Brain Functional Connectivity Mechanism of Cognitive Flexibility Impairment and rTMS Intervention in Major Depressive Disorder

Major depressive disorder (MDD) often involves cognitive deficits, particularly in cognitive flexibility, which is inadequately addressed by standard antidepressants. This study tests an innovative brain stimulation regimen: individualized dual-target repetitive transcranial magnetic stimulation (rTMS) to improve cognitive flexibility in MDD patients.

This is a randomized, double-blind, sham-controlled trial that plans to enroll 105 MDD patients with cognitive flexibility impairment. Participants will be randomly assigned to one of three groups: (1) Active dual-target group - receiving active rTMS over both the left inferior parietal lobule (IPL) and the right dorsolateral prefrontal cortex (DLPFC); (2) Active single-target group - receiving active rTMS over the left IPL and sham stimulation over the right DLPFC; (3) Sham control group - receiving sham stimulation over both targets. All participants will continue their stable antidepressant medication (SSRI or SNRI). The rTMS intervention lasts 10 days, with 5 stimulation sessions per day.

Cognitive flexibility, depressive symptoms, and brain functional connectivity will be assessed at baseline, immediately after the 10-day treatment, and at 2-week and 4-week follow-ups using neurocognitive tests, clinical rating scales (e.g., HAMD), and functional MRI. The results will help confirm the role of the IPL-DLPFC connectivity in cognitive flexibility and may establish a new treatment target for cognitive dysfunction in MDD.