Poster F91, Tuesday, March 28, 8:00 – 10:00 am, Pacific Concourse
Impact of preparatory attention on subsequent memory: individual differences in cortical oscillations
Anna Khazenzon1, Shao Fang Wang1, Stephanie Zhang1, Alex Gonzalez1, Stephanie Gagnon1, Monica Thieu1, Melina Uncapher2, Anthony Wagner1; 1Stanford University, 2University of California, San Francisco
Successful encoding into episodic memory can be impaired by goal-irrelevant distractors, as well as by lapses in goal-directed attention. Individual differences in distractor filtering, both within and across subjects, may contribute to variable subsequent memory. Fluctuations in top-down goal-directed attention may have dual consequences: they may contribute to variable distractor filtering success, and may also reflect lapses of attention even in the absence of external distraction. Here, we tested these hypotheses by examining how subsequent memory for words varies with (a) the presence of external distraction (goal-irrelevant visual stimuli), and (b) EEG oscillatory measures of goal-directed preparatory attention; this neural measure provides a means of indexing attentional lapses that lead to diminished distractor filtering (when distractors are present) and diminished target stimulus encoding. High-density (128 channel) EEG was recorded during an incidental encoding task, during which participants made semantic judgments about words while ignoring infrequent peripheral images of faces or objects. A subsequent old/new recognition memory test of the target words revealed that word memory (d’) was negatively impacted by the presence of external distractors. Spectral signatures of phasic fluctuations in top-down attention – pre-stimulus posterior alpha power– predicted subsequent retrieval success, suggesting that attentional lapses contribute to memory encoding failures. Moreover, this relationship was stronger on distractor-present trials, revealing the importance of preparatory top-down attention in target stimulus encoding in the presence of distraction. These data reveal a mechanism by which individual variability in preparatory attention impacts episodic encoding.
Topic Area: LONG-TERM MEMORY: Episodic