Realistic modeling of transcranial current stimulation: The electric field in the brain

Computational models of transcranial current stimulation (tCS) derived from MRI predict the electric field distribution in individual brains with reasonable accuracy and should be used to guide the selection of optimal stimulation parameters. Some recent advances that support this claim are: free toolboxes to generate individual head models for electric field calculations, the validation of model predictions in comparison to in-vivo measurements, and new algorithms to optimize the electric field at the target with multi-electrode stimulation. Electrical impedance tomography may provide subject-specific estimates of the electric conductivity of the scalp and skull, thereby improving the accuracy of the electric field calculations. In the future, electric field models should be coupled with electro-physiological models to predict experimental outcomes.