Stimulating the brain memory
Scientists have uncovered a method for improving short-term working memory by stimulating the brain with electricity to synchronize brain waves.
Researchers at Imperial College London found that applying a low voltage current can bring different areas of the brain in sync with one another, enabling people to perform better on tasks involving working memory.
The hope is 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.
The brain is in a constant state of chatter, with this activity seen as brain waves oscillating at different frequencies and different regions keeping a steady ‘beat.’
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Previous studies have shown that brain stimulation with electromagnetic waves or electrical current can affect brain activity.
But the field has remained controversial due to a lack of reproducibility.
The brain is in a constant state of chatter with brainwaves fluctuating at different frequencies and in different regions.
These fluctuations keep a steady ‘beat’ within the brain.
The Imperial study attempted to improve participants’ memory by ‘synchronizing’ brains waves from two regions to this beat.
They found that synchronizing the regions boosted key memory processes.
Whole-brain patterns elicited by synchronous and desynchronous tACS conditions. (A) Synchronous tACS during the 2-back task increased
The bold signal in brain regions underneath the parietal, IPL-electrode (inferior parietal lobule), and frontal, MFG-electrode (medial frontal gyrus electrodes [n = 21). (B) During the 2-back task, synchronous tACS showed significantly greater activity than tACS OFF in the right frontoparietal network.
TACS applied during the CRT task resulted in greater activity in occipitotemporal regions for both synchronous and desynchronous tACS conditions. (C) Increased BOLD signal for synchronous compared to desynchronous tACS conditions, for tACS stimulation relative to no tACS stimulation, was observed in the left hemisphere in the inferior parietal lobule (IPL), superior frontal gyrus (SFG) and orbitofrontal cortex (OFC.)
This difference in brain activity is explained by decreased activity during desynchronous compared to synchronous tACS, right plot. Images are at the Montreal Neurological Institute (MNI) space coordinates and in radiological space. R=right hemisphere. All images have been thresholded with FSL cluster-wise correction Z > 2.3, p<0.05.
The research team found that applying a weak electrical current through the scalp helped to align different parts of the brain, synchronizing their brain waves and enabling them to keep the same beat.
What they observed is that people performed better when the two waves had the same rhythm and at the same time.
In the trial, carried out in collaboration with University College London, the team used a technique called Transcranial Alternating Current Stimulation (TACS) to manipulate the brain’s regular rhythm.
They found that zapping the brain with electricity could give a performance boost to the same memory processes used when people try to remember names at a meeting, phone numbers, or even the way to a post office.
The research 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 (unsynchronized), 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.
Previously commissioned studies Have shown that brain stimulation with electromagnetic waves or electrical current can affect brain activity, the field has remained controversial due to a lack of reproducibility.
But using functional MRI to image the brain enabled the team to show changes in activity occurring during stimulation, with the electrical current potentially modulating the flow of information.
However, use TACS to manipulate the activity of key brain networks, and we can see what’s happening with fMRI.
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.
Although, 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.
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 that impair long-range communication in their brains.
The researchers hope is that it could eventually be used for these patients or even those who have suffered a stroke or who have epilepsy.
Researchers are hopeful that brain stimulation will enable them to treat patients, especially those 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.
Zapping the Brain’s Hippocampal
In my recent research paper, I have incorporated the zapping technique to stemmata the recalling of memory loss in patients suffering from dementia.
To reverse memory loss, we’ve designed an implant, which uses a learning algorithm that compares firing rate patterns with though of a person showing no physical signs of the dementia diseases.
The device algorithm then transferees these firing rate codes to a person suffering from dementia to their short-term memory. This restores some memory losses in the short-term patient memory, utilizing the patient’s own brain hippocampal spatiotemporal neural codes, which manages short-term memories.
The devices model uses new disciplines by which it’s predicting a memory retrieval of approximately 30 to 35 percent.
The procedure used to install this tiny implant: a small insertion is made in the groin.
The device is then inserted into the groin insertion with the five folded umbrella electrical circuit, by maneuvering the catheter up into the posterior cerebral artery, until it is in position near the brain’s hippocampus.
Once in position, the neuroscientist can activate the implant remotely, which releases the folded umbrellas to open, allowing the firing rate patterns to be activated.
Acknowledgments & References
Ines R Violante, Lucia M Li, David W Carmichael, Romy Lorenz, Robert Leech, Adam
Hampshire, John C. Rothwell, David J Sharp. Externally induced frontoparietal synchronization modulates network dynamics and enhances working memory performance, a small study published in the Journal eLife. Professor S David Shap Neurologist in Imperial’s Department of medicine.