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https://www.readbyqxmd.com/read/27921176/two-feet-on-the-membrane-uptake-of-clostridial-neurotoxins
#1
Andreas Rummel
The extraordinary potency of botulinum neurotoxins (BoNT) and tetanus neurotoxin (TeNT) is mediated by their high neurospecificity, targeting peripheral cholinergic motoneurons leading to flaccid and spastic paralysis, respectively, and successive respiratory failure. Complex polysialo gangliosides accumulate BoNT and TeNT on the plasma membrane. The ganglioside binding in BoNT/A, B, E, F, G, and TeNT occurs via a conserved ganglioside-binding pocket within the most carboxyl-terminal 25 kDa domain HCC, whereas BoNT/C, DC, and D display here two different ganglioside binding sites...
December 1, 2016: Current Topics in Microbiology and Immunology
https://www.readbyqxmd.com/read/27920095/functional-characterization-of-the-left-ventrolateral-premotor-cortex-in-humans-a-direct-electrophysiological-approach
#2
L Fornia, V Ferpozzi, M Montagna, M Rossi, M Riva, F Pessina, F Martinelli Boneschi, P Borroni, R N Lemon, L Bello, G Cerri
In monkeys, motor outputs from premotor cortex (PM) involve cortico-cortical connections with primary motor cortex (M1). However, in humans, the functional organization of PM and its relationship with the corticospinal tract (CST) is still uncertain. This study was carried out in 21 patients undergoing intraoperative brain mapping prior to tumor resection. The left ventrolateral premotor cortex (vlPM-BA6) was identified preoperatively by functional magnetic resonance imaging, and then investigated intraoperatively using high frequency direct electrical stimulation (HF-DES) of the convexity of M1 and vlPM-BA6, with simultaneous recording of motor-evoked potentials (MEPs) from oro-facial, hand and arm muscles...
December 5, 2016: Cerebral Cortex
https://www.readbyqxmd.com/read/27916956/functional-diversity-of-neurotrophin-actions-on-the-oculomotor-system
#3
REVIEW
Beatriz Benítez-Temiño, María A Davis-López de Carrizosa, Sara Morcuende, Esperanza R Matarredona, Rosa R de la Cruz, Angel M Pastor
Neurotrophins play a principal role in neuronal survival and differentiation during development, but also in the maintenance of appropriate adult neuronal circuits and phenotypes. In the oculomotor system, we have demonstrated that neurotrophins are key regulators of developing and adult neuronal properties, but with peculiarities depending on each neurotrophin. For instance, the administration of NGF (nerve growth factor), BDNF (brain-derived neurotrophic factor) or NT-3 (neurotrophin-3) protects neonatal extraocular motoneurons from cell death after axotomy, but only NGF and BDNF prevent the downregulation in ChAT (choline acetyltransferase)...
December 1, 2016: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/27913640/the-drosophila-hox-gene-ultrabithorax-acts-both-in-muscles-and-motoneurons-to-orchestrate-formation-of-specific-neuromuscular-connections
#4
Christian Hessinger, Gerhard M Technau, Ana Rogulja-Ortmann
Hox genes are known to specify motoneuron pools in the developing vertebrate spinal cord and to control motoneuronal targeting in several species. However, the mechanisms controlling axial diversification of muscle innervation patterns are still largely unknown. We present data showing that the Drosophila Hox gene Ultrabithorax (Ubx) acts in the late embryo to establish target specificity of ventrally projecting RP motoneurons. In abdominal segments A2 to A7, RP motoneurons innervate the ventro-lateral muscles VL1-4, with VL1 and VL2 being innervated in a Wnt4-dependent manner...
December 2, 2016: Development
https://www.readbyqxmd.com/read/27906103/progressive-impairment-of-cav1-1-function-in-the-skeletal-muscle-of-mice-expressing-a-mutant-type-1-cu-zn-superoxide-dismutase-g93a-linked-to-amyotrophic-lateral-sclerosis
#5
Donald Beqollari, Christin F Romberg, Gabriella Dobrowolny, Martina Martini, Andrew A Voss, Antonio Musarò, Roger A Bannister
BACKGROUND: Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disorder that is typically fatal within 3-5 years of diagnosis. While motoneuron death is the defining characteristic of ALS, the events that underlie its pathology are not restricted to the nervous system. In this regard, ALS muscle atrophies and weakens significantly before presentation of neurological symptoms. Since the skeletal muscle L-type Ca(2+) channel (CaV1.1) is a key regulator of both mass and force, we investigated whether CaV1...
