Intellectual effects of temporal-lobe damage in man.

The clinical literature on the intellectual effects of human brain damage reveals a constant preoccupation with the problem of the role of the frontal lobes, with a corresponding neglect of other parts of the cerebral cortex. In particular there is not a single systematic investigation of the effects of temporal-lobe damage in man, althrough there are several isolated and highly suggestive reports of individual cases. Fortunately the situation is quite different with regard to animal work, where the last few years have yielded numerous reports dealing with the effects of temporal-lobe lesions of varying extent on the learning ability of lower primates. This material is highly relevant to the present investigation, since it draws attention to types of deficit which might well be found at the human level also, but which have been neglected; for this reason the animal data will be presented in some detail, before passing to a review of the clinical literature. Since the present study deals only with cognitive functions, there will be no detailed discussion of the emotional changes often seen in temporal-lobe damage. In the monkey, a decrease in emotional reactivity regularly follows deep-temporal removals (Brown and Schafer, 1888; Kluver and Bucy, 1938; Bard, 1950; Thomson and Walker, 1951; Mishkin, 1951; Poirier, 1952); in man, electrographic abnormality in the anterior temporal region frequently gives rise to personality disturbances (Bailey and Gibbs, 1949) [...