Zapping the brain may help boost math skills, study hints

In the new study, the researchers recruited 72 students from the University of Oxford. The researchers assessed the volunteers' math prowess with tests before dividing the students into three subgroups with matched abilities, meaning each group had a mix of people with weaker and stronger math skills.

For the experiment, individuals in each group had electrodes placed on their scalps that could deliver mild electrical signals to the brain. Two of the groups received stimulation to either the dorsolateral prefrontal cortex (dlPFC) or the posterior parietal cortex (PPC) — brain areas linked to math ability in previous research. The third group received a sham stimulation.

The team then applied transcranial random noise stimulation (tRNS), which is just one of many types of non-invasive brain stimulation but is known to be more comfortable than other options. The current passed through the scalp is very low.

"Most of the people do not feel whether they're stimulated or not," said senior author Roi Cohen Kadosh, a neuroscientist at the University of Surrey. Each participant in the treated groups received 150 minutes of stimulation, paired with math tests, over five days of testing.

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The tests assessed the students' calculation skills and "drill learning." Calculation learning requires existing mathematical ability and challenges participants to work out the answer to a presented problem. Drill learning, in contrast, requires no mathematical ability and instead asks users to memorize a series of presented equations.

Based on past research, the authors hypothesized that dlPFC stimulation would enhance calculation learning, because this area is associated with learning new skills and high-level cognition. They thought that stimulating the PPC, meanwhile, which handles the retrieval of already learned skills, might enhance drill learning. In the study, they found dlPFC stimulation was indeed tied to improved calculation ability but PPC stimulation didn't improve drill learning.

Before testing began, the team had measured the connectivity of their participants' frontal and parietal lobes, found at the front and on the top of the brain. These two lobes are the sites of the dlPFC and PPC, respectively, and are activated together during math learning. The team hypothesized that having stronger connections between the two lobes would be linked to stronger calculation learning. This was borne out by the data: at baseline, the team observed a stronger connection in participants with better calculation abilities.

People with weaker connectivity who were in the sham stimulation group had a harder time getting to grips with the calculation problems than those with stronger connectivity in the same group. But individuals with weak connections who had their dlPFC stimulated showed the biggest improvements in their scores.

Notably, an earlier, small study the team undertook with a cohort of math professors showed that stimulation actually worsened the pros' performance on math tests. This suggests those who already have high math ability should avoid stimulation.

"It's an optimal system," Kadosh said of the math professors' brains. "You enter new noise into that, it's going to cause a detrimental effect."

Kadosh is the co-founder of Cognite Neurotechnology, a brain stimulation company, and is optimistic about rolling out the technology to the general public. Kadosh said that people in universities, workplaces and training centers could all benefit from it. He added that he was interested in expanding the technology to people with learning difficulties and neurodevelopmental disorders such as attention-deficit/hyperactivity disorder (ADHD).

Meanwhile, Sung-Joo Lim, a psychologist at Binghamton University who was not involved in the research, noted that while similar stimulation devices have already been cleared for at-home use, analyses looking at how well they work have made it clear that more research is needed.

Lim added that such devices may need to be personalized to individual users to reflect differences in their brain shapes. "When you're targeting to stimulate certain brain regions, it might not necessarily work so well unless you really consider the brain anatomical structure of individual people," she said.

Kadosh also said that any consumer devices borne of the research need to be anchored to solid evidence, and he argued that many existing consumer brain-stimulation devices have little scientific basis. "We need to show that we can use this technology at home," he said.

Editor's note: This story was updated on July 2 to correct the spelling of Sung-Joo Lim's name.

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