The canonical micro/macro-circuit of neocortex

A cortical sparse distributed coding model linking minicolumn- and macrocolumn-scale functionality

canonical cortical macrocircuit

Figure: Functional Architecture. The input field (F1) consists of binary feature detectors: a particular input consisting of five active features is shown.  The coding field, F2, is proposed as a macrocolumn analog.  It consists of winner-take-all competitive modules (CMs) proposed as analogous to minicolumns.  Each CM has K=3 binary units.  Bottom-up connectivity is all-to-all: gray lines signify initially zero weights.  The familiarity (G) of the input is proposed to be computed via a subcortical, neuromodulator-based mechanism, which then modulates the F2 unit activation function parameters (e.g., sigmoid height) contingent on G (purple arrows).

minicolumn operation

Figure: Hypothetical minicolumnar circuit. Panels A-E depict critical events transpiring in a single minicolumn at five points in time during the CSA’s computational cycle, which I propose corresponds to one gamma cycle: approximate timings relative to start of CSA cycle are shown across top.  The units labeled “C” (“B”) represent the local chandelier (basket cell) populations, respectively; See paper for detailed explanation