Textbook Group meeting for Parr, Pezzulo, Friston 2022 .

hello everyone thanks for joining or listening it's November 11th 11 11 22. and we're in cohort two of the active textbook group having a discussion of chapter five exploring some topics there are some questions that have been written in comments as well and then taking it wherever we want as we review the first half of the book that'll be today and then next week we'll be taking an even further step back and more of a focus on like feedback completing the feedback form how can we improve and structure future textbook group cohorts project ideas and so on but for today we're in chapter five so um does anyone want to give any thoughts or comments or just initial questions to raise about chapter five all right then let's go into the written questions okay how does the simple hierarchy with one-to-one mapping between levels as shown in the left hand side of figures 4 4 6. and 5.2 44 four six five two relate to actual brain hierarchies such as the classic fellerman and Van Essen diagram from retinal ganglion cells up to hippocampus with many to many mapping between Regional units ah I guess this is the famous diagram well what do people think how do these seemingly skyscraper like hierarchical models this one is laid out side to side but we can see ascending and descending so this could have been graphically laid out like this and then another one and then a third one on top of course top down the bottom-up are just spatial metaphors so um how do we reconcile computational hierarchical models with the empirical structural connectivity of the brain which has a wiring structure looking like this Ali between these two kinds of icons or kinds of maps because on one hand we have a kind of relational map and on the other hand there is a kind of architectural slash functional mapping of the brain so for example if we look at a circuit map of the of an electric circuit there's we have a relational map there right but when we want to implement that circuit I mean in terms of wiring and so on we need to have another kind of map which is architectural one so of course in some cases there's a possibility of translating one map perfectly onto the other but there isn't necessarily an isomorphism between those two kinds of map and I think in this case we don't necessarily see that isomorphism here as well excellent great answer totally agreed these kinds of diagrams are often described as hierarchical or heterotical or people use difference um words to describe it but it's describing the anatomical connectivity of different brain regions whereas the diagrams that are shown in these figures that were mentioned in the question are not anatomical Regions they're statistical variables connected by edges this is the difference between structural and effective and functional connectivity structural connectivity is what pieces are actually put together and through direct contact intermediating whereas functional connectivity has to do with the statistical relationships in the system and those are not necessarily for a given set of measurements or spatial or temporal scale or experimental stimuli those are not exactly the same thing there are cases where there are but that doesn't mean that in general they're the same thing so how do they relate to quote actual brain hierarchies they relate to each other in the way that Ali just described similarly between um uh architectural diagram and a functional diagram does anyone have any other thoughts on this yeah Giuseppe yeah I think that is a is a very good explanation on the other hand I think that at that stage of the of the description the idea was to see how active inference could also provide a process Theory so basically to to see how these information mechanism may be implemented in a neural circuits so yes the two are not completely the two descriptions are not isomorphic but I think there should be some degree of of uh agreement and in this case I think that what may be masking the the the…