Fig. 4.

(a) Method for the projection of scalp coordinates onto the surface of the cortex. (a1) Plane is fit to set of cortical mesh nodes (blue). (a2) Normal to plane (blue) that crosses scalp coordinate (green point in space) is selected. (a3) Intersection point between triangular mesh element and plane normal is calculated (red point on surface). (b) Regions of interest (ROI) selected throughout the brain. (The number of ROIs shown is less than the one used in the analysis for illustration purposes.) (c) Variable radius for a single ROI.