Two research teams funded by the Defense Advanced Research Projects Agency (DARPA) have recently presented evidence that memory gaps caused by traumatic brain injury can be bridged through the use of implanted electrodes, which mimic the electrical patterns involved in memory formation and storage.
The US military hopes these findings might help soldiers who suffered concussions on the field, as well as healthy adults who’ve lost some power of recall through normal aging.
In one of the studies, presented at the Society for Neuroscience meeting in Chicago, Illinois, on 17–21 October, researchers asked 12 people with epilepsy to look at pictures and then specify which ones they’d seen up to 90 seconds later.
While the participants did this, the team recorded firing patterns between CA3 and CA1 – two parts of the hippocampus – thought to play a major role in memory formation. Based on the activity in the CA1 cells, the researchers then developed an algorithm capable of predicting the pattern coming from CA3 with 80% accuracy.
By using this algorithm, the researchers should be able to stimulate the CA1 cells with a pattern that mimics an appropriate CA3 signal even if a person’s CA3 cells are damaged.
So far, this type of stimulation has been applied to only one subject, with results still to come, but the team hopes to test it in on more people in the coming months. Eventually, a device might be developed that would detect when the hippocampus is not efficiently encoding short-term into long-term memory and provide stimulation to support the process.
In another study, also presented at the meeting, a group of scientists led by Daniel Rizzuto from the University of Pennsylvania recorded brain activity in 28 people as they recalled a list of words. Using these patterns, the researchers developed an algorithm that predicted with high accuracy whether a person would remember a given word or not. Stimulating the brain only when a person read words that were likely to be forgotten, the researchers could boost performance by up to 140%.
Even though scientists don’t fully understand how this works, as long as it can be proved to be safe and effective, it may still be worth to develop therapeutic interventions based on it, said Thomas McHugh from the RIKEN Brain Science Institute in Tokyo who was not involved in the research.