Anatomical and fMRI-network comparison of multiple DLPFC targeting strategies for repetitive transcranial magnetic stimulation treatment of depression.

Background: The efficacy of repetitive transcranial magnetic stimulation (rTMS) for depression may vary depending on the subregion stimulated within the dorsolateral prefrontal cortex (DLPFC). Clinical TMS typically uses scalp-based landmarks for DLPFC targeting, rather than individualized MRI guidance.
Objective: In rTMS patients, determine the brain systems targeted by multiple DLPFC stimulation rules by computing several surrogate measures: underlying brain targets labeled with connectivity-based atlases, subgenual cingulate anticorrelation strength, and functionally connected networks.
Methods: Forty-nine patients in a randomized controlled trial of rTMS therapy for treatment resistant major depression underwent structural and functional MRI. DLPFC rules were applied virtually using MR-image guidance. Underlying cortical regions were labeled, and connectivity with the subgenual cingulate and whole-brain computed.
Results: Scalp-targeting rules applied post hoc to these MRIs that adjusted for head size, including Beam F3, were comparably precise, successful in directly targeting classical DLPFC and frontal networks, and anticorrelated with the subgenual cingulate. In contrast, all rules involving fixed distances introduced variability in regions and networks targeted. The 5 cm rule targeted a transitional DLPFC region with a different connectivity profile from the adjusted rules. Seed-based connectivity analyses identified multiple regions, such as posterior cingulate and inferior parietal lobe, that warrant further study in order to understand their potential contribution to clinical response.
Conclusion: EEG-based rules consistently targeted DLPFC brain regions with resting-state fMRI features known to be associated with depression response. These results provide a bridge from lab to clinic by enabling clinicians to relate scalp-targeting rules to functionally connected brain systems.
Competing Interests: Declaration of competing interest Dr. Rosen, Ms. Bhat, Dr. Cardenas, Dr. Ehrlich, Ms. Horwege, Mr. Lavacot, Mr. Roach, Dr. Glover, Dr. Forman, Dr. Yurgelun-Todd, and Dr. Yesavage have no conflicts to disclose. Dr. Mathalon is a consultant for Boehringer Ingelheim and Caden Therapeutics. Dr. Badran owns a minority stake in Bodhi NeuroTech Inc., which manufactures meditation enhancing devices and holds patents in this area assigned to the Medical University of South Carolina. Dr. George holds research grants through the Medical University of South Carolina with Brainsway and LivaNova. He is on the scientific advisory board, uncompensated, for Magstim, Brainsway. He has equipment loaned from MECTA and Nexstim. He is on the scientific advisory board for Neuralief (compensated). He has no ownership of any brain stimulation device company. He is the editor in chief of Brain Stimulation, published by Elsevier. Dr. Thase reports no conflicts of interest with this research. Dr. Thase reports the following other relationships over the past three years: Advisory/Consultant—Acadia, Alkermes, Allergan (Forest, Naurex), Axsome, Clexio, Johnson & Johnson (Janssen, Ortho-McNeil), Lundbeck, Merck, Novartis, Otsuka, Pfizer, Shire, Sunovion, Takeda; Grant Support—Acadia, Allergan (Forest, Naurex), Alkermes, Axsome, Clexio, Myriad (AssureRx), Axsome, Intracellular, Janssen, National Institute of Mental Health, Otsuka, Patient Centered Outcomes Research Institute, Takeda; Royalties—American Psychiatric Press, Guilford Publications, Herald House, W.W. Norton & Company, Inc. Dr. Thases's spouse, Diane Sloan, PharmD, is a Senior Medical Director for Peloton Advantage, which does business with a number of pharmaceutical companies.
(Copyright © 2021. Published by Elsevier Inc.)