Age-related differences in alpha power for distractor inhibition during visual working memory

As working memory (WM) is limited in capacity, neural resources must be directed towards task-relevant, and away from task-irrelevant information. Alpha oscillations (8-12 Hz) have been implicated in distractor inhibition during WM retention in younger adults, but it is unclear if alpha oscillations also support distractor inhibition in older adults. We recorded electroencephalography while 24 younger (aged 18-35) and 24 older (aged 60-86) adults completed a modified delay match-to-sample task where distractors of varying strength appeared during the retention period. We found: (1) strong distractors impaired WM performance in both age groups, but only older adults were impaired by weak distractors, relative to the no distractor condition; (2) younger adults demonstrated robust increases in alpha power from baseline during retention, while older adults showed little evidence for a change from fixation; (3) both age groups showed lower alpha power when anticipating distractors compared to no-distractor trials, but younger adults more strongly modulated this response based on distractor strength; and (4) higher pre-distractor alpha power was associated with better task performance in younger adults. Our results suggest age-related differences in both WM retention strategies and anticipatory distractor processing, each of which may contribute to older adults' greater susceptibility to distraction during visual WM.