Journal articles: 'Ventral nerve cord'

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Garriga, G., C. Desai, and H. R. Horvitz. "Cell interactions control the direction of outgrowth, branching and fasciculation of the HSN axons of Caenorhabditis elegans." Development 117, no. 3 (March 1, 1993): 1071–87. http://dx.doi.org/10.1242/dev.117.3.1071.

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The two serotonergic HSN motor neurons of the nematode Caenorhabditis elegans innervate the vulval muscles and stimulate egg laying by hermaphrodites. By analyzing mutant and laser-operated animals, we find that both epithelial cells of the developing vulva and axons of the ventral nerve cord are required for HSN axonal guidance. Vulval precursor cells help guide the growth cone of the emerging HSN axon to the ventral nerve cord. Vulval cells also cause the two HSN axons to join the ventral nerve cord in two separate fascicles and to defasciculate from the ventral nerve cord and branch at the vulva. The axons of either the PVP or PVQ neurons are also necessary for the HSN axons to run in two separate fascicles within the ventral nerve cord. Our observations indicate that the outgrowth of the HSN axon is controlled in multiple ways by both neuronal and nonneuronal cells.

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Temereva, Elena N. "Ventral nerve cord in Phoronopsis harmeri larvae." Journal of Experimental Zoology Part B: Molecular and Developmental Evolution 318B, no. 1 (September 6, 2011): 26–34. http://dx.doi.org/10.1002/jez.b.21437.

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Thompson, K. J. "Oviposition digging in the grasshopper. II. Descending neural control." Journal of Experimental Biology 122, no. 1 (May 1, 1986): 413–25. http://dx.doi.org/10.1242/jeb.122.1.413.

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Transection of the ventral nerve cord of female grasshoppers activates the rhythmical motor programme for oviposition digging. Electrical stimulation of the cut nerve cord had the following effects on elicited oviposition motor activity: short- and long-lasting inhibition of activity, phase resetting and modulation of burst frequency. Cold saline applied to the nerve cord reversibly elicited the oviposition motor programme. The effects of transection and stimulation at different levels of the nerve cord indicate that the higher neural control of the motor pattern is not confined to the head ganglia, but includes a thoracic component. In intracellular recordings of ventral opener motoneurones, stimulus-related IPSPs were observed in response to stimulation of the cut nerve cord. Stimulation also abolished slow wave synaptic input to the motoneurones during inhibition of the oviposition motor programme. It is suggested that oviposition digging behaviour is initiated and maintained by a mechanism of ‘release’ from descending neural inhibition.

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Wightman, B., R. Baran, and G. Garriga. "Genes that guide growth cones along the C. elegans ventral nerve cord." Development 124, no. 13 (July 1, 1997): 2571–80. http://dx.doi.org/10.1242/dev.124.13.2571.

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During nervous system development, growth cone pioneering and fasciculation contribute to nerve bundle structure. Pioneer growth cones initially navigate along neuroglia to establish an axon scaffold that guides later extending growth cones. In C. elegans, the growth cone of the PVPR neuron pioneers the left ventral nerve cord bundle, providing a path for the embryonic extensions of the PVQL and AVKR growth cones. Later during larval development, the HSNL growth cone follows cues in the left ventral nerve cord bundle provided by the PVPR and PVQL axons. Here we show that mutations in the genes enu-1, fax-1, unc-3, unc-30, unc-42 and unc-115 disrupt pathfinding of growth cones along the left ventral nerve cord bundle. Our results indicate that unc-3 and unc-30 function in ventral nerve cord pioneering and that enu-1, fax-1, unc-42 and unc-115 function in recognition of the PVPR and PVQL axons by the AVKR and HSNL growth cones.

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Oka, Kotaro, Hiroto Ogawa, and Shozo Fujita. "Glutamate-induced deporalization in earthworm ventral nerve cord." Neuroscience Letters 179, no. 1-2 (September 1994): 41–44. http://dx.doi.org/10.1016/0304-3940(94)90930-x.

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O'Toole, Donal, Gerald Wells, James Ingram, William Cooley, and Stephan Hawkins. "Ultrastrutitural Pathology of an Inherited Lower Motor Neuron Disease of Pigs." Journal of Veterinary Diagnostic Investigation 6, no. 2 (April 1994): 230–37. http://dx.doi.org/10.1177/104063879400600215.

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The ultrastructural features of a recently described inherited lower motor neuron disease were studied in 5 affected pigs. Clinical signs comprised progressive ataxia and paresis of variable severity. Affected pigs, 6, 7, 15, 15, and 19 weeks of age, and 2 unrelated healthy pigs, 9 and 15 weeks of age, were anesthetized and their tissues were fixed by whole body perfusion with mixed aldehydes. From 1 or more affected pigs, samples of cervical and lumbar spinal ventral horn, lateral and ventral spinal columns, dorsal and ventral lumbar spinal nerve roots, 2 peripheral nerves (Nn. phrenicus and fibularis communis), and 2 skeletal muscles (Mm. diaphragma and tibialis cranialis) were examined ultrastructurally. There was widespread degeneration of myelinated axons in peripheral nerves and in lateral and ventral columns of lumbar and cervical segments of spinal cord. Axonal degeneration was present in ventral spinal nerve roots and was absent in dorsal spinal nerve roots sampled at the same lumbar levels. Unmyelinated axons in peripheral nerves and spinal nerve roots were unaffected. In 4 of 5 affected pigs, there were atrophic alpha motor neurons in cervical spinal cord that contained dense, round osmiophilic perikaryal inclusions up to 4 μm in diameter and round swollen mitochondria. Axonal regeneration was present in N. phrenicus of the 19-week-old affected pig that had clinical signs of longest duration (10 weeks). There was no morphologic evidence of axonal degeneration or spinal neuronal atrophy in either control pig. The ultrastructural features of this motor neuron disease distinguish it from other reported progressive spinal neuropathies of pigs.

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Alam, J., M. S. Arifin, and M. T. Hussan. "MACROANATOMICAL ASPECTS OF BRACHIAL PLEXUS AND ITS BRANCHES IN THE INDIGENOUS DUCK." Bangladesh Journal of Veterinary Medicine 15, no. 1 (September 20, 2017): 1–6. http://dx.doi.org/10.3329/bjvm.v15i1.34046.

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The injury to the peripheral nervous system is common clinical problem especially injury to the wing is the most common in birds. The present study aimed to document the detailed features of the morphological structure and the innervations areas of the brachial plexus in indigenous duck (Anas platyrhynchos domesticus). A total of six mature indigenous ducks (three of them were male and three were female) were used in this study. After administering an anesthetic to the birds, the body cavities were opened. The birds were fixed with formaldehyde after draining of the blood. The nerves of the brachial plexus were dissected separately and photographed. The brachial plexus was formed by the union of the ventral branches of 14thand 15th cervical spinal nerve and 1st, 2nd and 3rd thoracic spinal nerves, which were confirmed by palpation and counting the cervical vertebrae. Present study revealed that few small and large branches originated from brachial plexus and innervated into the specific muscles and their adjacent structure. Five nerve roots formed three nerve trunks in the duck, which constitute the dorsal and ventral cords. The pectoral trunk and median-ulnar nerve originated from ventral cord, while dorsal cord gives axillary nerve continued as a radial nerve into the wing of duck. The axillary nerve innervated into to skin of the dorsal side of the wing and shoulder deltoideous muscles, coracobrachialis muscles and propatagiasis cervical muscles. The radial nerve innervated to the humuro-brachial and triceps muscles, extensor carpi radial and supinator muscles. The ulnar nerve innervated extensor aspect of joint, flexor carpi ulnar muscles and superficial flexor muscle. The median nerve innervated into the median surface of the brachial and metacarpal region, flexor carpi radial muscle, pronator teres muscles, superficial and profound digital flexor muscles. The general macroanatomical shape of the brachial plexus and the distribution of the nerves originating from this plexus displayed some differences from other birds.