June 23, 2016: Skeletal Muscle
https://www.readbyqxmd.com/read/27898262/characterization-of-genetic-loss-of-function-of-fus-in-zebrafish
#6
Svetlana Lebedeva, António M de Jesus Domingues, Falk Butter, René F Ketting
The RNA-binding protein FUS is implicated in transcription, alternative splicing of neuronal genes and DNA repair. Mutations in FUS have been linked to human neurodegenerative diseases such as ALS (amyotrophic lateral sclerosis). We genetically disrupted fus in zebrafish (Danio rerio) using the CRISPR-Cas9 system. The fus knockout animals are fertile and did not show any distinctive phenotype. Mutation of fus induces mild changes in gene expression on the transcriptome and proteome level in the adult brain...
November 29, 2016: RNA Biology
https://www.readbyqxmd.com/read/27891608/compensatory-axon-sprouting-for-very-slow-axonal-die-back-in-a-transgenic-model-of-spinal-muscular-atrophy-type-iii
#7
Esther Udina, Charles Putman, Luke Harris, N Tyreman, Victoria Cook, Tessa Gordon
Spinal muscular atrophy (SMA) is a common autosomal recessive disorder in humans and is the leading genetic cause of infantile death. Patients lack the SMN1 gene with the severity of the disease depending on the number of copies of the highly homologous SMN2 gene. Although motoneuron death in the Smn+/- transgenic mouse model of mildest form of SMA, SMA type III, has been reported, we have used retrograde tracing of sciatic and femoral motoneurons in the hindlimb with recording of muscle and motor unit isometric forces to count the number of motoneurons with intact neuromuscular connections...
November 28, 2016: Journal of Physiology
https://www.readbyqxmd.com/read/27891607/cortical-and-reticular-contributions-to-human-precision-and-power-grip
#8
Toshiki Tazoe, Monica A Perez
It is well accepted that the corticospinal tract contributes to the control of finger muscles during precision and power grip in humans but the neural mechanisms involved remain poorly understood. Here, we examined motor evoked potentials elicited by cortical and subcortical stimulation of corticospinal axons (MEPs and CMEPs, respectively) and the activity in intracortical circuits (suppression of voluntary electromyography) and spinal motoneurons (F-waves) in an intrinsic hand muscle during index finger abduction (control task), precision grip, and power grip...
November 28, 2016: Journal of Physiology
https://www.readbyqxmd.com/read/27891099/reduced-phrenic-motoneuron-recruitment-during-sustained-inspiratory-threshold-loading-compared-to-single-breath-loading-a-twitch-interpolation-study
#9
Mathieu Raux, Alexandre Demoule, Stefania Redolfi, Capucine Morelot-Panzini, Thomas Similowski
In humans, inspiratory constraints engage cortical networks involving the supplementary motor area. Functional magnetic resonance imaging (fMRI) shows that the spread and intensity of the corresponding respiratory-related cortical activation dramatically decrease when a discrete load becomes sustained. This has been interpreted as reflecting motor cortical reorganization and automatisation, but could proceed from sensory and/or affective habituation. To corroborate the existence of motor reorganization between single-breath and sustained inspiratory loading (namely changes in motor neurones recruitment), we conducted a diaphragm twitch interpolation study based on the hypothesis that motor reorganization should result in changes in the twitch interpolation slope...
2016: Frontiers in Physiology
https://www.readbyqxmd.com/read/27884958/activity-dependent-redistribution-of-kv2-1-ion-channels-on-rat-spinal-motoneurons
#10
Shannon H Romer, Adam S Deardorff, Robert E W Fyffe
Homeostatic plasticity occurs through diverse cellular and synaptic mechanisms, and extensive investigations over the preceding decade have established Kv2.1 ion channels as key homeostatic regulatory elements in several central neuronal systems. As in these cellular systems, Kv2.1 channels in spinal motoneurons (MNs) localize within large somatic membrane clusters. However, their role in regulating motoneuron activity is not fully established in vivo. We have previously demonstrated marked Kv2.1 channel redistribution in MNs following in vitro glutamate application and in vivo peripheral nerve injury (Romer et al...
