Enhanced functional connectivity between sensorimotor and visual cortex predicts covariation bias in spider phobia.

The overestimation of the relationship between fear-relevant stimuli and aversive consequences, a so called covariation bias, might contribute to the maintenance of anxiety disorders. In a recent fMRI study, we confronted spider phobia and healthy participants with pictures of spiders, mushrooms and puppies, randomly followed by painful electric stimuli (US). Spider phobics overestimated the spider-US association and displayed enhanced activity in US-related sensorimotor cortex (paracentral lobule, PCL). Here, we report results from an additional functional connectivity analysis. Within spider phobics but not in healthy controls, USs after spiders led to enhanced connectivity between PCL and left prefrontal cortex (PFC). Most importantly, covariation bias in spider phobia was predicted by connectivity between PCL and visual cortex, insula, primary sensorimotor cortex and secondary somatosensory cortex. Reduced covariation bias was predicted by connectivity between PCL and PFC. In response to spider pictures, the amygdala was functionally connected to somatosensory and visual areas. These results suggest that synchronous activity of sensory cortices may promote fear-sustaining associative memory bias, while right PFC might help to reduce bias.