@rhyolight
One aspect that Dr Sherman brought up was the soup of neurochemical receptors. It could be thought of as making the system hopelessly complicated.
In my mind I have simplified it as follows, start with these considerations:
- The thalamus is the gating and distribution network. You can think of it as attention and automatic gain control if that works for you.
- It is not likely that these complicated signaling pathways are somehow directly wired into the learned engrams. The influence has to be indirect or tonic in some way.
- Even though these various signaling pathways are not directly wired into the engrams they must be able to call up the related engrams as attractor nodes when the subcortical structures call for attention to them later.
- The only thing that the cortex gets is what is passed to it through the thalamus. If some of this gating is “anded” with valance driven signaling (various neurochemical signals) then the cortex will learn these things better and see these things better when those gates are enabled.
Q: Where do these circulating chemical and specialized signaling axons come from?
A: subcortical structures that do command and control of the brain.
So - I think that the presence of signaling from subcortical structures enhances attention in both learning and recall.
- In the attention/learning part the local areas that are being boosted by these messengers have an advantage and tend to prioritize learning in the attached cortex. This is a very fine-grained localized effect. This loads the perceived memory with valence.
- Later - in attention to something needed. The subcortical structures release chemical messengers related to this need and perception of things with this preloaded emotional valence are prioritized with attention to enter into the global workspace. This emotional valence was learned along with the perception of some prior perception.
- These islands of valance flavored learning will be attractors in future recognition/recall. Further activation with chemical messengers gates these attractors.
This scheme allows the rather dumb subcortical structures to reach out and interact with the very complicated things that the cortex is learning; more of the dumb boss/smart advisor model. What is going on at the HC/EC is related but at the episode level rather than the learned object level.