scholarly journals Fuxianhuiid ventral nerve cord and early nervous system evolution in Panarthropoda

2016 ◽  
Vol 113 (11) ◽  
pp. 2988-2993 ◽  
Author(s):  
Jie Yang ◽  
Javier Ortega-Hernández ◽  
Nicholas J. Butterfield ◽  
Yu Liu ◽  
George S. Boyan ◽  
...  
Keyword(s):  
Nervous System ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
The Body ◽  
Crown Group ◽  
Ground Pattern ◽  
Exceptional Preservation ◽  
Stem Group ◽  
Nervous System Evolution ◽  
Neurological Features

Panarthropods are typified by disparate grades of neurological organization reflecting a complex evolutionary history. The fossil record offers a unique opportunity to reconstruct early character evolution of the nervous system via exceptional preservation in extinct representatives. Here we describe the neurological architecture of the ventral nerve cord (VNC) in the upper-stem group euarthropodChengjiangocaris kunmingensisfrom the early Cambrian Xiaoshiba Lagerstätte (South China). The VNC ofC. kunmingensiscomprises a homonymous series of condensed ganglia that extend throughout the body, each associated with a pair of biramous limbs. Submillimetric preservation reveals numerous segmental and intersegmental nerve roots emerging from both sides of the VNC, which correspond topologically to the peripheral nerves of extant Priapulida and Onychophora. The fuxianhuiid VNC indicates that ancestral neurological features of Ecdysozoa persisted into derived members of stem-group Euarthropoda but were later lost in crown-group representatives. These findings illuminate the VNC ground pattern in Panarthropoda and suggest the independent secondary loss of cycloneuralian-like neurological characters in Tardigrada and Euarthropoda.

scholarly journals Mutations Affecting Nerve Attachment of Caenorhabditis elegans

Genetics ◽  
2001 ◽  
Vol 157 (4) ◽  
pp. 1611-1622 ◽  
Author(s):  
Go Shioi ◽  
Michinari Shoji ◽  
Masashi Nakamura ◽  
Takeshi Ishihara ◽  
Isao Katsura ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Body Wall ◽  
The Body ◽  
Genetic Loci ◽  
Muscle Attachment ◽  
C Elegans ◽  
Ventral Cord ◽  
Excretory Canal

Abstract Using a pan-neuronal GFP marker, a morphological screen was performed to detect Caenorhabditis elegans larval lethal mutants with severely disorganized major nerve cords. We recovered and characterized 21 mutants that displayed displacement or detachment of the ventral nerve cord from the body wall (Ven: ventral cord abnormal). Six mutations defined three novel genetic loci: ven-1, ven-2, and ven-3. Fifteen mutations proved to be alleles of previously identified muscle attachment/positioning genes, mup-4, mua-1, mua-5, and mua-6. All the mutants also displayed muscle attachment/positioning defects characteristic of mua/mup mutants. The pan-neuronal GFP marker also revealed that mutants of other mua/mup loci, such as mup-1, mup-2, and mua-2, exhibited the Ven defect. The hypodermis, the excretory canal, and the gonad were morphologically abnormal in some of the mutants. The pleiotropic nature of the defects indicates that ven and mua/mup genes are required generally for the maintenance of attachment of tissues to the body wall in C. elegans.

The ventral nerve cord in Cephalocarida (Crustacea): New insights into the ground pattern of Tetraconata

2013 ◽  
Vol 275 (3) ◽  
pp. 269-294 ◽  
Author(s):  
Martin E.J. Stegner ◽  
Georg Brenneis ◽  
Stefan Richter
Keyword(s):  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Ground Pattern

scholarly journals MUSCLE TENSION AND REFLEXES IN THE EARTHWORM

1923 ◽  
Vol 5 (3) ◽  
pp. 327-333 ◽  
Author(s):  
A. R. Moore
Keyword(s):  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Body Wall ◽  
Muscle Tension ◽  
Posterior Part ◽  
The Body ◽  
Entire Length ◽  
Sensory Cells ◽  
Ventral Region ◽  
Anterior Segments

