ABSTRACT
Faulty inhibition is implicated in age-related working memory decline. ERP signs of selection and inhibition of items in working memory (WM) are, respectively, a cue-locked parietal positivity (∼350 ms) and a probe-locked frontal negativity (∼520 ms). To determine when in the older age range differences in selective and inhibitory processes might occur, ERPs were recorded in a WM task from 20 young (20–28), 20 young–old (60–70), and 20 old–old (71–82) adults. A 4-digit display was followed by a cue indicating which 2 of 4 digits were relevant. Proactive interference (PI), the reaction time difference between a matching and non-matching to-be-ignored digit was larger, relative to the young, in both older groups. Compared to the young, both the cue- and probe-locked activities were prolonged in the older groups. Although there were no topographic differences among the age groups, the prolonged PI and associated ERPs suggest a relative age-related deficit in inhibition.
The present work was supported by Grant [#AG005213] from the NIA and the New York State Department of Mental Hygiene. We thank Timothy Martin, Julianna Kulik and Jenny Chen for assistance with data collection. We thank Mr Charles Brown, III for his help in the programming of the experiment. We are also grateful to all the participants who volunteered for this study.