectional communication would allow sending memories from the hippocampus to the brain's cortex for long-term storage, but new information wouldn't be registered by the hippocampus."

Upon awakening, the brain may need at least 2 minutes to jump-start its memory-encoding abilities. In a 2017 study published in the journal Frontiers in Human Neuroscience, researchers in France monitored sleep patterns in 18 people who reported remembering their dreams almost every day, and 18 others who rarely remembered their dreams. The team found that compared with low-dream recallers, high recallers woke up more frequently during the night. These middle-of-the-night awakenings lasted an average of 2 minutes for high recallers, whereas low-recallers' awakenings lasted for an average of 1 minute. [What Do Babies Dream About?]

Neurochemical soup

Our poor ability to encode new memories during sleep is also linked to changes in the levels of two neurotransmitters, acetylcholine and noradrenaline, which are especially important for retaining memories. When we fall asleep, acetylcholine and noradrenaline drop dramatically.

Then, something strange happens as we enter the rapid eye movement (REM) stage of sleep, where the most vivid dreams occur. In this stage, acetylcholine returns to wakefulness levels, but noradrenaline stays low.

Scientists have yet to work out this puzzle, but some suggest that this particular combination of neurotransmitters might be the reason we forget our dreams. The boost in acetylcholine puts the cortex in an aroused state similar to wakefulness, while low noradrenaline reduces our ability to recall our mental escapades during this time, according to a 2017 study in the journal Behavioral and Brain Sciences.

Sometimes your dreams are just not memorable

Do you remember what you were thinking about this morning when brushing your teeth? Our minds wander all the time, but we discard most of those thoughts as nonessential information. Dreams, especially mundane ones, may be just like daydreaming thoughts and deemed by the brain to be too useless to remember, the late dream researcher Ernest Hartmann, who was a professor of psychiatry at Tufts University School of Medicine, wrote in Scientific American.

But dreams that are more vivid, emotional and coherent seem to be better remembered — perhaps because they trigger more awakening, and their organized narrative makes them easier to store, Andrillon said.

If you are intent on improving your dream recall, there are a few tricks to try. Robert Stickgold, an associate professor of psychiatry at Harvard Medical School, suggests drinking water before bed, because it will make you wake up at night to use the bathroom. These "middle-of-the-night awakenings are frequently accompanied by dream recall," Stickgold told The New York Times.

Once in bed, repeatedly reminding yourself that you want to remember your dreams may increase your chances, and so does keeping a dream journal, some studies have suggested. Upon waking up, hang on to that fragile dream memory: Keep your eyes closed, stay still and replay the dream memory, until your hippocampus catches up and properly stores the memory.

Original article on Live Science.

Life is but a dream – if you're on LSD.

Taking hallucinogenic drugs really does put people into dream-like states, according to new research that statistically compared the way people talk about dreams to the way people talk about the effects of drugs, including LSD (lysergic acid diethylamide), "magic" mushrooms (psilocybin) or mescaline.

LSD is the drug most likely to induce a lucid dream-like state, which is a type of dream in which the dreamer knows he or she is dreaming and can often control his or her actions, according to the study, published Jan. 22 in thejournal Frontiers in Neuroscience. Drugs such as scopolamine and atropine, which come from the tropical plants of the Datura genus, induce a state that is a lot like low-lucidity dreaming, making people delirious and giving them hallucinations they don't realize are hallucinations. [7 Mind-Bending Facts About Dreams]

Dreams and drugs

People often casually compare the effects of drugs like LSD to dreams, so it might seem strange to formally study whether dreams and drugged states are similar. The goal, said study researcher Enzo Tagliazucchi, a neuroscientist at the University of Buenos Aires in Argentina, is both to illuminate the experience of hallucinogenic drugs and demystify dreams. Comparing the subjective experience of a hallucinogen with a particular aspect of neurochemistry could help explain how the brain spontaneously generates dreams, Tagliazucchi told Live Science in an email.

But to analytically compare dreams and drugs, anecdotes won't do. So Tagliazucchi and his colleagues turned to two enormous online repositories of experiences of both: Erowid.org, a site where people can report their experiences with various illicit substances, and dreamjournal.net, which hosts more than 200,000 dream reports, often including whether the dreams were low lucidity or high lucidity.

The researchers analyzed the words found in the self-reports of drug use and dreams in order to discover how semantically similar they were to one another.

The neurochemistry of experience

They found that the top 20 drugs that resulted in experiences that were most like dreams were all hallucinogens, except for three: THC (the active compound in marijuana), Salvia divinorum (a psychoactive plant) and MDMA (a stimulant often found in the drug ecstacy). The 20 drugs that produced experiences the least like dreams were mostly sedatives, stimulants, antipsychotic drugs and antidepressants, the researchers reported.

In both dreams and during psychedelic trips, people describe visual hallucinations ranging from mild distortions, like colorful trails dragging behind moving objects, to full-blown complex imagery, Tagliazucchi said. People also reported a sense of unreality and of being dissociated from their body, or of losing their sense of self and feeling at one with the world in both instances.

Some of the similarities and differences probably reflect how psychedelics work on the brain and how dreams are formed, Tagliazucchi said. Psychedelic imagery is usually less complex than dream imagery, and people don't always know they're dreaming, whereas they typically understand that they are having a psychedelic experience, he said. This may have to do with the fact that the neurotransmitter serotonin is not produced during dream states, Tagliazucchi said. In contrast, psychedelics mimic serotonin and act almost like the neurotransmitter, perhaps creating the almost-dream-like state of a psychedelic experience. [Trippy Tales: The History of 8 Hallucinogens]

Deliriants — types of hallucinogenic drugs that cause feelings of delirium — are quite similar to dreams in that people have complex hallucinations that may feel very real, Tagliazucchi said. Examples of deliriants include drugs derived from Daturaplants. (The danger, Tagliazuchhi added, is that people on Datura-derived drugs don't experience the muscle paralysis that the body undergoes during the dream state, so they can act out their hallucinations.) The mystery, he said, is that Datura blocks the action of a neurotransmitter called acetylcholine in the brain. Normally, acetylcholine is a crucial chemical for reaching the dream state.

"This is a paradox, and we believe solving it could yield important knowledge about how dreams are produced in the brain," Tagliazucchi said.

Tagliazucchi isn't just interested in drugs and dreams, though. He'd like the mine the vast amount of human experiences that people have dumped onto the internet for greater understanding of how many experiences humans can have.

"Now we want to compare the phenomenology of other non-ordinary states (religious experiences, out-of-the-body experiences, near-death experiences, etc.) to keep pursuing this line of research," he said.

Originally published on Live Science.

Where do dreams come from? Researchers now say they know: A specific group of cells in the brain stem is responsible for controlling dreaming sleep, also called Rapid Eye Movement (REM) sleep, a new study says.

The study also showed that damage to those cells could lead to a sleeping disorder called REM Behavior Disorder (RBD), which makes a person act out violent dreams.

The findings have far broader implications than pinpointing the neurological source of dreams, though, said the study's principal investigator, John Peever, a professor of cell and systems biology at the University of Toronto. Because previous studies have shown that 80 percent of people with RBD develop incurable brain diseases, the new research could give drug companies a specific group of cells to target for therapies that slow the progression of neurodegenerative diseases. [7 Mind-Bending Facts About Dreams]

"For some reason, the cells in the REM sleep area are the first to be sickened, and then the neurodegenerative disease spreads up into the brain and affects the other areas that cause disorders like Parkinson's disease," Peever told Live Science.

Peever presented his team's results May 29 at the 2017 Canadian Neuroscience Meeting in Montreal. The findings have not been published in a peer-reviewed medical journal.

During a healthy night's sleep, a person cycles through light sleep, deep sleep and REM sleep several times. During REM sleep, the neurons in the brain stem send signals to the brain's cerebral cortex — perhaps drawing the details for the dream from the parts of the brain responsible for learning, thinking and moving — as well as to the body's spinal cord, to prevent muscles from moving, Peever said.

During healthy REM sleep, most people do not move around much, although some do twitch or talk. And although some people are known to walk in their sleep, sleepwalking is not a part of REM sleep, but a part of the deep-sleep cycle, when dreaming doesn't occur.

In contrast, people who have RBD frequently have violent dreams and act them out during their REM sleep, injuring themselves and anyone who might be sleeping next them. 

The disorder was first described by Dr. Mark Mahowald and Dr. Carlos Schenck, of the University of Minnesota. In their book, "In Principles and Practice of Sleep Medicine," published in 1985, the two doctors presented case histories of people with the disorder, including a 77-year-old minister, who behaved violently in his sleep, sometimes injuring his wife; a 60-year-old surgeon, who reported the feeling of being attacked, and who would jump out of bed during nightmares; and a 57-year old retired school principal, who mistakenly punched and kicked his wife while having nightmares.

Peever said that studies done since then have showed that the vast majority of people who have RBD develop one of three progressive brain diseases. One is Parkinson's disease, which is a degenerative disorder of the central nervous system that afflicts the motor system. The second is dementia with Lewy bodies, which causes forgetfulness, fluctuations in alertness, visual hallucinations and trouble walking. The third is a disorder called multiple system atrophy, which affects the part of the nervous system that controls voluntary movement as well as involuntary movements, including blood pressure and digestion.

"REM Behavior Disorder is in fact the best-known predictor of the onset of Parkinson's disease," Peever said. [5 Surprising Sleep Discoveries]

The brain diseases like Parkinson's and dementia with Lewy bodies typically occur six to 15 years after a RBD diagnosis.

Until now, the link between RBD and these neurological diseases has been anecdotal, though, Peever said. Researchers who studied the brains of cadavers from people who suffered from both RBD and a brain disease found damage to the neurons in the brain stem. But that didn't mean the damage had caused RBD.

"There was a correlation, but no causality," Peever said. "What our study has done is taken away the correlation and show causality."

In the new study, Peever and his colleagues first identified which cells were responsible for healthy REM sleep. They used mice with cells in the brain stem that had been genetically modified to be sensitive to light. When they shined a light onto these cells, it activated the REM sleep in the mice. When they deactivated those cells, the mice did not have REM sleep.

Once the researchers had the cluster of neurons pinpointed, they used a genetically engineered virus to deliver a disease-causing protein – the same one that causes Parkinson's disease — into the REM-generating brain cells. The protein caused the cells to become sick and the mice started to exhibit behaviors indicative of people with REM Behavior Disorder, moving around much more during REM sleep.

"We're saying REM sleep cells get sick, and then you develop REM sleep behavior disorder," Peever said.

The long-term strategy of this research is to develop a drug therapy that could treat patients who have been diagnosed with RBD. Such a therapy would likely not cure the patient of RBD, since the brain cells that cause that disorder would have already been damaged, but it could prevent the disease from spreading to the rest of the brain, Peever said.

