Article

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.
CI - Copyright (c) 2012 Elsevier Ltd. All rights reserved.

Langue : ANGLAIS