ABSTRACT
ObjectiveTo investigate the central nervous system mechanisms of active of movement switch in the patients with Tourette' s syndrome( TS),and to explore the possible underlying distinct neural networks for tic trigger and generation. Methods Participants were 14 patients with TS and 14 age- and gender-matched healthy volunteers with no history of physical,psychiatric or neurological disease: All patients were assessed with functional magnetic resonances imaging (fMRI)of the brain during the intermittent performance of finger-tapping switch tasks,Blood-oxygen-level dependent-fMRI was performed using a 3.0 Tesla MR.The area over which the activation was distributed was calculated,and the activation volumes were also compared between the patients with TS and the control subjects.ResultsThe regions activated in the patients with TS and in the volunteers were similar in several brain regions,including contralateral precentral and postcentral gyrus,contralateral mesia pre-front gyrus,contralateral cingulate gyrus,contralateral insula and ipsilataral cerebellum. There were also many different activation areas between the patients and the control subjects. The patients with TS demonstrated more significant and extended activation in the contralateral pre- and postcentral gyrus than the healthy volunteers.The volume of the left pre- and postcentral gyrus of the TS patients was (8.024 ±0.071 ) cm3,while the volume of the left pre-and postcentral gyrus of the control subjects was ( 6.480 ± 0.026) cm3 ( t =3.026,P ＜ 0.01 ) ; The volume of the right pre- and postcentral gyrus was (6.192 ± 0.019) cm3 in the TS cases,while there was (5.608 ±0.037) cm3 in the control subjects (t =2.752,P ＜0.05).There were significant differences in the volumes of bilateral pre- and postcetral gyrus between the TS and control subjects. The activations of conralateral thalamus without contralateral insula were found in the patients with TS. Conversely, the contralateral insula activation without thalamus activation could be found in the healthy volunteers.ConclusionThe thalamus might play an important role in the aetiological and physiopathologic mechanisms of the TS. The thalamus along with the parietal cortex,cingulate cortex and insular cortex appear to constitute a distinct neural network for tic trigger and generation.