"You may have RBD, which is still unfortunate, but you won't develop one of those other brain disorders, which are far more disabling," he said.

Originally published on Live Science.

People who are in a deep slumber may not be able to say whether they're dreaming, but their brain waves might.

In a new study, scientists say they can predict whether people are dreaming by looking at the brain activity in a region at the back of the brain, which they dub the posterior cortical "hot zone."

"Monitoring this posterior 'hot zone' in real time predicted whether an individual reported dreaming or the absence of dream experiences … suggesting that it may constitute a core correlate of conscious experiences in sleep," the researchers wrote in the study, published online April 10 in the journal Nature Neuroscience. [7 Mind-Bending Facts About Dreams]

For many years, scientists thought that dreaming occurred mostly during a stage of sleep known as rapid eye movement, or "REM," sleep. But more recent studies have found that many people also report dreams when they are woken up during a different stage of sleep called non-REM sleep.

In the new study, the researchers monitored the brain waves of 46 people while they slept, using electroencephalography (EEG), a method of recording the brain's electrical activity. The researchers woke up the participants at different stages of sleep, and asked them whether they were dreaming just before they woke up. The researchers looked for differences in brain waves between the people who said they had just been dreaming versus the people who said they had not.

The researchers found that, when the participants were dreaming, they showed a decrease in low-frequency brain waves, and an increase in high-frequency brain waves, in the posterior hot zone, compared with when they weren't dreaming. They found this pattern regardless of whether the participants were dreaming during REM or non-REM sleep.

Using this brain wave pattern, the researchers found that they could predict whether a person was dreaming during non-REM sleep with about 90 percent accuracy, the report said.

The researchers also found that a person's pattern of brain activity could sometimes reveal a bit about what they had been dreaming about. For example, if there were faces in a person's dream, there was an increase in high-frequency brain waves during REM sleep in an area of the brain typically used to process information on faces.

The researchers said their findings may have implications beyond sleep, for the study of consciousness itself. That's because activity in the "hot zone" was linked with "conscious" experiences during sleep (dreams), as opposed to unconsciousness, or dreamless sleep, they said.

Original article on Live Science.

Sigmund Freud's work in psychoanalysis was prolific, and now you can own a piece of his career — for a price.

Freud's handwritten physician's oath from 1883 is up for auction today (Jan. 26), with bids starting at $195,000, according to Nate D. Sanders Auctions, the Los Angeles-based firm handling the sale. Also up for auction is a letter from later in Freud's career, regarding his research on dreams. Both documents offer some insight into Freud's storied career.

When Freud began working at Vienna General Hospital in 1882, he was required to sign a physician's oath. In the oath, Freud vowed to fulfill his medical duties "honorably, compliantly and diligently" and "to keep a scrupulously honorable moral conduct," according to Nate D. Sanders Auctions. The oath, which appeared in a hospital booklet, was signed by Freud in Vienna on April 30, 1883. [Top 10 Mysteries of the Mind]

During his time at Vienna General Hospital from 1882 to 1886, Freud worked in several departments, most notably Theodor Meynert's psychiatric ward. While at the hospital, Freud researched cerebral anatomy, including conducting studies on the effects of cocaine that led to his 1884 paper on medical application of the drug.

The letter on dreams, which Freud wrote on his personal stationary on May 28, 1935, will open with a starting bid of $95,000. The letter is written in German and was translated by the auction house. It appears to answer questions from the addressee about his 1899 book "The Interpretation of Dreams." In the letter, Freud discusses the real duration of dreams, which he said was "at present unsettled."

"Sigmund Freud is known as [a] pioneer in dream research," auction owner Nate Sanders said in a statement. "This letter is an important reflection of Freud's work and will be of tremendous interest to a collector."

Original article on Live Science.

Deep, dreamless sleep has long been thought of as a state of unconsciousness, but in a new paper, several researchers suggest that consciousness may not completely disappear when the mind recedes into deep sleep.

Instead, the article's authors suggest, people actually experience a range of different states within dreamless sleep. Traditionally, dreamless sleep has been straightforwardly defined as the part of sleep that occurs you're not dreaming, and it has been looked at as one uniform stage.

But "the idea that dreamless sleep is an unconscious state is not well-supported by the evidence," said Evan Thompson, one of the authors of the paper and a philosophy professor at the University of British Columbia. [5 Surprising Sleep Discoveries]

Rather, research shows that people have conscious experiences during all states of sleep, including deep sleep, Thompson told Live Science.

Three states of dreamlessness

In the paper, the researchers propose that there are three categories of dreamless sleep that people experience: One state involves "sleep thinking" and experiencing imagery, but not feeling immersed in that imagery as we do during dreams. The second state involves having some perceptions and bodily sensations, including sensations from the outside environment, such as the sound of an alarm.

The third category is a "selfless" state of sleep. The researchers said that this state not only involves dreamless sleep, but also a certain amount of conscious awareness on the part of the person that he or she is sleeping. This state may be similar to the experiences of Indian and Tibetan meditators, the researchers said. They suggested that people who are skilled at meditation are more likely to experience this third state, but more research is needed before scientists can tell whether or not this is true.

Studies have shown that some experienced meditators actually have brain rhythms that are distinct from those of nonmeditators — such as a higher level of activity called gamma-band activity, which has been linked to a number of different brain functions including attention and memory. However, more research is needed to see whether skilled meditators actually experience more of this third category of dreamless sleep, they said. [Mind Games: 7 Reasons You Should Meditate]

This proposed way of looking at dreamless sleep could aid memory research, the treatment of sleep disorders and our understanding of sleep states, the researchers said. Traditional views of memory formation during sleep rely on explanations that involve distinct sleep stages. For example, the stage of declarative memory, which is when memories of facts and events can be consciously recalled, has been linked to slow-wave (deep) sleep. Emotional processing and motor skill memory have been linked to REM sleep. However, the authors suggest that memory processing may actually be more complex, involving interactions between different sleep stages. Breaking down dreamless sleep into different states may help researchers understand these nuances, they said.

Sleep disorders

For people with sleep disorders such as sleepwalking, the authors hope that the new categories of dreamless sleep might shed light on the causes of these conditions. However, they wrote in their paper, "The exact relationship between sleep behavior and sleep experience remains far more of an open question than is commonly assumed." Additional research on sleep might help explain a variety of different behaviors, such as the shifts in posture muscle twitches that occur during sleep.

Finally, the authors said that they hope that more research into the possibility of the "selfless" state of dreamless sleep might help people with insomnia. For example, this research could show that mindfulness training might help people with insomnia to sleep better.

However, no current evidence shows that people can become aware of being asleep when they are not dreaming, Thompson said. Still, researchers hope that new research on dreams and sleep states could provide further support for their ideas.

Originally published on Live Science.

The "you" that stars in your dreams is a stripped-down version of your waking self, new research suggests.

Researchers found that a person's dream self is like a "mini-me" that doesn't change based on what's going on with the body in the real world, according to the findings, which were published Oct. 6 in the journal Consciousness and Cognition.

The study helps explain why people who are born with paralysis or deafness often dream of a body that doesn't have those conditions, and even why people can do fantastical things like fly or breathe underwater in dreams, said study author Judith Koppehele-Gossel.

In the study, the researchers tried to alter participants' dreams by dotting their arms with a red spot and asking them to focus on that spot before falling asleep. If a person's dream self is closely linked to his or her real self, the researchers thought, the people with red dots on their arms should have dreamed more about their arms or the color red. But that didn't happen: The dreamers with red-dotted arms were no more likely than those without to see red (or their arms) while sleeping.

"Although we know it is us who is running, swimming or just sitting around in our dream, and although we know somehow that we have a body in our dreams, we rarely see and feel this body," Koppehele-Gossel told Live Science. [7 Mind-Bending Facts About Dreams]

Dream body

The study that Koppehele-Gossel and her colleagues conducted was a follow-up to an earlier experiment that they had performed in their lab, in which they asked people to read stories that several other people wrote about their dreams, and try to determine which of the dreamers had been born with a disability, such as paralysis or deafness. The readers couldn't tell the difference, the researchers reported in 2011 in the journal Consciousness and Cognition.

That finding suggested that people with paraplegia and those who are deaf and mute "did not dream less about movement or speech and hearing, and they did not dream more often about such experiences" than people without those conditions, Koppehele-Gossel said. Other research on disability and dreams has likewise found that the body is frequently intact in the dream world, she said.

"The question that we wanted to address [in the new study] was: Under what circumstances are waking-life changes of the physical self incorporated into the dream self?" she said. "Does our waking self, in some predictable manner, affect our dream self?"

In the new study, 10 people (seven females and three males) recorded their dreams over a period of about three months. At first, all 10 were simply asked to write down what they could remember about their previous night's dreams each morning. After doing this for 10 dreams, the participants were asked to change the procedure slightly: Each night, they were told to stare at their right arm and focus on it carefully for 2 minutes before falling asleep. Then, the participants were asked to continue to write down dreams until they'd recorded another 10. In the third segment of the experiment, the researchers applied a waterproof red mark to the participants' arm. They were asked to stare at and think about this red mark before sleep and record a final 10 dreams. Throughout the study period, they were also asked to answer questionnaires about how they'd experienced their bodies during their dreams.

Dream world, real world?

The researchers combed through the dream narratives for references to arms, the color red, round marks and the right side of the body, looking to see whether the attention that people paid to their red marks when they were awake and self-suggestion activities had any influence on how they dreamed about their bodies. They found no differences among the three conditions.

"The major finding of our study was that the bodily dream self is not easily influenced by attention, auto-suggestion ('I want to dream about my arm') or experimental alterations," Koppehele-Gossel wrote in an email to Live Science. [Top 10 Spooky Sleep Disorders]

The research suggests that the dream self is a rather minimalist conception, Koppehele-Gossel said, which is why the researchers describe it as a "mini-me." Essentially, people who are dreaming have some sense of having a body, but it's rare for their dream body to appear in detail or to have much of a relationship to their waking body.

Rather, the dream body "is limited to some kind of standard template that is usually employed while dreaming and that is possibly the same for handicapped as well as non-handicapped people," Koppehele-Gossel said.

Dreaming is a special state because people are conscious on some level, Koppehele-Gossel said. They have experiences and emotional responses, she said. But that consciousness is limited: There is little sense of past or future, and typically there's little control over one's actions.

"Experimentally investigating embodiment in dreams is important to [learn more about] the characteristics of different levels of consciousness," Koppehele-Gossel said.

Original article on Live Science.

