Working memory can be boosted by stimulating the brain with electricity
Scientists have uncovered a process for improving short-term working memory, by stimulating the brain with electricity to synchronise brain waves.
Researchers at Imperial College London found that by applying a low voltage current, they can sync different areas of the brain enabling people to perform better on tasks involving working memory.
The researchers believe that the approach could one day be used to bypass damaged areas of the brain and relay signals in people with traumatic brain injury, stroke or epilepsy.
In a small study, published today in the journal eLife, the Imperial team found that applying a weak electrical current through the scalp helped to align different parts of the brain, synchronising their brain waves and enabling them to keep the same beat.
“What we observed is that people performed better when the two waves had the same rhythm and at the same time,” said Dr Ines Ribeiro Violante, a neuroscientist in the Department of Medicine at Imperial, who led the research.
In the trial, carried out in collaboration with University College London, the research team used a technique called transcranial alternating current stimulation to manipulate the brain’s regular rhythm.
They discover that by using the technique, a performance boost was given to the memory processes associated to remembering names, phone numbers or even a short shopping list.
Dr Violante and team used TACS to target two brain regions – the middle frontal gyrus and the inferior parietal lobule – which are known to be involved in working memory.
Ten volunteers were asked to carry out a set of memory tasks of increasing difficulty while receiving theta frequency stimulation to the two brain regions at slightly different times (unsynchronised), at the same time (synchronous), or only a quick burst (sham) to give the impression of receiving full treatment.
In the working memory experiments, participants looked at a screen on which numbers flashed up and had to remember if a number was the same as the previous, or in the case of the harder trial, if it the current number matched that of two-numbers previous.
Results showed that when the brain regions were stimulated in sync, reaction times on the memory tasks improved, especially on the harder of the tasks requiring volunteers to hold two strings of numbers in their minds.
“The classic behaviour is to do slower on the harder cognitive task, but people performed faster with synchronised stimulation and as fast as on the simpler task,” said Dr Violante.
However, one of the major hurdles for making such a treatment widely available is the individual nature of people’s brains. Not only do the electrodes have to get the right frequency, but target it to the right part of the brain and get the beat in time.
Dr Violante added: “We use a very cheap technique, and that’s one of the advantages we hope it will bring if it’s translatable to the clinic.
“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.
“The hope is that it could eventually be used for these patients, or even those who have suffered a stroke or who have epilepsy.”