Interesting post.

I think about neurophysiological memory in the same way I think about memory in general - memory is what specifies a particular state out of a set of possible states. Given an adult human brain has ~85 billion neurons with 10,000 synapses for each one, that's obviously an awfully large space of possible connections or 'states' (without even considering their activity levels).

I think thinking about a C Elegans gives a better way of thinking about triviality vs. non-triviality. We know each worm has 302 neurons, and we know all the patterns of connections between them. In a sense these neural connections are a kind of memory - they encode the evolutionary memory of which connection setups produce successful worm behaviour, out of the set of other possible ways of wiring up those neurons. This kind of memory is 'trivial' though when considering within-lifetime memory formation (as opposed to genetic memory) as it's preset, the same way neural circuitry controlling basic regulatory functions like heart rate in a human would be a 'trivial' genetic memory.

What is non-trivial is any kind of memory that indicates what happened to that particular worm, as opposed to any other c. elegans. A human equivalent would be some synaptic or morphological information that tells you something specific about that particular human's experiences, as opposed to a generic human. I think anything in this vein counts as 'non-trivial', and the better you can specify the particular experience the animal/human had out of a set of possible experiences they may have had, the better a job you've done of decoding a non-trivial memory.

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Oct 11, 2022Liked by Andy McKenzie

Brilliant! Btw, an alternative candidate as example of using electrophysiology (rather than static structure) would be the work by the Berger team at USC, which has already involved human volunteers who were implanted and tested while recovering from surgery for epilepsy. The spatio-temporal patterns recorded there were clearly memory-related and were even used to generate a model with which to stimulate and support memory encoding in the same volunteers.

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