| Abstract: | The effects of segmental reflexes on descending intersegmental reflexes to stimulation of forelimb afferents were studied in anesthetized cats by recording postsynaptic responses from single motoneurons. Interaction between these influences was found to be reciprocal in character for groups of neurons with primary connections with afferents of the superficial and deep branches of the peroneal nerve and afferents of the nerve to the gastrocnemius muscle. Excitatory postsynaptic responses arising in groups of motoneurons of the peroneal nerve to stimulation of forelimb afferents underwent profound and prolonged inhibition during conditioning stimulation of afferents in the deep and superficial peroneal nerves. Activation of segmental afferents during conditioning stimulation of the gastrocnemius nerve was accompanied by inhibition of excitatory intersegmental responses and deinhibition of inhibitory responses in motoneurons of the gastrocnemius muscle. Segmental inhibition of intersegmental descending impulse activity appeared in the interneuron system of the segmental reflex centers connecting the descending propriospinal tracts with the motoneurons of these centers.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 4, No. 2, pp. 16872-175, March–April, 1972. |
