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- Title
The Importance of Being Variable.
- Authors
Garrett, Douglas D.; Kovacevic, Natasa; McIntosh, Anthony R.; Grady, Cheryl L.
- Abstract
New work suggests that blood oxygen level-dependent (BOLD) signal variability can be a much more powerful index of human age than mean activation, and that older brains are actually less variable than younger brains. However, little is known of how BOLD variability and task performance may relate. In the current study, we examined BOLD variability in relation to age, and reaction time speed and consistency in healthy younger (20 -30 years) and older (56-85 years) adults on three cognitive tasks (perceptual matching, attentional cueing, and delayed match-to-sample). Results indicated that younger, faster, and more consistent performers exhibited significantly higher brain variability across tasks, and showed greater variability-based regional differentiation compared with older, poorer performing adults. Also, when we compared brain variability- and typical mean-based effects, the respective spatial patterns were essentially orthogonal across brain measures, and any regions that did overlap were largely opposite in directionality of effect. These findings help establish the functional basis of BOLD variability, and further support the statistical and spatial differentiation between BOLD variability and BOLD mean. We thus argue that the precise nature of relations between aging, cognition, and brain function is under appreciated by using mean-based brain measures exclusively.
- Subjects
REACTION time; BRAIN; COGNITIVE ability; ADULTS; OLDER people
- Publication
Journal of Neuroscience, 2011, Vol 31, Issue 12, p4496
- ISSN
0270-6474
- Publication type
Article
- DOI
10.1523/JNEUROSCI.5641-10.2011