Even as we sleep, our brains are busy organising memories, and now a new study has claimed to have got a glimpse of the process.
Published in the journal Cell Reports, the study reported the first direct evidence of human brains replaying waking experiences while we sleep, seen in two participants with intracortical microelectrode arrays placed in their brains as part of a brain-computer interface pilot clinical trial.
As per the study, the brain replays neural firing patterns experiences while awake, also known as “offline play”. Replaying experiences is thought to contribute to memory consolidation, the process by which recent memories acquire more permanence in their neural representation.
For the study, the two participants were asked to take a nap before and after playing a sequence-copying game. Instead of moving their arms, they were made to play with their minds. As the participants rested, played and rested again, researchers recorded the spiking activity of large groups of individual neurons in their brains through an implanted multi-electrode array (microscopic electrodes distributed over a small surface area).
Researchers observed the same neuronal firing patterns during both the game and post-game period, as though the participants kept playing after they were asleep, replaying same patterns in their brain at a neuronal level.
“This is the first piece of direct evidence that in humans, we also see replay during rest following learning that might help to consolidate those memories,” co-author Jarosiewicz was quoted as saying by Science Daily.
“All the replay-related memory consolidation mechanisms that we’ve studied in animals for all these decades might actually generalize to humans as well,” the author added.