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Abstract:
Abstract: Aging is associated with memory deficits, which are
more apparent when assessed explicitly than implicitly (e.g.,
Fleischman et al., 1995). For example, while elderly adults may
have difficulty explicitly endorsing an item as old, they may show
normal implicit repetition priming. Recently, Curran (1999)
demonstrated that the P300 event-related brain potential (ERP) is
larger to old than new items regardless of whether memory is
assessed implicitly during lexical decision or explicitly during
recognition. We asked whether P300 would reveal equally intact
memories in elderly adults when assessed implicitly and explicitly.
ERPs were elicited to real and pseudowords in repetition priming
and recognition memory experiments during lexicality and new/old
judgments. As expected, in young adults, when memory was tested
implicitly, old items elicited larger P300s than new items at
central and parietal, but not frontal sites. Conversely, in elderly
adults, this P300 effect was only seen at frontal sites and only
for pseudowords. When memory was tested explicitly, P300 was again
larger to old than new items in young, but not in elderly adults.
P300 shows some evidence of intact memory in the elderly, but only
when tested implicitly. P300 is equally sensitive to memories
tested explicitly and implicitly in young but not elderly adults.
NIMH (MH40052, MH40041 and MH30854), CA Alzheimer's Disease
Program, DVA.
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