An Electrophysiological Study of the Anatomical Relations of Two Giant Nerve Cells in Aplysia Depilans

1963 ◽  
Vol 40 (3) ◽  
pp. 469-486
Author(s):  
G. M. HUGHES
Keyword(s):  
Nervous System ◽  
Electrophysiological Study ◽  
Somatic Membrane ◽  
Mechanical Pressure ◽  
Direct Stimulation ◽  
Antidromic Stimulation ◽  
Large Spike ◽  
The Right ◽  
Pleural Ganglion ◽  
Stimulation Of

1. On either side of the nervous system in Aplysiathere is a giant cell (RGC and LGC) whose axon branches within the nervous system. The distribution of these branches has been traced in experiments involving stimulation and recording and the use of intracellular electrodes (in the soma) and extracellular electrodes (on nerves containing the axons). 2. On the right side the RGC sends an axon along the pleuro-visceral connective to the pleural-pedal ganglia where it divides and gives branches to the cerebro-pleural connective and each of the main nerves supplying the foot and parapodium. 3. Stimulation of any nerve containing a branch of this axon produces a large spike in the right connective and an antidromic potential in the soma. Transmission between the different branches is not always easy following antidromic stimulation but is always present in the orthodromic direction whether produced synaptically, by direct stimulation of the soma, or by mechanical pressure applied to the somatic membrane. 4. The LGC soma is in the left pleural ganglion near the origin of the left pleurovisceral connective. Similar techniques have shown that this cell sends branches to the corresponding nerves on the left side. 5. An hypothesis is suggested to account for the presence of the cell bodies of the RGC and LGC in two different ganglia, despite the similarities in branching of their axons. Possibly differences during torsion and detorsion in the fate of the ganglia in which these cells originate may account for their different locations in the adult. 6. The function of the RGC was investigated in whole-animal preparations. Although it tends to discharge when the animal makes spontaneous protective movements or is touched anywhere on its surface, stimulation of the cell directly through an intracellular electrode gives no overt movements of the animal.

scholarly journals VI. —Anaphylaxis and anaphylatoxins

1923 ◽  
Vol 211 (382-390) ◽  
pp. 273-315 ◽  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Guinea Pig ◽  
Anaphylactic Shock ◽  
The Body ◽  
Muscle Fibres ◽  
Direct Stimulation ◽  
Fundamental Conception ◽  
The Central Nervous System ◽  
Stimulation Of

In the study of the phenomena of anaphylaxis there are certain points on which some measure of agreement seems to have been attained. In the case of anaphylaxis to soluble proteins, with which alone we are directly concerned in this paper, the majority of investigators probably accept the view that the condition is due to the formation of an antibody of the precipitin type. Concerning the method, however, by which the presence of this antibody causes the specific sensitiveness, the means by which its interaction with the antibody produces the anaphylactic shock, there is a wide divergence of conception. Two main currents of speculation can be discerned. One view, historically rather the earlier, and first put forward by Besredka (1) attributes the anaphylactic condition to the location of the antibody in the body cells. There is not complete unanimity among adherents of this view as to the nature of the antibody concerned, or as to the class of cells containing it which are primarily affected in the anaphylactic shock. Besredka (2) himself has apparently not accepted the identification of the anaphylactic antibody with a precipitin, but regards it as belonging to a special class (sensibilisine). He also regards the cells of the central nervous system as those primarily involved in the anaphylactic shock in the guinea-pig. Others, including one of us (3), have found no adequate reason for rejecting the strong evidence in favour of the precipitin nature of the anaphylactic antibody, produced by Doerr and Russ (4), Weil (5), and others, and have accepted and confirmed the description of the rapid anaphylactic death in the guinea-pig as due to a direct stimulation of the plain-muscle fibres surrounding the bronchioles, causing valve-like obstruction of the lumen, and leading to asphyxia, with the characteristic fixed distension of the lungs, as first described by Auer and Lewis (6), and almost simultaneously by Biedl and Kraus (7). But the fundamental conception of anaphylaxis as due to cellular location of an antibody, and of the reaction as due to the union of antigen and antibody taking place in the protoplasm, is common to a number of workers who thus differ on details.

