White Matter Integrity Supports BOLD Signal Variability and Cognitive Performance in the Aging Human Brain. Burzynska, A., Z., Wong, C., N., Voss, M., W., Cooke, G., E., Mcauley, E., & Kramer, A., F.
White Matter Integrity Supports BOLD Signal Variability and Cognitive Performance in the Aging Human Brain [pdf]Paper  abstract   bibtex   
Decline in cognitive performance in old age is linked to both suboptimal neural processing in grey matter (GM) and reduced integrity of white matter (WM), but the whole-brain structure-function-cognition associations remain poorly understood. Here we apply a novel measure of GM processing–moment-to-moment variability in the blood oxygenation level-dependent sig-nal (SD BOLD)—to study the associations between GM function during resting state, perfor-mance on four main cognitive domains (i.e., fluid intelligence, perceptual speed, episodic memory, vocabulary), and WM microstructural integrity in 91 healthy older adults (aged 60-80 years). We modeled the relations between whole-GM SD BOLD with cognitive performance using multivariate partial least squares analysis. We found that greater SD BOLD was associat-ed with better fluid abilities and memory. Most of regions showing behaviorally relevant SD BOLD (e.g., precuneus and insula) were localized to inter-or intra-network " hubs " that con-nect and integrate segregated functional domains in the brain. Our results suggest that opti-mal dynamic range of neural processing in hub regions may support cognitive operations that specifically rely on the most flexible neural processing and complex cross-talk between differ-ent brain networks. Finally, we demonstrated that older adults with greater WM integrity in all major WM tracts had also greater SD BOLD and better performance on tests of memory and fluid abilities. We conclude that SD BOLD is a promising functional neural correlate of individual differences in cognition in healthy older adults and is supported by overall WM integrity.

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