TY  - JOUR
TI  - Cholinergic modulation of visual working memory during aging: a parametric PET study
ID  - eprints2960
AV  - none
KW  - Visual cortex
IS  - 5
UR  - http://www.sciencedirect.com/science/article/pii/S0361923009000604
PB  - Elsevier
VL  - 79
EP  -  332
A1  - Ricciardi, Emiliano
A1  - Pietrini, Pietro
A1  - Schapiro, Mark B.
A1  - Rapoport, Stanley I.
A1  - Furey, Maura L.
SP  - 322 
JF  - Brain Research Bulletin
N2  - Age-related differences in the regional recruitment of prefrontal cortex (PFC) during cognitive tasks suggests that aging is associated with functional reorganization. Cholinergic enhancement with physostigmine reduces activity in the {PFC} regions selectively recruited during working memory (WM) and increases activity in visual processing areas, suggesting that augmenting cholinergic function reduces task effort by improving the visual representation of {WM} stimuli. Here, we investigated how cholinergic enhancement influenced {PFC} and visual cortical activity in young and older subjects as {WM} difficulty was altered. Regional cerebral blood flow (rCBF) was measured using H215O-PET in 10 young and 10 older volunteers during a parametrically varied face {WM} task, following an i.v. infusion of saline and physostigmine. Reaction time decreased during physostigmine relative to placebo in both groups. Prefrontal brain regions selectively recruited in each age group that responded differentially to task demands during placebo, had no significant activity during physostigmine. Medial visual processing areas showed task-selective increases in activity during drug in both groups, while lateral regions showed decreased activity in young and increased activity in older participants at longer task delays. These results are consistent with our previous findings, showing that the modulatory role of the cholinergic system persists during aging, and that the effects of cholinergic enhancement are functionally specific rather than anatomically specific. Moreover, the use of the parametric design allowed us to uncover group specific effects in lateral visual processing areas where increasing cholinergic function produced opposite effects on neural activity in the two age groups.
SN  - 0361-9230
Y1  - 2009/06/30/
ER  -