with Tourette syndrome. To investigate whether thinning in sensorimotor cortices is important in this disorder, Sowell et al. examined 25 chil dren with Tourette syndrome (aged 7–18 years) and 35 agematched and sexmatched controls. All participants underwent high resolution T1weighted MRI and tests of tic symptom severity. Children in the Tourette group had consider ably thinner cortices than the control group in the ventral frontal (P = 0.0039 for left; P = 0.0082 for right) and the parietooccupital regions of the brain. The thinning was most prominent over the inferior portions of the primary motor and sensory cortices, which control muscles of the face, month and larynx. Tic severity corre lated with degree of thinning in left and right dorsal sensorimotor cortices—which control muscles of the trunk and extremities—rather than in ventral regions, where the differences in cortical thickness between groups were greatest. Thinning in ventral portions of the sensorimotor cortex in the Tourette group did correlate, however, with number of facial tics. The authors conclude that thinning in the sensorimotor regions of corticostriato thalamocortical circuits in children with Tourette syndrome correlates with tic symptoms. Longitudinal studies are needed to deter mine whether current therapies have long term effects on the structure and function of these circuits.