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Yang, Jie, Javier Ortega-Hernández, Nicholas J. Butterfield, Yu Liu, George S. Boyan, Jin-bo Hou, Tian Lan, and Xi-guang Zhang. "Fuxianhuiid ventral nerve cord and early nervous system evolution in Panarthropoda." Proceedings of the National Academy of Sciences 113, no. 11 (March 1, 2016): 2988–93. http://dx.doi.org/10.1073/pnas.1522434113.

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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.

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CARLSTEDT, T. "Experimental Studies on Surgical Treatment of Avulsed Spinal Nerve Roots in Brachial Plexus Injury." Journal of Hand Surgery 16, no. 5 (October 1991): 477–82. http://dx.doi.org/10.1016/0266-7681(91)90098-9.

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This review summarises studies aiming at a surgical treatment of spinal nerve root avulsions from the spinal cord in brachial plexus lesions. After dorsal root injury, regrowth of nerve fibres into the spinal cord occurs only in the immature animal. After ventral root avulsion and subsequent implantation into the spinal cord, neuroanatomical and neurophysiological data show that motoneurons are capable of producing new axons which enter the implanted root. Intra-neuronal physiological experiments demonstrate that new axons can conduct action potentials and elicit muscle responses. The neurons are reconnected in segmental spinal cord activity and respond to impulses in sensory nerve fibres. In primate experiments, implantation of avulsed ventral roots in the brachial plexus resulted in functional restitution. These studies indicate the possibility of surgical treatment of ventral root avulsion injuries in brachial plexus lesions in humans.

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Niven, Jeremy E., Christopher M. Graham, and Malcolm Burrows. "Diversity and Evolution of the Insect Ventral Nerve Cord." Annual Review of Entomology 53, no. 1 (January 2008): 253–71. http://dx.doi.org/10.1146/annurev.ento.52.110405.091322.

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Court, Robert, Shigehiro Namiki, J. Douglas Armstrong, Jana Börner, Gwyneth Card, Marta Costa, Michael Dickinson, et al. "A Systematic Nomenclature for the Drosophila Ventral Nerve Cord." Neuron 107, no. 6 (September 2020): 1071–79. http://dx.doi.org/10.1016/j.neuron.2020.08.005.

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Soto, Martha C. "Sequential Rosettes Drive C. elegans Ventral Nerve Cord Assembly." Developmental Cell 41, no. 2 (April 2017): 121–22. http://dx.doi.org/10.1016/j.devcel.2017.04.007.

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13

Liu, Song, Nozar Aghakhani, Nazaire Boisset, Gérard Said, and Marc Tadie. "Innervation of caudal denervated ventral roots and their target muscles by the rostral spinal motoneurons after implanting a nerve autograft in spinal cord—injured adult marmosets." Journal of Neurosurgery: Spine 94, no. 1 (January 2001): 82–90. http://dx.doi.org/10.3171/spi.2001.94.1.0082.

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Object. The authors conducted a study to determine the effects of using a nerve autograft (NAG) to promote and guide axonal regrowth from the rostral spinal cord to the caudal lumbar ventral nerve roots to restore hindlimb motor function in adult marmosets after lower thoracic cord injury. Methods. Nine animals underwent a left-sided hemisection of the spinal cord at T-12 via left-sided T9—L3 hemilaminectomy, with section of all ipsilateral lumbrosacral ventral nerve roots. In the experimental group (five animals), an NAG obtained from the right peroneal nerve was anastomosed with the sectioned and electrophysiologically selected lumbar ventral roots (left L-3 and L-4) controlling the left quadriceps muscle and then implanted into the left ventrolateral T-10 cord. In the control group (four animals), the sectioned/selected lumbar ventral roots were only ligated. After surgery, all marmosets immediately suffered from complete paralysis of their left hindlimb. Five months later, some clinical signs of reinnervation such as tension and resistance began to appear in the paralyzed quadriceps of all experimental animals that received autografts. Nine months postoperatively, three of the five experimental marmosets could maintain their lesioned hindlimb in hip flexion. Muscle action potentials and motor evoked potentials were recorded from the target quadriceps in all experimental marmosets, but these potentials were absent in the control animals. Horseradish peroxidase retrograde labeling from the distal sectioned/reconnected lumbar ventral roots traced 234 ± 178 labeled neurons in the ipsilateral T8–10 ventral horn, mainly close to the NAG tip. Histological analysis showed numerous regenerating axons in this denervated/reconnected nerve root pathway, as well as newly formed motor endplates in the denervated/reinnervated quadriceps. No axonal regeneration was detected in the control animals. Conclusions. These data indicate that the rostral spinal neurons can regrow into the caudal ventral roots through an NAG, thereby innervating the target muscle in adult marmosets after spinal cord injury.

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Parke, Wesley W., and Ryo Watanabe. "Lumbosacral intersegmental epispinal axons and ectopic ventral nerve rootlets." Journal of Neurosurgery 67, no. 2 (August 1987): 269–77. http://dx.doi.org/10.3171/jns.1987.67.2.0269.

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✓ An epispinal system of motor axons virtually covers the ventral and lateral funiculi of the human conus medullaris between the L-2 and S-2 levels. These nerve fibers apparently arise from motor cells of the ventral horn nuclei and join spinal nerve roots caudal to their level of origin. In all observed spinal cords, many of these axons converged at the cord surface and formed an irregular group of ectopic rootlets that could be visually traced to join conventional spinal nerve roots at one to several segments inferior to their original segmental level; occasional rootlets joined a dorsal nerve root. As almost all previous reports of nerve root interconnections involved only the dorsal roots and have been cited to explain a lack of an absolute segmental sensory nerve distribution, it is believed that these intersegmental motor fibers may similarly explain a more diffuse efferent distribution than has previously been suspected.

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Qtsuka, M., K. Yoshioka, M. Yanagisawa, H. Suzuki, F. Y. Zhao, J. Z. Guo, R. Hosoki, and T. Kurihara. "Use of NK1 receptor antagonists in the exploration of physiological functions of substance P and neurokinin A." Canadian Journal of Physiology and Pharmacology 73, no. 7 (July 1, 1995): 903–7. http://dx.doi.org/10.1139/y95-124.

