Central cell firing properties.

(A) Spike trains and burst profiles for the central neurons of different populations (electrode tip positioned at R = 2, 7, 11, 15, 21 and 31 deg). (B) Peak firing rates (dark green), number of spikes from the central cells (light green), and the durations of the central cell bursts (purple) for different neural populations between R = 2 and 65 deg. Note that the number of spikes for the central cell is constant at about 20 spikes throughout the motor map, while the peak firing rate at caudal sites drops to barely 50% of the rostral stimulation site. Note also that the durations of the central cell bursts increase monotonically with the movement amplitude.