Large-scale neural network correlates of response inhibition associated with antidepressant response in major depressive disorder.

BACKGROUND

A fundamental impairment of major depressive disorder (MDD) is response inhibition, which may serve as a predictor for inadequate responses to antidepressants. Nevertheless, the neurophysiological connections between treatment outcomes and response inhibition are not yet fully understood.

METHODS

This study involved 149 participants, consisting of 77 healthy controls (HCs) and 72 patients with MDD. All individuals undertook a Go/No-go task while undergoing magnetoencephalography (MEG) recording. Those patients with MDD showing at least a 50% decrease in symptom severity (the short 6-item version of Hamilton Depression Rating Scale) after four weeks were classified as responders. We assessed whole-brain connectivity within the beta-band.

RESULTS

Individuals with MDD demonstrated decreased connectivity in a right-lateralized network centred on inferior frontal gyrus. Additionally, non-responders displayed reduced functional connectivity in a left-dominant frontoparietal network centred on superior parietal gyrus and orbitofrontal cortex during response inhibition when compared to both responders and HCs. This identified dysregulation also has potential predictive value regarding the response to antidepressant treatment.

CONCLUSIONS

Hypoconnectivity in the left-lateralized frontoparietal network centred on superior parietal gyrus and orbitofrontal cortex indicate a decompensatory mechanism that may contribute to an insensitivity toward antidepressant interventions.