Reduced pre-treatment isolated effective coherence between the dorsolateral prefrontal cortex and the subgenual anterior cingulate cortex as a potential predictive marker for remission following repetitive transcranial magnetic stimulation in major depressive disorder

OBJECTIVES: Functional connectivity between the dorsolateral prefrontal cortex (DLPFC) and subgenual anterior cingulate cortex (sgACC) has been implicated in the antidepressant effects of repetitive transcranial magnetic stimulation (rTMS) for major depressive disorder (MDD). It remains unclear whether effective connectivity between these regions is associated with remission. We examined adults with MDD who received high-frequency rTMS targeting the left DLPFC. METHODS: This single-centre observational study analysed pre-treatment electroencephalography and clinical data of 30 patients. Directed connectivity between the DLPFC and sgACC in the alpha and theta bands was estimated using isolated effective coherence (iCoh) based on exact low-resolution electromagnetic tomography. RESULTS: = 0.02). No significant differences were observed in the theta band. CONCLUSIONS: Lower pre-treatment alpha-band effective connectivity from the left DLPFC to the sgACC was associated with remission following rTMS, suggesting that iCoh-derived measures may be a candidate biomarker for personalised rTMS in depression.