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Tachykinin NK1 receptor antagonists were used to explore the physiological functions of substance P (SP) and neurokinin A (NKA). Pharmacological profiles of three NK1 receptor antagonists, GR71251, GR82334, and RP 67580, were examined in the isolated spinal cord preparation of the neonatal rat. These tachykinin receptor antagonists exhibited considerable specificities and antagonized the actions of both SP and NKA to induce the depolarization of ventral roots. Electrical stimulation of the saphenous nerve with C-fiber strength evoked a depolarization lasting about 30 s of the ipsilateral L3 ventral root. This response, which is referred to as saphenous-nerve-evoked slow ventral root potential (VRP), was depressed by these NK1 receptor antagonists. In contrast, the saphenous-nerve-evoked slow VRP was potentiated by application of a mixture of peptidase inhibitors, including thiorphan, actinonin, and captopril in the presence of naloxone, but not after further addition of GR71251. Likewise, in the isolated coeliac ganglion of the guinea pig, electrical stimulation of the mesenteric nerves evoked in some ganglionic cells slow excitatory postsynaptic potentials (EPSPs), which were depressed by GR71251 and potentiated by peptidase inhibitors. These results further support the notion that SP and NKA serve as neurotransmitters producing slow EPSPs in the neonatal rat spinal cord and guinea pig prevertebral ganglia.Key words: substance P, neurokinin A, neurotransmitter, tachykinin antagonist, spinal cord.

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Wu, Sheng-Hua, Shu-Hung Huang, Kuang-I. Cheng, Chee-Yin Chai, Jwu-Lai Yeh, Tai-Cheng Wu, Yi-Chiang Hsu, and Aij-Lie Kwan. "Third-Degree Hindpaw Burn Injury Induced Apoptosis of Lumbar Spinal Cord Ventral Horn Motor Neurons and Sciatic Nerve and Muscle Atrophy in Rats." BioMed Research International 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/372819.

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Background. Severe burns result in hypercatabolic state and concomitant muscle atrophy that persists for several months, thereby limiting patient recovery. However, the effects of burns on the corresponding spinal dermatome remain unknown. This study aimed to investigate whether burns induce apoptosis of spinal cord ventral horn motor neurons (VHMNs) and consequently cause skeletal muscle wasting.Methods. Third-degree hindpaw burn injury with 1% total body surface area (TBSA) rats were euthanized 4 and 8 weeks after burn injury. The apoptosis profiles in the ventral horns of the lumbar spinal cords, sciatic nerves, and gastrocnemius muscles were examined. The Schwann cells in the sciatic nerve were marked with S100. The gastrocnemius muscles were harvested to measure the denervation atrophy.Result. The VHMNs apoptosis in the spinal cord was observed after inducing third-degree burns in the hindpaw. The S100 and TUNEL double-positive cells in the sciatic nerve increased significantly after the burn injury. Gastrocnemius muscle apoptosis and denervation atrophy area increased significantly after the burn injury.Conclusion. Local hindpaw burn induces apoptosis in VHMNs and Schwann cells in sciatic nerve, which causes corresponding gastrocnemius muscle denervation atrophy. Our results provided an animal model to evaluate burn-induced muscle wasting, and elucidate the underlying mechanisms.

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Arai, Yoshiyasu, Yoko Momose-Sato, Katsushige Sato, and Kohtaro Kamino. "Optical Mapping of Neural Network Activity in Chick Spinal Cord at an Intermediate Stage of Embryonic Development." Journal of Neurophysiology 81, no. 4 (April 1, 1999): 1889–902. http://dx.doi.org/10.1152/jn.1999.81.4.1889.

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Optical mapping of neural network activity in chick spinal cord at an intermediate stage of embryonic development. We have applied multiple-site optical recording of transmembrane potential changes to recording of neuronal pathway/network activity from embryonic chick spinal cord slice preparations. Spinal cord preparations were dissected from 8-day-old chick embryos at Hamburger-Hamilton stage 33, and transverse slice preparations were prepared with the 13th cervical spinal nerve or with the 2nd or 5th lumbosacral spinal nerve intact. The slice preparations were stained with a voltage-sensitive merocyanine-rhodanine dye (NK2761). Transmembrane voltage-related optical (dye-absorbance) changes evoked by spinal nerve stimulation with positive square-current pulses using a suction electrode were recorded simultaneously from many loci in the preparation, using a 128- or 1,020-element photodiode array. Optical responses were detected from dorsal and ventral regions corresponding to the posterior (dorsal) and anterior (ventral) gray horns. The optical signals were composed of two components, fast spike-like and slow signals. In the dorsal region, the fast spike-like signal was identified as the presynaptic action potential in the sensory nerve and the slow signal as the postsynaptic potential. In the ventral region, the fast spike-like signal reflects the antidromic action potential in motoneurons, and the slow signal is related to the postsynaptic potential evoked in the motoneuron. In preparations in which the ventral root was cut microsurgically, the antidromic action potential-related optical signals were eliminated. The areas of the maximal amplitude of the evoked signals in the dorsal and ventral regions were located near the dorsal root entry zone and the ventral root outlet zone, respectively. Quasiconcentric contour-line maps were obtained in the dorsal and ventral regions, suggesting the functional arrangement of the dorsal and ventral synaptic connections. Synaptic fatigue induced by repetitive stimuli in the ventral synapses was more rapid than in the dorsal synapses. The distribution patterns of the signals were essentially similar among C13, LS2, and LS5 preparations, suggesting that there is no difference in the spatiotemporal pattern of the neural responses along the rostrocaudal axis of the spinal cord at this developmental stage. In the ventral root-cut preparations, comparing the delay times between the ventral slow optical signals, we have been able to demonstrate that neural network-related synaptic connections are generated functionally in the embryonic spinal cord at Hamburger-Hamilton stage 33.

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Shioi, Go, Michinari Shoji, Masashi Nakamura, Takeshi Ishihara, Isao Katsura, Hajime Fujisawa, and Shin Takagi. "Mutations Affecting Nerve Attachment of Caenorhabditis elegans." Genetics 157, no. 4 (April 1, 2001): 1611–22. http://dx.doi.org/10.1093/genetics/157.4.1611.

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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.

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Hall, A., N. A. Giese, and W. D. Richardson. "Spinal cord oligodendrocytes develop from ventrally derived progenitor cells that express PDGF alpha-receptors." Development 122, no. 12 (December 1, 1996): 4085–94. http://dx.doi.org/10.1242/dev.122.12.4085.

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Platelet-derived growth factor alpha-receptors (PDGFR alpha) are expressed by a subset of neuroepithelial cells in the ventral half of the embryonic day 14 (E14) rat spinal cord. The progeny of these cells subsequently proliferate and migrate into the dorsal parts of the cord after E16. Here, we show that E14 ventral cells are able to generate oligodendrocytes in culture but that dorsal cells acquire this ability only after E16, coinciding with the appearance of PDGFR alpha-immunoreactive cells in the starting population. PDGFR alpha-positive cells in optic nerve and spinal cord cultures co-labelled with antibody markers of oligodendrocyte progenitors. When PDGFR alpha-positive cells were purified from embryonic rat spinal cords by immunoselection and cultured in defined medium, they all differentiated into oligodendrocytes. Very few oligodendrocytes developed in cultures of embryonic spinal cord cells that had been depleted of PDGFR alpha-expressing cells by antibody-mediated complement lysis. These data demonstrate that all PDGFR alpha-positive cells in the embryonic rat spinal cord are oligodendrocyte progenitors and that most or all early-developing oligodendrocytes are derived from these ventrally-derived precursors.

