Starting phase of kHz stimulation bursts impacts spatio-temporal pattern of fiber activation in porcine vagus nerve

downstream inhibitory effect on the motor cortex.We investigated the electric field strength, coil orientation/position to best stimulate the cerebellar cortex using the recently developed direct TMS solver that utilizes an FMM accelerated LU decomposition of the system matrix that is pre-computed only once per subject.This allows rapid retrieval of the Efields for arbitrary TMS coil location/orientation in ~5 seconds.We evaluated three coils (MagVenture C-B60, C-B35, D-B80) and 12 coil angles (0 o -180 o , 15 o increments).We used realistic head models with high-resolution surface meshes of the cerebellar surfaces from T1 MRI.For each subject, we used ~108000 stimulation scenarios (3000 locations x 12 coil angles x 3 coils).We found that the Crus II, Crus I, lobules VI, VII, IX and the vermis were the easiest to induce strong electric fields with TMS.The maximum electric field induced by C-B60, C-B35 and the D-B80 were found to be 0.93, 1.32 and 0.78 V/m per A/us respectively.As expected, TMS induced very small electric fields in the anterior lobes across all coils, angles, and stimulation points.The cerebellar TMS sensitivity maps can be used as an initial guide for selecting stimulation parameters for cerebellar TMS.