Figure 3.

Population data on motoneuron responses to contralateral intraspinal stimulation. A, Proportions of motoneurons sampled, which projected to different muscle categories. B, Proportions of motoneurons that responded to cISMS. C–E, Same as in B but compiled separately for motoneurons projecting to the different muscle groups. F, Scatter plot of response amplitude versus response latency. Symbol colors represent monosynaptic EPSPs (blue), polysynaptic EPSPs evoked by single stimuli (green, on basis of latency > 1.2 ms), and polysynaptic EPSPs evoked by trains of stimuli (small red symbols, based on a lack of responses to single stimuli). The horizontal and vertical histograms indicate the distribution of latencies and amplitudes, respectively, with bars coded using the same color scheme.