High-Level Visual Processing

The visual system in the primate brain has to recognize a large number of objects that can produce different retinal images in different situations. Moreover, object recognition eventually requires linkage between the analyzed objects and related knowledge. The inferior temporal (IT) cortex is thought to be involved in these processes, having several properties relevant to object recognition. First, anatomically, the IT cortex is situated at the end of the object vision pathway and has connections to the limbic memory system and the frontal cognitive control system. Second, damage to the IT cortex impairs object recognition in both humans and monkeys. Third, neurons in the IT cortex exhibit selectivity for complex visual stimuli and exhibit response invariance with transformation of those stimuli. Fourth, several lines of evidence suggest that IT neurons work cooperatively to represent whole objects on the cortex. Fifth, the response properties of IT neurons change through experience or learning. Specifically, IT neurons learn to reflect associative visual memory among multiple disparate objects. These points relevant to object recognition will be discussed in this chapter.