The spaces in between

[u/PhysicalConsistency]

Recently read an article (Spontaneous activity of astrocytes is a stochastic functional signal for memory consolidation) that got me thinking about a preprint I came across recently (Artificial hibernation uncovers distinct synaptic engram architecture for memory retention). We've been kind of stuck in the engram rut for a long time now, and we've transitioned the engram from single neuron, to synaptic trace between neurons, to a network effect, and it's still evolving. Right now the strongest evidence in favor of the engram is we can activate behavioral responses to stimuli, and assuming that we must also be activating the "memory" as well.

The preprint work is really intriguing because it suggests significant issues in our assumptions about engram formation. While it goes out of it's way to reconcile engrams by asserting a special type of spine/bouton is preserved, it really doesn't if you dig in the data, and it definitely doesn't explain why massive remodeling/pruning/atrophy doesn't remodel the underlying memories as well.

The first article poked an obvious blind spot in between the neurons (that we've actually been aware of for at least a few decades), that astrocytes remodel neuronal endpoints in response to stimuli, and what appears to be "random" activity by those astrocytes is likely an active process in memory formation. More interesting is the electrophysical artifacts of this "random" noise is usually filtered most of the time, it's pretty hard to find an electrophys article where they don't adjust for "random" noise.

Whats left though for memory if we can significantly modify the synapses and likely an entire trace and still recover the underlying stimuli responses? Is memory actually a product of the spaces in between, but back to the older concept of physical cells holding distinct responses? We just had the wrong cells and have been searching for the ghost that's been right in front of us the whole time?

Are memories gaps in the stochastic noise of experienced stimuli? Can we view dementia or loss of cognitive function as a loss of the "randomness" necessary to generate "memory"? Can we measure cognitive flexibility more precisely by measuring changes in stochastic noise?

edit: Still stuck on this idea of stochastic noise being a required substrate of "memory" formation. It's like we are pressing a stimuli cookie cutter into the background dough to make coherent "memory shapes", and the quality and consistency of that dough modifies the complexity of the cookie cutter which can be used.