Effects of model complexity and tissue anisotropic conductivity on cortical modulation during transcranial direct current stimulation

An anatomically accurate high-resolution finite-element head model and its derivatives have been employed to examine the influence of subcutaneous fat and muscle tissues on cortical modulation. The effects of skull, muscle and white matter (WM) directional conductivity have also been investigated. Results indicate that the inclusion of additional tissues in the head model have a profound effect on the magnitude and distribution pattern of induced current density. Similarly, anisotropic tissue conductivity caused a significant deterioration in spatial focality of cortical currents along with a more distorted and diffused distribution pattern across the cortex.