| |
Abstract:
Using PET, we compared the neural correlates of item and
temporal-order memory in young and older adults. Subjects studied a
word list, and were then scanned while retrieving information about
what words were in the list or when they occurred within the list.
A partial-least-squares analysis revealed 3 significant patterns of
blood flow changes. (1) Regions where older adults showed smaller
blood flow differences between item and temporal-order retrieval
conditions than young adults: temporal and basal forebrain regions
during item retrieval; frontal, cuneus/precuneus, and parietal
regions during temporal-order retrieval. (2) Regions where older
adults showed larger item/temporal-order differences than young
adults: a posterior parietal area during temporal-order retrieval;
precuneus and right precentral areas during item retrieval. (3)
Regions where older adults, but not younger adults, showed more
activation in a high- than in a low-performance item retrieval
condition: cerebellar, right posterior temporal, and left
prefrontal regions. The results suggest altered item and
temporal-order retrieval networks in elderly adults, as well as the
existence of compensatory mechanisms in the aging brain.
|
