Figure 4.

Geometry of the finite element model of a planar electrode adjacent to a cylindrical homogenous volume conductor. The tissue medium was modeled as a cylinder 10 cm in diameter and 10 cm in height with a conductivity of 0.2 S/m. A high resolution cylindrical region was introduced around the electrode (diameter of 40 mm and height of 40 mm) to ensure the high accuracy of FEM results needed for further simulation of neural activation. A population of 256 axons were distributed in a volume of 2 cm × 2 cm × 2 cm, placed 15 mm above the electrode (the cubic area and axons are shown schematically, not to scale).