Influence of Brain–Scalp Distance on Focality of the Quadruple Butterfly Coil for Transcranial Magnetic Stimulation

Transcranial magnetic stimulation (TMS) is a neuromodulation technique that noninvasively depolarizes neurons in the brain. During TMS, pulse (or multiple pulses) of time-varying field (H) delivered to brain using specialized coils. The quadruple butterfly coil (QBC) novel design shows increased focality induced electric over standard figure-of-eight (FoE) coil. Using 50 different head models created from resonance imaging (MRI) scans healthy individuals, our research investigated role brain-scalp distance (BSD) plays brain's response fields generated by QBC and FoE. variability BSD an inherent characteristic human population. As increases, so does between TMS Therefore, anatomical variation independent variable may play significant intensity produced Our results show no difference QBC's FoE with respect BSD.