A comparison between certain features of the spinal flexor reflex and of the decerebrate extensor reflex respectively.

Proc. Roy. Soc. B, 95. - London, Harrison and Sons, 1925, 8°, pp.299-339, 20 Figs., orig. wrappers. Offprint! "We described recently a difference between the spinal reflex of flexor muscles of knee and ankle on the one hand and the decerebrate crossed reflex of the knee extensor on the other in regard to transmission of the rhythm of the exciting stimulus applied to the afferent nerve. Another difference between these two types of reflexes is exhibited in the form of curve of tension development exhibited in isometric myograms of their tetani. Examination of these shows a divergence which cannot be accounted for by such differences as exist between the tetanic behaviour of the several muscles or motor nerves themselves. I.-Method. The method employed has been the same as in our previous paper. All muscles except that one whose contraction was to be recorded have been paralysed by nerve-section or resection; and the myograph has been of the isometric type with optical registration. As stimuli series of single shocks separated from an inductorium usually coreless have, by means of the vibrating key described in the previous paper, been delivered to the suitably bared afferent or efferent nerve, the anode for the shock being always towards the cut end of the nerve. The distance between the electrodes on the nerve has been 12 mm. Occasionally, the stimuli have been applied by a stigmatic kathode electrode in the skin. The preparation (cat) has been decerebrate, all of the brain anterior to the posterior colliculi being removed. For purely spinal reflexes, the spinal cord has, in addition, been transected either immediately or some days or weeks prior to the decerebration; the level of spinal transection has varied in different experiments between 12th thoracic and 3rd lumbar segments. " Liddell, et al. Sir Charles Scott Sherrington (1857-1952) was a British neurophysiologist. His experimental research established many aspects of contemporary neuroscience, including the concept of the spinal reflex as a system involving connected neurons (the "neuron doctrine"), and the ways in which signal transmission between neurons can be potentiated or depotentiated. Sherrington himself coined the word "synapse" to define the connection between two neurons. He was awarded the Nobel Prize in Physiology or Medicine in 1932 (along with Edgar Adrian). In addition to his work in physiology, Sherrington did research in histology, bacteriology, and pathology. Liddell, Edward George Tandy (1895-1981), physiologist, already as an undergraduate Liddell had come under Sherrington's spell and had learned, unlike the majority of undergraduates, to derive inspired instruction from his notoriously difficult lectures. "Sherrington was president of the Royal Society from 1920 to 1925 and had to spend much time in London. Much, therefore, of the responsibility for their experiments necessarily devolved on Liddell, Sherrington's sole collaborator. As he was a beginner, and self-effacing almost to a fault, his contribution was inevitably overshadowed by Sherrington's: but his share in their classic researches went well beyond the level of consummate experimental skills. Their collaboration began at a turning-point in studies of reflex action, when Sherrington's interest was moving away from exteroceptive reflexes as items of animal behaviour and towards the cellular basis of synaptic excitation and inhibition, conceived as summing algebraically at the post-synaptic membrane. The exteroceptive reflexes were elicited by graded electrical stimulation of afferent nerves in spinal and decerebrate animals; the synaptic actions were detected by quantitative high-speed myography. The classical discovery of the proprioceptive stretch reflex was important because it could be elicited only by a pure physiological stimulus, minimal lengthening of a muscle; and because of its essential role in reflex posture. " C. G. Phillips, Memoirs FRS, .…