CONCEPTUAL PRIMING IN PERCEPTUAL IDENTIFICATION FOR PATIENTS WITH ALZHEIMERS-DISEASE AND A PATIENT WITH RIGHT OCCIPITAL LOBECTOMY

Two experiments examined explicit recognition memory and perceptual an d conceptual contributions to implicit perceptual-identification repet ition priming for patients with Alzheimer's disease (AD) and Patient M .S. with right-occipital lobectomy. Participants read words (perceptua l encoding) and generated words (conceptual encoding) from a definitio n and letter cue (e.g., ''a vehicle for moving the injured-a_________' '). AD patients demonstrated impaired explicit and intact implicit mem ory for both perceptually and conceptually encoded words. M.S. demonst rated the opposite pattern: intact explicit and impaired implicit memo ry in both encoding conditions. The double dissociation between AD and M.S. on implicit and explicit memory tasks is discussed in terms of a putative visual memory mechanism in the right-occipital cortex that i nteracts with lexical mechanisms to yield perceptual-identification pr iming after perceptual and conceptual encoding.