Evidence for a cerebral cortical thickness network anti-correlated with amygdalar volume in healthy youths: implications for the neural substrates of emotion regulation

Abstract

Recent functional connectivity studies have demonstrated that, in resting humans, activity in a dorsally-situated neocortical network is inversely associated with activity in the amygdalae. Similarly, in human neuroimaging studies, aspects of emotion regulation have been associated with increased activity in dorsolateral, dorsomedial, orbital and ventromedial prefrontal regions, as well as concomitant decreases in amygdalar activity. These findings indicate the presence of two countervailing systems in the human brain that are reciprocally related: a dorsally-situated cognitive control network, and a ventrally-situated limbic network. We investigated the extent to which this functional reciprocity between limbic and dorsal neocortical regions is recapitulated from a purely structural standpoint. Specifically, we hypothesized that amygdalar volume would be related to cerebral cortical thickness in cortical regions implicated in aspects of emotion regulation. In 297 typically developing youths (162 females, 135 males; 572 MRIs), the relationship between cortical thickness and amygdalar volume was characterized. Amygdalar volume was found to be inversely associated with thickness in bilateral dorsolateral and dorsomedial prefrontal, inferior parietal, as well as bilateral orbital and ventromedial prefrontal cortices. Our findings are in line with previous work demonstrating that a predominantly dorsally-centered neocortical network is reciprocally related to core limbic structures such as the amygdalae. Future research may benefit from investigating the extent to which such cortical-limbic morphometric relations are qualified by the presence of mood and anxiety psychopathology.

Figure 1

Brain areas where local cortical thickness is associated with total amygdala volume (n=297; 572 MRIs). Colors correspond to t-statistic values, with cold shades depicting negative associations and warm shades representing positive associations. Controlled for age, gender, total brain volume, and scanner.

Figure 2

Brain areas where local cortical thickness is negatively associated with total amygdala volume (n=297; 572 MRIs). The figure is shown at q ≤ 0.05 with a false discovery rate correction. Controlled for age, gender, total brain volume, and scanner.

Figure 3

Comparison of cortical thickness-amygdalar volume relation (A.) and fMRI study of cognitive emotion regulation (B.) (from Kanske et al., 2011). In column B., blue shades correspond to activation during cognitive reappraisal, whereas red shades correspond to activation during attentional distraction. Column A. is displayed at q ≤ 0.05 with a false discovery rate correction (FDR), and column B. is shown at whole-brain FDR-corrected p ≤ 0.01 with an extent threshold of 20 voxels.