Sleep spindles reactivated
They then came back every day for a week and repeated the task without being scanned. After a week had elapsed, they had memorized the task, and were once again scanned during sleep and asked to recall the sequences.
“Our aim was to compare the sleep spindles from the night where the subjects learned the new information to the night where they didn’t have any new information to learn but were exposed to the same stimulus with the same faces,” Dang-Vu explains.
The researchers found that during spindles of the learning night, the regions of the brain that were instrumental in processing faces were reactivated. They also observed that the regions in the brain involved in memory — especially the hippocampus — were more active during spindles in the subjects who remembered the task better after sleep.
This reactivation during sleep spindles of the regions involved in learning and memory “falls in line with the theory that during sleep, you are strengthening memories by transferring information from the hippocampus to the regions of the cortex that are important for the consolidation of that specific type of information,” he says.
Using non-invasive imaging to identify the mechanisms that strengthen memories can, he hopes, lead to improvements in our understanding of how memories work — and can lead to improved interventions for people with sleep or memory issues.
Read the cited paper: “Cortical reactivations during sleep spindles following declarative learning.”
For more information on Thanh Dang-Vu's recent research, see this release.