Experimental: MDD subjects in the active group undergo 10 days of MRI-guided iTBS intervention

Neuronavigation procedure: During the iTBS treatment, the high-resolution T1-weighted scans of each subject will be uploaded to the BrainSight neuronavigation system (version 2.4.11), adjusted, and remodelled into a three-dimensional model. Then, the neuronavigation system is calibrated and validated on the subject. Next, we localized each participant's left-lateral dlPFC stimulation target using Talairach coordinates (-45, 45, 35). The head position is standardized using the nasal tip, sinuses, and bilateral ear screens as baseline markers, and the location of the target on the scalp is identified in each participant's natural space anatomical image. In the end, we observe on the computer screen whether the coil position is placed above the target through the navigation software and artificially control the coil to be tangent to the skull, with the center of the figure-of-eight coil always directly above the target.

Sham_comparator: MDD controls in the sham-iTBS group receive the same intervention but Beam F3 site.

Target Localization and Cap Placement Procedure: The stimulation target was the EEG 10-20 coordinate F3, corresponding to the probabilistic location of the left dorsolateral prefrontal cortex (DLPFC). We localized this site using the Beam F3 method and a TMS elastic cap (patent no. 201120150878.5, Wuhan YIRUIDE Medical Equipment Co., Ltd.), and verified it with the F3 electrode on the standard EEG cap. Before the first session, the elastic cap was aligned using anatomical landmarks (nasion, inion, and ears), and the F3 position was marked for consistent coil placement. This standardized approach ensured precise and repeatable targeting across TMS sessions.