Non-contact mapping and ablation of tachycardia originating in the right ventricular outflow tract

2002 ◽  
Vol 12 (3) ◽  
pp. 294-297 ◽  
Author(s):  
Thomas Paul ◽  
Andrew T. D. Blaufox ◽  
J. Philip Saul
Keyword(s):  
Ventricular Tachycardia ◽  
Right Ventricular ◽  
Electrophysiological Study ◽  
Right Ventricular Outflow Tract ◽  
Ventricular Outflow Tract ◽  
Outflow Tract ◽  
Mechanical Pressure ◽  
Contact Mapping ◽  
The Right ◽  
Endocardial Activation

We performed an electrophysiological study, using non-contact mapping, in an 8-year-old girl weighing 39.9 kg who had suffered recurrent symptomatic episodes of exercise-induced non-sustained ventricular tachycardia. Color-coded isopotential maps of the ventricular tachycardia identified the area of earliest endocardial activation high and anterior in the right ventricular outflow tract. Although partial deflation of the balloon was required to position the ablation catheter at the earliest site of activation, this site was still identified accurately, as demonstrated by termination of the ventricular tachycardia and ectopy upon mechanical pressure, as well as application of radiofrequency current.In this young patient, precise mapping of the earliest endocardial activation using the non-contact mapping system was safe and effective, allowing successful radiofrequency ablation of the tachycardia.

Blood Pressure and Pulse Rate in the Foetal Sheep

1945 ◽  
Vol 22 (1-2) ◽  
pp. 63-74
Author(s):  
JOSEPH BARCROFT ◽  
D. H. BARRON
Keyword(s):  
Blood Pressure ◽  
Central Nervous System ◽  
Nervous System ◽  
Pulse Rate ◽  
Umbilical Artery ◽  
The Central Nervous System ◽  
The Right ◽  
First Moment ◽  
Left Vagus ◽  
Stimulation Of

1. A method (the needle method) is described for the measurement of the pressure in the stream going through a vessel. 2. In the foetal sheep the needle method applied to the umbilical artery gives substantially the same results as the mercurial manometer applied to the carotid, until about half-way through the gestation period. 3. As gestation proceeds the needle method applied at the first moment at which it can be applied to the umbilical artery (or a branch) gives readings substantially lower, and increasingly lower as gestation proceeds, than does the mercurial manometer read at the first moment at which it can be read. 4. The discrepancy is due to the sum of a number of causes which are discussed, but of these the most important is an actual rise of pressure between the time of delivery and the completion of the dissections contingent on the use of the mercurial manometer. 5. The cause of this is not at present demonstrated, but either or both of two factors may be concerned: (a) a dulling of the central nervous system which weakens the depressor reflex; (b) the establishment of a greater degree of vasomotor tone consequent on the bombardment of the central nervous system with sensory stimuli. 6. The pulse rates in utero and just after delivery of the foetus into a saline bath at 39-40°C. (the umbilical circulation being unimpaired) are not significantly different. 7. The pulse rate quickens up to the 70th-80th day, after which it becomes slower as gestation proceeds. 8. If both vagi be severed, the pulse rate te to quicken throughout gestation. The pulse, therefore, comes increasingly under vagus inhibition from the 80th-90th day onwards. 9. Even after the vagi have been cut after the 120th day (it has not been tried before) adrenalin in sufficient quantity will cause a further quickening of the pulse. 10. The earliest date at which stimulation of the peripheral end of the right vagus was observed to slow the heart was the 77th day. On the 85th day peripheral stimulation of the left vagus also failed, but succeeded on the 101st day. 11. Central stimulation of the left vagus, with the right vagus intact, produced slowing on the 77th day. 12. Slowing of the heart synchronous with rise of arterial pressure has been observed on the 111th day. 13. Slowing of the heart which bears evidence of being reflex has been obtained by raising the blood pressure (clamping the cord) on the 121st day and by injection of adrenalin on the 118th day. 14. Approaching term both the carotid sinus and cardiac depressor mechanisms are functional. 15. Lowering of the blood pressure as the result of stimulation of the central end of the vagus and with both vagi severed can be demonstrated late in gestation.

Objective high-frequency tinnitus of middle-ear myoclonus

2004 ◽  
Vol 118 (3) ◽  
pp. 231-233 ◽  
Author(s):  
Khader J. Abdul-Baqi
Keyword(s):  
Middle Ear ◽  
High Frequency ◽  
Rare Case ◽  
Rare Condition ◽  
Rhythmic Movements ◽  
Direct Stimulation ◽  
Objective Tinnitus ◽  
The Right ◽  
Otoscopic Examination ◽  
Stimulation Of

Tinnitus produced by middle-ear myoclonus is a rare condition. In this article, a rare case of unilateral continuous high-frequency objective tinnitus caused by middle-ear myoclonus is described. This condition appears to be the second case reported in the literature. Otoscopic examination revealed visible rhythmic movements of the tympanic membrane. Weak clicking sounds were heard around the right ear by auscultation. Direct stimulation of the soft palate showed no evidence of palated myoclonus. Tympanometry confirmed rhythmic changes in the middle-ear compliance. The condition was effectively treated with a muscle relaxant (orphenadrine citrate).

