Some effects of de-afferentation on the developing amphibian nervous system

Development ◽  
1965 ◽  
Vol 14 (1) ◽  
pp. 75-87
Author(s):  
Arthur Hughes
Keyword(s):  
Nervous System ◽  
Quantitative Study ◽  
Peripheral Nerves ◽  
Hind Limb ◽  
Sensory Input ◽  
Bufo Marinus ◽  
Degenerative Changes ◽  
Normal Embryo

An adult anuran can still walk or swim if the nerves supplying one or even two limbs are de-afferentated (Gray, 1950). However, in a developing amphibian, a limb at motile stages becomes paralysed when deprived of its sensory input. A sequence of degenerative changes then follow in the cord and in peripheral nerves. Tadpoles of Bufo marinus and late embryos of Eleutherodactylus martinicensis have been submitted to this experiment; in these tropical forms the subsequent events follow rapidly. Most attention has been paid to Eleutherodactylus, on which a quantitative study of the numbers of fibres in nerves to the hind limb during development has recently been published (Hughes, 1965a). This work, together with a study of the behaviour of the normal embryo (Hughes, 1965b) has been used as a basis for the present experimental observations. The source of the embryos of E. martinicensis and the methods of culturing and observing them remain the same as in previous studies (Hughes, 1962,1964a & b, 1965a & b).

The thyroid and the development of the nervous system in Eleutherodactylus martinicensis: an experimental study

Development ◽  
1966 ◽  
Vol 16 (3) ◽  
pp. 401-430
Author(s):  
Arthur Hughes
Keyword(s):  
Experimental Study ◽  
Nervous System ◽  
Thyroid Hormones ◽  
Peripheral Nervous System ◽  
Peripheral Nerves ◽  
Hind Limb ◽  
Endocrine System ◽  
Normal Embryo ◽  
Stages Of Development ◽  
Quantitative Studies

In a recent paper (Hughes, 1965a) the ontogeny of the peripheral nervous system in Eleutherodactylus martinicensis was studied by counting the numbers of constituent fibres in the nerves of the hind limb at several stages of development. Eleutherodactylus is one of the smallest of living tetrapods and such quantitative studies are aided by the comparatively small numbers of fibres within its peripheral nerves. The next step in the analysis of the various changes which occur simultaneously in the normal embryo is to attempt to disengage them by some treatment which affects the general course or development. Interference with the endocrine system of the embryo is one obvious line of investigation, more particularly as a number of events in the development of the nervous system in other vertebrates have been shown to be influenced by thyroid hormones. The action of the thyroid in Eleutherodactylus has already been investigated by Lynn & Peadon (1955).

A quantitative study of the development of the nerves in the hind-limb of Eleutherodactylus martinicensis

Development ◽  
1965 ◽  
Vol 13 (1) ◽  
pp. 9-34
Author(s):  
Arthur Hughes
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
Peripheral Nervous System ◽  
Quantitative Study ◽  
Hind Limb ◽  
The Caribbean

The present study is part of an attempt to collect information by different methods of approach to the development of the peripheral nervous system in the Caribbean Bufonid Eleutherodactylus martinicensis. Because of the small size and the rapidity of development of this animal, particular problems can be attempted with special and, in some instances, with unique facility. The present study is mainly concerned with changes in the number of constituent fibres in the nerves of the hind-limb during development. Here, where the number of fibres in any nerve never much exceeds a thousand, quantitative study is a less formidable task than in larger creatures. In other Anura, for instance, numbers would be at least five times greater. Although the fibres at particular sites of the adult nervous system have been counted, as for instance by Häggqvist (1936) in the spinal cord of man, and by Dunn (1902) in the limb nerves of the Frog, it does not seem that comparable studies on any developing animal have been undertaken.

Preparing for the unpredictable: adaptive feedback enhances the response to unexpected communication signals

2012 ◽  
Vol 107 (4) ◽  
pp. 1241-1246 ◽  
Author(s):  
Gary Marsat ◽  
Leonard Maler
Keyword(s):  
Nervous System ◽  
Sensory Input ◽  
Low Frequency ◽  
Excitatory Input ◽  
Negative Image ◽  
Communication Signals ◽  
First Order ◽  
Communication Signal ◽  
Apical Dendrites ◽  
Spike Bursts

To interact with the environment efficiently, the nervous system must generate expectations about redundant sensory signals and detect unexpected ones. Neural circuits can, for example, compare a prediction of the sensory signal that was generated by the nervous system with the incoming sensory input, to generate a response selective to novel stimuli. In the first-order electrosensory neurons of a gymnotiform electric fish, a negative image of low-frequency redundant communication signals is subtracted from the neural response via feedback, allowing unpredictable signals to be extracted. Here we show that the cancelling feedback not only suppresses the predictable signal but also actively enhances the response to the unpredictable communication signal. A transient mismatch between the predictive feedback and incoming sensory input causes both to be positive: the soma is suddenly depolarized by the unpredictable input, whereas the neuron's apical dendrites remain depolarized by the lagging cancelling feedback. The apical dendrites allow the backpropagation of somatic spikes. We show that backpropagation is enhanced when the dendrites are depolarized, causing the unpredictable excitatory input to evoke spike bursts. As a consequence, the feedback driven by a predictable low-frequency signal not only suppresses the response to a redundant stimulus but also induces a bursting response triggered by unpredictable communication signals.

