Transmitting an electrical current through the scalp has shown to boost memory by synchronizing brain waves, say researchers from Imperial College London.
The new study, appearing in the journal eLife, may hold therapeutic promise for people with brain injuries or those dealing with the effects of neurological conditions such as stroke or epilepsy.
Using a technique known as transcranial alternating current stimulation, or TACS, the researchers stimulated the brains of study participants with a weak electrical signal and had them perform simultaneous memory tasks.
“What we observed is that people performed better when the two [brain] waves had the same rhythm and at the same time,” said lead researcher Dr. Ines Ribeiro Violante, a neuroscientist with Imperial College London.
Specifically, scientists were assessing two brain regions associated with working memory — the middle frontal gyrus and the inferior parietal lobule. Among 10 study participants, the researchers used different stimulation techniques — buzzing the two regions of the brain at different times, at the same time, or using a quick burst to replicate a placebo.
The study participants then performed memory tasks, recalling numbers that flashed on a screen with different levels of difficulty. For example, the study participants were asked to recall a number they had seen on the previous screen or, in more challenging parts, the number that appeared two screens before.
Overall, when patients’ brain waves were in sync, they performed better on the memory problems.
“The classic behavior is to do slower on the harder cognitive task, but people performed faster with synchronized stimulation and as fast as on the simpler task,” said Violante. “The results show that when the stimulation was in sync, there was an increase in activity in those regions involved in the task. When it was out of sync the opposite effect was seen.”
Gauging Future Treatment Possibilities
The researchers caution that extrapolating the treatment technology to a wider audience may prove difficult because people’s brains tend to work on individual frequencies. However, they hope their technique can help patients with existing neurological challenges.
“The next step is to see if the brain stimulation works in patients with brain injury, in combination with brain imaging, where patients have lesions which impair long range communication in their brains,” said Violante.
“The hope is that it could eventually be used for these patients, or even those who have suffered a stroke or who have epilepsy,” Violante added.
Because there are few current techniques to improve the memory of people who have suffered brain trauma, the new study offers a great deal of hope.
“We are very excited about the potential of brain stimulation to treat patients. I work with patients who often have major problems with working memory after their head injuries, so it would be great to have a way to enhance our current treatments, which may not always work for them,” said senior author David Sharp.
“Our next step is to try the approach out in our patients and we will see whether combining it with cognitive training can restore lost skills,” Sharp added.