Neurons That Confuse Mirror-Symmetric Object Views

Abstract

Neurons in inferotemporal cortex that respond similarly to many pairs of mirror-symmetric images -- for example, 45 degree and -45 degree views of the same face -- have often been reported. The phenomenon seemed to be an interesting oddity. However, the same phenomenon has also emerged in simple hierarchical models of the ventral stream. Here we state a theorem characterizing sufficient conditions for this curious invariance to occur in a rather large class of hierarchical networks and demonstrate it with simulations.