Figure 7. Comparison of latencies of EPSPs and IPSPs evoked from the ipsilateral and contralateral NR, PT and MLF.

Minimal latencies of EPSPs and IPSPs evoked by the 4th or 5th stimulus in the train of stimuli measured from stimulus artefacts. In A–C are data for motoneurones in which EPSPs or IPSPs were evoked from the ipsilateral NR, ipsilateral PT and ipsilateral or contralateral MLF. They are ranked in an increasing order for PSPs evoked from the NR with corresponding latencies of PSPs from the MLF and from the PT in the same motoneurones. In D–F are data for motoneurones in which EPSPs or IPSPs were evoked from the contralateral NR, contralateral PT and ipsilateral or contralateral MLF plotted in the same way. Horizontal dotted lines in A and D indicate mean latencies of monosynaptic EPSPs from the MLF. G, mean latencies (±s.e.m.) of EPSPs and IPSPs evoked from the ipsilateral (ipsi) and contralateral (co) NR, PT and MLF plotted in A–F. The PSPs evoked by stimulation of the MLF (either ipsilateral or contralateral to the motoneurones) had significantly shorter latencies than those evoked by NR or PT stimulation as indicated by * (t test, P < 0.005). However, no statistically significant differences were found between the mean latencies of any PSPs evoked by the ipsilaterally or the contralaterally descending pathways, or between those evoked by stimulation in the ipsilateral or in the contralateral sites (ANOVA).