Aging impairs primary task resumption and attentional control processes following interruptions

Attentional selection of working memory content is impaired after an interruption. Here we investigate the neural correlates underlying attentional selection within working memory. We focus especially on how older and younger adults differ in attentional selection processes during primary task resumption. Participants performed a working memory task, while being frequently interrupted with either a cognitively low- or high-demanding arithmetic task. Afterwards, a retrospective cue (retro-cue) indicated the working memory content required for later report. The detrimental effect of the interruption was evident in both age groups, but while younger adults were more strongly affected by a high- than by a low-demanding interruption, the performance deficit appeared independently of the cognitive requirements of the interruption task in older adults. A similar pattern was found regarding frontal-posterior connectivity in the theta frequency range, suggesting that aging decreases the ability to selectively maintain relevant information within working memory. The power of mid-frontal theta oscillations (~4-9 Hz) featured a comparable effect of interruptions in both age groups. However, posterior alpha/beta power (~8-30 Hz) following the retro-cue was more diminished by a preceding interruption in older adults. These results suggest an age-related deficit in the attentional selection and maintenance of primary task information following an interruption that appeared independent from the cognitive requirements of the interrupting task.