Fig. 6.

Population plots of activity in different subregions of area 4. We compare the phase of the significantly modified periods of discharge activity for the populations of cell recorded in areas 4δc (A), the hindlimb representation of the primary motor cortex, 4γHL (B), the forelimb representation of the primary motor cortex, 4γFL (C), and 4δr (D). For each area, we illustrate rank-ordered phase plots of the cell discharge in the contralateral (part i) and the ipsilateral (part ii) lead conditions. Red and green lines in (i) and (ii) indicate cusums of the onset of cell discharge. We also illustrate the summed activity of the discharge during the contralateral (red) and ipsilateral (green) lead conditions (part iii), together with cusums of this summed activity (see Methods). Data in all plots are aligned to the onset of activity in the coClB/Br (phase = 0). In cells with more than one burst of activity, the period of discharge showing the largest change in activity was used for the alignment. Black horizontal bars in parts (i) and (ii) indicate increases of activity; gray horizontal bars indicate decreases of activity. Binwidth in part iii = 0.1 step, ~50 ms. N, number of cells in each plot that show modified activity in the indicated condition.