Metabolic imaging of anterior capsular stimulation in refractory obsessive-compulsive disorder: a key role for the subgenual anterior cingulate and ventral striatum

Abstract

High-frequency anterior capsular stimulation is a new, promising, and reversible neuromodulatory treatment in the research stage for patients with refractory obsessive-compulsive disorder (OCD). The mechanism of action is unknown but hypothesized to be secondary to interruption of the corticothalamostriatocortical circuit.

Methods: (18)F-FDG PET was performed on 6 consecutive OCD patients preoperatively and after stimulation. The results were compared with those of 20 age- and sex-matched healthy volunteers by using both a standardized volume-of-interest-based approach for subcortical areas and statistical parametric mapping. Correlations were investigated with Yale-Brown Obsessive Compulsive Scale scores (Y-BOCS) and Hamilton Depression Rating Scale scores (HAM-D).

Results: Chronic anterior capsular electrostimulation resulted in a further decrease of prefrontal metabolic activity, especially in the subgenual anterior cingulate (P < 0.001). Correlation analysis demonstrated that decreases in Y-BOCS and HAM-D with anterior capsular electrostimulation were inversely related to the metabolic activity changes in the left ventral striatum, left amygdala, and left hippocampus (P < 0.01). Preoperative resting metabolic activity in the subgenual anterior cingulate was predictive of therapeutic response (P = 0.001).

Conclusion: These observations provide evidence that the subgenual anterior cingulate and ventral striatum have a key role in the neuronal circuitry involved in the pathophysiology of OCD with associated major depression and in the neuromodulatory mechanism of anterior capsular stimulation.