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Leuzinger, S., F. Hirth, D. Gerlich, D. Acampora, A. Simeone, W. J. Gehring, R. Finkelstein, K. Furukubo-Tokunaga, and H. Reichert. "Equivalence of the fly orthodenticle gene and the human OTX genes in embryonic brain development of Drosophila." Development 125, no. 9 (May 1, 1998): 1703–10. http://dx.doi.org/10.1242/dev.125.9.1703.

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Members of the orthodenticle gene family are essential for embryonic brain development in animals as diverse as insects and mammals. In Drosophila, mutational inactivation of the orthodenticle gene results in deletions in anterior parts of the embryonic brain and in defects in the ventral nerve cord. In the mouse, targeted elimination of the homologous Otx2 or Otx1 genes causes defects in forebrain and/or midbrain development. To determine the morphogenetic properties and the extent of evolutionary conservation of the orthodenticle gene family in embryonic brain development, genetic rescue experiments were carried out in Drosophila. Ubiquitous overexpression of the orthodenticle gene rescues both the brain defects and the ventral nerve cord defects in orthodenticle mutant embryos; morphology and nervous system-specific gene expression are restored. Two different time windows exist for the rescue of the brain versus the ventral nerve cord. Ubiquitous overexpression of the human OTX1 or OTX2 genes also rescues the brain and ventral nerve cord phenotypes in orthodenticle mutant embryos; in the brain, the efficiency of morphological rescue is lower than that obtained with overexpression of orthodenticle. Overexpression of either orthodenticle or the human OTX gene homologs in the wild-type embryo results in ectopic neural structures. The rescue of highly complex brain structures in Drosophila by either fly or human orthodenticle gene homologs indicates that these genes are interchangeable between vertebrates and invertebrates and provides further evidence for an evolutionarily conserved role of the orthodenticle gene family in brain development.

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Tiwari, R. K., K. P. Srivastava, and J. N. Tiwari. "Role of ventral nerve cord and peripheral nerves in metamorphosis and nerve cord shortening in the lemon-butterfly, Papilio demoleus (Lepidoptera)." International Journal of Tropical Insect Science 10, no. 03 (June 1989): 319–25. http://dx.doi.org/10.1017/s1742758400003556.

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Tani, Masaki, and Taketeru Kuramoto. "Cool-sensitive Neurons in the Ventral Nerve Cord of Crustaceans." Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 119, no. 3 (March 1998): 845–52. http://dx.doi.org/10.1016/s1095-6433(98)01025-3.

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Kitamura, Y., H. Horita, H. Ogawa, K. Oka, and K. Tanishita. "Nitric oxide synthase localized in ventral nerve cord of earthworm." Seibutsu Butsuri 39, supplement (1999): S63. http://dx.doi.org/10.2142/biophys.39.s63_4.

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Dallo, João Gabriel Martins, Bernardo Vergara Reichert, José Benedito Ramos Valladão Júnior, Camila Silva, Bianca Aparecida de Luca, Beatriz de Freitas Azevedo Levy, and Gerson Chadi. "Differential astroglial responses in the spinal cord of rats submitted to a sciatic nerve double crush treated with local injection of cultured Schwann cell suspension or lesioned spinal cord extract: implications on cell therapy for nerve repair." Acta Cirurgica Brasileira 22, no. 6 (December 2007): 485–94. http://dx.doi.org/10.1590/s0102-86502007000600013.

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PURPOSE: Reactive astrocytes are implicated in several mechanisms after central or peripheral nervous system lesion, including neuroprotection, neuronal sprouting, neurotransmission and neuropathic pain. Schwann cells (SC), a peripheral glia, also react after nerve lesion favoring wound/repair, fiber outgrowth and neuronal regeneration. We investigated herein whether cell therapy for repair of lesioned sciatic nerve may change the pattern of astroglial activation in the spinal cord ventral or dorsal horn of the rat. METHODS: Injections of a cultured SC suspension or a lesioned spinal cord homogenized extract were made in a reservoir promoted by a contiguous double crush of the rat sciatic nerve. Local injection of phosphate buffered saline (PBS) served as control. One week later, rats were euthanized and spinal cord astrocytes were labeled by immunohistochemistry and quantified by means of quantitative image analysis. RESULTS: In the ipsilateral ventral horn, slight astroglial activations were seen after PBS or SC injections, however, a substantial activation was achieved after cord extract injection in the sciatic nerve reservoir. Moreover, SC suspension and cord extract injections were able to promote astroglial reaction in the spinal cord dorsal horn bilaterally. Conclusion: Spinal cord astrocytes react according to repair processes of axotomized nerve, which may influence the functional outcome. The event should be considered during the neurosurgery strategies.

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Liu, Song, Phong Damhieu, Pauline Devanze, Gérard Saïd, Jean Michel Heard, and Marc Tadié. "Efficient reinnervation of hindlimb muscles by thoracic motor neurons after nerve cross-anastomosis in rats." Journal of Neurosurgery 99, no. 5 (November 2003): 879–85. http://dx.doi.org/10.3171/jns.2003.99.5.0879.

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Object. Peripheral motor axons can regenerate through motor endoneurial tubes of foreign nerves to reinnervate different target muscles. This regenerative capacity has been brought to clinical applications for restorative surgery after nerve or root injury. In this study the authors explore the extent to which nerve cross-anastomosis between lower intercostal nerves and lumbar ventral roots would be effective in inducing reinnervation of paralyzed hindlimb muscles after spinal cord hemisection at the thoracolumbar boundary in rats. Methods. The proximal extremities of sectioned intercostal nerves T10–12 were surgically connected to the distal extremities of sectioned ipsilateral lumbar ventral roots L3–5, respectively. Motor activity reappeared 2 months postsurgery; however, locomotion was not restored and inappropriate motor patterns persisted at 9 months postsurgery. At that time, data from electrophysiological and histological studies and horseradish peroxidase retrograde labeling demonstrated efficient regrowth of thoracic motor neuron axons that reached hindlimb muscles. They also revealed a persistent maturation defect of regrown fibers, as shown by size heterogeneity and presumable extensive axonal branching. These features are consistent with reduced neural activity subsequent to continuing inappropriate motor patterns. Conclusions. These results indicate that cross-anastomosis of intercostal nerves with lumbar ventral roots allows efficient reinnervation of paralyzed hindlimb muscles after spinal cord hemisection in rats. Stimulating the reorganization of the neuronal circuitry in the central nervous system by locomotion training or other methods would presumably result in both functional and anatomical improvements. This experimental setting provides a convenient animal model to investigate these processes.

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Panciera, R. J., K. E. Washburn, R. N. Streeter, and J. G. Kirkpatrick. "A Familial Peripheral Neuropathy and Glomerulopathy in Gelbvieh Calves." Veterinary Pathology 40, no. 1 (January 2003): 63–70. http://dx.doi.org/10.1354/vp.40-1-63.

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Nine Gelbvieh calves originating in four herds and clinically presenting with rear limb ataxia/ paresis had histopathologically confirmed peripheral neuropathy and a proliferative glomerulopathy. Degenerative lesions were severe in peripheral nerves, dorsal and ventral spinal nerve roots, and less marked in dorsal fasciculi of the spinal cord. Cell bodies of spinal ganglia were minimally diseased; ventral horn neurons occasionally had central chromatolysis and nuclear displacement. Glomerular lesions ranged from mild mesangial hypercellularity to glomerulosclerosis. Pedigree analysis of affected animals from one herd indicated a strong familial relationship and probable hereditary basis for the syndrome.