1. By the use of preparations of earthworm in which the cutaneous receptors have been anesthetized with a solution of M/8 MgCl2, it is shown that peristalsis can be initiated by tension alone. 2. The receptors of the tension reflex are the intermyal sensory cells of the ventral region of the body wall. 3. It is concluded that Straub obtained the tension reflex because his preparations contained the intermyal receptors; Budington was unable to observe the tension reflex in any preparation from which the intermyal receptors had been removed. 4. Intermyal receptors are the receptors of the following reaction: Passive unilateral tension of the posterior part of an earthworm induces active homolateral tension of the musculature of the anterior segments, and results in the course of progress being brought into line with the enforced orientation of the tail. This reaction is termed the homostrophic reflex. 5. The receptors for the reaction are distributed throughout the entire length of the worm, the effectors are limited to the anterior 15 to 20 segments. The impulse is conducted by the ventral nerve cord. 6. The interaction of the homostrophic reflex and tropisms is considered.

The Giant Nerve-Fibres in the Central Nervous System of Myxicola (Polychaeta, Sabellidae)

1948 ◽  
Vol s3-89 (5) ◽  
pp. 1-45
Author(s):  
J.A. C. NICOL
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Nerve Cord ◽  
Size Structure ◽  
Nerve Cells ◽  
The Body ◽  
Usual Sense ◽  
Fibrous Sheath ◽  
Giant Fibre ◽  
The Central Nervous System

1. A description is given of the main features of the central nervous system of Myxicola infundibulum Rénier. 2. The nerve-cord is double in the first four thoracic segments and single posteriorly. It shows segmental swellings but is not ganglionated in the usual sense in that nerve-cell accumulations are not related directly to such swellings of the cord. 3. A very large axon lies within the dorsal portion of the nerve-cord and extends from the supra-oesophageal ganglia to the posterior end of the animal. It is small in the head ganglia where it passes transversely across the mid-line, increases in diameter in the oesophageal connectives, and expands to very large size, up to 1 mm., in the posterior thorax and anterior abdomen, and gradually tapers off to about 100µ in the posterior body. It shows segmental swellings corresponding to those of the nerve-cord in each segment. It occupies about 27 per cent, of the volume of the central nervous system and 0.3 per cent, of the volume of the animal. The diameter of the fibre increases during contraction of the worm. 4. The giant fibre is a continuous structure throughout its length, without internal dividing membranes or septa. Usually a branch of the giant fibre lies in each half of the nerve-cord in the anterior thoracic segments and these several branches are continuous with one another longitudinally and transversely. 5. The giant fibre is connected with nerve-cells along its entire course; it arises from a pair of cells in the supra-oesophageal ganglia, and receives the processes of many nerve-cells in each segment. There is no difference between the nerve-cells of the giant fibre and the other nerve-cells of the cord. 6. A distinct fibrous sheath invests the giant fibre. A slight concentration of lipoid can be revealed in this sheath by the use of Sudan black. 7. About eight peripheral branches arise from the giant fibre in each segment. They have a complex course in the nerve-cord where they anastomose with one another and receive the processes of nerve-cells. Peripherally, they are distributed to the longitudinal musculature. 8. Specimens surviving 16 days following section of the nerve-cord in the thorax have shown that the giant fibre does not degenerate in front of or behind a cut, thus confirming that it is a multicellular structure connected to nerve-cells in the thorax and abdomen. 9. It is concluded that the giant fibre of M. infundibulum is a large syncytial structure, extending throughout the entire central nervous system and the body-wall of the animal. 10. The giant fibre system of M. aesthetica resembles that of M. infundibulum. 11. Some implications of the possession of such a giant axon are discussed. It is suggested that its size, structure, and simplicity lead to rapid conduction and thus effect a considerable saving of reaction time, of considerable value to the species when considered in the light of the quick contraction which it mediates. The adoption of a sedentary mode of existence has permitted this portion of the central nervous system to become developed at the expense of other elements concerned with errant habits.

