How does the brain decide which memories to keep and which to get rid of?

Written By Mark

We’ve known for some time that during sleep, the brain undergoes a memory cleaning process, during which thoughts collected during that day are converted into long-term memories or discarded.

It makes sense that this brain cleansing would occur at night when the brain is idle, considering that it is impossible for the massive human brain to have enough space for everything we receive in the day.

Until recently, researchers did not understand how the brain chooses what to keep. But, in a study recently published in the journal Science, researchers demonstrated for the first time that during the day the brain goes through a series of steps trying to select specific memories to be stored that night.

How does the brain store memories?

Researchers found that when the brain is idle during the day, synchronized waves of neurons cluster together in so-called sharp wave ripples that tell the brain that this memory is important and needs to be marked for storage later that evening, according to a report by the author by Sarah Novak on Discover.

While spikes of sharp waves occur less frequently during the day, their role is important because at night a series of 2,000 to 4,000 sharp waves occur, causing the brain to condense its collection of memories.

“Sharp wave ripples are the pattern that occurs in the hippocampus, and in the waking state, this is the pattern that chooses what will be put into permanent storage and what will be sorted,” says study author Gyorgy Buzaki, a professor of neuroscience at New York University School of Medicine.

Condensation of ideas

The brain seems to interrupt experiences that occur during our day and combine them with other experiences that also occurred. Fragments are removed, and ideas are condensed.

“Many parts of our waking experience are cut out and connected to other experiences using this pattern in the hippocampus,” Buzsáki says.

It turns out that the brain has two modes or algorithms: the acquisition mode (collecting information) and the storage mode. It is not that the brain is at rest when we sleep, but rather that it stores what was marked during the day.

“The spikes happen when we’re not paying attention, but they’re just as important as the active state,” says Buzsaki.

This is part of the reason why rest periods are important for the brain to function at a higher level. Going for a run or taking a coffee break is the best way to remember or learn something complex. You need to be at ease in creative work in order to get the best results.