Effects of TMS Coil Orientation on Neuronal, Network, and Behavioral Responses – A TMS-fMRI Investigation

• Applicant: Dr. Severin Schramm
• Subject Area: Human Cognitive and Systems Neuroscience
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 576091606

Transcranial magnetic stimulation (TMS) is a brain stimulation technique with numerous clinical applications. Although its therapeutic efficacy has been established for various diagnoses such as depression, neuropathic pain, and stroke rehabilitation, it is unclear how certain TMS parameters affect the results of stimulation. This limits the benefits that clinicians can derive from TMS. One relevant parameter is coil orientation (CO). The orientation of the coil relative to the head determines the direction of the induced electric field and where it is maximized in the brain. Although simulations suggest that this parameter influences the effects of stimulation, the topic has received little research attention to date. The proposed series of experiments aims to systematically investigate how the orientation of the TMS coil relative to the head influences stimulation responses. At the heart of the experiments lies the technique of simultaneous TMS/fMRI. This allows for the measurement of TMS effects on brain activity directly during stimulation using MR imaging. Experiment 1: Establishment of a fundamental relationship between CO and stimulation responses in TMS/fMRI; stability of the stimulation response under different CO conditions; identification of the minimum number of measurements required for reliable results. Experiment 2: Interaction of CO with stimulation intensity; dynamics of local and network-wide stimulation responses at increasing intensities. Experiment 3: Interaction of CO with stimulation timing; influence of CO on behavioral metrics. The aim of the series of experiments is to derive a model for the influence of CO on TMS effects. Such a model would be able to significantly advance the personalization of TMS in clinical applications and thus improve TMS treatment outcomes across all diagnoses.

• DFG Programme: Fellowship
• International Connection: Austria
• Host: Dr. Martin Tik, Ph.D.