Empathy and aversion: the neural signature of mentalizing in Tourette syndrome

Previous studies suggest that adults with Tourette syndrome (TS) can respond unconventionally on tasks involving social cognition. We therefore hypothesized that these patients would exhibit different neural responses to healthy controls in response to emotionally salient expressions of human eyes. Twenty-five adults with TS and 25 matched healthy controls were scanned using fMRI during the standard version of the Reading the Mind in the Eyes Task which requires mental state judgements, and a novel comparison version requiring judgements about age. During prompted mental state recognition, greater activity was apparent in TS within left orbitofrontal cortex, posterior cingulate, right amygdala and right temporo-parietal junction (TPJ), while reduced activity was apparent in regions including left inferior parietal cortex. Age judgement elicited greater activity in TS within precuneus, medial prefrontal and temporal regions involved in mentalizing. The interaction between group and task revealed differential activity in areas including right inferior frontal gyrus. Task-related activity in the TPJ covaried with global ratings of the urge to tic. While recognizing mental states, adults with TS exhibit greater activity than controls in brain areas involved in the processing of negative emotion, in addition to reduced activity in regions associated with the attribution of agency. In addition, increased recruitment of areas involved in mental state reasoning is apparent in these patients when mentalizing is not a task requirement. Our findings highlight differential neural reactivity in response to emotive social cues in TS, which may interact with tic expression.