Fig. 6: Cumulative, integrated spike activity across channels and simultaneous joint position and electromyographic activity.

The integrated neural activity fluctuated with joint position and residual left forearm electromyographic activity. The summed spike activity across channels and run through a leaky integrator²⁹ (solid black line) appeared to fluctuate with specific residual actions in the left upper extremity (a). Proximal residual activity generated a normal appearing pattern as seen between 290 and 310 s, biceps (dashed light blue line) and triceps (solid dark blue line) activity alternate (b). In the distal upper extremity, however, wrist flexor (dashed gray line) and wrist extensor (solid gray line) activity, tend to occur simultaneous in an abnormal manner (simultaneous agonist and antagonist contraction); also, wrist flexor activity is abnormally synergistic with biceps activity (an abnormal flexor synergy). The summed, integrated spiking activity across channels (black line) appears to covary with wrist flexor activity. Numerical data that was used to generate this figure is available in Supplementary Data 2.