Despite how important and intriguing it is, and how much effort scientists put into it, we still do not know a lot about memory. Now a new study from UCL has demonstrated that when we are resting brain replays memories and places them in a different area. Not only this once again underlines the importance of good rest, but it also provides more information about formation of memories.
Scientists think that this process when experiences and events are being replay during rest is important for memory consolidation – brain firms up the memories and prepares them to be recalled quickly if needed. This is especially important when researching diseases and conditions that affect memory consolidation. For example, Alzheimer’s disease makes people quickly forget recent events, but usually long term memory is not affected. And it looks like scientists are on the right track – parts studied in this research are the first areas of the brain affected by Alzheimer’s disease.
Researchers analysed two brain areas of resting rats. However, it is important to give rats something to remember so that memory formation could be studied. Six rats were made to run for 30 minutes on a six meter long track before resting for 90 minutes. During the rest scientists set out to study two main areas involved in the memory formation: hippocampus, where memories are formed, and grid cells in the entorhinal cortex, where memories were found to be transported for long term storage. Scientists found that during rest brain of the rats reran entire track covered during active hours, but, of course, did it much faster than it actually happened – tracks passed by 10-20 times faster than they were experienced in reality.
What makes scientists believe that this rerun has a purpose of transporting memories to another region in the brain is that the same replay was observed in grid cells in the entorhinal cortex just 10 millisecond later. Dr Caswell Barry, supervisor of the study, said: “The hippocampus constantly absorbs information but it seems it can’t store everything so replays the important memories for long term storage and transfers them to the entorhinal cortex, and possibly on to other areas of the brain, for safe-keeping and easy access”.
Now scientists are planning to test the same principle with mice with Alzheimer’s. This should help better the understanding about how memories are formed and how what is the link between quality of sleep and amnesiac conditions. Although we did not need more proofs to see that quality sleep is important for our health, this demonstrates one of the processes our body goes through while we rest.