scholarly journals Reflexes elicited by visceral stimulation in the acute spinal animal

1946 ◽  
Vol 105 (1) ◽  
pp. 80-94 ◽  
Author(s):  
C. B. B. Downman ◽  
B. A. McSwiney
Keyword(s):  
Spinal Animal

Spinal cord participation in the Cushing reflex in the dog

1970 ◽  
Vol 33 (6) ◽  
pp. 662-675 ◽  
Author(s):  
Glenn A. Meyer ◽  
David L. Winter
Keyword(s):  
Spinal Cord ◽  
Time Course ◽  
Spinal Neurons ◽  
Content Type ◽  
Arterial Perfusion ◽  
Adverse Conditions ◽  
Autonomic Nervous ◽  
Spinal Animal ◽  
Acting In Concert ◽  
Increased Pressure

✓ The vasopressor response to increased intradural pressure (Cushing reflex) is caused by decreased arterial perfusion (hypoxia) and the mechanical effects of pressure acting in concert. Increased pressure in the range 50–200 mm Hg alters ongoing activity in all neurons concerned with the autonomic nervous system at multiple levels of the neuroaxis. Therefore, the response of an intact organism is highly variable and unpredictable. Conversely, the response to increased pressure exerted upon the spinal cord of a spinal animal is relatively uniform and predictable. Spinal neurons of both the somatic and autonomic nervous systems show facilitation followed by inhibition, but the time course and magnitude of these events are much different for the two systems. Autonomic neurons retain the ability to fire under very adverse conditions, thus enhancing the organism's chance for survival.

Spontaneous Rhythms in the Motoneurons of Spinal Dogfish (Scyliorhinus Canicula)

1969 ◽  
Vol 49 (1) ◽  
pp. 33-49 ◽  
Author(s):  
B. L. Roberts
Keyword(s):  
Spinal Cord ◽  
Motor Activity ◽  
Motor Pattern ◽  
Sensory Stimulation ◽  
Spinal Neurons ◽  
Scyliorhinus Canicula ◽  
Dorsal Roots ◽  
Long Duration ◽  
Motor Rhythm ◽  
Spinal Animal

The swimming musculature of spinal dogfish, Scyliorhinus canicula (L.), was paralysed with curare while recordings were made of the motor activity in the abdominal spinal nerves. Spontaneous, periodic motor bursts of long duration and decreasing frequency were detected during the first 2 h or so of the experiment. The spinal neurons were incapable of sustaining motor activity for more than 1 or 2 h and were dependent on proprioceptive feedback to maintain their excitability; their discharge frequency could, however, be enhanced by un-patterned sensory stimulation.The spinal neurons on each side of the cord are sufficiently organized to dis-charge alternately but the longitudinal co-ordination of the locomotory wave is disrupted in the absence of phasic sensory excitation.INTRODUCTIONIt has been assumed that the locomotory movements of spinal dogfish, which persist with undiminished vigour for several hours, are co-ordinated in one of two ways. One possibility is that the entire periodic motor output is formulated by the nerve cells of the spinal cord (Gray & Sand, 1936 a, b; Le Mare, 1936); alternatively, it is conceivable that the motor pattern is triggered by sensory signals fed back to the spinal cord by proprioceptors stimulated during locomotory movements (ten Cate, 1933; Lissmann, 1946a, b).Lissmann attempted to distinguish between these two general hypotheses by cutting all the dorsal roots of spinal dogfish and thereby isolating the spinal neurons from sensory stimulation. His experiments showed that the spinal animal would swim normally even when a considerable number of dorsal roots had been sectioned but as complete de-afferentation produced im-mobile preparations he concluded'that the motor rhythm was ultimately dependent on proprioceptive activity.

Physiology in Relation to Psychological Medicine

1928 ◽  
Vol 74 (307) ◽  
pp. 647-652
Author(s):  
B. A. McSwiney
Keyword(s):  
Nervous System ◽  
Normal Activity ◽  
Voluntary Contraction ◽  
The Body ◽  
Cerebral Function ◽  
Physiological Factors ◽  
Quantitative Measurements ◽  
Psychological Medicine ◽  
Spinal Animal ◽  
The Brain

