Current evidence suggests that older adults have reduced suppression of, and greater implicit memory for, distracting stimuli, due to age-related declines in frontal-based control mechanisms. In this study, we used fMRI to examine age differences in the neural underpinnings of attentional control and their relationship to differences in distractibility and subsequent memory for distraction. Older and younger adults were shown a rapid stream of words or nonwords superimposed on objects and performed a 1-back task on either the letters or the objects, while ignoring the other modality. Older adults were more distracted than younger adults by the overlapping words during the 1-back task, and they subsequently showed more priming for these words on an implicit memory task. A multivariate analysis of the imaging data revealed a set of regions, including the rostral PFC and inferior parietal cortex, that younger adults activated to a greater extent than older adults during the ignore-words condition, and activity in this set of regions was negatively correlated with priming for the distracting words. Functional connectivity analyses using right and left rostral PFC seeds revealed a network of putative control regions, including bilateral parietal cortex, connected to the frontal seeds at rest. Older adults showed reduced functional connectivity within this frontoparietal network, suggesting that their greater distractibility may be due to decreased activity and coherence within a cognitive control network that normally acts to reduce interference from distraction.

We recently found activity in default mode and reward-related regions during self-relevant tasks in young adults. Here we examine the effect of aging on engagement of the default network (DN) and reward network (RN) during these tasks. Previous studies have shown reduced engagement of the DN and reward areas in older adults, but the influence of age on these circuits during selfrelevant tasks has not been examined. The tasks involved judging personality traits about one's self or a well known other person. There were no age differences in reaction time on the tasks but older adults had more positive Self and Other judgments, whereas younger adults had more negative judgments. Both groups had increased DN and RN activity during the self-relevant tasks, relative to non-self tasks, but this increase was reduced in older compared to young adults. Functional connectivity of both networks during the tasks was weaker in the older relative to younger adults. Intrinsic functional connectivity, measured at rest, also was weaker in the older adults in the DN, but not in the RN. These results suggest that, in younger adults, the processing of personally relevant information involves robust activation of and functional connectivity within these two networks, in line with current models that emphasize strong links between the self and reward. The finding that older adults had more positive judgments, but weaker engagement and less consistent functional connectivity in these networks, suggests potential brain mechanisms for the "positivity bias" with aging.