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Abstract:
In order to examine whether aging affects neuronal network
activation during priming, we recorded fMRI measures of neural
activation in young and elderly adults during performance of a
visual repetition priming task. Subjects viewed a series of color
images (duration 2 s) and pressed a button when they saw the color
red. Images (high pleasantness - low/moderate arousal) were
selected from of a quantified set of photographs. A series of 16
photographs were presented, then repeated in a different order.
Baseline images, unrecognizable color patterns with the same
luminance and hue ranges as the photographs, were also presented,
but were not repeated. Subjects had no history of CNS disease or
damage, and there were no group differences education or
neuropsychological test performance. Whole head blood oxygenation
level-dependent (BOLD) data was obtained using a neuro-optimized
imaging sequence in approximately 20 parallel 5-mm thick slices
(3.75 mm in-plane resolution, no interslice gap). Both young and
elderly subjects showed reaction time priming (RT in s: Young, new
993.5 ± 108, repeated 896.1 ± 121, t=7 p<0.001;
Elderly, new 1013.2 ± 120, repeated 940.6 ± 104, t=6
p<0.01). Both young and elderly subjects showed increased BOLD
activation in inferior temporo-occipital cortex to new vs repeated
images, although elderly subjects showed reductions in percent
voxel activation which approached significance (Young 8.1 ±
6.3, Elderly 0.7 ± 0.4, t(4.04)=2.60 p=0.059, Satterthwaite
correction for unequal variances).
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