An Electrophysiological Study of the Photo-Excitative Neurones of Onchidium Verruculatum in Situ

1972 ◽  
Vol 57 (3) ◽  
pp. 661-671
Author(s):  
NOZOMU HISANO ◽  
HIDEKI TATEDA ◽  
MASUTARO KUWABARA
Keyword(s):  
Electrical Stimulation ◽  
Electrophysiological Study ◽  
Spontaneous Discharge ◽  
Light Stimulation ◽  
Direct Response ◽  
Intracellular Stimulation ◽  
The Right ◽  
Animal Preparation ◽  
Stimulation Of

1. The distribution of the axons of the photo-excitative neurones in Onchidium verruculatum has been traced by intracellular stimulation of the soma and extracellular stimulation of the axon. They send axon branches mainly into the pleuroparietal and abdominal nerves in both sides. 2. In the whole-animal preparation, photo-excitative spikes could be recorded from neither the soma nor the nerves of inherently photo-excitative neurones during light stimulation. ‘On’ and ‘off’ spikes were initiated only immediately after the beginning and the cessation of illumination of a whole animal. 3. ‘Off’ spikes originated from dorsal eyes and stalk eyes to which shadow stimuli were applied. Those spikes were not the direct response of photo-excitative neurones to light. 4. The excitation of the inherently photo-excitative neurones in situ was suppressed by inhibitory inputs coming through the right and left pleuro-parietal nerves. Cutting one (or some) of the pleuro-parietal nerves was the only condition that diminished the inhibitory inputs to the photo-excitative neurones in the present work. Adequate electrical stimulation of the pleuro-parietal nerves inhibited spikes of photo-excitative neurones due to photo-excitator or spontaneous discharge.

Neuronal organization of crayfish escape behavior: inhibition of giant motoneuron via a disynaptic pathway from other motoneurons

1977 ◽  
Vol 40 (5) ◽  
pp. 1078-1097 ◽  
Author(s):  
J. J. Wine
Keyword(s):  
Nervous System ◽  
Escape Behavior ◽  
Inhibitory Interneuron ◽  
Repetitive Stimulation ◽  
Inhibitory Interneurons ◽  
Neuronal Organization ◽  
Direct Stimulation ◽  
Monosynaptic Connection ◽  
Behavior Inhibition ◽  
Stimulation Of

1. A circuit that produces a 70-100 ms IPSP in the crayfish giant motoneuron is described. The IPSP is produced by a disynaptic pathway from the nongiant fast flexor motoneurons to the motor giant. 2. An inhibitory interneuron in the pathway has been identified. Its axon runs at least the entire length of the abdominal nervous system. The inhibitory interneuron is excited bilaterally in all abdominal ganglia except the last and bilaterally inhibits the motor giants thoughout the abdominal CNS. 3. Evidence for a monosynaptic connection between the interneuron and the motor giant includes short latency, stability during repetitive stimulation, gradual decrement in high-Mg2+ solutions, and persistence in high-Ca2+ solutions. Similar but less complete evidence suggests a monosynaptic connection from the fast flexor motoneurons to the inhibitory interneuron. 4. A single impulse in the inhibitor can produce a prolonged IPSP in the motor giant. The inhibitor did not display trains of impulses and was not spontaneously active. 5. The inhibitory interneuron appears to be highly specific; no other outputs were observed. 6. Direct stimulation of axons in the connectives suggests that four pairs of inhibitory interneurons converge on the motor giants; at least two pairs are activated by the fast flexor motoneurons. 7. This circuit limits the burst duration of the motor giant and may function to protect the motor giant's depression-prone neuromuscular junction.

scholarly journals Direct stimulation of the autonomic nervous system modulates activity of the brain at rest and when engaged in a cognitive task

2012 ◽  
Vol 34 (7) ◽  
pp. 1605-1614 ◽  
Author(s):  
Barbara Basile ◽  
Andrea Bassi ◽  
Giovanni Calcagnini ◽  
Stefano Strano ◽  
Carlo Caltagirone ◽  
...  
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Cognitive Task ◽  
Direct Stimulation ◽  
Autonomic Nervous ◽  
The Brain ◽  
Stimulation Of
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