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.

Frontoparietal Structural Connectivity in Childhood Predicts Development of Functional Connectivity and Reasoning Ability: A Large-Scale Longitudinal Investigation

“…Although we and others have demonstrated the development of a concurrent relationship between frontoparietal FC and reasoning (Bazargani et al, 2014;Wendelken et al, 2016), we did not observe here any lead-lag developmental relationship between these two measures. Specifically, whereas RLPFC-IPL FC was associated with reasoning ability in adolescents and adults, the level of RLPFC-IPL FC did not predict future changes in reasoning ability.…”

“…This marked increase in frontoparietal FC in late childhood is consistent with reports from prior investigations (Smit et al, 2012;Barber et al, 2013;Ernst et al, 2015).…”

“…This demonstration of frontoparietal white matter development extended across a relatively broad age range is consistent with prior reports (Asato et al, 2010;Lebel et al, 2012). Notably, development of SC appears to both precede and follow the period of greatest change in FC.…”

“…In addition to the frontoparietal network, the cingulo-opercular network, which is most frequently linked to cognitive control, has also been implicated in reasoning (Cocchi et al, 2014). Future investigations should assess whether cingulo-opercular and/or other connections also contribute to reasoning development.…”

“…In particular, prior research has emphasized the importance of FC among components of the lateral frontoparietal network (LFPN), which supports reasoning and other higher cognitive functions (Jung and Haier, 2007;Shokri-Kojiri et al, 2012;Cocchi et al, 2014). Prior studies have also examined links between SC and reasoning, reporting associations between reasoning and multiple white matter tracts (Tamnes et al, 2010;Peters et al, 2014) or between reasoning and global white matter during childhood (Ferrer et al, 2013).…”