title: Aberrant anterior cingulate activation in obsessive-compulsive disorder is related to task complexity.
abstract: OBJECTIVE
  Evidence for working memory (WM) deficits in obsessive-compulsive disorder (OCD) is increasing. However, findings regarding the underlying neural substrates are heterogeneous. Moreover, the influence of cognitive demand on the severity of these deficits and associated activation alterations is a matter of debate.
  
  
  METHODS
  To further address this question the present fMRI study examined a sample of 21 predominantly medication-free inpatients with OCD and 21 matched healthy volunteers using a parametric verbal n-back task.
  
  
  RESULTS
  In agreement with earlier studies patients exhibited focused activation alterations that could be found to be critically dependent on WM demands: There were no differences in activation between patients and healthy volunteers under low cognitive demands. However, patients exhibited a significantly decreased activation in the dorsal anterior cingulate cortex (dACC) in association with increasing task demands. While dACC activation in controls showed a linear increase with increasing task demands, this linearity was not detectable in patients with OCD.
  
  
  CONCLUSIONS
  Present findings provide further support for the relevance of the anterior cingulate in OCD and illustrate that both task demands and task processes are of major influence in this context.
authors.affiliation: Department of Psychiatry and Psychotherapy, University Hospital Jena, Philosophenweg 3, 07740 Jena, Germany. kathrin.koch@med.uni-jena.de
authors.forename: Kathrin
authors.initials: K
authors.lastname: Koch
authors.forename: Gerd
authors.initials: G
authors.lastname: Wagner
authors.forename: Claudia
authors.initials: C
authors.lastname: Schachtzabel
authors.forename: Gregor
authors.initials: G
authors.lastname: Peikert
authors.forename: C Christoph
authors.initials: CC
authors.lastname: Schultz
authors.forename: Heinrich
authors.initials: H
authors.lastname: Sauer
authors.forename: Ralf G
authors.initials: RG
authors.lastname: Schlösser
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D005260:Female; D006179:Gyrus Cinguli / Q000098:blood supply* / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D009771:Obsessive-Compulsive Disorder / Q000473:pathology*; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology; D055815:Young Adult
chemical_list: D010100:Oxygen