scholarly journals STUDIES ON THE NERVOUS SYSTEM IN DEFICIENCY DISEASES

1934 ◽  
Vol 59 (1) ◽  
pp. 21-34 ◽  
Author(s):  
H. M. Zimmerman ◽  
Ethel Burack
Keyword(s):  
Nervous System ◽  
Peripheral Nerves ◽  
Progressive Disease ◽  
Water Soluble ◽  
Persistent Vomiting ◽  
Fiber Tracts ◽  
Heat Stable ◽  
Loss Of Weight ◽  
The Central Nervous System ◽  
Deficiency Diseases

Adult dogs maintained on an artificial, balanced ration adequate in all dietary essentials as far as is known except water-soluble, heat-stable vitamin B2 (G) developed, after a sufficient time, a slowly progressive disease characterized by loss of weight, persistent vomiting and diarrhea, and marked muscular weakness, which ended fatally in from 200 to over 300 days. The clinical features of this condition, as pointed out in the discussion, are quite different from those characterizing the canine disease known as black tongue. The anatomic changes in this condition consist of marked demyelination of the peripheral nerves, including the vagus; degeneration of the medullary sheaths and replacement by gliosis of the posterior columns of the spinal cord, particularly the fasciculi graciles; degeneration of the medullary sheaths of the posterior and less often of the anterior nerve roots of the cord; occasionally slight degenerative changes in most of the other fiber tracts of the cord. Attention is called to the fact that degenerative lesions in the central nervous system similar or identical with these have frequently been described in pellagra in man.

ULTRASONIC STUDY IN DIAGNOSTICS OF PERIPHERAL NEUROPATHIES (CASE FROM PRACTICE)

2021 ◽  
pp. 144-146
Author(s):  
Hamanovich A.I. ◽  
◽  
Baida A.G. ◽  
Koyalo L.G. ◽  
Levantsevich V.V. ◽  
...  
Keyword(s):  
Nervous System ◽  
Gold Standard ◽  
Peripheral Nerves ◽  
Peroneal Nerve ◽  
Clinical Case ◽  
Clinical Symptoms ◽  
Nerve Trunk ◽  
Peripheral Neuropathies ◽  
Ultrasound Scanning ◽  
Electrophysiological Methods

Electrophysiological methods, such as electromyography and neuromyography, are traditionally recognized as the "gold standard" for detecting pathology of the peripheral nervous system. It should be noted, however, that the information obtained during the above examinations does not give an idea of the state of the surrounding tissues, does not indicate the nature and cause of damage to the nerve trunk, and does not always accurately reflect the localization of changes. At the same time, it is this information that helps to determine the tactics of conservative or surgical treatment of the patient. Ultrasound scanning is quite successfully used in the diagnosis of damage and diseases of the peripheral nerves. The article presents a clinical case of a diagnostic search for a causative disease in a patient with clinical symptoms of neuropathy of the peroneal nerve.

Serologic differentiation of peripheral nerves (especially the autonomic nervous system) from the cerebral cortex

1935 ◽  
Vol 31 (7) ◽  
pp. 909-909
Author(s):  
F. Plaut
Keyword(s):  
Nervous System ◽  
Cerebral Cortex ◽  
Autonomic Nervous System ◽  
Peripheral Nerves ◽  
Autonomic Nervous

The author showed that the sera obtained by immunizing rabbits with a suspension of n. sympathicus and n. vagus, do not show specific properties when tested with alcoholic extracts from the same nerves; these serums have only the properties of ordinary neuroanti-serums.

scholarly journals Lankesterella alencari n. sp., a toxoplasma-like organism in the central nervous system of Amphibia (Protozoa, Sporozoa)

1971 ◽  
Vol 69 (3) ◽  
pp. 397-411 ◽  
Author(s):  
Sylvio Celso Gonçalves da Costa ◽  
Neize de Moura Pereira
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Ascitic Fluid ◽  
Intraperitoneal Injection ◽  
Bufo Marinus ◽  
South American ◽  
Susceptible Host ◽  
Experimental Inoculation ◽  
The Central Nervous System ◽  
American Frog

Lankesterella alencari n. sp. a Sporozoa that occur in the blood and CNS of the South American frog Leptodactylus acellatus is described. Since the tissue forms of this parasite have been previously reported as belonging to the genus Toxoplasma, we attempted in fection of 2 species of amphibia (Bufo marinus an dLeptodactylus ocellatus) with a Toxoplasma strain of human origen; inoculation was by intraperitoneal injection of parasite-containing ascitic fluid from infected mice. Attempt of experimental inoculation of the parasite found in the CNS of L. ocellatus in a highly susceptible host (mice) was unsuccessful. These results suggest that Toxoplasma does not occur naturally in the amphibia; be related to Toxoplasma is excluded. The following genera of haematozoa found in brazilian amphibia have been considered briedfly: Haemobartonella, Cytamoeba, Dactylosoma, Hepatozoon and Trypanosoma.