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Carlstedt, Thomas, V. Peter Misra, Anastasia Papadaki, Donald McRobbie, and Praveen Anand. "Return of spinal reflex after spinal cord surgery for brachial plexus avulsion injury." Journal of Neurosurgery 116, no. 2 (February 2012): 414–17. http://dx.doi.org/10.3171/2011.7.jns111106.

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Motor but not sensory function has been described after spinal cord surgery in patients with brachial plexus avulsion injury. In the featured case, motor-related nerve roots as well as sensory spinal nerves distal to the dorsal root ganglion were reconnected to neurons in the ventral and dorsal horns of the spinal cord by implanting nerve grafts. Peripheral and sensory functions were assessed 10 years after an accident and subsequent spinal cord surgery. The biceps stretch reflex could be elicited, and electrophysiological testing demonstrated a Hoffman reflex, or Hreflex, in the biceps muscle when the musculocutaneous nerve was stimulated. Functional MR imaging demonstrated sensory motor cortex activities on active as well as passive elbow flexion. Quantitative sensory testing and contact heat evoked potential stimulation did not detect any cutaneous sensory function, however. To the best of the authors' knowledge, this case represents the first time that spinal cord surgery could restore not only motor function but also proprioception completing a spinal reflex arch.

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Gailite, Ieva, Birgit L. Aerne, and Nicolas Tapon. "Differential control of Yorkie activity by LKB1/AMPK and the Hippo/Warts cascade in the central nervous system." Proceedings of the National Academy of Sciences 112, no. 37 (August 31, 2015): E5169—E5178. http://dx.doi.org/10.1073/pnas.1505512112.

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The Hippo (Hpo) pathway is a highly conserved tumor suppressor network that restricts developmental tissue growth and regulates stem cell proliferation and differentiation. At the heart of the Hpo pathway is the progrowth transcriptional coactivator Yorkie [Yki–Yes-activated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) in mammals]. Yki activity is restricted through phosphorylation by the Hpo/Warts core kinase cascade, but increasing evidence indicates that core kinase-independent modes of regulation also play an important role. Here, we examine Yki regulation in the Drosophila larval central nervous system and uncover a Hpo/Warts-independent function for the tumor suppressor kinase liver kinase B1 (LKB1) and its downstream effector, the energy sensor AMP-activated protein kinase (AMPK), in repressing Yki activity in the central brain/ventral nerve cord. Although the Hpo/Warts core cascade restrains Yki in the optic lobe, it is dispensable for Yki target gene repression in the late larval central brain/ventral nerve cord. Thus, we demonstrate a dramatically different wiring of Hpo signaling in neighboring cell populations of distinct developmental origins in the central nervous system.

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Trailović, S. M., Z. Zurovac, S. Gruborović, D. S. Marjanović, and J. Nedeljković-Trailović. "Presynaptic and postsynaptic regulation of muscle contractions in the ascarid nematode Ascaris suum: a target for drug action." Journal of Helminthology 90, no. 6 (November 27, 2015): 698–705. http://dx.doi.org/10.1017/s0022149x15000978.

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AbstractThe aim of this study was to determine the role in contractions of postsynaptic nicotinic acetylcholine (nACh) and γ-aminobutyric acid (GABA) receptors, in the bag region of Ascaris suum muscle cells, as well as the role of synaptic receptors between interneurons and motor neurons in the dorsal and ventral nerve cord. We have measured the isometric contractions of isolated segments of A. suum, with or without the nerve cord (dorsal or ventral). Contractions were caused by increasing concentrations of ACh or by electrical field stimulation (EFS). Based on our results, the presence of the nerve cord is essential for the contractile effects of ACh. The EC50 value of ACh for innervated muscle strips was 10.88 μm. Unlike intact (innervated) preparations, there was no contraction of the muscle flaps when the nerve cord was mechanically removed. Furthermore, continuous EFS produced stable contractions of innervated muscle strips, but they are not sensitive to mecamylamine (100 μm). However, GABA (30 μm) significantly inhibited the EFS-induced contractions. EFS with the same characteristics did not cause muscle contractions of denervated muscle strips, but EFS with a wider pulse induced the increasing of tone and irregular contractions. These contractions were completely insensitive to the effect of GABA. The EC50 for ACh did not differ between the dorsal and ventral segments (9.83 μm and 9.45 μm), while GABA exhibited features of competitive and non-competitive antagonists, regardless of whether it acted on the dorsal or ventral segments of A. suum. It is obvious that drugs will be more effective if they act on both the synaptic and extrasynaptic nACh and GABA receptors.

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Bogovic, John A., Hideo Otsuna, Larissa Heinrich, Masayoshi Ito, Jennifer Jeter, Geoffrey Meissner, Aljoscha Nern, et al. "An unbiased template of the Drosophila brain and ventral nerve cord." PLOS ONE 15, no. 12 (December 31, 2020): e0236495. http://dx.doi.org/10.1371/journal.pone.0236495.

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The fruit fly Drosophila melanogaster is an important model organism for neuroscience with a wide array of genetic tools that enable the mapping of individual neurons and neural subtypes. Brain templates are essential for comparative biological studies because they enable analyzing many individuals in a common reference space. Several central brain templates exist for Drosophila, but every one is either biased, uses sub-optimal tissue preparation, is imaged at low resolution, or does not account for artifacts. No publicly available Drosophila ventral nerve cord template currently exists. In this work, we created high-resolution templates of the Drosophila brain and ventral nerve cord using the best-available technologies for imaging, artifact correction, stitching, and template construction using groupwise registration. We evaluated our central brain template against the four most competitive, publicly available brain templates and demonstrate that ours enables more accurate registration with fewer local deformations in shorter time.

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Zhao, Guoyan, and James B. Skeath. "The Sox-domain containing geneDichaete/fish-hookacts in concert withvndandindto regulate cell fate in theDrosophilaneuroectoderm." Development 129, no. 5 (March 1, 2002): 1165–74. http://dx.doi.org/10.1242/dev.129.5.1165.

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In the Drosophila embryonic central nervous system, neural stem cells, called neuroblasts, acquire fates in a position-specific manner. Recent work has identified a set of genes that functions along the dorsoventral axis to enable neuroblasts that develop in different dorsoventral domains to acquire distinct fates. These genes include the evolutionarily conserved transcription factors ventral nerve cord defective and intermediate neuroblasts defective, as well as the Drosophila EGF receptor. We show that the Sox-domain-containing gene Dichaete/fish-hook also plays a crucial role to pattern the neuroectoderm along the DV axis. Dichaete is expressed in the medial and intermediate columns of the neuroectoderm, and mutant analysis indicates that Dichaete regulates cell fate and neuroblast formation in these domains. Molecular epistasis tests, double mutant analysis and dosage-sensitive interactions demonstrate that during these processes, Dichaete functions in parallel with ventral nerve cord defective and intermediate neuroblasts defective, and downstream of EGF receptor signaling to mediate its effect on development. These results identify Dichaete as an important regulator of dorsoventral pattern in the neuroectoderm, and indicate that Dichaete acts in concert with ventral nerve cord defective and intermediate neuroblasts defective to regulate pattern and cell fate in the neuroectoderm.

