Figure 6.

Polar plots of evoked EMG activity and their summation. Each axis represents the integrated EMG activity of a given muscle. Line segments join the points plotted on each axis, thus giving a geometrical representation of the evoked muscle-coordination pattern. Graphs in the first two columns represent the muscle-coordination pattern evoked by separate stimulation of two cortical points. Graphs in the third column represent the muscle coordination pattern obtained when the two points were simultaneously stimulated (Points 1 and 2, red line) and the linear sum expected by addition of the two separate patterns (black dashed lines). Note that the expected and experimentally obtained muscle-coordination patterns are nearly the same in the three examples shown (A–C). Figure from Ethier et al. (2006).