Journal: Neuropsychopharmacology (2025)
Authors: Baldi S, Chiulli N, Palm S, Frandsen S, Pell GS, Zibman S, Rodriguez-Ponde J, Brown JC, Siddiqi SH.
Background:
The efficacy of transcranial magnetic stimulation (TMS) for depression may depend on targeting specific brain circuits. However, this has not been tested for TMS with the H1 coil, a widely used device believed to target more broadly and deeply than TMS with figure-of-8 coils.
Objective:
This study examined whether targeting a specific brain circuit with H1 coil TMS treatment may impact depressive symptom improvement.
Methods:
We retrospectively analyzed data from 97 patients at McLean Hospital, who received at least 19 TMS sessions and had incidentally completed an anatomical brain MRI. We modeled each patient’s electric (E-)field using SimNIBS and estimated the connectivity of the E-field using a normative connectome (n = 1000), which was correlated with depression improvement as measured by the Quick Inventory of Depressive Symptomatology.
Results:
H1 E-fields improving depression were preferentially connected to a distinct brain circuit, validated with leave-one-out cross-validation (p = 0.0005). This circuit was significantly similar to a predefined causal depression circuit (spatial r = 0.59, p = 0.04) derived from TMS, deep brain stimulation, and lesion studies. E-fields with greater connectivity similarity to this circuit led to greater symptom improvement (r = 0.41, p < 0.001). Post-hoc analyses revealed that more posterior coil positioning increases H1 E-field overlap with the depression circuit, with high overlap at scalp locations 3-6 cm anterior to the motor hotspot.
Conclusions:
H1 coil stimulation sites that improve depression converge on a common causal depression circuit. Prospective studies are needed to validate these findings.
Full Publication: Targeting depression circuitry with H1 coil Transcranial Magnetic Stimulation: a retrospective circuit mapping study | Neuropsychopharmacology