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Whelan, Patrick, Agnes Bonnot, and Michael J. O'Donovan. "Properties of Rhythmic Activity Generated by the Isolated Spinal Cord of the Neonatal Mouse." Journal of Neurophysiology 84, no. 6 (December 1, 2000): 2821–33. http://dx.doi.org/10.1152/jn.2000.84.6.2821.

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We examined the ability of the isolated lumbosacral spinal cord of the neonatal mouse (P0–7) to generate rhythmic motor activity under several different conditions. In the absence of electrical or pharmacological stimulation, we recorded several patterns of spontaneous ventral root depolarization and discharge. Spontaneous, alternating discharge between contralateral ventral roots could occur two to three times over a 10-min interval. We also observed other patterns, including left-right synchrony and rhythmic activity restricted to one side of the cord. Trains of stimuli delivered to the lumbar/coccygeal dorsal roots or the sural nerve reliably evoked episodes of rhythmic activity. During these evoked episodes, rhythmic ventral root discharges could occur on one side of the cord or could alternate from side to side. Bath application of a combination of N-methyl-d,l-aspartate (NMA), serotonin, and dopamine produced rhythmic activity that could last for several hours. Under these conditions, the discharge recorded from the left and right L1–L3 ventral roots alternated. In the L4–L5segments, the discharge had two peaks in each cycle, coincident with discharge of the ipsilateral and contralateral L1–L3 roots. The L6 ventral root discharge alternated with that recorded from the ipsilateral L1–L3 roots. We established that the drug-induced rhythm was locomotor-like by recording an alternating pattern of discharge between ipsilateral flexor and extensor hindlimb muscle nerves. In addition, by recording simultaneously from ventral roots and muscle nerves, we established that ankle flexor discharge was in phase with ipsilateral L1/L2 ventral root discharge, while extensor discharge was in phase with ipsilateral L6 ventral root discharge. Rhythmic patterns of ventral root discharge were preserved following mid-sagittal section of the spinal cord, demonstrating that reciprocal inhibitory connections between the left and right sides of the cord are not essential for rhythmogenesis in the neonatal mouse cord. Blocking N-methyl-d-aspartate receptors, in both the intact and the hemisected preparation, revealed that these receptors contribute to but are not essential for rhythmogenesis. In contrast, the rhythm was abolished following blockade of kainate/AMPA receptors with 6-cyano-7-nitroquinoxalene-2,3-dione. These findings demonstrate that the isolated mouse spinal cord can produce a variety of coordinated activities, including locomotor-like activity. The ability to study these behaviors under a variety of different conditions offers promise for future studies of rhythmogenic mechanisms in this preparation.

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Cameron, C. B., and G. O. Mackie. "Conduction pathways in the nervous system of Saccoglossus sp. (Enteropneusta)." Canadian Journal of Zoology 74, no. 1 (January 1, 1996): 15–19. http://dx.doi.org/10.1139/z96-003.

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A species of Saccoglossus from Barkley Sound, British Columbia, was observed in the field and found to exhibit a startle withdrawal response. Optical and electron microscopy of the nerve cords failed to reveal giant axons. The dorsal collar cord and ventral trunk cord consist of small axons with a mean diameter of 0.4 μm. The majority of the axons run longitudinally and there is no indication of a specialized integrative centre. Electrical recordings from the nerve cords show events interpreted as compound action potentials. The potentials are through-conducted from proboscis to trunk. Such propagated events probably mediate startle withdrawal. Conduction velocities did not exceed 40 cm∙s−1 in any part of the nervous system.

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VORTSEPNEVA, ELENA, ALEXANDER TZETLIN, and EUGENI TSITRIN. "Nervous system of the dwarf ectoparasitic male of Scolelepis laonicola (Polychaeta, Spionidae)." Zoosymposia 2, no. 1 (August 31, 2009): 437–45. http://dx.doi.org/10.11646/zoosymposia.2.1.31.

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The nervous system of the ectoparasitic male of Scolelepis laonicola (Tzetlin, 1985), which attaches to the dorsal side of the female, was investigated by immunohistochemical methods in combination with confocal laser scanning microscopy. The male’s nervous system is reduced; no ganglia are found in the central nervous system. The circumesophageal connective is split into dorsal and ventral roots. Two median and one paramedial nerve run along the midventral axis of the male. The peripheral nervous system is well developed. Five commissures arise from each main cord per segment. There are two dorsolateral and two ventrolateral longitudinal nerves. The biggest segmental transverse nerve runs to the parapodia and diverges into a few fine nerves at the top of the parapodia. The nerve cord turns 90° in the male-female contact zone. Well-developed peripheral nerves, the presence of lateral nerves, and the absence of differentiated ganglia indicate the progenetic origin of the S. laonicola male. Well-developed parapodial nerves in immobilized mature males suggest an important role of the parapodia prior to settlement and possible presence of chaetae in the larva.

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Bui, Hung Xuan, and Nathan E. Schroeder. "Postembryonic Ventral Nerve Cord Development and Gonad Migration in Steinernema carpocapsae." Journal of Nematology 50, no. 1 (August 29, 2017): 27–32. http://dx.doi.org/10.21307/jofnem-2018-005.

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Kitamura, Yoshiichiro, Yuichi Naganoma, Haruhito Horita, Noriko Tsuji, Ryosaku Shimizu, Hiroto Ogawa, and Kotaro Oka. "Visualization of nitric oxide production in the earthworm ventral nerve cord." Neuroscience Research 40, no. 2 (June 2001): 175–81. http://dx.doi.org/10.1016/s0168-0102(01)00226-7.

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del Pliego, Margarita González, Jesús Hernández-Falcón, Elsa Aguirre-Benitez, Roberto Gutiérrez-Novoa, Beatriz Fuentes-Pardo, Margarita Gonzalez del Pliego, Jesus Hernandez-Falcon, and Roberto Gutierrez-Novoa. "Ventral Nerve Cord Transection in Crayfish: A Study of Functional Anatomy." Journal of Crustacean Biology 18, no. 3 (August 1998): 449. http://dx.doi.org/10.2307/1549410.

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Chang, Xiao, Michael D. Kim, Rachel Stephens, Tiange Qu, Akira Chiba, and Gavriil Tsechpenakis. "Part-based motor neuron recognition in the Drosophila ventral nerve cord." NeuroImage 90 (April 2014): 33–42. http://dx.doi.org/10.1016/j.neuroimage.2013.12.023.

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Page, Damon T., and Birgitta Olofsson. "Multiple roles for apoptosis facilitating condensation of theDrosophila ventral nerve cord." genesis 46, no. 2 (2008): 61–68. http://dx.doi.org/10.1002/dvg.20365.

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Hendy, Christopher H., and Mustafa B. A. Djamgoz. "Effects of deltamethrin on ventral nerve cord activity in the cockroach." Pesticide Science 16, no. 5 (October 1985): 520–29. http://dx.doi.org/10.1002/ps.2780160511.

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Choi, M. K., and S. E. Fahrbach. "Evidence for an endogenous neurocidin in theManduca sexta ventral nerve cord." Archives of Insect Biochemistry and Physiology 28, no. 3 (1995): 273–89. http://dx.doi.org/10.1002/arch.940280308.

