Older adults use different parts of their brain than younger people to store memories of the bad times, a finding that may have to do with the resilience of seniors.
It is no surprise that older people tend to have more difficulty trying to remember an array of events, but neuroscientists from Duke University Medical Center wanted to see how the connections that do this type of memory work change with age.
So the researchers compared brain scans of older and younger adults when the two groups were asked to remember events that yielded unpleasant emotions. The scans showed that while younger adults relied more on the brain region involved in emotions (known as the amygdala) and another involved in recalling memories (the hippocampus), the elder subjects called upon a "higher thinking" area of the brain called the frontal cortex.
The frontal cortex is an area of the brain that is involved in complex cognitive functions such as planning, organizing, problem-solving and abstract thoughts. It also controls the lower-order parts of the brain such as the amygdala.
Here are the experiment details: The older and younger subject groups, with average ages of 70 and 24 respectively, were hooked up to an fMRI machine and shown a series of 30 photographs, some of which had strong negative content. Later they were asked to complete a recall task to determine whether the brain activity that occurred while looking at the pictures could predict what types of content were memorized more accurately.
Both age groups were equally affected by the emotional content depicted by the pictures, such as violent acts or attacking snakes. What differed were the brain connections used to remember those pictures later on, said Roberto Cabeza, a neuroscientist with Duke University’s Center for Cognitive Neuroscience.
And younger participants were able to recall more of the emotional photos. They coupled their feelings more with memory retrieval. The older people showed a reduction in memory for pictures with a more negative emotional content, indicating that perhaps with age, people learn to be less affected by negative information in order to maintain their well being and emotional states.
"It wasn’t surprising that older people showed a reduction in memory for negative pictures, but it was surprising that the older subjects were using a different system to help them to better encode those pictures they could remember," said researcher Peggy St. Jacques, a graduate student in the Cabeza laboratory.
The research is detailed online in the January 2009 issue of the journal Psychological Science.