Researchers have discovered that synchronizing brain waves with electrical brain stimulation can improve short-term working memory. They discovered that the application of a low voltage current can synchronize different areas of the brain with each other, making it possible for better performance on tasks which involve working memory. Hopefully this method can eventually be made use of for bypassing damaged brain areas and relay signals in individuals who have epilepsy, stroke or traumatic brain injury.
The constant activity of the brain is observed as brainwaves that oscillate at different frequencies in different brain areas which keep a steady ‘beat’. The researchers discovered that application of a weak electrical current via the scalp helps align different areas of the brain, synchronizing brain waves and allowing the areas to maintain the same beat. Study participants performed better when the 2 waves had the same rhythm as well as at the same time.
To manipulate the regular rhythm of the brain, the researchers made use of a method known as transcranial alternating current stimulation, or TACS. The researchers discovered that stimulating the brain with electricity provided a performance boost to the memory processes utilized when people attempt to remember telephone numbers, names of people at a party, or a short grocery list. They made use of TACS to target 2 brain areas which are known to be associated with working memory – the inferior parietal lobule and the middle frontal gyrus.
Ten participants were instructed to perform a set of memory tasks increasing in difficulty while having theta frequency stimulation to the 2 brain areas at unsynchronized times (slightly different), at synchronous times (the same), or just a quick burst to provide the perception of having full treatment. The study participants viewed numbers flashing up on a screen and were required to remember if a number matched the previous number, or in the case of the more difficult task, if the number was the same as the two previous numbers.
Results revealed improvement in response times on the memory tasks when areas of the brain were stimulated synchronously, particularly on the more difficult tasks which required participants to remember 2 strings of numbers. The usual response is to perform slower on the more difficult cognitive task, but participants had faster performance with synchronous stimulation and performed just as fast as on the easier task.
Although other research has demonstrated that brain stimulation with electrical current or electromagnetic waves can affect brain activity, it’s remained controversial because it’s not been reproducible. But making use of functional MRI for imaging the brain allowed the researchers to reveal changes in activity while being stimulated, with the flow of information being potentially modulated by the electrical current. TACS can be used for manipulating the key brain network activity and fMRI can be used to see what’s happening.
Although the technique used for the study is very cheap, a major obstacle for making a treatment like this so easily available is the individual nature of the brains of people.