Enhanced top-down sensorimotor processing in somatic anxiety

Functional neuroimaging research on anxiety has traditionally focused on brain networks associated with the psychological aspects of anxiety. Here, instead, we target the somatic aspects of anxiety. Motivated by the growing appreciation that top-down cortical processing plays a crucial role in perception and action, we used resting-state functional MRI data from the Human Connectome Project and Dynamic Causal Modeling (DCM) to characterize effective connectivity among hierarchically organized regions in the exteroceptive, interoceptive, and motor cortices. In people with high (fear-related) somatic arousal, top-down effective connectivity was enhanced in all three networks: an observation that corroborates well with the phenomenology of anxiety. The anxiety-associated changes in connectivity were sufficiently reliable to predict whether a new participant has mild or severe somatic anxiety. Interestingly, the increase in top-down connections to sensorimotor cortex were not associated with fear affect scores, thus establishing the (relative) dissociation between somatic and cognitive dimensions of anxiety. Overall, enhanced top-down effective connectivity in sensorimotor cortices emerges as a promising and quantifiable candidate marker of trait somatic anxiety.

Automated summary

This study focuses on the somatic aspects of anxiety and explores the effective connectivity among different brain regions using functional MRI data and dynamic causal modeling. It finds that in people with high somatic arousal, top-down connectivity is enhanced in three networks, which is consistent with the psychology of anxiety. The changes in connectivity are reliable enough to predict the severity of somatic anxiety in new participants. Interestingly, the increase in connectivity is not associated with fear affect scores, indicating a relative dissociation between somatic and cognitive dimensions of anxiety.