Dynamic range in BOLD modulation: Lifespan aging trajectories and association with performance

Publication date: Available online 5 September 2017
Source:Neurobiology of Aging
Author(s): Kristen M. Kennedy, Maria A. Boylan, Jenny R. Rieck, Chris M. Foster, Karen M. Rodrigue
Alteration of dynamic range of modulation to cognitive difficulty has been proposed as a salient predictor of cognitive aging. Here we examine in 171 adults (aged 20-94 years) the effects of age on dynamic modulation of BOLD activation to difficulty in parametrically increasing working memory load (0-,2-,3-,4-back conditions). First, we examined parametric increases and decreases in activation to increasing WM load (positive modulation effect and negative modulation effect). Second, we examined the effect of age on modulation to difficulty (WM load) to identify regions that differed with age as difficulty increased (age-related positive and negative modulation effects). Weakened modulation to difficulty with age was found in both the positive-modulation (middle frontal, superior/inferior parietal) and negative-modulation effect (deactivated) regions (insula, cingulate, medial superior frontal, fusiform, and parahippocampal gyri, hippocampus, and lateral occipital cortex). Age-related alterations to positive modulation emerged later in the lifespan than negative modulation. Further, these effects were significantly coupled in that greater up-modulation was associated with lesser down-modulation. Importantly, greater frontal-parietal up-modulation to difficulty and greater down-modulation of deactivated regions was associated with better task accuracy and up-modulation with better working memory span measured outside the scanner. These findings suggest that greater dynamic range of modulation of activation to cognitive challenge is in service of current task performance, as well as generalizing to cognitive ability beyond the scanner task, lending support to its utility as a marker of successful cognitive aging.



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