All higher order cognition (e.g., remembering autobiographical events, reasoning, and problem solving) depends critically on two broad classes of memory function, working memory(WM) and long term memory (LTM). Aging is associated with deficits in both WM and LTM and such deficits have an impact on the cognitive functioning of older adults in all areas of their lives. Working memory refers to the information from perception and long-term memory that is currently active, and the set of processes that maintain and manipulate this active information. It allows us to keep something in mind after the initiating stimulus disappears, make connections and comparisons between events, and sustain goal directed behavior. Furthermore, WM processes are """"""""encoding"""""""" processes for information that will be available later in LTM as part of the cumulative record of our past experiences. Neuronal studies with monkeys, human brain damage studies, and recent human neuroimaging studies point to the prefrontal cortex (PFC) as critical for WM and important in understanding memory and aging (e.g., age-related decreases in neuronal loss may be greatest within PFC). By capitalizing on converging developments in current memory theories and breakthroughs in neuroimaging technology, the proposed research combines a component process approach to memory with fMRI imaging techniques in order to characterize more precisely, cognitively and neurally, memory deficits associated with aging. For example, we test the hypotheses that (a) maintenance involves ventral PFC whereas manipulating information (combining features, shifting between tasks, cumulative rehearsal, temporal judgements) involves dorsal PFC and (b) there are greater age-related changes in component process subserved by dorsal than ventral PFC. The proposed project has four major goals: (1) further clarify the component processes that underlie the maintenance and manipulation of information in working memory and to identify their neural bases, (2) Identify the WM component processes most affected by aging (3) explore the relations between WM component processes and LTM, and the implications for LTM of age-related changes in these component processes, (4) further develop and improve fMRI techniques for studying age-related changes in the neural basis of memory.
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