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Aurelio, O. "Immunoglobulin-Domain Proteins Required for Maintenance of Ventral Nerve Cord Organization." Science 295, no. 5555 (January 25, 2002): 686–90. http://dx.doi.org/10.1126/science.1066642.

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Venkatasubramanian, Lalanti, and Richard S. Mann. "The development and assembly of the Drosophila adult ventral nerve cord." Current Opinion in Neurobiology 56 (June 2019): 135–43. http://dx.doi.org/10.1016/j.conb.2019.01.013.

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Connelly, C. A., and R. D. Wurster. "Spinal pathways mediating respiratory influences on sympathetic nerves." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 249, no. 1 (July 1, 1985): R91—R99. http://dx.doi.org/10.1152/ajpregu.1985.249.1.r91.

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The location of spinal pathways mediating the respiratory modulation of sympathetic nerve activity was determined. Left inferior cardiac sympathetic, phrenic, and external intercostal (T1) nerve activities were recorded in 16 alpha-chloralose-anesthetized, vagotomized, paralyzed cats. Baroreceptor reflex activation of sympathetic activity was tested by bilateral carotid occlusion. Eight cats received C6-C7 level ventral spinal cord hemisections followed by cumulative lesions leading to total spinal cord transection. Eight other cats received C6-C7 level dorsolateral funiculus (DLF) lesions followed by dorsal spinal cord hemisection and subsequent spinal cord transection. The respiratory modulation of sympathetic activity was quantitatively assessed using respiration-triggered computer summation of sympathetic activity. Ventral hemisection had no significant effect on the respiratory modulation of sympathetic activity or bilateral carotid occlusion responses. In contrast, bilateral DLF lesions eliminated both the respiratory modulation and bilateral carotid occlusion responses. Unilateral disruption of DLF pathways ipsilateral to the recorded sympathetic nerve indicated spinal level decussations. Thus bilaterally descending DLF pathways with spinal level decussations mediate the respiratory modulation of sympathetic activity.

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Ortega-Hernández, Javier, Rudy Lerosey-Aubril, and Stephen Pates. "Proclivity of nervous system preservation in Cambrian Burgess Shale-type deposits." Proceedings of the Royal Society B: Biological Sciences 286, no. 1917 (December 11, 2019): 20192370. http://dx.doi.org/10.1098/rspb.2019.2370.

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Recent investigations on neurological tissues preserved in Cambrian fossils have clarified the phylogenetic affinities and head segmentation in pivotal members of stem-group Euarthropoda. However, palaeoneuroanatomical features are often incomplete or described from single exceptional specimens, raising concerns about the morphological interpretation of fossilized neurological structures and their significance for early euarthropod evolution. Here, we describe the central nervous system (CNS) of the short great-appendage euarthropod Alalcomenaeus based on material from two Cambrian Burgess Shale-type deposits of the American Great Basin, the Pioche Formation (Stage 4) and the Marjum Formation (Drumian). The specimens reveal complementary ventral and lateral views of the CNS, preserved as a dark carbonaceous compression throughout the body. The head features a dorsal brain connected to four stalked ventral eyes, and four pairs of segmental nerves. The first to seventh trunk tergites overlie a ventral nerve cord with seven ganglia, each associated with paired sets of segmental nerve bundles. Posteriorly, the nerve cord features elongate thread-like connectives. The Great Basin fossils strengthen the original description—and broader evolutionary implications—of the CNS in Alalcomenaeus from the early Cambrian (Stage 3) Chengjiang deposit of South China. The spatio-temporal recurrence of fossilized neural tissues in Cambrian Konservat-Lagerstätten across North America (Pioche, Burgess Shale, Marjum) and South China (Chengjiang, Xiaoshiba) indicates that their preservation is consistent with the mechanism of Burgess Shale-type fossilization, without the need to invoke alternative taphonomic pathways or the presence of microbial biofilms.

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Smith, Brandon W., Kate W. C. Chang, Hemant A. Parmar, Mohannad Ibrahim, and Lynda J. S. Yang. "MRI evaluation of nerve root avulsion in neonatal brachial plexus palsy: understanding the presence of isolated dorsal/ventral rootlet disruption." Journal of Neurosurgery: Pediatrics 27, no. 5 (May 2021): 589–93. http://dx.doi.org/10.3171/2020.9.peds20326.

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OBJECTIVE The evaluation, treatment, and prognosis of neonatal brachial plexus palsy (NBPP) continues to have many areas of debate, including the use of ancillary testing. Given the continued improvement in imaging, it is important to revisit its utility. Nerve root avulsions have historically been identified by the presence of pseudomeningoceles or visible ruptures. This “all-or-none” definition of nerve root avulsions has many implications for the understanding and management of NBPP, especially as characterization of the proximal nerve root as a potential donor remains critical. This study examined the ability of high-resolution MRI to more specifically define the anatomy of nerve root avulsions by individually examining the ventral and dorsal rootlets as they exit the spinal cord. METHODS This is a retrospective review of patients who had undergone brachial plexus protocol MRI for clinical evaluation of NBPP at a single institution. Each MR image was independently reviewed by a board-certified neuroradiologist, who was blinded to both established diagnosis/surgical findings and laterality. Each dorsal and ventral nerve rootlet bilaterally from C5 to T1 was evaluated from the spinal cord to its exit in the neuroforamen. Each rootlet was classified as avulsed, intact, or undeterminable. RESULTS Sixty infants underwent brachial plexus protocol MRI from 2010 to 2018. All infants were included in this study. Six hundred individual rootlets were analyzed. There were 49 avulsed nerve rootlets in this cohort. Twenty-nine (59%) combined dorsal/ventral avulsions involved both the ventral and dorsal rootlets, and 20 (41%) were either isolated ventral or isolated dorsal rootlet avulsions. Of the isolated avulsion injuries, 13 (65%) were dorsal only, meaning that the motor rootlets were intact. CONCLUSIONS A closer look at nerve root avulsions with MRI demonstrates a significant prevalence (approximately 41%) of isolated dorsal or ventral nerve rootlet disruptions. This finding implies that nerve roots previously labeled as “avulsed” but with only isolated dorsal (sensory) rootlet avulsion can yet provide donor fascicles in reconstruction strategies. A majority (99%) of the rootlets can be clearly visualized with MRI. These findings may significantly impact the clinical understanding of neonatal brachial plexus injury and its treatment.

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Hurlbert, R. John, Charles H. Tator, Michael G. Fehlings, Greg Niznik, and R. Dean Linden. "Evoked potentials from direct cerebellar stimulation for monitoring of the rodent spinal cord." Journal of Neurosurgery 76, no. 2 (February 1992): 280–91. http://dx.doi.org/10.3171/jns.1992.76.2.0280.

