Ventral temporal lobe lesions and visual oddity performance

Monkeys were trained pre-operatively on a range of visual oddity discrimination tasks. Large inferotemporal (LT) lesions resulted in severely impaired oddity performance, but even when the concept had been reattained the relearning scores were related to the perceptual difficulty of the individual tasks, particularly in the case of the form discrimination. Smaller lesions to the posterior segment of the inferotemporal region (PT) resulted in only a slight loss of oddity performance as such but a severe impairment on the form problem. Thus in contrast to the group LT, post-operative performance in the group PT was clearly influenced primarily by the perceptual nature of the discrimination.