Brain activation in paediatric obsessive compulsive disorder during tasks of inhibitory control.

BACKGROUND Obsessive-compulsive disorder (OCD) may be related to a dysfunction in frontostriatal pathways mediating inhibitory control. However, no functional magnetic resonance imaging (fMRI) study has tested this in children. AIMS To test whether adolescents with OCD in partial remission would show abnormal frontostriatal brain activation during tasks of inhibition. METHOD Event-related fMRI was used to compare brain activation in 10 adolescent boys with OCD with that of 9 matched controls during three different tasks of inhibitory control. RESULTS During a 'stop' task, participants with OCD showed reduced activation in right orbitofrontal cortex, thalamus and basal ganglia; inhibition failure elicited mesial frontal underactivation. Task switching and interference inhibition were associated with attenuated activation in frontal, temporoparietal and cerebellar regions. CONCLUSIONS These preliminary findings support the hypothesis that paediatric OCD is characterised by a dysregulation of frontostriatothalamic brain regions necessary for motor inhibition, and also demonstrate dysfunction of temporoparietal and frontocerebellar attention networks during more cognitive forms of inhibition.