Fig. 4.

Panels (A)–(D) are arranged in order of increasing distance between stimulation sites on the scalp (arrows). Current densities in white matter representing the face and arms (circles) were lowest (40 A/m) for C1 and C2 stimulation sites (A) and highest (89 A/m) for the lateral sulci sites (D). In contrast, currents densities in the scalp between stimulation sites were greater in (A) as compared to (D). Gray and white matter representing the arms and face are indicated by the stippling on the right hand side of each model.