Abstract
It is generally conceded that there are no well isolated reflex arcs. Nervous energy released in the reflex arc sense organs spreads apparently to immediately circumjacent and even to distant and perhaps to all parts of the central nervous system.∗ Positive evidence pertaining directly to this point has been furnished by recent experiments. 1 In the rat it has been demonstrated that the electrical energy released in the reflex arc sense organs was conducted to all parts of the cerebral cortex studied. These studies did not disclose the possible immediacy of spread of the electrical energy in the cord. The energy recorded in the cortex might have reached there by relatively sharply delimited circuits to spread subsequently to all cortical fields. It might have reached there by way of all of the afferent spino cerebral-paths. To shed further light upon this particular problem as well as upon the general problem of mass responsiveness in the central nervous system the present study was undertaken.
The apparatus used consisted of 2 identical, non-interfering, resistance coupled amplifiers, acoustically and electrically shielded which gave identical reproduction of any impressed voltage with respect to wave form, phase, and amplitude. With 2 equally sensitive, approximately critically damped oscillograph elements the complete apparatus made possible the faithful simultaneous recording of electrical currents from varyingly separated parts of the nervous system. The recording of the instant of stimulation was accomplished by means of a specially devised vacuum tube circuit which upon the striking of a small copper plate over the tendon activated an oscillograph element. Time values of 0.001 second used for reading the reflex conduction latencies were furnished by a General Radio Type 377 low frequency oscillator.
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