Quantitative relation between discharge frequencies of a Renshaw cell and an intracellularly depolarized motoneuron

Synaptic Connectivity between Renshaw Cells and Motoneurons in the Recurrent Inhibitory Circuit of the Spinal Cord

“…Continuous firing in a motoneuron can increase spiking in Renshaw cells (Ross et al, 1975) and drive discharge rates up to Ն60 Hz (Ross et al, 1976). While these observations are consistent with the reliable generation of spikes in Renshaw cells seen in our dual current-clamp recordings, we also observed alternation between successes and failures in responses to presyn- Peripheral nerve volley experiments suggest considerable convergence onto Renshaw cells from motoneurons innervating functionally synergistic muscles (Ryall, 1981).…”

“…The capability of the recurrent circuitry depends on the efficacies of both the excitatory and the inhibitory components. Simultaneous recordings between connected pairs of presynaptic motoneurons and Renshaw cells have been made previously (Ross et al, 1975(Ross et al, , 1976Van Keulen, 1981), but responses were only recorded using extracellular electrodes that preclude detection and assessment of subthreshold activity. Although extracellular recordings have shown a strong increase in Renshaw cell firing in response to single motoneuron inputs, the reported paired recording (Nishimaru et al, 2005) of an EPSC of only ϳ10 pA indicates a change in conductance insufficent to modulate firing.…”

Inhibitory connections of ipsilateral semicircular canal afferents onto Renshaw cells in the lumbar spinal cord of the cat.

“…That a low level of motor activity may well be sufficient to explain the Renshaw cell activity observed can be inferred from the observation that single a-motoneurones are capable of eliciting action potentials and even burst responses in these interneurones , 1976van Keulen, 1981). The reduction of the vestibularly induced Renshaw cell responses by dihydro-fl-erythroidine seen in our experiments is also in favour of the idea that motoneurones are intercalated in the pathway.…”

The measurement of single motor‐axon recurrent inhibitory post‐synaptic potentials in the cat.

“…Interactions between individual neurones in the recurrent Renshaw circuit To date, this study and three preceding ones (Ross et al 1975(Ross et al , 1976Van Keulen, 1981) Previous studies of the relationship between the profile of an e.p.s.p. and the resulting peaks of the cross-correlogram (indicating the increase in probability of discharge) have provided evidence that the cross-correlogram peaks may have a form similar to that of the potential itself (Moore, Segundo, Perkel & Levitan, 1970), the derivative of the potential (Knox, 1974;Knox & Poppele, 1977;Fetz & Gustafsson, 1983), or a combination of both (Kirkwood & Sears, 1978Gustafsson & McCrea, 1984).…”

“…Eccles et al (1954) attributed the long duration of recurrent i.p.s.p.s evoked by antidromic volleys to the high-frequency repetitive discharge of Renshaw cells. While some Renshaw cells display prolonged bursts in response to activation of collaterals of single motor axons (Ross et al 1975(Ross et al , 1976Van Keulen, 1981) such bursts would not be expected in the majority of Renshaw cells. None the less, as shown in Table 1, the half-widths of single-axon recurrent i.p.s.p.s were similar in duration to those of recurrent i.p.s.p.s produced by composite activation.…”