Water gushes into a sink, spilling over the edge and pooling on the floor. In the middle of a suburban street, sits a figure whose head, wrapped in layers of plastic, vibrates wildly. A woman climbs off a table in a deserted operating room, searching for the baby she has just delivered — which has mysteriously disappeared.

Images that appear in dreams are frequently unsettling and inexplicable. Typically they are beyond our control, though in some works of speculative fiction, characters can shape their dreams by interacting with technology in fantastic ways that sleep researchers might envy, but can only, well, dream about.

Certain areas of psychology and neuroscience have already offered tantalizing glimpses of what happens in people's brains when they dream, and hint at how dreams may reflect or even influence how brains perceive the waking world. But to what extent is controlling dreams really possible?

Two new television shows, introduced at New York Comic Con this month, explore dream control. One program is a dark comedy, and the other is a psychological thriller, but both introduce narratives suggesting that outside agents can manipulate dreams and dreamers. Sometimes, this benefits the fictional dreamer, but other times … not so much. [7 Mind-Bending Facts About Dreams]

"Dream Corp, LLC" combines animation with live action to tell the stories of desperate people seeking a questionably qualified scientist's assistance to improve their lives through controlled dreaming. "Falling Water" presents an eerie tale of three unrelated characters slowly coming to terms with the realization that they are sharing a common dream.

The fantastic dream technology that these stories describe doesn't exist. But the ability to detect images generated by sleeping brains and even influence how those images take shape is very real indeed, experts told Live Science.  

Dream weaver

When you sleep, your brain "goes offline," though it is still just as active as when you're awake, said Robert Stickgold, a sleep researcher at Harvard Medical School. The brain needs time to process all the information that it takes in while a person is awake, and dreams may play a part in sorting and prioritizing experiences and other input, Stickgold told Live Science in 2015.

How the brain might do that is a matter of some debate among scientists, said Moran Cerf, a professor of neuroscience and business at Northwestern University in Illinois, and a scientific consultant for "Falling Water."

Cerf, who has investigated how dreams interact with short-term memory, told Live Science that one theory describes dreams as a means for the brain to explore potential outcomes for a recent event. Freudian theory, on the other hand, says that the brain uses dreams to call up suppressed memories. And yet another theory suggests that dreams are created when memories are shuffled from one area of the brain to another, Cerf said.

For most dreamers, the result is a hodgepodge of baffling images and scenes that frequently fade upon waking. Some people experience a state known as lucid dreaming, in which they are aware that they are dreaming and can even control what they dream about.

The prospect of guided dream control drives the story in "Dream Corps," in which "Dr. Roberts" (Jon Gries) wires up hapless patients in his strip-mall laboratory and walks them through dreamscapes where they confront their problems, such as erectile dysfunction. In the process, they have their lives changed, "but with some terrible side effects that come out down the line," Gries told Live Science. [Top 11 Spooky Sleep Disorders]

Dream a little dream

"Seeing" what someone else is dreaming isn't as far-fetched as it might sound. Scientists recently used functional magnetic resonance imaging (fMRI) to scan sleepers' brains, and the researchers were able to identify imagery based on brain-wave activity.

And controlling what people dream about is also possible — up to a point, Cerf explained.

"Right now, we are in the beginning of mapping things that you can do to a person so it will penetrate their dreams — but not wake them up," he said. For example, Cerf explained, if you were to spray water on a dreamer, the person would likely report water in the dream.

"It could be a waterfall, or sitting by the ocean. When I spray water on your body, the tactile experience of water gets into your story," Cerf said. "Neuroscientists are now mapping all the things that you can do to a person sleeping — concentration, duration, all the details — in hope of having a menu of things that won't wake you up but can penetrate dreams," he added.

As for the ability to dream collectively, like the characters in "Falling Water," dreamers who live in the same regions or who have shared common experiences — especially traumatic ones — have been known to dream about similar themes, Cerf told Live Science.

"After 9/11, people in New York City had nightmares about planes hitting buildings," he said. "Events in the outside world that are shared by a society are also shared in their dreams."

"Falling Water" (USA Network) debuted Oct. 13, and "Dream Corp, LLC" (Adult Swim) debuted Oct. 23.

Original article on Live Science.

Robert Lawrence Kuhn is the creator, writer and host of "Closer to Truth," a public television series and online resource that features the world's leading thinkers exploring humanity's deepest questions. Kuhn is co-editor, with John Leslie, of "The Mystery of Existence: Why Is There Anything at All?" (Wiley-Blackwell, 2013). This article is based on a "Closer to Truth" episode produced and directed by Peter Getzels and streamed at www.closertotruth.com. Kuhn contributed this article to Live Science's Expert Voices: Op-Ed & Insights.

A friend who is suddenly sick asks that I drive him home on his motorcycle. I've never driven a motorcycle, the trip will take an hour on the highway, I have no helmet, and there's a second passenger. I ask if we could use surface streets; he says no. I ask what's the slowest speed we can go; he says 50 mph. I say I won't do it. Others crowd around, pressuring me to drive that bike. I say I'll order Uber and pay for everyone. I am smart enough to know that I should not drive that bike, but not smart enough to know that I am dreaming.

As I awake, I marvel. On the one hand, I was reasoning well, dealing rationally with complex ideas; on the other hand, I had no sense of basic reality. Both from the same brain at the same time. There is meaning here: what we assume to be a unified self is multiple mental faculties, each related to different brain areas or systems.

All my life I've been entranced by the brain. (I did a doctorate in brain research, and although I've done other things since, my passion for neuroscience and its implications has not dimmed). The brain is the mechanism by which we perceive the world — it's the most sophisticated organization of matter in the universe (as far as we know); it's matter aware of itself. Dreaming and sleeping, I suspect, are deep clues to human physiology and psychology. [7 Mind-Bending Facts About Dreams]

Start with sleep. When I'm tired, sleep is natural; but from an evolutionary perspective, sleep should be unexpected. To spend 6 to 8 hours a day unconscious — totally out — would make one vulnerable to pre-procreation death, an easy mark for hungry predators or social enemies. The ancient world was violent and brutish. Why, then, did evolution select for creatures that needed to sleep?

As for dreams, they have always mystified. All manner of folklore and superstition have arisen from dreams, as have innumerable religious experiences and perhaps whole religions. Some claim, even today, that dreams are windows into higher realities.

Sometimes sleep scares me. To go unconscious — to pass from being to nonbeing — seems astonishing. It's not that I fret not awaking up. It's that I'm awe-struck by the blankness before waking up, the sheer nothingness of my unconsciousness (in non-dream sleep). I'm obsessed by the mystery of consciousness, the opposite of blankness and nothingness. How does such subjective inner awareness come about?

One way to explore the mystery of consciousness is to investigate its absence, and sleep, in a sense, is the absence of consciousness. Another way is to examine altered states of consciousness — such as dreams. What might sleeping and dreaming reveal about consciousness?

The science of sleep and dreams

Robert Stickgold, a sleep researcher at Harvard Medical School, told me that when we sleep we're "doing as much work as when we are awake. It might turn out that, for every 2 hours our brain spends 'online' [i.e., awake], taking in new information, our brain needs an hour 'offline' [i.e., asleep], figuring out what it means." 

Stickgold said that our brains need to "go offline" — to tune out other information — so we can process internally the information we already have. The brain, he added, "shuts out external inputs, cuts off the outside world, so it can do what it needs to do."

The benefits of sleep apply not only to managing information in our brains but also to ensuring our body processes function optimally, Stickgold said. For example, a good night's sleep enables a vaccine to produce a good antibody response. There's evidence that insufficient sleep can alter insulin production (this might help explain the growing epidemic of obesity). And sleep seems to affect cognitive enhancement and emotional regulation. [5 Things You Must Know About Sleep ]

"I talk to pianists, who say, 'Bob, I was working on a Chopin étude and even after two hours of practicing I just couldn't get a three-line measure right,'" Stickgold explained. "'I went to bed, I got up the next morning, I sat down at the piano, and first time through, I had it perfectly.'"

Research confirms that sleep enables memory consolidation and thus learning, stimulates the immune system and thus fights disease, and regulates emotion and perhaps controls obesity. Continue without sleep and you will die. One can survive longer without food than without sleep.

What actually happens during sleep? There are two basic kinds or stages of sleep — REM (rapid eye movement sleep), during which we have our most intense dreams, and non-REM, when there is little brain activity and we are largely not dreaming (which to most people is sleep).

Evidence suggests that sleep — REM sleep, dreams, in particular — may facilitate creativity. 

Boston University neuroscientist Patrick McNamara told me "dreams are creative," explaining how "dreams take some basic elements, recombine them in unusual ways, and generate a radically different, counterfactual picture of the world."

To me, intense dreams feel more bizarre than creative. But according to McNamara, if you wake people during REM sleep and ask them to describe their dreams, the vast majority are creative, not bizarre, experiences.

Deirdre Barrett, a Harvard Medical School psychologist and dream researcher, agreed, citing for me well-documented instances of dreams solving actual problems that had seemed intractable. Favorable conditions include when there is a visual-spatial issue, where seeing something vividly reorients the problem, or when conventional wisdom is wrong and one needs to think outside the box. "Dreams have directly contributed to two Nobel prizes," Barrett noted.

Here's the big question about dreams: Are dreams meaningful in themselves, the way mystics and psychotherapists have imagined? Or are dreams the incidental byproducts of purely physiological functions of sleep?

And either way, can dreams stimulate creativity, perhaps by making strange connections and conjuring up bizarre ideas?

So, here's sleep, seemingly ordinary, but comprised of two radical elements: the utter blankness of non-consciousness and reality-bending, fantastical dreams.

The purpose of sleep and dreams

I went to the University of Cambridge to visit Nicholas Humphrey, an English psychologist who explains consciousness via evolution. "Dreams are a form of play and serve the same functions as ordinary play in waking life," Humphrey told me. "This allows us to experiment with alternative realities in a safe environment. We can play doctors and nurses, or cowboys and Indians, all sorts of games, adult games too, in which we take on roles that we've never experienced before."

"We play even more so at night," Humphrey hypothesized, "in the theater of our dreams, completely safe. … Nature sees to it that we paralyze our bodies from the neck down so we don't act out our dreams — and then we can fly, we can fight, we can make love, or do whatever it may be, in completely new kinds of situations, with new people, or with old people, friends who have no idea how we're exploiting them in our dreams."

Sleep, Humphrey said, is "a sort of little death, and what this 'death' tells us is that we survive it: we go to sleep — our consciousness is obliterated, we are obliterated — but, sure thing, next day, we recreate ourselves. And this is such a regular occurrence that, of course, we just take it for granted, but it is a kind of miracle — we lose consciousness and then out of nothing it all comes back again."

"It's like a kind of Big Bang. The universe created out of nothing. We repeat that every day when we wake up."

