Reflex figures in the decerebrate and spinal state

Abstract

The flexors and extensors of the hind limb of the cat were simultaneously activated by stretch of a homolateral flexor muscle or by a nocuous stimulus to the homolateral paw under the conditions of the present experiments, in which the muscles under investigation were maximally retracted after detachment of the tendons from their insertions. The simultaneous activation of flexors and extensors was observed in acute and chronic spinal preparations, and sometimes in decerebrate animals. However, when in such preparations the extensor muscle was made to contract by loading its tendon, stretch of the antagonistic flexor muscles and pinching of the toes of the homolateral leg usually resulted in extensor inhibition and flexor excitation, in agreement with the classical tenet of reciprocal innervation. The reflex figure seems to be to an important extent the result of the inflow of afferent impulses.