Targeting of White Matter Tracts with Transcranial Magnetic Stimulation

Brain Stimulation

Lawrence L. Wald¹  Van J. Wedeen²  Matti S. Hämäläinen³  Jennifer A. McNab⁴  Yoshio Okada⁴  Ruopeng Wang⁵  Alvaro Pascual-Leone⁵  Peter Savadjiev⁶  Tommi Raij⁶  Aapo Nummenmaa⁶ 

[1]Brigham and Women's Hospital, MA, USA

[2]Department of Neurology, Boston Children's Hospital, MA, USA

[3]Department of Radiology, Stanford University, CA, USA

[4]Harvard Medical School, MA, USA

[5]Harvard Medical School, MA, USA

[6]MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, MA, USA

关键词: Transcranial magnetic stimulation;    TMS;    Diffusion MRI tractography;    Electromagnetic modeling;    Navigation;    Coil orientation;   

DOI  :  

来源: DOAJ

【 摘 要 】

Background: TMS activations of white matter depend not only on the distance from the coil, but also on the orientation of the axons relative to the TMS-induced electric field, and especially on axonal bends that create strong local field gradient maxima. Therefore, tractography contains potentially useful information for TMS targeting. Objective/methods: Here, we utilized 1-mm resolution diffusion and structural T1-weighted MRI to construct large-scale tractography models, and localized TMS white matter activations in motor cortex using electromagnetic forward modeling in a boundary element model (BEM). Results: As expected, in sulcal walls, pyramidal cell axonal bends created preferred sites of activation that were not found in gyral crowns. The model agreed with the well-known coil orientation sensitivity of motor cortex, and also suggested unexpected activation distributions emerging from the E-field and tract configurations. We further propose a novel method for computing the optimal coil location and orientation to maximally stimulate a pre-determined axonal bundle. Conclusions: Diffusion MRI tractography with electromagnetic modeling may improve spatial specificity and efficacy of TMS.

【 授权许可】

Unknown