Summing up, why sleep? Good health and good thinking. 

Why dream? Some say creativity and adaptability — to swim with the strange, to play without harm, to enter the mind of others. But to others, dreams are just byproducts of brain biology, mere nocturnal housekeeping.

Was sleep required in evolution? To lose consciousness with predators prowling would seem a weak adaptation, not given to prolific offspring. Perhaps, though, sleep strengthens the waking state.

Because we lose consciousness, some call sleep the little death. And because we always awake after sleep, some believe that we will likewise awake after death. 

But as an argument for life after death, I'm afraid, the analogy between sleep and death falls short.

Sleep as a window on the wonders of consciousness? That I like better. By experiencing blankness, we appreciate awareness.

Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook, Twitter and Google+. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Live Science.

Your brain on psychedelic drugs looks similar to your brain when you're dreaming, suggests a new study that may also explain why people on psychedelics feel they are expanding their mind.

In the study, the researchers scanned the brains of 15 people before and after they received an injection of psilocybin, the hallucinogen found in magic mushrooms.

Under psilocybin, the activity of primitive brain areas thought to be involved in emotion and memory — including the hippocampus and the anterior cingulate cortex — become more synchronized, suggesting these areas were working together, the researchers said.

This pattern of brain activity is similar to that seen in people who are dreaming, the researchers said. [Trippy Tales: The History of 8 Hallucinogens]

"I was fascinated to see similarities between the pattern of brain activity in a psychedelic state and the pattern of brain activity during dream sleep," study researcher Robin Carhart-Harris, of Imperial College London in the United Kingdom, said in a statement. "People often describe taking psilocybin as producing a dreamlike state and our findings have, for the first time, provided a physical representation for the experience in the brain."

In contrast, the activity in brain areas involved in "high-level" thinking (such as self-consciousness) were less coordinated under psilocybin, the study found.

Finally, using a new technique to analyze the brain data, the researchers found that there were more possible patterns of brain activity when participants were under the influence of psilocybin, compared with when they were not taking the drug. This may be one reason why people who use psychedelic drugs feel that their mind has expanded — their brain has more possible states of activity to explore, the researchers said.

The researchers caution that, because some techniques used in the study are new, more research is needed to confirm the findings. The study is published today (July 3) in the journal Human Brain Mapping.

Follow Rachael Rettner @RachaelRettner. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

If you eat cheese before bed you're sure to get nightmares. At least, that's a common piece of folk wisdom.

But in 2005, the British Cheese Board (a cheese industry group) tried to put this old wives' tale to bed. The team gave 200 participants a snack of cheese 30 minutes before bedtime and then asked them to record their dreams.

None reported nightmares and many had pleasant night reveries. The researchers even classified cheeses by their effect: Blue stilton produced the trippiest dreams, involving warrior kittens and vegetarian crocodiles, the Nature Mind Read blog reported. Cheshire cheese produced the dullest effect, with most people dreaming about nothing at all. The researchers didn't have a control group, so there's no way to know how the cheese-tinted dreams stacked up against those who didn't have a bedtime cheese snack or those who had another snack, say, soy-based cheese.

Some theories suggests that the bacterial and fungal elements of cheese contain psychoactive ingredients that affect dreams, but there's no data to support that idea.

Follow Tia Ghose on Twitter and Google+. Follow LiveScience @livescience, Facebook & Google+. 

A computer can predict what you're dreaming about based on brain wave activity, new research suggests.

By measuring people's brain activity during waking moments, researchers were able to pick out the signatures of specific dream imagery — such as keys or a bed — while the dreamer was asleep.

"We know almost nothing about the function of dreaming," said study co-author Masako Tamaki, a neuroscientist at Brown University. "Using this method, we might be able to know more about the function of dreaming."

The findings, which were published today (April 4) in the journal Science, could also help scientists understand what goes on in the brain when people have nightmares.

Sleepy mystery

Exactly why people dream is a mystery. Whereas the founder of psychoanalysis Sigmund Freud may have thought dreams were about wish fulfillment, others believe dreams are irrelevant byproducts of the sleep cycle. And yet another theory holds that dreams allow the mind to continue working on puzzles faced during the day. In general, most people believe their dreams have meaning.

Scientists have dreamt of being able to look inside the brain's sleepy wonderland. Past studies had suggested that people's brain activity can be decoded to reveal what they are thinking about: For instance, scientists have decoded movie clips from brain waves.

Dream reading

So why not try to read dreams?

Tamaki and her colleagues tracked brain activity using functional magnetic resonance imaging (fMRI) of three people as they were sleeping; the researchers woke up the trio every few minutes to have them describe their dreams. In total, the scientists collected about 200 visual images. [7 Mind-Bending Facts About Dreams]

The researchers then tied the dream content that participants described in their waking moments to specific patterns in brain activity (as seen in the blood flow in fMRI scans) and had a computer model learn those signatures.

The computer model then analyzed each person's dreams. The model was able to pick out the time when each person dreamed of specific objects based on their brain activity when they were awake.

Those findings showed the same brain regions are activated when people are awake as when they are actually having the associated dream.

"We were amazed," Tamaki said.

Even though the team just tried to read dream imagery from one person's waking brain activity, they found some common patterns for broad classes of imagery, such as scenery versus people, Tamaki told LiveScience.

"There is a similarity amongst the subjects, so from that result, we could pick up some basic dream content and then we can build a model from those base contents, and they may apply to other people," Tamaki said.

Follow Tia Ghose on Twitter @tiaghose. Follow LiveScience @livescience, Facebook & Google+. Original article on LiveScience.com.

The dream of modifying a person's dreams has just gotten a step closer, as MIT scientists were able to manipulate what lab rats "saw" in their sleep using audio cues.

Scientists have known that during sleep, a part of the brain called the hippocampus "replays" the day's events in a process that might help solidify a person's memories. The same has been shown in rats that dream about running through mazes after a day's work in a lab at MIT.

In the new MIT study, researchers Matthew Wilson and Daniel Bendor trained rats to run through a maze using audio cues, with one sound directing the animals to a reward on the right side of the track, and another sound leading the rats to a reward on left.

The rat brains showed specific patterns of activation of certain sets of neurons in the hippocampus depending on whether they ran to the right or the left side of the maze. These neurons, so-called place cells, tell the rats where they are spatially and are known to fire in certain patterns when a rat is in a particular location.

When the animals went to sleep, the researchers re-analyzed the neural activity in the hippocampus; during non-REM sleep, the researchers played about once every five to 10 seconds a random sound, including the two sounds associated with the two sides of the maze. "When the sound associated with the left side of the maze was played, the dream content switched to memories of running down the left side of the maze," Wilson told LiveScience. "When the sound associated with the right side was played, the dream content switched to the right side of the maze."

Even though the sounds were played for less than a second, the influence on dream content persisted, Wilson said, for five to 10 seconds. "[S]o the sounds were not simply driving the dream content, but seemed to be biasing or selecting the memories that would be subsequently replayed," he said.

This same phenomenon didn't show up when the rats were awake and not in the maze.

"When we played the sounds while the animals were just sitting quietly and 'thinking' but not sleeping, we were not able to influence replayed memory content," Wilson said.

The study, detailed online Sept. 2 in the journal Nature Neuroscience, suggest memories could be modified during sleep. "This could be thought of as a simple form of dream engineering and opens up the possibility of more extensive control of memory processing during sleep to enhance selected memories and to block or modify unwanted memories," Wilson and Bendor write.

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When your head hits the pillow, for many it's lights out for the conscious part of you. But the cells firing in your brain are very much awake, sparking enough energy to produce the sometimes vivid and sometimes downright haunted dreams that take place during the rapid-eye-movement stage of your sleep.

Why do some people have nightmares while others really spend their nights in bliss? Like sleep, dreams are mysterious phenomena. But as scientists are able to probe deeper into our minds, they are finding some of those answers.

Here's some of what we know about what goes on in dreamland.

1. Violent dreams can be a warning sign

As if nightmares weren't bad enough, a rare sleep disorder — called REM sleep behavior disorder — causes people to act out their dreams, sometimes with violent thrashes, kicks and screams. Such violent dreams may be an early sign of brain disorders down the line, including Parkinson's disease and dementia, according to research published online July 28, 2010, in the journal Neurology. The results suggest the incipient stages of these neurodegenerative disorders might begin decades before a person, or doctor, knows it.

2. Night owls have more nightmares

Staying up late has its perks, but whimsical dreaming is not one of them. Research published in 2011 in the journal Sleep and Biological Rhythms, revealed that night owls are more likely than their early-bird counterparts to experience nightmares.

In the study 264 university students rated how often they experienced nightmares on a scale from 0 to 4, never to always, respectively. The stay-up-late types scored, on average, a 2.10, compared with the morning types who averaged a 1.23. The researchers said the difference was a significant one, however, they aren’t sure what's causing a link between sleep habits and nightmares. Among their ideas is the stress hormone cortisol, which peaks in the morning right before we wake up, a time when people are more prone to be in REM, or dream, sleep. If you’re still sleeping at that time, the cortisol rise could trigger vivid dreams or nightmares, the researchers speculate. [Top 10 Spooky Sleep Disorders]

3. Men dream about sex

As in their wake hours, men also dream about sex more than women do. And comparing notes in the morning may not be a turn-on for either guys or gals, as women are more likely to have experienced nightmares, suggests doctoral research reported in 2009 by psychologist Jennie Parker of the University of the West of England.

She found women's dreams/nightmares could be grouped into three categories: fearful dreams (being chased or having their life threatened); dreams involving the loss of a loved one; or confused dreams.

4. You can control your dreams

If you're interested in lucid dreaming, you may want to take up video gaming. The link? Both represent alternate realities, said Jayne Gackenbach, a psychologist at Grant MacEwan University in Canada.

"If you're spending hours a day in a virtual reality, if nothing else it's practice," Gackenbach told LiveScience in 2010. "Gamers are used to controlling their game environments, so that can translate into dreams." Her past research has shown that people who frequently play video games are more likely than non-gamers to have lucid dreams where they view themselves from outside their bodies; they were also better able to influence their dream worlds, as if controlling a video-game character.

That level of control may also help gamers turn a bloodcurdling nightmare into a carefree dream, she found in a 2008 study. This ability could help war veterans suffering from post-traumatic stress disorder (PTSD), Gackenbach reasoned.

5. Why we dream

Scientists have long wondered why we dream, with answers ranging from Sigmund Freud's idea that dreams fulfill our wishes to the speculation that these wistful journeys are just a side effect of rapid-eye-movement (REM) sleep. Turns out, at least part of the reason may be critical thinking, suggests Harvard psychologist Deirdre Barrett who presented her theory in 2010 at the Association for Psychological Science meeting in Boston.

