Fig. 4. Activity of CF5 neurons during locomotion.A, A representative record of a CF5 neuron discharge at rest and during simple and complex locomotion. The bottom trace shows the swing (Sw) and stance (St) phases of the step cycle of the forelimb contralateral to the recording site in the cortex. B, D, Activity of the same CF5 neuron during simple locomotion is presented as a raster of 50 step cycles (B) and as a histogram (D). In the raster, the duration of step cycles is normalized to 100%, and the raster is rank-ordered according to the duration of the swing phase. The beginning of the stance phase in each step is indicated by an open triangle. In the histogram, the dashed lineshows the level of activity at rest. C, E, Activity of the same neuron during complex locomotion presented as a raster (C) and as a histogram (E).F, G, Distribution of preferred phases (positions of mean vectors) of activity of all CF5 neurons in the normalized step cycle during simple (F) and complex (G) locomotion. H, I, Proportion of neurons in which the mean discharge frequency increased (black), decreased (gray), and did not change (white) on transition from rest to locomotion (H) and from simple to complex locomotion (I). J, Proportion of neurons in which the coefficient of frequency modulation increased, decreased, and did not change on transition from simple to complex locomotion; color codes are same as in H andI.