title: Complexity in relational processing predicts changes in functional brain network dynamics.
abstract: The ability to link variables is critical to many high-order cognitive functions, including reasoning. It has been proposed that limits in relating variables depend critically on relational complexity, defined formally as the number of variables to be related in solving a problem. In humans, the prefrontal cortex is known to be important for reasoning, but recent studies have suggested that such processes are likely to involve widespread functional brain networks. To test this hypothesis, we used functional magnetic resonance imaging and a classic measure of deductive reasoning to examine changes in brain networks as a function of relational complexity. As expected, behavioral performance declined as the number of variables to be related increased. Likewise, increments in relational complexity were associated with proportional enhancements in brain activity and task-based connectivity within and between 2 cognitive control networks: A cingulo-opercular network for maintaining task set, and a fronto-parietal network for implementing trial-by-trial control. Changes in effective connectivity as a function of increased relational complexity suggested a key role for the left dorsolateral prefrontal cortex in integrating and implementing task set in a trial-by-trial manner. Our findings show that limits in relational processing are manifested in the brain as complexity-dependent modulations of large-scale networks.
authors.affiliation: Queensland Brain Institute and.
authors.forename: Luca
authors.initials: L
authors.lastname: Cocchi
authors.affiliation: School of Psychology, The University of Queensland, Brisbane 4067, Australia, Behavioural Basis of Health, Griffith Health Institute and School of Applied Psychology, Griffith University, Brisbane 4122, Australia and.
authors.forename: Graeme S
authors.initials: GS
authors.lastname: Halford
authors.affiliation: Melbourne Neuropsychiatry Centre, The University of Melbourne, Melbourne 3053, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Zalesky
authors.affiliation: Melbourne Neuropsychiatry Centre, The University of Melbourne, Melbourne 3053, Australia.
authors.forename: Ian H
authors.initials: IH
authors.lastname: Harding
authors.affiliation: Behavioural Basis of Health, Griffith Health Institute and School of Applied Psychology, Griffith University, Brisbane 4122, Australia and.
authors.forename: Brentyn J
authors.initials: BJ
authors.lastname: Ramm
authors.affiliation: Behavioural Basis of Health, Griffith Health Institute and School of Applied Psychology, Griffith University, Brisbane 4122, Australia and.
authors.forename: Tim
authors.initials: T
authors.lastname: Cutmore
authors.affiliation: Behavioural Basis of Health, Griffith Health Institute and School of Applied Psychology, Griffith University, Brisbane 4122, Australia and.
authors.forename: David H K
authors.initials: DH
authors.lastname: Shum
authors.affiliation: Queensland Brain Institute and School of Psychology, The University of Queensland, Brisbane 4067, Australia.
authors.forename: Jason B
authors.initials: JB
authors.lastname: Mattingley
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000502:physiology; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D013850:Thinking / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology; D055815:Young Adult
keywords: cognitive control; connectivity; fMRI; prefrontal cortex; reasoning