Her research revealed that our slumbering hours may help us solve puzzles that have plagued us during daylight hours. The visual and often illogical aspects of dreams make them perfect for the out-of-the-box thinking that is necessary to solve some problems, she speculates.

So while dreams may have originally evolved for another purpose, they have likely been refined over time for multiple tasks, including helping the brain reboot and helping us solve problems, she said.

Follow LiveScience for the latest in science news and discoveries on Twitter @livescience and on Facebook.

Dream Scape

You are getting sleepy, very sleepy. When your head hits the pillow it’s lights out for the brain and body, right? Not if you consider the brain cells that must fire to produce the sometimes vivid and sometimes downright haunted dreams that take place during the rapid-eye-movement stage of your sleep. Why do some people have nightmares while others really spend their nights in bliss? Like sleep, dreams are mysterious phenomena. But as scientists are able to probe deeper into our minds, they are finding some of those answers. Here's some of what we know about what goes on in dream land.

Dreams are meaningful

If you dream about winning the lottery or having an accident, should you prepare? If you answered "yes," you’re not alone, according to a study published in the February 2009 issue of the Journal of Personality and Social Psychology. The researchers ran six experiments, finding that not only do we put stock in our dreams, we also judge dreams that fit with our own beliefs as more meaningful than ones that go against the grain.

"Psychologists' interpretations of the meaning of dreams vary widely," study researcher Carey Morewedge, an assistant professor at Carnegie Mellon University, said in a statement. "But our research shows that people believe their dreams provide meaningful insight into themselves and their world."

In one study, 182 commuters in Boston imagined one of four scenarios had happened the night before a scheduled trip: national threat level was raised to orange; they consciously thought about their plane crashing; they dreamed about a plane crash; or a real plane crash occurred on the route they planned to take. Results showed a plane-crash dream was more likely to affect travel plans than either thinking about a crash or a government warning, while the crash dream also produced a similar level of anxiety as did an actual crash.

In another study, 270 men and women completed an online survey in which they were asked to remember a past dream they had about a person they knew. People ascribed more importance to pleasant dreams about a person they liked than they did a person they didn't like. And they were more likely to report a negative dream as more meaningful if it was about a person they disliked than one about a friend.

Violent dreams can be warning sign

As if nightmares weren't bad enough, a rare sleep disorder causes people to act out their dreams, sometimes with violent thrashes, kicks and screams. Such violent dreams may be an early sign of brain disorders down the line, including Parkinson's disease and dementia, according to research published online July 28, 2010, in the journal Neurology. The results suggest the incipient stages of these neurodegenerative disorders might begin decades before a person, or doctor, knows it. [Read full story]

Night owls have more nightmares

Staying up late has its perks (as long as you can hit the snooze button the next morning), but light dreams is not one of them. Research published in 2011 in the journal Sleep and Biological Rhythms, revealed that night owls are more likely than their early-bird counterparts to experience nightmares.

In the study 264 university students rated how often they experienced nightmares on a scale from "0," (meaning "never") to "4" (meaning "always"). The stay-up-late types scored, on average, a 2.10, compared with the morning types who averaged a 1.23. The researchers said the difference was a significant one, however, they aren’t sure what's causing a link between sleep habits and nightmares. Among their ideas is the stress hormone cortisol, which peaks in the morning right before we wake up, a time when people are more prone to be in REM, or dream, sleep. If you’re still sleeping at that time, the cortisol rise could trigger vivid dreams or nightmares, the researchers speculate. [Read full story]

Dreams help us solve puzzles

Scientists have long wondered why we dream, with answers ranging from Sigmund Freud's idea that dreams fulfill our wishes to the speculation that these wistful journeys are just a side rapid-eye-movement, or REM, sleep. Turns out, at least part of the reason may be critical thinking, according to Harvard psychologist Deirdre Barrett who presented her theory in 2010 at the Association for Psychological Science meeting in Boston. She has found that our slumbering hours may help us solve puzzles that have plagued us during daylight hours.

According to Barrett, it's the visual and often illogical aspects of dreams that make them perfect for out-of-the-box thinking that is necessary to solve some problems.

"Whatever the state we're put in, we're still working on the same problems," Barrett said, adding that while dreams may have original evolved for another purpose, they have likely been refined over time for multiple tasks, including helping the brain reboot and helping us solve problems. [Read full story]

Men dream about sex

No surprise here, men are more likely than women to dream about sex. And comparing notes in the morning may not be a turn on for either guys or gals, as women are more likely to have experienced nightmares, according to doctoral research reported in 2009 by psychologist Jennie Parker of the University of the West of England.

In her study of nearly 200 men and women, ages 18 to 25, Parker found that women's nightmares could be broadly divided into three categories: fearful dreams (being chased or life threatened), dreams involving the loss of a loved one, or confused dreams.

"If women are asked to report the most significant dream they ever had, they are more likely than men to report a very disturbing nightmare," Parker said. "Women reported more nightmares, and their nightmares were more emotionally intense than men's." [Read full story]

This doesn't mean women have no fun in their dreams. A study presented in 2007 at a meeting of the Associated Professional Sleep Societies (APSS) revealed that of about 3,500 home dream reports about 8 percent contain some form of sexual-related activity. The most common sexual dream involved sexual intercourse, followed by sexual propositions, kissing, fantasies and masturbation.

You can control your dreams

If you're interested in lucid dreaming, you may want to take up video gaming. Both represent alternate realities, according to Jayne Gackenbach, a psychologist at Grant MacEwan University in Canada. Of course they aren't completely the same. While video games are controlled by computers and gaming consoles, dreams arise from the human mind.

"If you're spending hours a day in a virtual reality, if nothing else it's practice," Gackenbach told LiveScience in 2010. "Gamers are used to controlling their game environments, so that can translate into dreams." Her past research has shown that people who frequently play video games are more likely than non-gamers to have lucid dreams where they view themselves from outside their bodies; they also were better able to influence their dream worlds, as if controlling a video-game character.

That level of control may also help gamers turn a bloodcurdling nightmare into a carefree dream, she found in a 2008 study. This bar of sorts against nightmares could help war veterans suffering from post-traumatic stress disorder (PTSD) after combat, Gackenbach reasons. [Read full story]

Dreams can take the edge off

Taking the edge off may require, not a stiff drink, but a trip to la-la land. UC Berkeley scientists report in the Nov. 23, 2011, issue of the journal Current Biology that during the dream phase of sleep (also called REM sleep), participants' brains showed decreased levels of certain chemicals associated with stress.

"We know that during REM sleep there is a sharp decrease in levels of norepinephrine, a brain chemical associated with stress," study researcher Matthew Walker, associate professor of psychology and neuroscience, said in a statement. "By reprocessing previous emotional experiences in this neuro-chemically safe environment of low norepinephrine during REM sleep, we wake up the next day, and those experiences have been softened in their emotional strength. We feel better about them, we feel we can cope."

The findings, Walker and colleagues say, may explain why people with post-traumatic stress disorder (PTSD), such as war veterans, have such a tough time recovering from painful experiences and suffer reoccurring nightmares. They also provide at least one explanation for why we dream. [Read full story]

A bad day may not seem quite so painful after we dream, a new study suggests.

The results show that during nighttime dreaming, also known as REM sleep, the brain processes emotional experiences in a "safe" environment, or one in which stress chemicals are low. This processing may take the emotional edge off of difficult memories, the researchers said.

"We wake up the next day, and those experiences have been softened in their emotional strength," said study researcher Matthew Walker, an associate professor of psychology and neuroscience at the University of California, Berkeley."We feel better about them, we feel we can cope."

The findings may explain why people with post-traumatic stress disorder (PTSD), such as war veterans, have a hard time recovering from painful experiences, the researchers said.

For people with PTSD, Walker said, this overnight therapy may not be working effectively, so when a "flashback is triggered by, say, a car backfiring, they relive the whole visceral experience once again, because the emotion has not been properly stripped away from the memory during sleep," Walker said.

Previous studies indicate that sleep patterns are disrupted in people with mood disorders such as PTSD and depression, Walker said.

Good dreams

The study involved 35 healthy adults, divided into two groups. Each group viewed 150 emotional images — including a man holding a gun, a shark and a snake about to bite — while they had their brains scanned using magnetic resonance imaging (MRI).

Half of the participants viewed the images in the morning and again in the evening, staying awake between the two viewings. The other half viewed the images in the evening and again the next morning, after a full night of sleep.

Those who slept between viewings reported a significant decrease in their emotional reaction to the images. In addition, MRI scans showed a dramatic reduction in activity in the amygdala, a part of the brain that processes emotions — this reduction would allow the brain's "rational" prefrontal cortex to regain control of the participants' emotional reactions, the researchers said.

The researchers also recorded the electrical activity in participants' brains while they slept. During REM dream sleep, that the researchers saw reduced levels of stress chemicals in the brain, which could be helping to soothe emotional reactions to the previous day's experiences.

"During REM sleep, memories are being reactivated, put in perspective and connected and integrated, but in a state where stress neurochemicals are beneficially suppressed," said study researcher Els van der Helm, a doctoral student in psychology at UC Berkeley.

Effect on PTSD

Walker said he was tipped off to the possible beneficial effects of REM sleep when a physician at a U.S. Department of Veterans Affairs hospital told him of a blood pressure drug that was inadvertently preventing reoccurring nightmares in PTSD patients.

It turns out that the generic blood pressure drug had a side effect of suppressing stress chemicals in the brain, thereby creating a more stress-free brain during REM. This may reduce nightmares and promote a better quality of sleep.

"This study can help explain the mysteries of why these medications help some PTSD patients and their symptoms as well as their sleep," Walker said. "It may also unlock new treatment avenues regarding sleep and mental illness."

The study is published today (Nov. 23) in the journal Current Biology.

Pass it on: Dreaming may help to make bad memories feel less painful.

This story was provided by MyHealthNewsDaily, a sister site to LiveScience. Follow MyHealthNewsDaily on Twitter @MyHealth_MHND. Find us on Facebook.

It's not quite "Inception," but new research has allowed scientists to "read" some people as they dream.

Using brain imaging, researchers at the Max Planck Institute of Psychiatry in Germany said they were able to compare the brain activity of "lucid dreamers" as they entertained the same thoughts awake and asleep. The brain activity was similar, if weaker during sleep, the researchers said.

Lucid dreamers are sleepers who are aware that they are dreaming and can deliberately control their dream actions. According to the researchers, lucid dreaming is a learned skill, one very useful to scientists trying to understand the secrets of dreams.

