The role of the dorsal anterior cingulate cortex in obsessive-compulsive disorder

Despite extensive research efforts, the pathophysiology of obsessive-compulsive disorder (OCD) is still largely unknown. The dorsal anterior cingulate cortex (dACC) plays an important role in cognitive control and is therefore hypothesized to contribute to the pathogenesis of OCD. In this review, we aim to gain a wider understanding of the specific functions of the dACC and its role in the pathophysiology of OCD. The dACC is part of the cortico-basal ganglia-thalamo-cortical loop, where it forms connections between sensory input streams, cognitive and affective processing regions, and structures that regulate behaviour. This position facilitates a broad function for the dACC in multiple domains, which center on goal-directed behaviour and reward-based learning. When presented with a certain threatening stimulus, the dACC instructs downstream structures to select actions to respond to this particular stimulus, based on previous experiences We hypothesize that hyperactivity of the dACC may impair goal-directed behaviour in OCD patients which in turn may lead to obsessive-compulsive symptoms by creating an over-reliance on threatening stimuli and inadequate selection of neutralizing actions. The working mechanisms of cognitive behavioural therapy, serotonergic medication, repetitive transcranial magnetic stimulation and deep brain stimulation in OCD may be in part explained by the normalization of the activity of the dACC within the cortico-basal ganglia-thalamo-cortical (CBGTC) loop.