[Synaptic organization of supraspinal control of the propriospinal neurons of the ventral horn of the cat and monkey spinal cord].

In experiments carried out on cats and monkeys synaptic actions evoked in propriospinal interneurons of the upper lumbar segments by reticulo-, vestibulo- and cortico-spinal volleys were investigated by means of intra- and extracellular recording. Propriospinal interneurons identified by antidromic invasion from the fibres of the ventrolateral funiculi were located in different zones of the ventral horn of the upper lumbar segments. In cats a monosynaptic effect could be evoked by a vestibulo- and reticulo-spinal volley. In monkeys monosynaptic brain-stem-propriospinal actions are complemented by cortico-propriospinal monosynaptic connections. The convergence of monosynaptic effects from different supraspinal sources was shown.