Neuroanatomical and functional correlates in tic disorders and Tourette's syndrome: A narrative review

Tic disorders represent a developmental neuropsychiatric condition whose causes can be attributed to a variety of environmental, neurobiological, and genetic factors. From a neurophysiological perspective, the disorder has classically been associated with neurochemical imbalances (particularly dopamine and serotonin) and structural and functional alterations affecting, in particular, brain areas and circuits involved in the processing and coordination of movements: the basal ganglia, thalamus, motor cortical area, and cingulate cortex; however, more recent research is demonstrating the involvement of many more brain regions and neurotransmission systems than previously observed, such as the prefrontal cortex and cerebellum. In this paper, therefore, we summarize the evidence to date on these abnormalities with the intent to illustrate and clarify the main neuroanatomical differences between patients with tic disorders and healthy individuals.