November 2016: Physiological Reports
https://www.readbyqxmd.com/read/27879456/hindlimb-spasticity-after-unilateral-motor-cortex-lesion-in-rats-is-reduced-by-contralateral-nerve-root-transfer
#11
Hai Yang Zong, Fenfen Ma, Lai Yin Zhang, Hui Ping Lu, Jing Ru Gong, Min Cai, Hao Dong Lin, Yizhun Zhun Zhu, Chun Lin Hou
The aim was to test the feasibility and effectiveness of contralateral nerve root transfer in reducing post stroke spasticity of the affected hindlimb muscles in rats. In our study, we for the first time created a novel animal hindlimb spastic hemiplegia model in rats with photothrombotic lesion of unilateral motor cortex and we established a novel surgical procedure in reducing motor cortex lesion induced hindlimb spastic hemiplegia in rats. Thirty six rats were randomized into three groups. In group A, rats received sham operation...
November 22, 2016: Bioscience Reports
https://www.readbyqxmd.com/read/27874249/role-of-neural-integrators-in-oculomotor-systems-a%C3%A2-systematic-narrative-literature-review
#12
REVIEW
Katherine Sanchez, Fiona J Rowe
PURPOSE: To evaluate the role of neural integrators (NI) in the oculomotor system. METHODS: A literature search was carried out using several electronic databases during the months of June 2014 to March 2015. The following keywords were used to generate focused results: 'neural integrators', 'gaze-holding', 'oculomotor integration', 'impaired gaze-holding', 'gaze evoked nystagmus' and 'gaze dysfunction'. Further materials were found through searching relevant articles within reference lists...
November 22, 2016: Acta Ophthalmologica
https://www.readbyqxmd.com/read/27872607/disparate-changes-in-plasma-and-brainstem-cytokine-levels-in-adult-and-ageing-rats-associated-with-age-related-changes-in-facial-motor-neuron-number-snout-muscle-morphology-and-exploratory-behavior
#13
Viythia Katharesan, Martin David Lewis, Robert Vink, Ian Paul Johnson
An overall increase in inflammatory cytokines with age in both the blood and the central nervous system (CNS) has been proposed to explain many aspects of ageing, including decreased motor function and neurodegeneration. This study tests the hypothesis that age-related increases in inflammatory cytokines in the blood and CNS lead to facial motor neuron degeneration. Groups of 3-5 female Sprague-Dawley rats aged 3, 12-18, and 24 months were used. Twelve cytokines interleukin (IL)-1α, IL-β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p70, IL-13, tumor necrosis factor-α (TNFα), interferon-γ, and granulocyte macrophage-colony stimulating factor were measured in blood plasma and compared with those in the brainstem after first flushing blood from its vessels...
2016: Frontiers in Neurology
https://www.readbyqxmd.com/read/27872027/how-the-emotional-motor-system-controls-the-pelvic-organs
#14
REVIEW
Gert Holstege
INTRODUCTION: The brain has two goals: survival of the individual and survival of the species. It ensures that the body resides in safe circumstances and can obtain sufficient drink and food. It also has to produce and protect offspring. Its most important tool is its motor system, which consists of the voluntary and emotional motor systems. AIM: To explain how the brain uses its emotional motor system to control the pelvic organs. METHODS: Anatomic and physiologic data in cats and humans are used to find out how this motor system works and what parts of the brain and brainstem are involved...
October 2016: Sexual Medicine Reviews
https://www.readbyqxmd.com/read/27866119/group-iii-iv-locomotor-muscle-afferents-alter-motor-cortical-and-corticospinal-excitability-and-promote-central-fatigue-during-cycling-exercise
#15
Simranjit K Sidhu, Joshua C Weavil, Tyler S Mangum, Jacob E Jessop, Russell S Richardson, David E Morgan, Markus Amann
OBJECTIVE: To investigate the influence of group III/IV muscle afferents on the development of central fatigue and corticospinal excitability during exercise. METHODS: Fourteen males performed cycling-exercise both under control-conditions (CTRL) and with lumbar intrathecal fentanyl (FENT) impairing feedback from leg muscle afferents. Transcranial magnetic- and cervicomedullary stimulation was used to monitor cortical versus spinal excitability. RESULTS: While fentanyl-blockade during non-fatiguing cycling had no effect on motor-evoked potentials (MEPs), cervicomedullary-evoked motor potentials (CMEPs) were 13±3% higher (P<0...
