In experiments carried out on cats unitary PSPs evoked in lumbar motoneurons by stimulation of single identified ventral horn propriospinal neurons receiving mono- and polysynaptic inputs from reticular nuclei were recorded by means of the averaging computer. The amplitudes of the unitary proprio-motoneuronal EPSPs and IPSPs were 49.6 +/- +/- 6.0 muV and 28.9 +/- 2.9 muV, respectively. A synaptic delay was 0.34 +/- 0.05 ms. An individual propriospinal cell of the upper lumbar segments can establish monosynaptic articulations with several motoneurons of the lower lumbar segments.