Effective connectivity in cortical and subcortical visual fear processing networks during fearful face viewing in body dysmorphic disorder.

Individuals with body dysmorphic disorder (BDD) demonstrate emotional processing biases; however, it is unclear whether differences are related to visual fear procesing network dysfunction. Understanding neural connectivity patterns during visual processing of threatening stimuli could provide insights into mechanisms that maintain BDD symptoms. Participants with BDD (n=32) and healthy controls (n=37) completed a fearful face processing task during fMRI. Using dynamic causal modeling, we compared effective connectivity between groups in connections among regions implicated in fearful face processing: the bilateral pulvinar, amygdala, fusiform face area and the medial orbitofrontal cortex (mOFC). We found through Bayesian model selection that both BDD and control groups were fit by the same connectivity model, with driving input of fearful faces to the pulvinar and amygdala and bidirectional connections between each region. Using parametric empirical bayes to test for group differences, we found strong evidence for higher connectivity from the left amygdala to the left mOFC and within the left FFA as well as reduced connectivity from the right amygdala to the right pulvinar in individuals with BDD. However, we did not observe strong evidence for associations with body dysmorphic symptoms. BDD may be characterized by aberrations in the fearful face viewing network. Future studies could address whether these effects are specific to BDD or may also characterize other disorders with emotional face processing dysfunction.