title: Neuroimaging of tic genesis: Present status and future perspectives.
abstract: Tics are hyperkinetic movements that are distinctive by their variety in semiology and duration and by their ability to be modulated by cognitive control. They are the hallmark of Gilles de la Tourette syndrome. Despite the variety of clinical presentations in this syndrome, dysfunction of cortico-striato-pallido-thalamo-cortical networks is suggested as a core pathophysiological mechanism. We review recent structural and functional neuroimaging studies that focused on the anatomical substrate of tics and their possible genesis. These studies showed a consistent relationship between structural and functional abnormalities within motor cortico-basal ganglia circuits and occurrence of tics. The failure of top-down cortical control over motor pathways because of the atypical trajectory of brain development could be a possible mechanism of tic genesis. Occurrence of tics results in several adaptive mechanisms, including modification of cortico-striatal network activity (reduced functional activation of the primary motor cortex) and neurochemical (increased γ-aminobutyric acid concentrations in the supplementary motor area) and microstructural white matter pathways rearrangements.
authors.affiliation: Département de Neurologie, Pôle des Maladies du Système Nerveux, Hôpital de la Pitié-Salpêtrière, Paris, France.|Sorbonne Universités, UPMC Université Paris, Institut du Cerveau et de la Moelle, Paris, France.|Centre de Référence National Maladie Rare 'Syndrome Gilles de la Tourette,' Pôle des Maladies du Système Nerveux, Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.
authors.forename: Yulia
authors.initials: Y
authors.lastname: Worbe
authors.affiliation: Sorbonne Universités, UPMC Université Paris, Institut du Cerveau et de la Moelle, Paris, France.|Centre de NeuroImagerie de Recherche, CENIR, ICM, Paris, France.|Service de Neuroradiologie, Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.
authors.forename: Stephane
authors.initials: S
authors.lastname: Lehericy
authors.affiliation: Département de Neurologie, Pôle des Maladies du Système Nerveux, Hôpital de la Pitié-Salpêtrière, Paris, France.|Sorbonne Universités, UPMC Université Paris, Institut du Cerveau et de la Moelle, Paris, France.|Centre de Référence National Maladie Rare 'Syndrome Gilles de la Tourette,' Pôle des Maladies du Système Nerveux, Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.
authors.forename: Andreas
authors.initials: A
authors.lastname: Hartmann
mesh_terms: D000818:Animals; D001479:Basal Ganglia / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D009044:Motor Cortex / Q000503:physiopathology; D009434:Neural Pathways / Q000473:pathology; D059906:Neuroimaging / Q000379:methods* / Q000639:trends*; D020323:Tics / Q000209:etiology* / Q000473:pathology*
keywords: magnetic resonance imaging; premonitory urges; tics