Quantifying uncertainty in Transcranial Magnetic Stimulation - A high resolution simulation study in ICBM space.

Area of Science:

• Neuroscience
• Bioelectromagnetics
• Computational Biology

Background:

• Transcranial Magnetic Stimulation (TMS) is a promising noninvasive brain stimulation technique.
• Existing TMS models often use single-subject data, limiting generalizability.
• Uncertainties in brain conductivity and stimulation parameters (coil positioning, orientation) are not well quantified.

Purpose of the Study:

• To develop a population-representative head model for bioelectromagnetic simulations.
• To quantify the impact of uncertainties in conductivity and stimulation setup on induced fields and currents in TMS.

Main Methods:

• Construction of a high-resolution anisotropic head model in standard ICBM space.
• Application of Monte-Carlo simulations to assess the propagation of uncertainties.
• Analysis of induced field and charge distributions under varying parameters.

Main Results:

• Demonstrated significant, regionally dependent dispersions in induced fields and currents.
• Quantified the impact of conductivity uncertainties on simulation outcomes.
• Highlighted variability in commonly assumed 'ground truth' values.

Conclusions:

• The developed framework allows quantification of uncertainties in noninvasive brain stimulation.
• Results are relevant for both investigative and therapeutic applications of TMS.
• Accurate modeling requires accounting for inter-subject variability and parameter uncertainties.