Corticolimbic functional connectivity in adolescents with bipolar disorder

Abstract

Convergent evidence supports regional dysfunction within a corticolimbic neural system that subserves emotional processing and regulation in adolescents and adults with bipolar disorder (BD), with abnormalities prominent within the amygdala and its major anterior paralimbic cortical connection sites including ventral anterior cingulate, orbitofrontal, insular and temporopolar cortices. Recent studies of adults with BD demonstrate abnormalities in the functional connectivity between the amygdala and anterior paralimbic regions suggesting an important role for the connections between these regions in the development of the disorder. This study tests the hypothesis that these functional connectivity abnormalities are present in adolescents with BD. Fifty-seven adolescents, twenty-one with BD and thirty-six healthy comparison (HC) adolescents, participated in functional magnetic resonance imaging while processing emotional face stimuli. The BD and HC groups were compared in the strength of functional connectivity from amygdala to the anterior paralimbic cortical regions, and explored in remaining brain regions. Functional connectivity was decreased in the BD group, compared to the HC group, during processing of emotional faces in ventral anterior cingulate (VACC), orbitofrontal, insular and temporopolar cortices (p<0.005). Orbitofrontal and VACC findings for the happy condition, and additionally right insula for the neutral condition, survived multiple comparison correction. Exploratory analyses did not reveal additional regions of group differences. This study provides evidence for decreased functional connectivity between the amygdala and anterior paralimbic cortices in adolescents with BD. This suggests that amygdala-anterior paralimbic connectivity abnormalities are early features of BD that emerge at least by adolescence in the disorder.

Figure 1. The axial-oblique images display regions where functional connectivity was significantly decreased (p<0.005, cluster>20) in 21 adolescents with bipolar disorder, compared to 36 healthy comparison participants during fearful (a), happy (b) and neutral (c) faces processing.

The color bar represents the range of T values. Montreal Neurological Institute z-plane coordinates (millimeters) are presented. R = right.