An Emergent Model of Visual Cortical Orientation Selectivity

We demonstrate a cortical circuit based on known anatomical details and cellular properties which achieves sharp orientation tuning despite poorly tuned thalamocortical input. Sharp tuning arises emergently from excitatory interactions between similarly tuned neurons, which also receive broadly tuned inhibition. This model accounts for data obtained from intracellular recording and pharmacological blockade studies, which had previously appeared to conflict over the role of inhibition. We suggest that inhibition acts non-specifically and indirectly to maintain the selectivity of individual neurons by balancing strong intracortical excitation at the columnar level.