Summary page only
“Engram” is used to describe the neural substance of memories. As we learn, we generate persistent neural structures that can be reactivated due to related stimuli. Evidence was initially scarce, but Hebbian learning (synaptic connections strengthening/weakening based on stimulus) seemed promising.
Later experiments showed that destroying or activating specific neurons could impede or aid memory retrieval. Experiments also suggest that neurons “compete” to be a part of memory, and this competition results in the larger scale structure of the brain. Competition over excitability and neural plasticity work hand-in-hand to create memory. There is also a suggestion that engrams can exist in different states (e.g. they can be unrecoverable, or “silent”).
Research is now ongoing to better understand and characterize these engrams.
THOUGHTS: the diagrams are approachable. Easy to get lost in the details of neurochemistry, might just be useful to read at a high-level and grapple with the diagrams.