Sleep serves an important biological purpose to heal and renew, and we’ve just learned that a great deal of the time spent asleep is actually replaying memories. In never-before-seen study, experiences were replayed in the brain during sleep, leading to a greater understanding of how the brain consolidates memories.
Through the work of a team of academic researchers from Stanford University, Brown University, Case Western Reserve University, and Massachusetts General Hospital, a brain-computer interface conducted its pilot clinical trials. The interface, known as BrainGate, have been developed for implantation in the brains of patients with severe motor disabilities. By using their brain signals, severely disabled patients may be able to recuperate motor functions through other technological devices designed to act as robotic arms or to help them with operating computers.
The electrode array placed in the brain is similar to other medically approved electrodes already being used to treat epilepsy patients or those with Parkinson’s disease. However, these electrodes can’t detect how individual neurons are firing. BrainGate is the first of its kind to record the activities of single neurons.
The study had two participants who underwent neurosurgery before the start of the study to implant the electrodes. The participants played a sequence game where there was a cursor controlled by neural activity. The electrodes monitored individual neural patterns as they fired during the game, and the participants then took a nap. While they napped, their brain activity was monitored.
During sleep, the brain replayed the experience of playing the game. The same firing patterns occurred during sleep just as when it was occurring. This is the first concrete evidence that the brain is replaying experiences as we sleep. Replay of memories is a significant part of consolidating memories, and to make the most of this knowledge: make sure you take time to rest after you’ve absorbed or studied a lot of information. And sleep well before any major tests!
Jean-Baptiste Eichenlaub, Beata Jarosiewicz, Jad Saab, Brian Franco, Jessica Kelemen, Eric Halgren, Leigh R. Hochberg, Sydney S. Cash. Replay of Learned Neural Firing Sequences during Rest in Human Motor Cortex. Cell Reports, 2020; 31 (5): 107581 DOI: 10.1016/j.celrep.2020.107581