Investigations of the Pathophysiology of Gilles de la Tourette Syndrome. Part 2: 7T MRI

Gilles de la Tourette syndrome (GTS; also known as Tourette syndrome) is a congenital neuropsychiatric disorder. Characteristic symptoms are so-called tics-rapid, repetitive movements (motor tics) or vocalizations (vocal tics) that start suddenly without any apparent purpose. Previous research supports the hypothesis of defective regulation (dysregulation) of the dopaminergic system, with particular discussion of dysfunction of tonic/phasic dopamine release or dopaminergic hyperinnervation. Moreover, given the complex interaction of different neurotransmitters, especially in the basal ganglia, it can be assumed that abnormal dopaminergic transmission also affects other transmitter systems, such as glutamate (Glu) or γ-aminobutyrate (GABA). Furthermore, recent results suggest an abnormality in cerebral iron metabolism in GTS. Since iron is accumulated in dopamine vesicles and plays a central role in dopamine synthesis, this observation may also be related to dysfunction of the dopaminergic system. Therefore, in this multimodal study, the investigators aim to combine positron emission tomography (PET), magnetic resonance imaging (MRI), and magnetic resonance spectroscopy (MRS) methods comparing patients with GTS and a control cohort. In Part 2 of this study, MRI and MRS at 7 Tesla are employed to investigate (i) the concentrations of Glu, glutamine and GABA in the corpus striatum and the cortex cingularis anterior and (ii) the subcortical iron concentration.