Interindividual differences in cognitive flexibility: Influence of gray-matter volume, functional connectivity and trait impulsivity

Introduction: Cognitive flexibility, a core aspect of executive functioning, is required for the speeded shifting between different tasks and sets. Using an interindividual-differences approach, we examined whether cognitive flexibility is associated with gray matter volume (GMV) and functional connectivity (FC) of regions in a core executive-control network as well as with different facets of trait impulsivity. Methods: The core executive network was derived from three large-scale meta-analyses and only included regions that showed consistent associations with sustained attention, working memory as well as inhibitory control. We tested to what extent self-reported impulsivity as well as GMV and resting-state FC in the executive network predicted performance in the Delis-Kaplan card-sorting test independently and incrementally. Results: Our analyses revealed that card-sorting performance positively correlated with GMV of the right anterior insula, FC between left anterior insula and midcingulate cortex/supplementary motor area as well as the impulsivity dimension “Premeditation”. Importantly, GMV, FC and impulsivity together accounted for more variance of card-sorting performance than every parameter alone. Conclusions: Our results therefore indicate that various factors contribute individually to cognitive flexibility, underlining the need to search across multiple modalities when aiming to unveil the mechanisms behind executive functioning.