And are these stored discretely?
I need to dig around for a bit for the references on these, but there was a bit of research awhile ago linking 4th ventricle CSF impingement to “executive function” degradation. The ventricular zone “VZ” is one of the few places radial glia (stem cells/”neurogenesis”) we’ve been able to verify are generated throughout human lifespans. The rate of production in this area seems to correlate very tightly to “learning” ability as a whole.
During fetal and post natal development, nearly all of our new circuit roots start in the VZ, migrate to the SVZ, and then settle in either one of the rhinal cortexes or hippocampal/DG areas.
Taking a step back, it looks like these cells form the roots of object representations during early development, so a particular astrocyte may actually be a representation of something very specific in most nervous systems. These objects really primitive and require extra information to “fill in”, which allows them to be adapted to current external state/sensory environment more flexibly.
This conceit posits that the first few years of development for humans (or any animal with a “dependent period”) are spent accumulating enough cerebellar object model cells to graft flexible sensory (“social”) information on top of.
I keep squinting at semantic memory and it keeps looking like “context” vs. episodic memory which looks more like “sensory”.
Work like this: A causal role for the cerebellum in semantic integration: a transcranial magnetic stimulation study ties the object creation/binding stage pretty firmly to the cerebellum itself.
I’m so stuck on that .90 correlation coefficient for “cognitive flexibility” in the cerebellum, it’s such a stunning result. We wouldn’t need “flexibility” to recall straight sensory information, but would need it to recall objects since they need to be constructed from existing sensory information. For example, “knowing” which of a set is the most contextually appropriate for current information would be an example of that flexibility in play.
Older work like this: Cerebellar tDCS Modulates Neural Circuits during Semantic Prediction: A Combined tDCS-fMRI Study suggests that at least some aspects of episodic memory recall are greatly modified by the semantic prediction, implying that these are not quite as disparate the processes that’s assumed.
Thinking about individuals with exceptional memories, they nearly always seem to excel at one type, but are average/poor at the other type. For example, if someone has exceptional sensory recall (can remember what everyone wore on any particular date for instance), they are almost always really poor at remembering “facts” or “rules” (and usually are behaviorally similar to “autism” without the stupid stuff like “repetition”). On the obverse, people who tend to be really exceptional at memorizing “facts” tend to have a signficantly less rich use of sensory based language.
One of the thought paths I’ve been chugging through is the idea that the overwhelming majority of psychiatric descriptions are better understood as differences in “memory construction”. An example of this is that something like “schizophrenia” mostly represents an overweight “object” memory, and we might be able to alleviate symptoms significantly by re-weighting object memory. This path leads to thinking about “depression” as an example of “underweight” sensory memory, and figuring out how to get that sensory flow “unstuck” might be an interesting approach.
Ultimately the hope here is that if we address the language and try to tie more closely to the actual physiological processes, we can get a better idea of what is actual “defect” and what is natural variation in processing.