"The main obstacle in studying specific dream content is that spontaneous dream activity cannot be experimentally controlled, as subjects typically cannot perform pre-decided mental actions during sleep," study researcher Michael Czisch said in a statement. "Employing the skill of lucid dreaming can help to overcome these obstacles."

Researchers at the Munich-based institute said they recruited six practiced lucid dreamers, all of them adult men. The volunteers slumbered in a functional magnetic resonance imaging (fMRI) machine, which measures blood flow to regions of the brain. An increase in blood flow suggests that particular region of the brain is active and working. Meanwhile, the men were asked to make a series of hand-clenching movements and eye movements (beneath closed eyelids) when they entered into a lucid dream-state.

The sensory and motor areas activated by those movements in wakefulness also lit up the brain scans during the movements in lucid dreams. However, the dream activation was only about half as strong, meaning it was either weaker or confined to smaller segments of the brain.

Scanning the brains of lucid dreamers eventually may allow researchers to guess at the content of dreams by analyzing a slumberer's brain activity. Another group of scientists already has made movies reconstructing the things that awake people have seen, by analyzing their brain waves.

The new study was published Thursday (Oct. 27) in the journal Current Biology.

You can follow LiveScience senior writer Stephanie Pappas on Twitter @sipappas. Follow LiveScience for the latest in science news and discoveries on Twitter @livescience and on Facebook.

The soldier frantically searched a forest for his rifle as an unknown threat hunted him. When he finally found the weapon and turned to shoot, the trigger felt like it had a 1,000-pound pull and his bullets failed to hit the target. It was a classic nightmare scenario.

But combat dreams don't always go that way. Soldiers who spend long hours playing "hardcore" games such as "Call of Duty: Modern Warfare 2" and "Battlefield: Bad Company 2" seem better able to take control and fight back against aggressive threats and violence in their dreams, according to a preliminary online survey. By contrast, soldiers who did not play video games much suffered from more emotional distress and a frozen sense of helplessness in their dreams.

Past research suggests that frequent video game players, known as gamers, may possess greater awareness and control in dreams, and so researchers have theorized that games might act as a virtual reality rehearsal for the threat simulations found in nightmares. The recent study looked at 98 mentally healthy soldiers and classified them into high gaming and low gaming groups to examine the differences in their dreams.

"Within this high-functioning group, [gaming] is clearly adaptive," said Jayne Gackenbach, a psychologist at Grant MacEwan University in Canada. For the study, she worked with a colleague and students at Athabasca University in Canada.

The high gaming group played military-themed shooter games such as “Call of Duty” and “America's Army,” as well as strategy simulations and massively multiplayer online games such as "World of Warcraft." The low gaming group favored casual games such as the puzzle game "Bejeweled," and did not play daily or weekly like the heavy gamers did.

Both groups saw about the same levels of deployment and combat in real life, and experienced about the same level of aggression and threat in their dreams. The big difference was how the soldiers reacted to dream threats.

"The low-end gamers were sadder, angrier and more fearful [in real life]," Gackenbach told InnovationNewsDaily. "That's concerning, but again I controlled for that because it was the gaming I was interested in."

Gackenbach's group coded the dream elements based on a system created by a researcher who had studied nightmares among Vietnam War veterans.

The survey excluded anyone who was suicidal, had addictions or reported symptoms of mental disorders such as post-traumatic stress disorder (PTSD). Still, Gackenbach hopes to someday study the effects of gaming in that population as well, given that nightmares are a classic symptom of PTSD.

Of course, the findings could use more validation from bigger surveys even if all the evidence is "lining up pretty nicely," Gackenbach said. She presented the survey results at the Game Developers Conference held in San Francisco from Feb. 28 to Mar. 4.

But the U.S. military already seems intrigued by the idea of gamelike simulations having somewhat of a protective effect against combat traumas. It has funded work by Albert "Skip" Rizzo, a University of Southern California psychologist, to help create a virtual simulation that could help new recruits mentally prepare for the potential stresses of war.

This story was provided by InnovationNewsDaily, a sister site to LiveScience.

A rare sleep disorder in which people act out their dreams, sometimes with violent thrashes, kicks and screams, may be an early sign of brain disorders down the line, including Parkinson's disease and dementia, a new study suggests.

The results suggest the incipient stages of these neurodegenerative disorders might begin decades before a person, or doctor, knows it, according to the researchers, who detail their findings online July 28 in the journal Neurology.

The researchers examined Mayo Clinic medical records to identify cases of the so-called REM sleep behavior disorder reported from 2002 to 2006. The researchers identified 27 patients who developed the REM sleep behavior disorder at least 15 years before showing symptoms of neurodegenerative ailments.

Of these patients, 13 developed what was likely dementia and mild cognitive impairment, 12 developed Parkinson's disease, one person Parkinson's-dementia, and one person multiple system atrophy (a disorder that causes symptoms similar to Parkinson's). The dementia category included dementia with Lewy bodies, which is the most common form of progressive dementia, defined partly by recurrent visual hallucinations.

Results showed the time between the start of the sleep disorder and the symptoms of the neurologic disorders ranged up to 50 years.

Scientists have estimated the REM sleep disorder has an estimated prevalence in adults of 0.4 percent to 0.5 percent and predominantly affects older adults. The main symptom of REM sleep behavior disorder is dream-enacting behavior, which can end in the person injuring themselves or a bed mate. When the person awakes, he or she might vividly recall the dream corresponding to the kicking or thrashing around. Past research has suggested a link between the dream-enacting behaviors and certain neurodegenerative ailments.

"A long-duration preclinical phase has important implications for epidemiologic studies and future interventions designed to slow or halt the neurodegenerative process," the researchers conclude.

• Top 10 Spooky Sleep Disorders
• 5 Things You Must Know About Sleep
• Top 10 Mysteries of the Mind

BOSTON – The slumbering mind might not seem like an apt tool for any critical thinking, but humans can actually solve problems while asleep, researchers say. Not only that, but one purpose for dreaming itself may be to help us find solutions to puzzles that plague us during waking hours.

Dreams are highly visual and often illogical in nature, which makes them ripe for the type of "out-of-the-box" thinking that some problem-solving requires, said Deirdre Barrett, a psychologist at Harvard University.

Barrett's theory on dreaming, which she discussed at the Association for Psychological Science meeting here last month, boils down to this: Dreaming is really just thinking, but in a slightly different state from when our eyes are open. [Why we dream is just one mystery of the mind.]

"Whatever the state we're put in, we're still working on the same problems," Barrett said. Although dreams might have initially evolved for a different purpose, they likely have been refined over time so they can serve double-duty: help the brain reboot itself and problem-solve.

Dreams and evolution

A theory to explain dreams, or any human behavior for that matter, needs to take into account evolution, Barrett said. But many early theories of dreaming either didn't address evolution at all, or downright contradicted it, she said.

For instance, Sigmund Freud proposed dreams exist to fulfill our wishes. But such gratification in an imaginary world would do little to help us adapt our instincts to the physical world, which is one key point of evolution, Barrett said.

Others have proposed dreams are more of a side effect of the sleep cycle. Dreams usually occur during Rapid Eye Movement, or REM, sleep. This stage is thought to serve several functions: to rest a part of the brain (since some areas are active while others aren't) and to replenish brain chemicals, such as neurotransmitters.

This has led some to say that dreams happen simply because REM sleep happens, Barrett said. The psychologist Steven Pinker once likened dreams to computer screen savers, saying that it perhaps "doesn't really matter what the content is as long as certain parts of the brain are active."

However, Barrett disagrees. "My opinion is that, evolution just isn't wasteful, that when things evolve for one purpose, that generally they don't continue throughout time to have only that purpose, but anything else that may be useful about them gets refined," she said in a telephone interview with LiveScience prior to the convention.

She also noted that REM sleep has been around for quite some time, since mammals evolved some 220 million years ago. "The longer something has existed during evolutionary history, the likelier it is to have other functions overlaid on it," she said at the convention.

Problem-solving

Barrett has studied problem-solving in dreams for more than 10 years, and documented many examples of the phenomenon.

In one experiment, Barrett had college students pick a homework problem to try to solve in a dream. The problems weren't rocket science; they were fairly easy questions that the student simply hadn't gotten around to solving yet. Students focused on the problem each night before they went to bed. At the end of a week, about half the students had dreamed about the problem and about a quarter had a dream that contained the answer, Barrett said.

So at least in the cases where problems are relatively easy, some people can solve them in their sleep.

Barrett has also extensively reviewed scientific and historical literature, looking for examples of problems solved in dreams.

She found examples of almost every type of problem being solved in a dream, from the mathematical to the artistic. But many were related to problems that required individuals to visualize something in his or her mind, such as an inventor picturing a new device.

The other major category of problems solved in dreams included "ones where the conventional wisdom is just wrong about how to approach the problem," Barrett said.

Dreams might have evolved to be particularly good at allowing us to work out puzzles that fall into those two categories, she said.

"I think that dreams and REM sleep have probably further evolved to be useful for really as many of the things that our thinking is useful for," Barrett said. "It's just extra thinking time, so potentially any problem can get solved during it, but it's thinking time in the state that's very visual and looser in associations, so we've evolved to use it especially to work on those kinds of problems."

• Top 10 Mysteries of the Mind
• Top 10 Spooky Sleep Disorders
• Video Gamers Can Control Dreams, Study Suggests

Playing video games before bedtime may give people an unusual level of awareness and control in their dreams, LiveScience has learned.

That ability to shape the alternate reality of dream worlds might not match mind-bending Hollywood films such as "The Matrix," but it could provide an edge when fighting nightmares or even mental trauma.

Dreams and video games both represent alternate realities, according to Jayne Gackenbach, a psychologist at Grant MacEwan University in Canada. But she pointed out that dreams arise biologically from the human mind, while video games are technologically driven by computers and gaming consoles.

"If you're spending hours a day in a virtual reality, if nothing else it's practice," said Jayne Gackenbach, a psychologist at Grant MacEwan University in Canada. "Gamers are used to controlling their game environments, so that can translate into dreams."

Gackenbach first became interested in video games in the 1990s, when she watched her son repeatedly kiss a new Nintendo gaming console on the way home from a Toys "R" Us. She had previously focused on studying lucid dreams, in which people have awareness of being in a dream.

The last decade of game-related research has since yielded several surprises, although the findings represent suggestive associations rather than definitive proof, Gackenbach cautioned. She is scheduled to discuss her work as a featured speaker at the Sixth Annual Games for Health Conference in Boston this week.

What dreams may come

Several intriguing parallels between lucid dreams and video games first emerged when Gackenbach examined past research on games. Both lucid dreamers and gamers seemed to have better spatial skills and were less prone to motion sickness.

The two groups have also demonstrated a high level of focus or concentration, whether honed through lucidity-training activities, such as meditation, or through hours spent fighting virtual enemies to reach the next level in a game.

