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Abstract

The functional properties of neurons in the inferotemporal cortex (IT) have been studied extensively in both awake and anesthetized monkeys. While neurons in these areas show high selectivity for complex patterns, faces, and objects, their role in perception remains unclear. A previous electrophysiological study demonstrated that during binocular rivalry, when excitatory and non-excitatory stimuli were continually presented, most neurons in the inferotemporal cortex responded only when the excitatory stimulus was perceived (Sheinberg and Logothetis, 1997), suggesting that the activity of IT neurons is tightly linked with conscious perception. Recent evidence from our laboratory has suggested that active visual mechanisms of perceptual organization, including those related to binocular rivalry, can continue to operate under diminished states of consciousness that follow the administration of low doses of the dissociative anesthetic ketamine. In the present study, we examined the perception-related responses of IT neurons during rivalry in the monkey under a variety of conscious states, including wakefulness, ketamine dissociation, and general anesthesia. Single unit, multiunit, and local field activity was measured during extended periods of dichoptic stimulation, as well as during Flash suppression stimulus sequences that strongly bias subject's perception in the normal condition. Our analysis will focus on the extent of perception-related modulation of neural signals in the different conditions and characterize the functional significance of IT to perceptual organization.
Supported by Max Planck Society.