On the Restoration of the Peripheral Nerves [Ueber die Regeneration peripherischer Nerven]. (Arch. f. Psychiat., Bd. xxxv, H. 3.) Bethe

1902 ◽  
Vol 48 (200) ◽  
pp. 147-148
Author(s):  
William W. Ireland
Keyword(s):  
Nervous System ◽  
Nerve Cell ◽  
Peripheral Nerves ◽  
Ganglion Cells ◽  
Pathological Process ◽  
Cell Theory ◽  
Intimate Connection ◽  
Neuron Theory

At the meeting of German neurologists and alienist physicians in Baden-Baden, June, 1901, Dr. Bethe, of Strasburg, explained that during the last decade a new nerve-cell theory had come into vogue. It was assumed that the so-called neuron was an anatomical, functional, pathological, and developmental entity. But it had been shown by Apáthy that there is a direct and intimate connection between the neurons through the primitive nerve-fibrillæ, and Dr. Bethe himself had demonstrated that in the carcinas mænas the nervous system performs its function without any ganglion cells. Thus the cell cannot be a necessary instrument in the process like the pendulum of a clock, or the wheel of a watch. Nissl has shown that the observations of pathologists give no sure support to the neuron theory. Further objections may be taken from the fact that several organs are affected after section of the nerves supplying them. In the case of degeneration of muscles and glands, it may be said that this process may be owing to atrophy from inactivity of their functions; but degeneration of the papillæ circumvallatæ et foliatæ of the tongue in the rabbit has been observed to follow, in from about two to three weeks after section of the glossopharyngeals, although the stimulus has not ceased to be applied to these organs. From this it appears that the pathological process goes further than the boundary of the neuron.

Spatial aspects of neural induction in Xenopus laevis

Development ◽  
1989 ◽  
Vol 107 (4) ◽  
pp. 785-791 ◽  
Author(s):  
E.A. Jones ◽  
H.R. Woodland
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Peripheral Nerves ◽  
Neural Differentiation ◽  
Neural Induction ◽  
Neural Tissue ◽  
Thoracic Region ◽  
Lateral Extent ◽  
Tail Tip ◽  
Developing Nervous System

A monoclonal antibody, 2G9, has been identified and characterised as a marker of neural differentiation in Xenopus. The epitope is present throughout the adult central nervous system and in peripheral nerves. Staining is first detected in embryos at stage 21 in the thoracic region. By stage 29 it stains the whole central nervous system, except the tail tip. The epitope is present in a 65K Mr protein, and includes sialic acid. The antibody also reacts with neural tissue in mice and axolotls and newts. 2G9 was used to show that both notochord and somites are capable of neural induction, and the stimulus is present as late as stage 22. Attempts to demonstrate the induction of nervous system by developing nervous system (homoiogenetic induction) were unsuccessful. The view that the lateral extent of the nervous system might be determined by that of the inductive stimulus is discussed. Neural induction was detected as early as stage 10 and occurs in embryos without gastrulation and without cell division from stage 7 1/2.

Discharge Patterns of Coxal Levator and Depressor Motoneurones of the Cockroach, Periplaneta Americana

1970 ◽  
Vol 52 (1) ◽  
pp. 139-165
Author(s):  
K. G. PEARSON ◽  
J. F. ILES
Keyword(s):  
Peripheral Nerves ◽  
Sensory Input ◽  
Periplaneta Americana ◽  
Motor Axon ◽  
Extracellular Recordings ◽  
Before And After ◽  
Collateral Pathways ◽  
Discharge Patterns ◽  
Flexion And Extension ◽  
Leg Movements

1. Observation of movements of the metathoracic legs of the cockroach before and after section of peripheral nerves allowed identification of muscles involved in flexion and extension of the femur. 2. Extracellular recordings from the nerves to these coxal muscles show that during rhythmic leg movements bursts of activity in a number of levator motor axons were strongly reciprocal and generally non-overlapping with those of a slow depressor motor axon. 3. These reciprocal patterns persisted after removal of all sensory input from the legs. 4. The durations of levator bursts were relatively constant compared to those of the depressor, corresponding to the behavioural observations on leg protraction time. The pattern was asymmetric: levator bursts could be generated without depressor activity, but never the reverse. 5. No evidence was found for inhibitory collateral pathways between antagonist motoneurones. 6. It is proposed that levator motoneurones are driven by a group of bursting interneurones which simultaneously inhibit the ongoing depressor activity.

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