Inhibitory Mechanisms Underlying Stimulus-Selective Responses of Inferior Temporal Neurons

Abstract

Visual information regarding the shape and surface characteristics of objects is processed in the primate brain along the cortical pathway projecting to the inferior temporal cortex. Individual neurons in cytoarchitectonic area TE of the inferior temporal cortex respond preferentially to a range of complex visual stimuli such as shapes, shapes combined with color or texture, or complex images such as faces [1]. The prestriate areas V2 and V4, as well as the posterior part of the inferior temporal cortex, also contain a substantial population of neurons that respond better to shapes such as crosses and hyperbolic or polar gratings than to bars, edges, or linear grat­ings [2]. The stimuli necessary for strong activation of neurons in these areas are gen­erally simpler than those that excite TE neurons. Object information carried by single neurons is integrated gradually into complex forms in successive areas. Both con­vergent/divergent projections between areas and local excitatory and inhibitory interaction within an area contribute to this process. Inhibitory neurons have been implicated in various sensory processing including the generation of orientation selectivity in the primary visual cortex [3]. Here we discuss the role of area TE inhibitory interneurons in the generation of complex stimulus selectivity.