Figure 8.

The effect of flexor activity on extensor spindle output. A, As in Figure 7B, but here only data across the no bias load and flexion-resistive bias load conditions were used (i.e., blue and red conditions indicated in Fig. 1B). Only angular velocity and flexor EMG had a significant effect on extensor spindle output, with flexor activity exerting a negative effect. B, The dark gray bar represents the accounted-for variance in afferent ensemble firing rate (i.e., adjusted r²) resulting from the regression in A, and the light gray bar is the equivalent of the dark gray bar but having not included flexor EMG as a predictor in the regression. The two bars in B differed significantly (p = 0.005). Error bars in A represent 95% confidence intervals.