Distribution of gamma-aminobutyric acid (GABA) in the central nervous system of the male mud crab, Scylla olivacea

Crustaceana ◽  
2020 ◽  
Vol 93 (9-10) ◽  
pp. 1123-1134
Author(s):  
Kanjana Khornchatri ◽  
Jirawat Saetan ◽  
Sirirak Mukem ◽  
Prasert Sobhon ◽  
Tipsuda Thongbuakaew
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Distribution Pattern ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Mud Crab ◽  
Decapod Crustaceans ◽  
The Central Nervous System

Abstract Gamma-aminobutyric acid (GABA) is a neurotransmitter that is widely spread in vertebrate and invertebrate nervous systems and modulates essential physiological roles. Previous studies have reported the distribution of several neurotransmitters throughout the central nervous system (CNS) of decapod crustaceans. However, the existence and distribution of GABA in the mud crab’s, Scylla olivacea, CNS has still not been reported. In this study, we investigated the distribution of GABA using immunohistochemistry. The result revealed that GABA immunoreactivity (-ir) was observed in neurons and fibres throughout the CNS, including the eyestalk, brain, and ventral nerve cord of S. olivacea. Therefore, the existence and extensive distribution pattern of GABA in the CNS of the male mud crab suggest its possible roles in feeding, locomotion, and also reproduction.

The ventral nerve cord in cephalocarida (Crustacea): New insights into the ground pattern of tetraconata

2014 ◽  
Vol 275 (3) ◽  
pp. NA-NA
Author(s):  
Martin E.J. Stegner ◽  
Georg Brenneis ◽  
Stefan Richter
Keyword(s):  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Ground Pattern

First detection of serotonin in the nervous system of the marine calanoid copepod Centropages typicus

2005 ◽  
Vol 85 (1) ◽  
pp. 71-72 ◽  
Author(s):  
D. Benzid ◽  
C. Morris ◽  
R.-M. Barthélémy
Keyword(s):  
Nervous System ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Calanoid Copepod ◽  
Marine Species ◽  
Biological Processes ◽  
Calanoid Copepods ◽  
The Brain ◽  
Serotoninergic Nervous System ◽  
Centropages Typicus

This investigation constitutes the first study of the serotoninergic nervous system in calanoid copepods (crustaceans). Serotonin (5-HT), a neurotransmitter which plays a part in many biological processes, has been detected by immunofluorescence in the brain, the circumoesophageal collar and the ventral nerve cord of the marine species Centropages typicus.

Vasculitis and collagen vascular diseases

2011 ◽  
Author(s):  
Neil Scolding
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Systemic Disease ◽  
Central Nervous System Involvement ◽  
Disease Diagnosis ◽  
The Body ◽  
Therapeutic Trial ◽  
Collagen Vascular Diseases ◽  
Diagnosis And Management ◽  
Neurological Features

That part of the clinical interface between neurology and general medicine occupied by inflammatory and immunological diseases is neither small nor medically trivial. Neurologists readily accept the challenges of ‘primary’ immune diseases of the nervous system: these tend to be focussed on one particular target such as oligodendrocytes or the neuro-muscular junction present in predictable ways, and are amenable as a rule to rational, methodological diagnosis, and occasionally even treatment. This is proper neurology.‘Secondary’ neurological involvement in diseases mainly considered systemic inflammatory conditions—for example, SLE, sarcoidosis, vasculitis, and Behçet’s—is a rather different matter. It may be difficult enough to secure such a diagnosis even when systemic disease has previously been diagnosed and new neurological features need to be differentiated from iatrogenic disease, particularly drug side effects or the consequences of immune suppression. But all the diseases mentioned may present with and confine themselves wholly to the nervous system; they may mimic one another, and pursue erratic and unpredictable clinical courses. In central nervous system disease, diagnosis by tissue biopsy is potentially hazardous and unattractive. Few neurologists enjoy excesses of confidence or expertise when faced with such clinical problems: the cautious diagnostician is perplexed, and the evidence-based neuroprescriber confounded. Unsurprisingly, great variations in approaches to diagnosis and management are seen (Scolding et al. 2002b).But rheumatologically inclined general, renal or respiratory physicians, comfortable when managing inflammation affecting their system or indeed other parts of the body designed to support the nervous system, are generally also ill at ease when faced with neurological features whose differential diagnosis may be large, particularly given the near universal diagnostic non-specificity of either imaging or CSF analysis.Here then is the subject material for this chapter: the diagnosis and management of central nervous system involvement in inflammatory and immunological systemic diseases (Scolding 1999a). In not one of these neurological conditions has a single controlled therapeutic trial been reported, and much that is published on these conditions is misleading or inaccurate. And yet the frequency with which the diagnosis is only confirmed or even first emerges at autopsy bears stark witness to both the severity and evasiveness of these disorders.

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