There is a gap in my understanding of how the activation of cells happens biologically. I hope somebody is able to provide clarifying insight.
Let us say there exist learned sequences 'ABC' and 'FBD'. When A columns fire, specific cells in B columns become active. When, after that, B columns fire, specific cells in C columns become active, but not in D columns because B was fired in the context of 'AB'. My question is, under which exact circumstances and how does a cell get activated?
The reason I ask for the clarification is this seeming contradiction: if the rule is "the firing of a column activates cells strongly related to that column", then after firing columns of A and B, predictied cells in columns C as well as D would activate, because they are both part of learned sequences following B and thus strongly related to B.
However, if the rule was "the firing of a column which had a predicted cell, activates those cells related to its correctly predicted cell", then columns C would activate.
In NuPIC, both of these rules are used (right?). The latter is used unless there was no correctly predicted cell. In that case, the former is used.
But how could the biological system possibly make this distinction? Biologically, you would expect that, if the firing of a column can activate all strongly related cells, it would always do so. Concretely in this case, if B is seen without context, it activates strongly related cells of columns C and D.
So, a correctly predicted cell would have to shut off the rest of the column or something? As far as I understand, it doesn't add up entirely.
Thank you for your help!