Pathophysiology of Tourette's syndrome: striatal pathways revisited.

Stereotypic behaviors and thoughts are manifested in a range of neuropsychiatric disorders including Tourette's syndrome. To understand and to treat these pathologic stereotypies it is important to establish the molecular, pharmacological and systems-level alterations in brain circuits that accompany such behaviors. We review here experiments performed in rodents and primates that focus on neural concomitants of stereotypies induced by dopaminergic treatments. These studies emphasize the functional importance of the compartmental organization of the striatum and raise the possibility that differential activation of striosomes is related to the severity of the expressed stereotypies and sensitized responses.