Complex composition of synaptic potentials of the rubrospinal neurons to corticofugal impulses

Abstract

Complex, multicomponent excitatory postsynaptic potentials (EPSPs) of the red nucleus rubrospinal neurons evoked by stimulation of the sensorimotor cortex and associative field of the parietal cortex were studied in acute experiments on pentobarbitalized cats by the intracellular recording technique. Complex cortical EPSPs were recorded in two-thirds of the studied number of neurons. Monosynaptic nature of the first two components of EPSPs evoked by corticofugal impulses propagating at an average velocity of 18.5 ms and 7.5 ms was revealed. Participation of the corticospinal input in the genesis of EPSPs mentioned was revealed by selective activation of corticospinal fibers on the level of medullary pyramids as well as by studying peculiarities of their interaction with effects of cortical stimulation. It was shown that both corticospinal and corticorubral (predominantly slow conducting) neurons participate in the genesis of the first two components of complex EPSPs. © 1988.