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✓ Although the assessment of spinal cord function by electrophysiological techniques has become important in both clinical and research environments, current monitoring methods do not completely evaluate all tracts in the spinal cord. Somatosensory and motor evoked potentials primarily reflect dorsal column and pyramidal tract integrity, respectively, but do not directly assess the status of the ventral funiculus. The present study was undertaken to evaluate the use of evoked potentials, elicited by direct cerebellar stimulation, in monitoring the ventral component of the rodent spinal cord. Twenty-nine rats underwent epidural anodal stimulation directly over the cerebellar cortex, with recording of evoked responses from the lower thoracic spinal cord, both sciatic nerves, and/or both gastrocnemius muscles. Stimulation parameters were varied to establish normative characteristics. The pathways conducting these “posterior fossa evoked potentials” were determined after creation of various lesions of the cervical spinal cord. The evoked potential recorded from the thoracic spinal cord consisted of five positive (P1 to P5) and five negative (N1 to N5) peaks. The average conduction velocity (± standard deviation) of the earliest wave (P1) was 53 ± 4 m/sec, with a latency of 1.24 ± 0.10 msec. The other components followed within 4 msec from stimulus onset. Unilateral cerebellar stimulation resulted in bilateral sciatic nerve and gastrocnemius muscle responses; there were no significant differences (p > 0.05) in the thresholds, amplitudes, or latencies of these responses elicited by right- versus left-sided stimulation. Recordings performed following creation of selective lesions of the cervical cord indicated that the thoracic response was carried primarily in the ventral funiculus while the sciatic and gastrocnemius responses were mediated through the dorsal half of the spinal cord. It is concluded that the posterior fossa evoked potential has research value as a method of monitoring pathways within the ventral spinal cord of the rat, and should be useful in the study of spinal cord injury.

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Hoffmann, Carel F. E., Enrico Marani, J. Gert van Dijk, Wim V. D. Kamp, and Ralph T. W. M. Thomeer. "Reinnervation of avulsed and reimplanted ventral rootlets in the cervical spinal cord of the cat." Journal of Neurosurgery 84, no. 2 (February 1996): 234–43. http://dx.doi.org/10.3171/jns.1996.84.2.0234.

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✓ Spinal nerve root avulsions frequently occur in brachial plexus injuries caused by traction. Such lesions are considered to afflict the central nervous system (CNS) and are, therefore, believed to be beyond surgical repair. The present experimental study was initiated to challenge this hypothesis. The ventral rootlets of C-7 were avulsed from the spinal cord in 28 cats via an anterior approach and subsequently reimplanted into the cord at the site of origin. In nonoperated control cats and cats undergoing reimplantation, electrophysiological experiments were performed and horseradish peroxidase was administered to the spinal nerve on the reimplanted side after survival times ranging from 6 to 293 days. Spinal cord sections in all cats were stained for neurofilament, acetylcholinesterase (AChE), Nissl, and glial fibrillary acidic protein. Horseradish peroxidase—labeled ventral horn motoneurons were found as early as 14 days after reimplantation and their number increased with time. On Days 209 and 293, the number of labeled neurons equaled the number of labeled ventral horn neurons in the two control cats that did not undergo surgery. Starting on Day 6 after reimplantation, the appearance of the ventral horn and the white matter in the neurofilament, AChE, and Nissl-stained sections changed as a result of the CNS response to the injury. A return to their normal appearance could be observed in these stainings from Day 209 onward. Glial fibrillary acidic protein—positive astrocytic tissue was consistently found in the ventral horn and in the white matter reimplantation area. From Day 69 onward, electrophysiological stimulation of the spinal nerve C-7 on the reimplanted side elicited an electromyogram response in the spinodeltoid muscle. The latency and threshold intensity of the C-7 responses were initially increased but equalized to match the nonoperated controls between 98 and 122 days after reimplantation. The results of this study show that functional regeneration of ventral horn neurons after root avulsion and subsequent reimplantation in the cat is possible.

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Song, Chao, Gui-bin Zhong, Zu-de Liu, Wei Li, Peng-wen Ni, and Zhi-guang Qiao. "Effective reinnervation of the quadriceps femoris by spinal ventral root cross-anastomosis in rats." Acta Cirurgica Brasileira 27, no. 5 (May 2012): 330–37. http://dx.doi.org/10.1590/s0102-86502012000500009.

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PURPOSE: To study the effective recovery of the quadriceps femoris by spinal ventral root cross-anastomosis in rats. METHODS: End-to-end anastomosis was performed between the left L1 and L3 ventral roots using autogenous nerve graft ,and the right L1 and L3 roots were left intact. In control animals, the left L3 ventral root was cut and shortened, and anastomosis was not performed. Six months postoperatively, the movement of low extremities was detected by electrophysiological examination, hindlimb locomotion and basso, beattie and bresnahan (BBB) scoring at one, three, seven, 14, 21 and 28 days after SCI. Fluorescence retrograde tracing with TRUE BLUE (TB) and HE staining were performed to observe the nerve regeneration. RESULTS: Six months after surgery, the anastomotic nerve was smooth and not atrophic. The amplitudes of action potential were 7.63±1.86 mV and 6.0±1.92 mV respectively before and after the spinal cord hemisection. The contraction of left quadriceps femoris was induced by a single stimulation of the anastomotic nerve. The locomotion of left hindlimb was partially restored after spinal cord hemisection while creeping and climbing. In addition, there was significant difference in the BBB score at one, three and seven days after SCI. TB retrograde tracing and neurophysiologic observation indicated efficient reinnervation of the quadriceps femoris. CONCLUSION: The cross-anastomosis between spinal ventral root can partially reconstruct the function of quadriceps femoris following SCI and may have clinical implication for the treatment of human SCI.

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Fournier, Henri-Dominique, Philippe Mercier, and Philippe Menei. "Lateral interscalenic multilevel oblique corpectomies to repair ventral root avulsions after brachial plexus injury in humans: anatomical study and first clinical experience." Journal of Neurosurgery: Spine 95, no. 2 (October 2001): 202–7. http://dx.doi.org/10.3171/spi.2001.95.2.0202.

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Object. Because central nervous system white matter exerts a powerful inhibitory effect on axonal growth, implantation of nerve grafts or rootlets into the cervical spinal cord following ventral root avulsion injury should, ideally, be performed directly through the ventral root exit zone (VRExZ), which is located near the anteromedial aspect of the anterior horn; the grafts/rootlets should not be implanted into the white matter of the lateral cord. This is not possible when using a conservative posterior approach. Therefore, the authors have studied the anatomy encountered when using the anterolateral approach and evaluated the technique in the particular case of avulsed ventral nerve roots. They also present a case illustration of the procedure, which is used currently in their department. Methods. Anterior access to the rootlets is obtained using a lateral interscalenic approach; the vertebral artery is exposed and mobilized, and oblique drilling of the vertebral bodies (VBs) is performed. Because the articular processes and half of the VBs are preserved, fusion is not required. The approach allows the surgeon to expose the anterior aspect of the cervical dura and the entire length of the emerging spinal nerves. The anterior aspect of the dura is opened at the desired levels for VRExZ exposure, and the position is ideal for implantation of the graft/rootlets. The interscalenic dissection is mandatory so that the lesions of the supraclavicular plexus can be evaluated and repaired. If necessary, the anterior approach allows for exploration of the infraclavicular plexus during the same procedure. Conclusions. The use of a true anterior approach to the ventral rootlets appears to be a valuable and appropriate approach that avoids extensive laminectomy/facetectomy while reimplantation is performed through the anterolateral sulcus itself. In this approach, however, reimplantation of dorsal roots into the spinal cord remains impossible.

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Journal articles on the topic 'Ventral nerve cord'

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