Inferotemporal versus combined pulvinar-prestriate lesions in the rhesus monkey: Effects on color, object and pattern discrimination

Abstract

Monkeys with inferotemporal lesions were compared to monkeys with combined lesions of the pulvinar and prestriate cortex on discrimination problems and on tests of sensory function. Inferotemporal lesions severely impaired discrimination of colors, objects, and patterns, but did not produce any sensory loss. By contrast, combined pulvinar-prestriate lesions impaired only discrimination of patterns, an impairment associated with sensory deficits and with degeneration of the lateral geniculate nucleus. Thus, inferotemporal lesions affected visual discriminations per se, whereas combined pulvinar-prestriate lesions affected discriminations related to specific dimensions of visual stimuli. These qualitatively different effects of inferotemporal and combined pulvinar-prestriate lesions are discussed in terms of current models of central processing of visual information.