Electrophysiological analysis of the central mechanisms correlating interoceptive influences on skeletal muscles

Summary

Acute experiments on cats were used to study the influence of stimulation of the mechanoreceptors of the rectum on the mono- and polysynaptic reflex responses from the flexor motor neurons.

It was found that reflex monosynaptic potentials in the overwhelming majority of experiments were insignificantly inhibited or remained unchanged, whereas the polysynaptic discharges were inhibited in all cases irrespective of the monosynaptic ones. Experiments proved that the interoceptive afferent impulses may be conveyed to the spinal cord both through the ipsi- and contralateral dorsal roots. In addition, it was found that the corrective interoceptive influences may be exercised at the level of the spinal cord, without the participation of the suprasegmental formations of the central nervous system.

On the basis of an analysis of the results obtained and literature data it is supposed that the interoceptive inhibition is presynaptic in character.