That encouraged Gackenbach to survey the dreams of both non-gamers and hardcore gamers, beginning with two studies published in 2006. She had prepared by conducting larger surveys in-class and online to get a sense of where to focus questions.

The first study suggested that people who frequently played video games were more likely to report lucid dreams, observer dreams where they viewed themselves from outside their bodies, and dream control that allowed people to actively influence or change their dream worlds – qualities suggestive of watching or controlling the action of a video-game character.

A second study tried to narrow down the uncertainties by examining dreams that participants experienced from the night before, and focused more on gamers. It found that lucid dreams were common, but that the gamers never had dream control over anything beyond their dream selves.

The gamers also frequently flipped between a first person view from within the body and a third person view of themselves from outside, except never with the calm detachment of a distant witness.

"The first time we simply asked people how often they had lucid dreams, looking back over their life and making judgment calls," Gackenbach told LiveScience. "That's open to all kinds of bias, [such as] certain memory biases, self-reported biases."

Gackenbach eventually replicated her findings about lucid dreaming and video games several times with college students as subjects, and refined her methods by controlling for factors such as frequency of recalling dreams.

Mastering the nightmare world

Finding awareness and some level of control in gamer dreams was one thing. But Gackenbach also wondered if video games affected nightmares, based on the "threat simulation" theory proposed by Finnish psychologist Antti Revonsuo.

Revonsuo suggested that dreams might mimic threatening situations from real life, except in the safe environment of dream world. Such nightmares would help organisms hone their avoidance skills in a protective environment, and ideally prepare organisms for a real-life situation.

To test that theory, Gackenbach conducted a 2008 study with 35 males and 63 females, and used independent assessments that coded threat levels in after-dream reports. She found that gamers experienced less or even reversed threat simulation (in which the dreamer became the threatening presence), with fewer aggression dreams overall.

In other words, a scary nightmare scenario turned into something "fun" for a gamer.

"What happens with gamers is that something inexplicable happens," Gackenbach explained. "They don't run away, they turn and fight back. They're more aggressive than the norms."

Levels of aggression in gamer dreams also included hyper-violence not unlike that of an R-rated movie, as opposed to a non-gamer PG-13 dream.

"If you look at the actual overall amount of aggression, gamers have less aggression in dreams," Gackenbach said. "But when they're aggressive, oh boy, they go off the top."

No fear

The gamer dream experience of high aggression levels matched with little or no fear inspired Gackenbach to pursue a new study with Athabasca University in Canada. If gaming can act as a semi-protective function against nightmares, she reasoned, maybe it could help war veterans who experience post-traumatic stress disorder (PTSD) after enduring combat.

"I don't think anyone has looked at whether there's been a protective function," Gackenbach said. "It makes a lot of sense, but it's a hypothesis."

Psychologists consider nightmares as one of the symptoms of PTSD, and studies have shown incredibly high rates of nightmares ranging from 71 to 96 percent among PTSD patients. By contrast, just 3 to 5 percent of civilians reported the same levels of nightmares.

Virtual reality simulators have already been used to help PTSD patients gradually adjust to the threatening situations that plague their waking and sleeping thoughts. If Gackenbach's hunch is correct, perhaps video games could also help relieve the need for nightmares.

Finding the balance

Gackenbach hopes to someday get a sleep lab and perhaps a virtual reality lab to verify her results, even if studies about video games and dreams have not proven the highest priority for receiving funds. Yet studying video games has attracted more interest and respect from colleagues than studying just dreams alone, she has noticed.

Some of Gackenbach's latest work includes studying the violence levels in games, based upon the video game ratings given out by the Entertainment Software Rating Board, and seeing what effect they have upon aggression within dreams.

"I'm not saying [gamers] don't get more aggressive, not saying there's not more problems with addiction, and not saying there's not obesity issues," Gackenbach said. "As with everything else, there's a balance."

Any military personnel or veterans interested in the Athabasca University study on the military and gaming can e-mail jayneg@athabascau.ca to find out how to participate.

• Top 10 Spooky Sleep Disorders
• Video – Virtual Out-of-Body Experience
• Top 10 Unexplained Phenomena

Scientists have long wondered why we sleep and why we dream. A new study provides evidence for some long-held notions that sleep and dreams boost learning and help us to make sense of the real world. Even naps can help, the researchers found.

Test subjects who dreamt about a challenging task performed it better than those who didn't have such dreams.

This newfound link between dreaming and learning gives insight into why humans bother to sleep at all. The study is thought to be the first to show "the relationship between dreaming and function in the outside world," said senior researcher Robert Stickgold of Harvard Medical School.

While dreams have always mystified mankind, scientists have been equally curious about sleep. "It is dangerous to go to sleep," Stickgold said, evolutionarily speaking. Unconscious beings lying flat on their backs are especially prone to attack, he pointed out.

So why have we evolved to spend a third of our lives sleeping?

Previous research has shown that sleep benefits the immune and endocrine systems, but it hasn't been clear that sleep per se is necessary. Resting quietly may be enough to meet these needs, Stickgold told LiveScience.

Sleep, however, might affect the brain in a way that no other state can equal, suggests the study published in the most recent issue of the journal Current Biology. The effect is likely critical for learning and making sense of life -- skills worth sleeping for, scientists think.

Dreaming about it

During the study, 99 participants were taught to navigate a virtual maze on a computer screen. Half were then allowed to nap for two hours, while the other half remained awake. Later that day, all participants were re-tested on the maze task.

Those who reported dreaming about the maze significantly improved their performance. They did better than people who had slept, but did not dream. And better than those who stayed awake rehearsing the task in their minds. Specifically, the dreamers bettered their performance more than six times the improvements of all other participants.

Instead of simply rehashing the maze experience, participants described dreams that made broad associations between mazes and other aspects of their lives -- like recalling an experience exploring bat caves or seeing their future job application process depicted with maze-like features.

"Every day, we are gathering and encountering tremendous amounts of information and new experiences," said lead researcher Erin Wamsley, also of Harvard Medical School, in a press statement. "It would seem that our dreams are asking the question, 'How do I use this information to inform my life?'"

Dreams have priorities

Sleeping essentially lets the chaos of life sink in so we can make sense of it. A study earlier this year found that even naps boost learning.

"We can't really process one stream of information while we are taking in another one… so sleep becomes necessary," Stickgold said in a telephone interview. "It may be that for every two hours we are awake, it takes our brain an hour to process that information, so we need eight hours of sleep a night."

To remember something in particular -- say, the lines of a play or formulas for an exam -- it might help to study right before dozing, whether that means studying late at night or napping directly after a cram session, Stickgold said.

And if you can get yourself to dream about the material, you are at a particular advantage. Unfortunately, "dream content is notoriously hard to control," Stickgold said. The non-conscious brain "has its own rules," and focuses on whatever it deems most important, he added.

So your best bet for inducing an exam-acing dream is convincing yourself (and your brain) that the material truly matters, Stickgold said ¾ something that is, of course, easier to do for some subjects than others.

Dream interpretation

While some scientists have previously brushed off theories that dreams have meaning, Stickgold says dreams aren't random. "In dreams, we are seeing the brain's calculation of 'Do I care' and 'Why do I care?'" he explained.

The brain is also making associations between new information and past experiences. "What makes the human brain so brilliant is that we can take learning in one area and apply it to another," Stickgold said. And sleep may be critical for this level of understanding to occur.

Scientists used to think snoozing was only a cure for sleepiness. "It was as if we thought the only function of eating was to cure hunger, not to nourish our bodies," Stickgold said.

But now, researchers might have an understanding of dreams that even mystics may envy.

By reflecting the brain's effort to prioritize information and make associations, Stickgold said, "dreaming may be part of the process that creates the meaning of our lives."

• Top 10 Spooky Sleep Disorders
• 5 Things You Must Now About Sleep
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Lucid dreaming — that is, being aware of and able to control your dreaming state — may sound like a typical nocturnal experience to some, and just a pipe dream to others.

Whatever your opinion, the phenomenon of lucid dreaming has been observed in the laboratory. Subjects have been able to communicate to the waking world from their dreams using agreed-upon signals: namely, patterns of eye movement. Much dreaming seems to accompany a sleeper's rapid eye movement (REM), which occurs at a specific stage in the sleep cycle. Eye muscles are exempt from the paralysis that prevents other muscles in the body from acting out one's dream-movements. A lucid dreamer can shift eyes downward in a dream and the sleeping body will duplicate the action.

Several books and films (notably "Waking Life") have dealt with the notion of controlling one's dreams, but in the scientific world the study of lucid dreaming has remained peripheral to sleep research.

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Dreams might mean nothing, but many people take them seriously nonetheless, as Sigmund Freud did, new research finds.

People in at least three countries, including the United States, believe dreams contain important hidden truths, said researcher Carey Morewedge, an assistant professor at Carnegie Mellon University in Pittsburgh.

In six different studies, Morewedge and his colleagues surveyed nearly 1,100 people about their dreams. The results are detailed in the February issue of the Journal of Personality and Social Psychology.

"Psychologists' interpretations of the meaning of dreams vary widely," Morewedge said. "But our research shows that people believe their dreams provide meaningful insight into themselves and their world."

In one study that surveyed general beliefs about dreams, Morewedge and co-author Michael Norton, an assistant professor at Harvard Business School, surveyed 149 university students in the United States, India and South Korea. The researchers asked the students to rate different theories about dreams.

Across all three cultures, an overwhelming majority of the students endorsed the theory that dreams reveal hidden truths about themselves and the world, a belief also endorsed by a nationally representative sample of Americans, Morewedge said.

In another study, Morewedge and his colleagues wanted to explore how dreams might influence people's waking behavior. A total of 182 commuters at a Boston train station were asked to imagine that one of four possible scenarios had happened the night before a scheduled airline trip: The national threat level was raised to orange, indicating a high risk of terrorist attack; they consciously thought about their plane crashing; they dreamed about a plane crash; or a real plane crash occurred on the route they planned to take.

A dream of a plane crash was more likely to affect travel plans than either thinking about a crash or a government warning, and the dream of a plane crash produced a similar level of anxiety as did an actual crash, Morewedge found.

Finally, Morewedge wanted to find out whether people perceive all dreams as equally meaningful, or whether their interpretations were influenced by their waking beliefs and desires. So, in another study, 270 men and women from across the United States took a short online survey in which they were asked to remember a dream they had had about a person they knew. People ascribed more importance to pleasant dreams about a person they liked as compared to a person they did not like, while they were more likely to consider an unpleasant dream more meaningful if it was about a person they disliked.

