[Postsynaptic processes in rubrospinal neurons of the cat brain exposed to different corticofugal influences]

EPSPs of the red nucleus neurons evoked in response to stimulation of the cerebellar nucleus interpositus as well as the sensorimotor and associative parietal region of the cerebral cortex were studied in acute experiments on nembutalized cats. As in the case of the two previous structures mentioned a monosynaptic connection of the associative cortex with the rubrospinal neurons was shown to exist. Unitary EPSPs having latent periods 1.5-2.7 ms, time to peak 1.1-3.1 ms and amplitude of 0.22-0.65 mV were observed in the rubrospinal neurons in response to associative cortex stimulation. Analysis of the time parameters of the unitary EPSPs showed that synapses formed by fibres from the associative cortex are located on the somadendritic membrane of the neuron more proximally comparing with synapses formed by fibres from the sensorimotor cortex.