Physiology and biochemistry in modern medicine . s stimulus) the homolateralperoneal nerve was excited (as shown in the lower signal), with the result that the contractionof the flexors was inhibited at the same time that the extensors contracted. On removal of thelatter stimulus, the former one reasserted its influence. This experiment demonstrates very clearlythe accurate coincidence of the reciprocal action. (From Sherrington.) -]- THE CENTRAL NERVOUS SYSTEM acting on the same groups of neurons will produce a flexion reflex, othersan extension reflex; thus, stimulation of the contralateral
Physiology and biochemistry in modern medicine . s stimulus) the homolateralperoneal nerve was excited (as shown in the lower signal), with the result that the contractionof the flexors was inhibited at the same time that the extensors contracted. On removal of thelatter stimulus, the former one reasserted its influence. This experiment demonstrates very clearlythe accurate coincidence of the reciprocal action. (From Sherrington.) -]- THE CENTRAL NERVOUS SYSTEM acting on the same groups of neurons will produce a flexion reflex, othersan extension reflex; thus, stimulation of the contralateral peroneal nerveproduces a flexion reflex of the hind limb (excitatory for flexors, in-hibitory for extensors), whereas stimulation of the homolateral peronealnerve produces an extension (inhibitory for flexors, excitatory for ex-tensors). By taking advantage of these facts further proof may besupplied that inhibition and contraction occur simultaneously, as shownin Fig. 214. It is impossible to demonstrate any trace of inhibition of the skeletal. Fig. 215.—Sherringtons diagram illustrating the mechanism of reciprocal innervation. Theafferent fibers (5) from the skin of the leg and (5) from the flexor muscles of the knee (inhamstring nerve) pass to tEe spinal cord, where each gives off a branch which divides into twoothers, of which one in each case goes to a motor neuron of the extensor muscles (£) and theother to a motor neuron (5) of the flexor muscles (F). Branches also pass across the medianline to similar motor neurons on the opposite side of the cord. As indicated by the plus andminus signs, the afferent stimuli either stimulate or inhibit the activities cf the motor neurons,the determination of the exact effect beinj a function of the synapsis. (From Sherrington.) muscles by stimulation of their motor nerves, thus indicating that in-hibition is dependent upon the nerve center. Furthermore, since inhibitionoccurs along with flexion of the antagonistic muscle, we must as
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