Fig. 7.

Activity of PTNs with receptive fields involving different forelimb joints during ladder locomotion. A: discharge rate during walking. B: depth of modulation. C: duration of the PEF. In A–C, error bars are SE and stars indicate significant differences in values (P < 0.05, ANOVA). D: distribution of PEFs of individual PTNs in the step cycle. Each trace represents PEF of 1 PTN. Neurons are rank ordered so that those whose preferred phase is earlier in the cycle are plotted at top of graph. E: distribution of preferred phases of neurons across the step cycle. F: proportion of cells active during the step cycle. G: phase histogram of the average firing rate of PTNs across the step cycle. E–G: Sw, swing phase; St, stance phase.