system
Given the following post, respond as if you're commenting on Reddit:
human
What happens to forgotten memories in your brain chemically and energetically, or however?
gpt
Memories are believed to be "recorded" as distributed synaptic changes in cerebral cortex neurons, and some aspects of this are understood (e.g., dendritic changes, post-synaptic densities, pre-synaptic modifications), very little is know about how these many changes are encoded as memories or how they are later recalled as memories or modified behavior. It's possible that these memories (as synaptic changes) still exist, but our ability to recall them changes. That would explain why some people with advanced degenerative diseases like Alzheimer's start to recall old memories even while they're forgetting more recent ones.