6) Hippocampus
I am important for many processes, including memory. If I am damaged, humans and mice lose the ability to form new memories (new episodic memories to be exact).
Interestingly, they also forget what happened shortly before the damage. It means that I am critically important for the formation of new memories, as well as for remembering recent events. I am no longer needed for remote memories. Therefore, people with damage to the hippocampus remember old events from their lives but cannot memorize new ones.
During everyday life, engrams of cells are formed within me, reflecting each event.
These engrams form very quickly.
Previously, it was believed that After learning I slowly transmit this information to the cortex, mainly during sleep, thus "teaching" the cortex so it would get the knowledge that I have. However, recent studies have shown that the engram in the prefrontal cortex is formed right at the moment of learning as well, but it is not yet functional for a few days after event.
That is, during sleep, I am not teaching the cortex something it didn't know before me but rather helping the existing memory engram to mature, so it would be useful and I would no longer be needed.