Figure 4. Examples of monosynaptic excitation of commissural interneurones, from either group II muscle afferents or the MLF.

A–C and D–F show records from two different commissural interneurones, both of which were antidromically activated from the contralateral gastrocnemius–soleus motor nuclei and which were recorded in the same experiment. The antidromically evoked responses (C and F) are illustrated with records obtained just before and/or after the penetration of the interneurones. In the upper and middle rows, the lower records in each pair are from the cord dorsum. Voltage calibrations (0.5 mV) are for intracellular records. The arrow in A indicates a disynaptic IPSP evoked from group I afferents (evoked at threshold of < 2T) preceding the group II EPSP.