Poster B88, Sunday, March 26, 8:00 – 10:00 am, Pacific Concourse
Age differences in pre-stimulus subsequent memory effects: An event-related potential study
Joshua Koen1, Erin Horne1, Nedra Hauck1, Michael Rugg1; 1University of Texas at Dallas
Pre-stimulus subsequent memory effects are thought to reflect proactive processes that benefit episodic memory encoding. The present study investigated age differences in pre-stimulus subsequent memory effects indexed by differences in ERP amplitude that occur just before the onset of successfully versus unsuccessfully encoded events. Healthy young and older adults incidentally encoded words for a subsequent memory test. Participants were given a task cue (X or O) before each word that cued which semantic judgment (shoebox or manmade) to perform on the word. Words were presented for either a short (300 ms) or long (1000 ms) duration with the aim of placing differential demands on proactive processing initiated by the task cue. ERPs for subsequent successful and unsuccessful recollection were estimated time-locked to a task cue that onset 2000 ms before each study word. In young adults, a frontally distributed negative modulation of the pre-stimulus ERP predicted subsequent recollection success or failure in the short duration condition. A similar, but polarity reversed (successful > unsuccessful), pre-stimulus effect was observed for the long duration condition. These results suggest that proactive processes supporting encoding are sensitive to the perceptual demands made by the study item. By contrast, older adults showed no evidence of a pre-stimulus subsequent memory effect in the short duration condition and only a small negative going effect in the long duration condition. These results are broadly consistent with the proposal that older adults are less able to engage proactive processes that benefit memory encoding.
Topic Area: LONG-TERM MEMORY: Development & aging