Some Mechanisms of Tactile Localization Revealed by a Study of Leucotomized Patients

This investigation was undertaken following a suggestion that finger agnosia occurred after pre-frontal leucotomy. A preliminary investigation did not reveal the presence of finger agnosia as des-cribed by Gerstmann (1924) but confirmed the existence of a post-operative difficulty in localizing tactile stimuli on the fingers. Accordingly, the present investigation was designed with the object of examining the extent and nature of this defect and in the hope that the nature of the errors would reveal something of the mechanism by which normal localization of tactile stimuli occurs. Although tests of tactile localization are used clinically, and may assist in the diagnosis of cerebral damage, very little is known concerning the neuro-