"In other words, people attribute meaning to dreams when it corresponds with their pre-existing beliefs and desires," Morewedge said. "This was also the case in another experiment which demonstrated that people who believe in God were likely to consider any dream in which God spoke to them to be meaningful; agnostics, however, considered dreams in which God spoke to be more meaningful when God commanded them to take a pleasant vacation than when God commanded them to engage in self-sacrifice."

More research is needed to explore fully how people interpret their dreams, and in what cases dreams may actually reveal hidden information, Morewedge said.

"Most people understand that dreams are unlikely to predict the future but that doesn't prevent them from finding meaning in their dreams, whether their contents are mundane or bizarre," he said.

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Women have more nightmares than men, a British researcher says, but men are more likely to dream about sex.

Psychologist Jennie Parker of the University of the West of England asked 100 women and 93 men between the ages of 18 and 25 to fill out dream diaries, priming participants before dreams occurred to record them. The research was part of her doctoral dissertation.

"My most significant finding is that women in general do experience more nightmares than men," she said. "An early study into dreams led to my discovering that normative research procedures into dream research often considered the structure of dreams, but that there is a gaping hole in terms of academic study that investigates emotional significance in the analysis of dreams."

Women's nightmares can be broadly divided into three categories: fearful dreams (being chased or life threatened), losing a loved one or confused dreams, Parker said. Parker corroborated participants' dreams with actual life experiences and found that the anxieties about past occurrences reoccur many times as "emblem" dreams.

"It is these emblem dreams that are particularly significant," Parker said. "If women are asked to report the most significant dream they ever had, they are more likely than men to report a very disturbing nightmare. Women reported more nightmares and their nightmares were more emotionally intense than men's." Sex dreams

Men's dreams contained more references to sexual activity, Parker said, and men reported more actual intercourse, while women reported more kissing and sexual fantasies about other dream characters.

Women's dreams also were found to contain more family members, more negative emotion, more indoor settings and less physical aggression than men's dreams, Parker said. Men made more references to attacks, or serious threat, but reported fewer verbally aggressive or covert acts of aggression. Men's and women's friendly behavior in dreams was the same; most often they reported helping other dream characters.

Recurring themes

In a comparison of pleasant versus unpleasant dreams among men and women, Parker found that men and women were more likely to be victims of aggressive interactions in unpleasant dreams than they were in pleasant dreams.

"In pleasant dreams the dreamer was more often the aggressor," Parker said. "Women had more unpleasant dreams than men and unpleasant dreams contained more misfortune, self-negativity and failures."

A lecture by former UWE researcher Susan Blackmore gave Parker a moment of epiphany that inspired her to examine more closely the stuff that dreams are made of, she said. "My own nightmares had two reoccurring themes, one concerned standing on the beach at Weston Super Mare, my home town, when the tide suddenly goes out very fast and returns as a huge tidal wave that is about to engulf me," Parker said. "The other dream includes a dinosaur roaming the streets at night and looking in at my window. I wondered if my experience was common amongst women."

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Japanese researchers say they've imaged thoughts and dreams and displayed them on a computer screen.

At the web site of the journal Neuron, where the findings are to be published, the researchers summarize their work: "The results suggest that our approach provides an effective means to read out complex perceptual states from brain activity."

Brain imaging is nothing new. And the images are reportedly very simple, but the researchers claim the technique could lead to the ability to unlock the secrets of dreams.

"By applying this technology, it may become possible to record and replay subjective images that people perceive like dreams," the scientists are quoted as saying in The Telegraph of London. In one experiment, test subjects were shown the six letters of the word "neuron," and the subsequent brain activity was used to reconstruct the letters on a screen.

Scientists mostly agree that dreaming happens during the phase called Rapid Eye Movement (REM). Some researchers think you dream about tasks and emotions that were not dealt with fully, and that dreaming can help solidify thoughts and memories.

Even animals dream. And some people think they can control their dreams. The jury is still out on that, but studies show that some dreamers can communicate with researchers during a dream.

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Robert Roy Britt is the Editorial Director of Imaginova. In this column, The Water Cooler, he takes a daily look at what people are talking about in the world of science and beyond.

Sleep Waking is an unusual art work that combines recorded brainwave activity and REM sleep with robot behaviors. The Sleep Waking robot plays back your dreams, or, if you will, presents an interpretive dance of your dreams. The Sleep Waking robot is the result of a collaboration between Fernando Orellana and Brendan Burns. Orellana spent a night in The Albany Regional Sleep Disorder Center in New York. The staff wired him up and collected data of every conceivable kind: EEG, EKG, rapid eye movement - you name it. Orellana describes the use of the data to animate the robot in this way: "The eye position data we simply apply to the position the robot's heads is looking. So if my eye was looking left, the robot looks left. The use of the EEG data is a bit more complex. Running it through a machine learning algorithm, we identified several patterns from a sample of the data set (both REM and non-REM events). We then associated preprogrammed robot behaviors to these patterns. Using the patterns like filters, we process the entire data set, letting the robot act out each behavior as each pattern surfaces in the signal. Periods of high activity (REM) where associated with dynamic behaviors (flying, scared, etc.) and low activity with more subtle ones (gesturing, looking around, etc.). The "behaviors" the robot demonstrates are some of the actions I might do (along with everyone else) in a dream." Orellana and Burns used a Kondo KHR-2HV humaniod robot for their project. Orellana believes that the Sleep Waking robot is a metaphor in which the robot is allowed to augment or act out human experience. The robot becomes an extension of the person and (I would add) an extension of the deeper unconscious level of the person (see video ). In the classic 1956 film Forbidden Planet, Dr. Morbius unconsciously uses Krell machinery when sleeping; the unthinkably powerful Krell technologies act upon his unconscious cues, and destroy his enemies. You might want to have some constraints built into the robot that is going to act out your dreams. Sleep is important; you might want to try the Metronap Sleep Pod or even Orexin, the sleep surrogate . From Robot 'plays back' dreams . (This Science Fiction in the News story used with permission of Technovelgy.com - where science meets fiction )

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When rats snuggle up for a nap, they replay "movies" of their daily activities in what scientists suggest is the animal equivalent of dreaming, a new study suggests.

The research supports the idea that memories are cemented into the brain during sleep.

"This work brings us closer to an understanding of the nature of animal dreams and gives us important clues as to the role of sleep in processing memories of our past experiences," said co-researcher Matthew Wilson at the Massachusetts Institute of Technology (MIT).

In a past study, Wilson measured activity in rats' hippocampuses, the brain's memory center, while awake and sleeping. They found that rats do form memories of events they experienced while awake, and that the rodents replayed the memories while snoozing. But whether the rats replayed actual images was unknown.

In human dreams, vivid images typically weave together to form a memory movie. To find out if rats replay visuals, Wilson and Daoyun Ji, also of MIT, measured brain activity in the hippocampus and visual cortex while rats ran through mazes with different designs on the floors and walls. The brain regions showed specific patterns as the animals sensed their surroundings in the maze.

Then, while the rodents slept the scientists re-measured the brain activity. Turns out rats reeled through a string of images showing the maze-running experiences. The exact patterns of neuron-firing while awake also showed up during sleep in the visual and memory regions.

Also, the scientists recorded activity of individual neurons in the rats' brains while the animals were awake and asleep. They found that the same neurons spiked during wakeful play got reactivated during sleep.

From this the scientists infer that during sleep, neurons in the visual region "talk" to those in the hippocampus in a sort of "conversation," suggesting that rat naps help consolidate daily experiences and make these memories stick.

For the first time, this work shows that the brain is replaying memory events in two locations at once--in the visual and memory centers.

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Your brain never stops working. But it does cease talking to itself when you lose consciousness, a new study shows.

Scientists have long wondered what the brain does and doesn't do during deep sleep. It remains active, they know. So what's the difference between consciousness and the lack of it?

When we're awake, different parts of the brain use chemicals and nerve cells to communicate constantly across the entire network, similar to the perpetual flow of data between all the different computers, routers and servers that make up the Internet.

In the deepest part of sleep, however, the various nodes of your cranial Internet all lose their connections.

"The brain breaks down into little islands that can't talk to one another," said study leader Giulio Tononi of the University of Wisconsin-Madison.

Tononi's team used a non-invasive procedure to activate select parts of the brain. Subjects had electrodes attached to their heads to monitor how each stimulation triggered reactions elsewhere.

In the early morning, when subjects were dreaming, signals careened around the noggin similarly to when they were awake. But at night, during deeper sleep, the picture was much different.

"During deep sleep early in the night," Tononi said, "the response is short-lived and doesn't propagate at all."

Consciousness has long mystified scientists. The new finding suggests that it depends on the brain's ability to integrate information, Tononi says.

The compartmentalization might also help the brain's synapses, which make all the connections that give us thought, to take a break, according to Tononi's colleague, Marcello Massimini.

"This process would allow cortical circuits to eliminate noisy synapses and renormalize in order to be ready for the next day," Massimini told LiveScience. The reduced activity might also help explain why performance in various tasks improves after sleep, he said.

The machine used to conduct the experiments is new. It generates a magnetic field to provide stimulation, and Tononi's team expects this to be the first of many similar studies that will help researchers better understand the mind and specific disorders of the brain.

The study is detailed in the Sept. 30 issue of the journal Science.

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Analyzed as portents of the future and windows to the subconscious, dreams have fascinated human beings since the dawn of recorded history. Their purpose, from a strictly cognitive point of view, remains a puzzle.

But a rare instance of dream loss in a patient with localized brain damage may pinpoint the where, if not the why, of dreaming.

The case involves a 73-year-old woman, who was admitted to the emergency room for a sudden loss of vision and weakness on the left side of her body. She had suffered a stroke that had damaged a small area in the back of her brain where visual processing is done.

Her sight returned after a couple of days, but subsequently she could no longer recall any dreams. Prior to the stroke she typically would remember three of four dreams a week.

Doctors from the University Hospital of Zurich, Switzerland, studied the woman while she slept on several occasions over a six-week period. As reported in a recent online version of the Annals of Neurology, they found that she continued to exhibit rapid eye movement (REM), which typically occurs at the same time as dreaming.

Yet, when the doctors woke the patient during REM, she still reported no dreams. All other aspects of her sleeping state were normal, and she showed no signs of disorientation or memory loss while awake.

"We know that REM is generated in the brain stem," said Jerome M. Siegel of the Brain Research Institute at the University of California, Los Angeles, so these results confirm that dreaming originates from a separate brain region.

The woman's stroke affected the inferior lingual gyrus, which is known to be important in recognizing faces and landmarks and in dealing with emotions. The authors suggest that this area plays a key role in the dream experience.

One possibility is that REM activity acts like an internal movie, but when the processing center is damaged, "the movie is still playing, but the patient is not watching it, or forgets that they watched it," Siegel said.