Going against research findings in the past about how memory is consolidated when we are asleep or under anesthesia, researchers from UCLA have found that the dialogue between the neocortex and the hippocampus also includes another third key player – the entorhinal cortex.
Speaking of their findings when measuring neuronal activity in three parts of the brain, Mayank Mehta, team leader and a professor of neurophysics at UCLA, said, “This is a whole new way of thinking about memory consolidation theory. We found there is a new player involved in this process and it’s having an enormous impact. And what that third player is doing is being driven by the neocortex, not the hippocampus. This suggests that whatever is happening during sleep is not happening the way we thought it was. There are more players involved so the dialogue is far more complex, and the direction of the communication is the opposite of what was thought.”
The study, which included researchers from Heidelberg and Brown University as well as the Max Planck Institute for Medical Research, conducted the experiment on mice, and focused on three parts of brain namely the neocortex, hippocampus and the entorhinal cortex.
While earlier research stated that dialogue occurs in the brain between the neocortex and the hippocampus, no one had been able to determine how the entorhinal cortex, a brain area that connects these two parts, contributes to memory formation.
However, in this study, it was found that the neocortex drives the entorhinal cortex, which begins exhibit activity that recalls something while this drives the hippocampus.
Mehta believes that this process of communication is to get rid of junk in the form of useless memories as well as irrelevant data that was gathered and processed during the day.