People with Tourette’s syndrome may be hyper-responsive to social cues such as emotional facial expressions, new research suggests.
Tics in people with Tourette’s syndrome are exacerbated by stress and can be triggered by external stimuli, so a team from Brighton and Sussex Medical School, UK, looked at the effect of facial expressions of others.
They predicted that angry facial stimuli may be the most potent social threat cue, even triggering reactions in healthy individuals. The team recruited 21 people with Tourette’s syndrome and 21 without, and gave them functional MRI scans at the same time as looking at pictures of faces with either neutral or angry expressions.
Both groups showed enhanced brain activation in areas known to be linked to face perception, but those with Tourette’s syndrome group showed additional responses in an area called the anterior insula. The responses were seen to images of both neutral and angry faces.
Greater brain functional connectivity was also seen in the Tourette’s syndrome group during face viewing. Specifically, connectivity in the presupplementary motor area, premotor cortex, primary motor cortex, and the putamen. These areas have all be linked to tics, and were not activated in people without Tourette’s syndrome.
In the journal Brain this month the authors write: "Medicinal and psychological therapies that focus on reducing insular hyper-reactivity to social stimuli may have potential benefit for tic reduction in people with Tourette’s syndrome."
Researcher Dr Charlotte Rae said: "People with Tourette’s syndrome often report that their tics get worse in stressful social situations where they are under public scrutiny. Now for the first time, functional MRI scanning has shown how this is probably occurring."
Rae, C. L. et al. Face perception enhances insula and motor network reactivity in Tourette syndrome. Brain 1 November 2018; doi: 10.1093/brain/awy254
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