Resting-state functional connectivity abnormalities in limbic and salience networks in social anxiety disorder without comorbidity

The neurobiology of social anxiety disorder (SAD) is not yet fully understood. Structural and functional neuroimaging studies in SAD have identified abnormalities in various brain areas, particularly the amygdala and elements of the salience network. This study is the first to examine resting-state functional brain connectivity in a drug-naive sample of SAD patients without psychiatric comorbidity and healthy controls, using seed regions of interest in bilateral amygdala, in bilateral dorsal anterior cingulate cortex for the salience network, and in bilateral posterior cingulate cortex for the default mode network. Twelve drug-naive SAD patients and pair-wise matched healthy controls, all drawn from the Netherlands Study of Depression and Anxiety sample, underwent resting-state fMRI. Group differences were assessed with voxel-wise gray matter density as nuisance regressor. All results were cluster corrected for multiple comparisons (Z>2.3, p<.05). Relative to control subjects, drug-naive SAD patients demonstrated increased negative right amygdala connectivity with the left middle temporal gyrus, left supramarginal gyrus and left lateral occipital cortex. In the salience network patients showed increased positive bilateral dorsal anterior cingulate connectivity with the left precuneus and left lateral occipital cortex. Default mode network connectivity was not different between groups. These data demonstrate that drug-naive SAD patients without comorbidity show differences in functional connectivity of the amygdala, and of areas involved in self-awareness, some of which have not been implicated in SAD before. (C) 2012 Elsevier B.V. and ECNP. All rights reserved.