Brenda Milner and H. M.

The case of H.M. presented by Milner. The patient complained of severe epilepsy, and following a medical work-up, a bilateral surgical excision (of the medial temporal region) was done to relieve him of the symptoms. The procedure removed parts of the temporal lobe, including the hippocampus. The patient then became profoundly amnesic and could not seem to store new information in LTM; his STM was unimpaired. He could recall a series of numbers shortly presented. His function to retain similar information over long periods of time did not work. The study shows that the hippocampus is an interim depository for long-term memory in which early experiment information is processed and then transferred to the cerebral cortex for more permanent storage.

However, Milner made a startling discovery that changed the way STM and LTM was conceptualized. In the case of H.M., his temporal lobe lesions can learn implicit types of tasks that involve perceptual and motor skills. Furthermore, he can retain the memory of these tasks for long periods. For example: H.M. could learn to draw an image in a mirror and retain that skill over time.

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