The proposed research comprises five studies designed to answer five fundamental questions about the functional neural architecture of human memory. The studies test five hypotheses about the relation between implicit memory (measured by tests of repetition priming) and explicit memory (measured by tests of recall and recognition) in amnesic patients, patients with focal lesions, and normal subjects. The questions are: (1) Is memory failure in global amnesia better characterized by systems (explicit/implicit) or processing (conceptual /perceptual) dichotomies?; (2) When do explicit memory processes contribute to implicit memory test performance?; (3) What kind of implicit new associations can be learned in global amnesia?; (4) What kinds of novel stimuli can be represented by implicit memory mechanisms?; and (5) Are fluency contributions to recognition memory the same thing as perceptual priming? The studies aim to find convergent evidence from normal memory performance and from abnormal memory performance due to neuroanatomical injury (amnesia). The results from the proposed experiments ought to provide new insights into the nature of memory processing performed by limbic-diencephalic and by cortico-cortical neural systems, and into the conditions that engage those systems in memory performance. The goal of the studies is to contribute towards an integrated theory of human memory that is constrained both by neuropsychological and normative empirical evidence. The implicit/explicit distinction in memory has proven remarkably useful in analyzing normal memory, changes in memory associated with child development and aging, and pathologies of memory in Alzheimer's disease, Parkinson's disease, Huntington's disease, schizophrenia, and depression. The resolution of fundamental questions about the implicit/explicit memory distinction, in relation both to psychological mechanisms and neural structures, therefore, ought to have consequences for all of these areas of research.