An invitation to address a gathering of medical psychologists is, to the physiologist, a great temptation, and on such occasions he is apt to leap into the whirlpools of psychology in an attempt to explain the workings of the brain by hypotheses based, alas, on insufficient evidence. The paucity of information on cerebral function in physiological text-books has an explanation. Our lack of knowledge is due to the absence of available methods for investigating the normal activity of the higher nerve centres. Explanations are too often advanced without a due appreciation of the function of the lower nervous system in bringing about the exquisite co-ordination and relationship that exists between the different areas and organs of the body. This function is well exemplified in the reciprocal innervation of which we have evidence with every normal voluntary contraction. The difficulties of investigation have their root in the complexity of the reactions of an animal endowed with a well-developed cerebral cortex, compared with those seen in the lower types of life, or in the spinal animal. It must be clear that if our knowledge of the physiological factors controlling mental activity is to advance, the physiologist must continue to make measurements, accurate, quantitative measurements, if possible, on structures which he can control, and on preparations in which he is able to isolate the disturbing factors, and from these results and conclusions to construct by slow degrees a knowledge and understanding of the nervous system.

On the innervation of antagonistic muscles. Sixth note

1900 ◽  
Vol 66 (424-433) ◽  
pp. 66-67 ◽  
Keyword(s):  
Spinal Reflexes ◽  
Spinal Animal ◽  
Antagonistic Muscles

Machine-like regularity and fatality of reaction, although charac­teristic of spinal reflexes, is yet not exemplified by them to such extent that similar stimuli will always elicit from the spinal animal similar responses. This want of certainty as to response is an interesting difficulty attending the study of spinal reactions.

scholarly journals On the Spinal Animal Being the Marshall Hall Prize Address

1899 ◽  
Vol MCT-82 (1) ◽  
pp. 449-477 ◽  
Author(s):  
Charles S. Sherrington
Keyword(s):  
Spinal Animal

scholarly journals Oxidation and storage of glucose under the action of insulin

1926 ◽  
Vol 100 (700) ◽  
pp. 55-71 ◽  
Keyword(s):  
Oxygen Consumption ◽  
Simultaneous Measurement ◽  
Balance Sheet ◽  
Quantitative Test ◽  
Spinal Animal ◽  
And Storage

Experiments published by three of us (B., H., and M.) (1) have demonstrated that, in a spinal animal with the muscles at rest, a large part of the glucose disappearing from the circulation under the action of insulin is deposited as glycogen in the muscles. The view that the remainder, which was in most cases the larger, and in some cases the much larger part, had been oxidized, was quite compatible with the observations of Burn and Dale (2), who had measured the oxygen consumption, but not the glycogen increase, under similar conditions. It was important, however, to put this possibility to a quantitative test by simultaneous measurement of the consumption of oxygen and the accumulation of glycogen in the same preparation. The experiments here described represent such an attempt to make a complete experimental balance sheet, representing the fate of the whole of the glucose. The methods of making the preparation, infusing glucose, and taking samples for analysis were identical with those described in earlier papers ( (1) and (2) ), the eviscerated spinal cat being used in all cases.

THE CAUSE OF REFLEX AFTERDISCHARGE IN THE FROG'S SPINAL CORD

1956 ◽  
Vol 34 (1) ◽  
pp. 456-465
Author(s):  
B. Delisle Burns
Keyword(s):  
Spinal Cord ◽  
Electrical Stimulation ◽  
Biceps Femoris ◽  
Single Stimulus ◽  
Spinal Reflex ◽  
Reflex Response ◽  
Strong Stimulus ◽  
Spinal Animal ◽  
Reflex Stimulation ◽  
Stimulation Of

It is usually assumed that spinal reflex afterdischarge in the decerebrate or spinal animal is due to functional circuits of interneurons around which excitation can "chase its own tail" until fatigue brings the process to an end. This hypothesis has been tested in the frog. Reflex afterdischarge of motoneurons innervating the biceps femoris was produced by electrical stimulation of the ipsilateral foot. After the end of reflex stimulation, but during the afterdischarge, a direct single stimulus was applied to the animal's spinal cord. A strength of stimulus (of duration greater than five milliseconds) could always be found which would terminate the afterdischarge abruptly. This strong stimulus did not halt the afterdischarge by producing transient damage to the neurons of the cord, for when the stimulus was given during stimulation of the foot, there was no interruption of either reflex response or afterdischarge. Such experimental results are consistent with Forbes' hypothesis of reverberatory circuits.

Inhibiting the hyperreflexic bladder with electrical stimulation in a spinal animal model

1993 ◽  
Vol 12 (3) ◽  
pp. 241-252 ◽  
Author(s):  
James S. Walter ◽  
John S. Wheeler ◽  
Charles J. Robinson ◽  
Robert D. Wurster
Keyword(s):  
Animal Model ◽  
Electrical Stimulation ◽  
Spinal Animal
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