Abnormal Corticostriatal Pathway in Patients With Tourette Syndrome

Introduction: Tourette syndrome (TS) is complex neuropsychiatric childhood disorder characterized by involuntary non rhythmic movement and vocal symptoms called tic that are quite often associated with co-morbid neuropsychiatric comorbidities such as OCD, ADHD (REF). These tics and follow a waxing and waning pattern of severity and usually peak during the early second decade of life with many subjects (80%) showing a marked reduction of severity by the end of adolescence. Many evidences form postmortem and neuroimaging studies have implicated the involvement of fronto-striato-thalamic-cortical (FSTC) circuitry in the involvement of tic generation [1,2]. Tract Based Spatial Statistics (TBSS) is a well designed technique for the study of cerebral white matter (WM) which makes use of the intrinsic anisotropic property of the WM and projects the fractional anisotropy values of the WM tracts onto a virtual skeleton which runs at the median part of a WM tract [3]. In this present study we used TBSS to identify abnormalities in minor WM tract changes in children with TS (17 right handed, age = 11.6± 2.4 years, 14 males) and compared them to healthy controls (mean age: 12.3±3.2 years, 6 males). Methods: Neurobehavioral measures for hyperactivity, attention, externalizing, internalizing, and obsessive and compulsive problems were also measured in TS children and for 15 of them the tic severity score or the period of one week prior to the MRI scan was noted according to the