Temporal Lobe Lesions and Memory in the Monkey

Abstract

IN 1954 Mishkin and Pribram^1,2 demonstrated that removal of the inferotemporal cortex in the monkey produced a severe visual discrimination deficit. Subsequent studies have investigated the parameters of this deficit, but its basic nature is still not clear^3–7. Since 1954 considerable clinical evidence has accumulated showing that bilateral ventral medial temporal lesions are associated with a severe memory loss in man, characterized by a difficulty in retaining new information for more than a brief period^8,9. It has been suggested that bilateral removal or injury to the hippocampus and the nearby ventral neocortex is responsible for this deficit. In view of the fact that during the evolution of the primate temporal lobe there has been an enlargement of the neocortex and subsequent lateral-ventral movement of tissue¹⁰, it is our hypothesis that inferotemporal lesions in the monkey may in some degree be analogous to the more medial lesions in man and that inferotemporal monkeys fail discrimination learning tasks because of inability to store visual information.