October 26, 2016: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/27865907/differential-regulation-of-glial-reactions-in-the-central-facial-tract-and-the-facial-nucleus-after-facial-neurorrhaphy
#16
Tzu-Yin Yeh, Shang-Ming Wang, Guo-Fang Tseng, Pei-Hsin Liu
We previously reported that perineuronal astrocytic and microglial reactions are drastically upregulated in the facial nucleus after facial axotomy at the brain stem surface or the stylomastoid foramen. Furthermore, periaxonal astrocytic and microglial reactions develop retrogradely in the central facial tract which contains proximal facial axons in the brain stem. Because reconnection of interrupted peripheral nerve by microsurgical suture is a common clinical practice, the aim of this study was to investigate the spatiotemporal patterns of glial reactions in the central facial tract and the facial nucleus after facial neurorrhaphy...
November 16, 2016: Journal of Chemical Neuroanatomy
https://www.readbyqxmd.com/read/27864939/gabaergic-innervation-of-the-ciliary-ganglion-in-macaque-monkeys-a-light-and-electron-microscopic-study
#17
Miriam Barnerssoi, Paul J May, Anja K E Horn
The vertebrate ciliary ganglion (CG) is a relay station in the parasympathetic pathway activating the iris sphincter and ciliary muscle to mediate pupillary constriction and lens accommodation, respectively. While the postganglionic motoneurons in the CG are cholinergic, as are their inputs, there is evidence from avian studies that GABA may also be involved. Here, we used light and electron microscopic methods to examine the GABAergic innervation of the CG in Macaca fascicularis monkeys. Immunohistochemistry for the gamma aminobutyric acid synthesizing enzyme glutamic acid decarboxylase (GAD) and choline acetyltransferase (ChAT) revealed that all CG neurons are contacted by ChAT-positive terminals...
November 16, 2016: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/27862051/comparison-of-the-ballistic-contractile-responses-generated-during-microstimulation-of-single-human-motor-axons-with-brief-irregular-and-regular-stimuli
#18
Michael Leitch, Vaughan G Macefield
INTRODUCTION: Ballistic contractions are induced by brief, high frequency (60-100 Hz) trains of action potentials in motor axons. During ramp voluntary contractions, human motoneurones exhibit significant discharge variability of ∼20% and have shown to be advantageous to the neuromuscular system. We hypothesized that ballistic contractions incorporating discharge variability generate greater isometric forces than regular trains with zero variability. METHODS: High impedance tungsten microelectrodes were inserted into the fibular nerve, and single motor axons were stimulated with both irregular and constant-frequency stimuli at mean frequencies ranging from 57...
November 11, 2016: Muscle & Nerve
https://www.readbyqxmd.com/read/27861192/generation-of-repeater-f-waves-in-healthy-subjects
#19
Elisabeth Chroni, Dimitra Veltsista, Chris Papapaulou, Eftychia Trachani
INTRODUCTION: F waves identical in latency, size and shape, known as repeater F waves, have been observed occasionally in normal motor conduction recordings. The purpose of this study was to examine the occurrence and characteristics of repeater F waves in healthy subjects under different testing conditions, aiming to selectively excite lower and higher threshold motor fibers. METHODS: Sessions of 40 traces were recorded from the ulnar nerve in 12 volunteers, applying/ using supramaximal, submaximal stimuli (intensity able to elicit 30% and 60% of the maximum compound muscle action potential amplitude) and a collision technique...
November 17, 2016: Journal of Clinical Neurophysiology: Official Publication of the American Electroencephalographic Society
https://www.readbyqxmd.com/read/27859267/human-motoneurone-excitability-is-depressed-by-activation-of-5ht1a-receptors-with-buspirone
#20
Jessica M D'Amico, Annie A Butler, Martin E Héroux, Florence Cotel, Jean-François M Perrier, Jane E Butler, Simon C Gandevia, Janet L Taylor
Intense serotonergic drive in the turtle spinal cord results in serotonin spillover to the axon initial segment of the motoneurones where it activates 5HT1A receptors and inhibits generation of action potentials. We examined whether activation of 5HT1A receptors decreases motoneurone excitability in humans by determining the effects of a 5HT1A receptor partial agonist, buspirone, on F waves and cervicomedullary motor evoked potentials (CMEPs). In a placebo-controlled double-blind study, 10 participants were tested on two occasions where either placebo or 20 mg buspirone was administered orally...
November 17, 2016: Journal of Physiology
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