FIG. 4.

Pooled coherence and test of difference. Pooled coherence of all motor-unit pairs from FPL-FDP2 and FPL-FDP3 during 2-digit grasp (A and B, respectively) and 5-digit grasp (C and D, respectively). The values on the y axis are the magnitude of the pooled coherence across the frequency range of interest (x axis; bin width = 0.78 Hz). Horizontal dashed line indicates the 95% confidence limit above which the magnitude of the pooled coherence is statistically significant. Right: test of difference between the transformed coherency functions of FPL-FDP2 and FPL-FDP3 during the 2- and 5-digit grips, (top and bottom, respectively). Bottom: the test of difference between the transformed coherency functions of the two- and five-digit grips, for both FPL-FDP2 and FPL-FDP3 (left and right, respectively). Values falling outside the 95% confidence interval (horizontal dotted lines) indicate a significant difference between the two transformed coherency functions at that frequency.