下側頭葉皮質局所抑制回路の物体像視覚認識における役割

抄録

Neurons in area TE of the monkey inferior temporal cortex respond selectively to images of particular objects and are considered to be a neural basis for visual object recognition. The mechanism of generation of the stimulus selectivity, however, is largely unknown. We addressed the role of inhibitory TE neurons in this process by examining their visual response properties and interactions with adjacent target neurons. We applied cross-correlation analysis to spike trains simultaneously recorded from pairs of adjacent neurons in anesthetized macaques (Macaca fuscata). Neurons whose activity preceded a decrease in activity from their partner were presumed to be inhibitory neurons. Most inhibitory neurons responded to a variety of visual stimuli in our stimulus set, which consisted of several dozen geometrical figures and photographs of objects, with a clear stimulus preference. On average, 10% of the stimuli increased firing rates of the inhibitory neurons. Degree of stimulus selectivity of inhibitory neurons was similar to that of excitatory neurons. Although inhibitory neurons occasionally shared the most preferred stimuli with their target neurons, overall stimulus preferences were less similar between adjacent neurons with inhibitory linkages than adjacent neurons with common inputs and/or excitatory linkages. These results suggest that inhibitory neurons in area TE are activated selectively and exert stimulus-specific inhibition on adjacent neurons, contributing to shaping of stimulus selectivity of TE neurons. [J Physiol Sci. 2006;56 Suppl:S34]