Inferior temporal cortex is necessary for normal visual perception and visual learning in adult humans and monkeys. Several line of behavioral, anatomical and physiological evidence suggest that inferior temporal cortex continues to develop in the first year of post-natal life. This possibility will be examined by studying the properties of inferior temporal neurons in normally reared macaques at various times in the first year of life and comparing them to the properties of inferior temporal neurons in adult monkeys. The single neuron properties studied will include responsiveness, modality specificity, receptive field size and location, and stimulus selectively. The role of specific visual experience in the development of the properties of inferior temporal neurons will also be investigated. In adult macaques some inferior temporal neurons respond selectively to faces. In animals raised from birth for one year without exposure to faces the incidence of face-selective neurons will be compared to that in normally reared animals. Some animals will also be raised with extensive exposure to an artifical stimulus and the selectivity of inferior temporal cells for this stimulus will be subsequently tested. The proposed research should enhance understanding of the development of human visual learning and perception and its interference by disease, trauma and developmental disorders.