title: Divergent subcortical activity for distinct executive functions: stopping and shifting in obsessive compulsive disorder.
abstract: BACKGROUND
  There is evidence of executive function impairment in obsessive compulsive disorder (OCD) that potentially contributes to symptom development and maintenance. Nevertheless, the precise nature of these executive impairments and their neural basis remains to be defined.
  
  
  METHODS
  We compared stopping and shifting, two key executive functions previously implicated in OCD, in the same task using functional magnetic resonance imaging, in patients with virtually no co-morbidities and age-, verbal IQ- and gender-matched healthy volunteers. The combined task allowed direct comparison of neural activity in stopping and shifting independent of patient sample characteristics and state variables such as arousal, learning, or current symptom expression.
  
  
  RESULTS
  Both OCD patients and controls exhibited right inferior frontal cortex activation during stopping, and left inferior parietal cortex activation during shifting. However, widespread under-activation across frontal-parietal areas was found in OCD patients compared to controls for shifting but not stopping. Conservative, whole-brain analyses also indicated marked divergent abnormal activation in OCD in the caudate and thalamus for these two cognitive functions, with stopping-related over-activation contrasting with shift-related under-activation.
  
  
  CONCLUSIONS
  OCD is associated with selective components of executive function, which engage similar common elements of cortico-striatal regions in different abnormal ways. The results implicate altered neural activation of subcortical origin in executive function abnormalities in OCD that are dependent on the precise cognitive and contextual requirements, informing current theories of symptom expression.
authors.affiliation: Behavioural and Clinical Neuroscience Institute,University of Cambridge,Cambridge,UK.
authors.forename: S
authors.initials: S
authors.lastname: Morein-Zamir
authors.affiliation: Behavioural and Clinical Neuroscience Institute,University of Cambridge,Cambridge,UK.
authors.forename: V
authors.initials: V
authors.lastname: Voon
authors.affiliation: Department of Psychology,University of Exeter,UK.
authors.forename: C M
authors.initials: CM
authors.lastname: Dodds
authors.affiliation: Behavioural and Clinical Neuroscience Institute,University of Cambridge,Cambridge,UK.
authors.forename: A
authors.initials: A
authors.lastname: Sule
authors.affiliation: Department of Psychiatry,University of Cambridge,Cambridge,UK.
authors.forename: J
authors.initials: J
authors.lastname: van Niekerk
authors.affiliation: Behavioural and Clinical Neuroscience Institute,University of Cambridge,Cambridge,UK.
authors.forename: B J
authors.initials: BJ
authors.lastname: Sahakian
authors.affiliation: Behavioural and Clinical Neuroscience Institute,University of Cambridge,Cambridge,UK.
authors.forename: T W
authors.initials: TW
authors.lastname: Robbins
mesh_terms: D000328:Adult; D001143:Arousal / Q000502:physiology; D001921:Brain / Q000503:physiopathology*; D016022:Case-Control Studies; D002421:Caudate Nucleus / Q000503:physiopathology; D003071:Cognition / Q000502:physiology; D056344:Executive Function / Q000502:physiology*; D005625:Frontal Lobe / Q000503:physiopathology; D059907:Functional Neuroimaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D017072:Neostriatum / Q000503:physiopathology; D009771:Obsessive-Compulsive Disorder / Q000503:physiopathology*; D010296:Parietal Lobe / Q000503:physiopathology; D013647:Task Performance and Analysis; D013788:Thalamus / Q000503:physiopathology
keywords: Cognitive flexibility; OCD; functional magnetic resonance imaging (fMRI); response inhibition; shifting; stopping