Improving the Precision and Targeting of Transcranial Magnetic Stimulation

I describe a framework for improving the targeting and precision of transcranial magnetic stimulation (TMS), a noninvasive brain stimulation technique used for research and clinical applications. The framework designs coils that double the precision of spatial targeting (focality) of existing TMS coils. This is the first significant advancement in the depth-focality trade-off of TMS coils since the introduction of the standard figure-of-eight coil three decades ago, and likely represents the fundamental physical limit. Moreover, the framework quantifies uncertainty in TMS induced electric fields due to system setup and patient variability, and it identifies key parameters that affect targeting precision. Results show that coil position is a key contributor to TMS variability, supporting the need for more precise neuro-navigation devices.  Finally, I show how this framework can also be used for determining coil placements that optimally target specific brain regions. By improving the accuracy and precision of TMS targeting this frameworks enables the development of more effective clinical and research TMS protocols.

Learning Objectives:

1. Learn about the physics behind transcranial magnetic stimulation, and the spatial characteristics of the TMS coil stimulating fields.
2. Learn about the specific TMS session parameters that contribute most to variation in the TMS induced stimulating field. Furthermore, they should learn about different approaches to coil placement and their precision in terms of targeting.