Tourette’s syndrome (SGT) like many neurological diseases has a genetic component. Although not inherited, there is a genetic predisposition that increases the risk of developing the disease for a patient’s relatives.
Biological mechanisms of Tourette’s syndrome
The precise mechanisms underlying the symptoms of Tourette’s syndrome are still poorly understood. However, the cerebral networks connecting the cerebral cortex to deep structures, known as basal ganglia, play a key role in the genesis of tics and other related symptoms.
Recently, a histological analysis conducted by the Yale University team suggested that the observed abnormalities may reflect a disturbed migration of GABAergic interneurons in the striatum, a key structure of the basal ganglia. The striatum plays a central role by relaying cortical information and allowing the selection of the action most suited to a given situation. GABAergic interneurons, absent or dysfunctional in this region, are essential for the synaptic integration of cortical information, thus conditioning the precision of the interactions between sensation and action.
A study conducted at the Brain Institute by Professor Yulia Worbe and her collaborators in the MOV’IT team used an advanced computer analysis method to explore resting brain connectivity in people with Tourette’s syndrome. The results revealed significant differences in brain networks, including the striatum, cerebellum, and insular cortex, that distinguish patients from those without the disease. The analysis also showed that patients under treatment have different brain connections than untreated patients, particularly between the caudate nucleus (part of the striatum) and the insular cortex. This work highlights the key role of brain networks in this syndrome and paves the way for the use of brain imaging to improve diagnosis and more accurately assess treatment effectiveness.
At Paris Brain Institute
- Team « Mov’It : Movement, Investigations, Therapeutics. Experimental pathophysiology and Therapeutics" directed by Profs. VIDAILHET and Prof. LEHERICY.
Work in patients with sudden manifestations of verbal or physical aggression has shown by functional MRI a decrease in connections within the orbito-frontal cortex and a dysfunction in connectivity between the orbito-frontal cortex, amygdala and hippocampus. This study concludes that these explosive "crises" result from ineffective control of actions and dysfunction of emotional regulation and impulsivity.
• In a study published in the journal Brain, Yulia Worbe and her collaborators (Team "Mov’It: Mouvement, Investigations, Therapeutics. Experimental pathophysiology and Therapeutics" led by Professor VIDAILHET and Professor LEHERICY) have shown that patients with Tourette’s syndrome develop more habitual behaviours than healthy subjects of the same age.
These results shed new light on the mechanisms underlying the formation and persistence of tics, which could be partly learned actions becoming automatic, and persisting in the same way as bad habits. Alterations in certain neural networks involved in the genesis of habits may explain the exacerbation of these behaviours in patients.
For more information: https://institutducerveau-icm.org/
