title: Abnormal metabolic brain networks in Tourette syndrome.
abstract: OBJECTIVE
  To identify metabolic brain networks that are associated with Tourette syndrome (TS) and comorbid obsessive-compulsive disorder (OCD).
  
  
  METHODS
  We utilized [(18)F]-fluorodeoxyglucose and PET imaging to examine brain metabolism in 12 unmedicated patients with TS and 12 age-matched controls. We utilized a spatial covariance analysis to identify 2 disease-related metabolic brain networks, one associated with TS in general (distinguishing TS subjects from controls), and another correlating with OCD severity (within the TS group alone).
  
  
  RESULTS
  Analysis of the combined group of patients with TS and healthy subjects revealed an abnormal spatial covariance pattern that completely separated patients from controls (p < 0.0001). This TS-related pattern (TSRP) was characterized by reduced resting metabolic activity of the striatum and orbitofrontal cortex associated with relative increases in premotor cortex and cerebellum. Analysis of the TS cohort alone revealed the presence of a second metabolic pattern that correlated with OCD in these patients. This OCD-related pattern (OCDRP) was characterized by reduced activity of the anterior cingulate and dorsolateral prefrontal cortical regions associated with relative increases in primary motor cortex and precuneus. Subject expression of OCDRP correlated with the severity of this symptom (r = 0.79, p < 0.005).
  
  
  CONCLUSIONS
  These findings suggest that the different clinical manifestations of TS are associated with the expression of 2 distinct abnormal metabolic brain networks. These, and potentially other disease-related spatial covariance patterns, may prove useful as biomarkers for assessing responses to new therapies for TS and related comorbidities.
authors.affiliation: Center for Neurosciences, The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, NY 11030, USA. afeigin@nshs.edu
authors.forename: M
authors.initials: M
authors.lastname: Pourfar
authors.forename: A
authors.initials: A
authors.lastname: Feigin
authors.forename: C C
authors.initials: CC
authors.lastname: Tang
authors.forename: M
authors.initials: M
authors.lastname: Carbon-Correll
authors.forename: M
authors.initials: M
authors.lastname: Bussa
authors.forename: C
authors.initials: C
authors.lastname: Budman
authors.forename: V
authors.initials: V
authors.lastname: Dhawan
authors.forename: D
authors.initials: D
authors.lastname: Eidelberg
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000000981:diagnostic imaging / Q000378:metabolism*; D009771:Obsessive-Compulsive Disorder / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism*; D011877:Radionuclide Imaging; D012720:Severity of Illness Index; D005879:Tourette Syndrome / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism*