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Postural Reflex

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https://www.readbyqxmd.com/read/29035981/clinical-utility-of-oculomotor-and-electrophysiological-measures-in-identifying-concussion-history
#1
Patrick S Ledwidge, Jessie N Patterson, Dennis L Molfese, Julie A Honaker
OBJECTIVE: To examine whether oculomotor and electrophysiological measures improve the clinical performance of the typical concussion protocol for classifying collegiate athletes with a history of concussion. DESIGN: Cross-sectional. SETTING: University Athletic Medicine and Research Facility. PARTICIPANTS: Forty-five varsity collegiate athletes. INDEPENDENT VARIABLES: Collegiate varsity athletes with or without a history of a diagnosed concussion...
October 10, 2017: Clinical Journal of Sport Medicine: Official Journal of the Canadian Academy of Sport Medicine
https://www.readbyqxmd.com/read/29021750/cough-anal-reflex-may-be-the-expression-of-a-pre-programmed-postural-action
#2
Paolo Cavallari, Francesco Bolzoni, Roberto Esposti, Carlo Bruttini
When coughing, an involuntary contraction of the external anal sphincter occurs, in order to prevent unwanted leakages or sagging of the pelvis muscular wall. Literature originally described such cough-anal response as a reflex elicited by cough, therefore identifying a precise cause-effect relationship. However, recent studies report that the anal contraction actually precedes the rise in abdominal pressure during cough expiratory effort, so that the sphincter activity should be pre-programmed. In recent years, an important family of pre-programmed muscle activities has been well documented to precede voluntary movements: these anticipatory actions play a fundamental role in whole body and segmental postural control, hence they are referred to as anticipatory postural adjustments (APAs)...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28972121/gaze-stabilizing-central-vestibular-neurons-project-asymmetrically-to-extraocular-motoneuron-pools
#3
David Schoppik, Isaac H Bianco, David A Prober, Adam D Douglass, Drew N Robson, Jennifer M B Li, Joel S F Greenwood, Edward Soucy, Florian Engert, Alexander F Schier
Within reflex circuits, specific anatomical projections allow central neurons to relay sensations to effectors that generate movements. A major challenge is to relate anatomical features of central neural populations -- such as asymmetric connectivity -- to the computations the populations perform. To address this problem, we mapped the anatomy, modeled the function, and discovered a new behavioral role for a genetically-defined population of central vestibular neurons in rhombomeres 5-7 of larval zebrafish...
September 29, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28951323/preparatory-cortical-and-spinal-settings-to-counteract-anticipated-and-non-anticipated-perturbations
#4
Michael Wälchli, Craig D Tokuno, Jan Ruffieux, Martin Keller, Wolfgang Taube
Little is known about how the central nervous system prepares postural responses differently in anticipated compared to non-anticipated perturbations. To investigate this, participants were exposed to translational and rotational perturbations presented in a blocked (anticipated) and a random (non-anticipated) design. The preparatory setting ('central set') was measured by H-reflexes, motor-evoked potentials (MEPs), and short-interval intracortical inhibition (SICI) shortly before perturbation onset in the soleus of 15 healthy adults...
September 23, 2017: Neuroscience
https://www.readbyqxmd.com/read/28929183/altered-neurofilament-protein-expression-in-the-lateral-vestibular-nucleus-in-parkinson-s-disease
#5
Thomas P Wellings, Alan M Brichta, Rebecca Lim
A major cause of morbidity in Parkinson's disease (PD) is postural instability. The neuropathology underlying postural instability is unknown. Postural control is mediated by Deiters' neurons of the lateral vestibular nucleus (LVN), which are the brainstem origin of descending vestibulospinal reflexes. Deiters' neurons express the cytostructural protein, non-phosphorylated neurofilament protein (NPNFP). In PD, reduced expression of NPNFP in substantia nigra (SN) neurons is believed to contribute to dysfunction...
September 19, 2017: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
https://www.readbyqxmd.com/read/28913614/researchers-must-be-aware-of-their-roles-at-the-interface-of-ecosystem-services-science-and-policy
#6
Emilie Crouzat, Isabelle Arpin, Lucas Brunet, Matthew J Colloff, Francis Turkelboom, Sandra Lavorel
Scientists working on ecosystem service (ES) science are engaged in a mission-driven discipline. They can contribute to science-policy interfaces where knowledge is co-produced and used. How scientists engage with the governance arena to mobilise their knowledge remains a matter of personal choice, influenced by individual values. ES science cannot be considered neutral and a discussion of the values that shape it forms an important part of the sustainability dialogue. We propose a simple decision tree to help ES scientists identify their role and the purpose of the knowledge they produce...
September 14, 2017: Ambio
https://www.readbyqxmd.com/read/28887013/morphine-exposure-and-maternal-deprivation-during-the-early-postnatal-period-alter-neuromotor-development-and-nerve-growth-factor-levels
#7
Carla de Oliveira, Vanessa L Scarabelot, Rafael Vercelino, Natalia P Silveira, Lauren N S Adachi, Gabriela G Regner, Lisiane S Silva, Isabel Cristina de Macedo, Andressa de Souza, Wolnei Caumo, Iraci L S Torres
The objective of this study was to verify whether repeated morphine administration and maternal deprivation in early life alter neurobehavioral development and central nerve growth factor (NGF) levels. A total of 58 male Wistar rat pups were used in our study. From postnatal day 1 (P1), litters were daily deprived of their mother for 3h; this was continued for the first 10days of life. Animals were divided into 5 groups: total control (C), did not receive any intervention; saline (S), received saline solution; morphine (M), received morphine; deprived-saline group (DS), were subjected to maternal deprivation and received saline solution; and deprived-morphine (DM), were subjected to maternal deprivation and received morphine...
September 5, 2017: International Journal of Developmental Neuroscience
https://www.readbyqxmd.com/read/28843638/local-vibration-inhibits-h-reflex-but-does-not-compromise-manual-dexterity-and-does-not-increase-tremor
#8
Francesco Budini, Luca Laudani, Sergio Bernardini, Andrea Macaluso
The present work aimed at investigating the effects of local vibration on upper limb postural and kinetic tremor, on manual dexterity and on spinal reflex excitability. Previous studies have demonstrated a decrease in spinal reflex excitability and in force fluctuations in the lower limb but an increase in force fluctuation in the upper limbs. As hand steadiness is of vital importance in many daily-based tasks, and local vibration may also be applied in movement disorders, we decided to further explore this phenomenon...
August 24, 2017: Human Movement Science
https://www.readbyqxmd.com/read/28818139/bed-rest-and-intermittent-centrifugation-effects-on-human-balance-and-neuromotor-reflexes
#9
William H Paloski, Millard F Reschke, Alan H Feiveson
INTRODUCTION: The effects of repeated centrifugation in association with head-down tilt (HDT) bed rest (BR) on the mediation of basic reflexes associated with the major postural muscles was investigated as a potential countermeasure for maintaining balance control and neuromotor reflex function. METHODS: There were 15 male volunteers who were exposed to 21 d of 6° HDT-BR. Eight were treated with daily 1-h artificial gravity (AG) exposures aboard a short radius centrifuge that provided 1-g footward loading at heart level...
September 1, 2017: Aerospace Medicine and Human Performance
https://www.readbyqxmd.com/read/28798718/vestibular-modulation-of-sympathetic-nerve-activity-to-muscle-and-skin-in-humans
#10
REVIEW
Elie Hammam, Vaughan G Macefield
We review the existence of vestibulosympathetic reflexes in humans. While several methods to activate the human vestibular apparatus have been used, galvanic vestibular stimulation (GVS) is a means of selectively modulating vestibular afferent activity via electrodes over the mastoid processes, causing robust vestibular illusions of side-to-side movement. Sinusoidal GVS (sGVS) causes partial entrainment of sympathetic outflow to muscle and skin. Modulation of muscle sympathetic nerve activity (MSNA) from vestibular inputs competes with baroreceptor inputs, with stronger temporal coupling to the vestibular stimulus being observed at frequencies remote from the cardiac frequency; "super entrainment" was observed in some individuals...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28764704/objective-impairments-of-gait-and-balance-in-adults-living-with-hiv-1-infection-a-systematic-review-and-meta-analysis-of-observational-studies
#11
Karina Berner, Linzette Morris, Jochen Baumeister, Quinette Louw
BACKGROUND: Gait and balance deficits are reported in adults with HIV infection and are associated with reduced quality of life. Current research suggests an increased fall-incidence in this population, with fall rates among middle-aged adults with HIV approximating that in seronegative elderly populations. Gait and postural balance rely on a complex interaction of the motor system, sensory control, and cognitive function. However, due to disease progression and complications related to ongoing inflammation, these systems may be compromised in people with HIV...
August 1, 2017: BMC Musculoskeletal Disorders
https://www.readbyqxmd.com/read/28746244/the-effect-of-unicycle-riding-course-on-trunk-strength-and-trunk-stability-functions-in-children
#12
Andrej Kocjan, Nejc Sarabon
PURPOSE: The aim of the study was to assess the effect of unicycling on trunk strength and timing of automatic stability actions of the selected trunk muscles (multifidus, obliquus externus, erector spine). METHODS: Twenty healthy 12-year-old children (12 boys, 8 girls; age 12.1 ± 0.2 yrs; body height 1.57 ± 0.05 m; body mass 52.8 ± 10.6 kg) were assigned to experimental and control group. Experimental group performed a supervised 12-session course of unicycling...
July 24, 2017: Journal of Strength and Conditioning Research
https://www.readbyqxmd.com/read/28743726/why-new-spinal-cord-plasticity-does-not-disrupt-old-motor-behaviors
#13
Yi Chen, Lu Chen, Yu Wang, Xiang Yang Chen, Jonathan R Wolpaw
When new motor learning changes the spinal cord, old behaviors are not impaired; their key features are preserved by additional compensatory plasticity. To explore the mechanisms responsible for this compensatory plasticity, we transected the spinal dorsal ascending tract before or after female rats acquired a new behavior-operantly conditioned increase or decrease in the right soleus H-reflex-and examined an old behavior-locomotion. Neither spinal dorsal ascending tract transection nor H-reflex conditioning alone impaired locomotion...
August 23, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28740669/impact-of-thoracic-surgery-on-esophageal-motor-function-evaluation-by-high-resolution-manometry
#14
Anja Wäsche, Arne Kandulski, Peter Malfertheiner, Sandra Riedel, Patrick Zardo, Thomas Hachenberg, Jens Schreiber
BACKGROUND: Alteration of esophageal function is a potential risk factor for postoperative complications in thoracic surgery. This prospective study investigates esophageal motility and function during and after thoracic procedures via high resolution manometry (HRM) and impedance technology with spatiotemporal representation of pressure data. METHODS: Twelve consecutive patients eligible for elective thoracic surgery underwent preoperative and postoperative (48 hours and 7 days) esophageal HRM...
June 2017: Journal of Thoracic Disease
https://www.readbyqxmd.com/read/28734171/muscle-synergies-reveal-impaired-trunk-muscle-coordination-strategies-in-individuals-with-thoracic-spinal-cord-injury
#15
Matija Milosevic, Hikaru Yokoyama, Murielle Grangeon, Kei Masani, Milos R Popovic, Kimitaka Nakazawa, Dany H Gagnon
Spinal cord injury (SCI) can result in paralysis of trunk muscles, which can affect sitting balance. The objective of this study was to analyze trunk muscle coordination of individuals with thoracic SCI and compare it to able-body individuals. A total of 27 individuals were recruited and subdivided into: (a) high thoracic SCI; (b) low thoracic SCI; and (c) able-body groups. Participants were seated and asked to lean their trunk in eight directions while trunk muscle activity was recorded. Muscle coordination was assessed using the non-negative matrix factorization (NMF) method to extract muscle modules, which are the synergistic trunk muscle activations, and their directional activation patterns...
October 2017: Journal of Electromyography and Kinesiology
https://www.readbyqxmd.com/read/28733210/threat-effects-on-human-oculo-motor-function
#16
E N Naranjo, T W Cleworth, J H J Allum, J T Inglis, J Lea, B D Westerberg, M G Carpenter
Neuro-anatomical evidence supports the potential for threat-related factors, such as fear, anxiety and vigilance, to influence brainstem motor nuclei controlling eye movements, as well as the vestibular nuclei. However, little is known about how threat influences human ocular responses, such as eye saccades (ES), smooth pursuit eye tracking (SP), and optokinetic nystagmus (OKN), and whether these responses can be facilitated above normal baseline levels with a natural source of threat. This study was designed to examine the effects of height-induced postural threat on the gain of ES, SP and OKN responses in humans...
July 18, 2017: Neuroscience
https://www.readbyqxmd.com/read/28723718/three-dimensional-head-mounted-gaming-task-procedure-maximizes-effects-of-vestibular-rehabilitation-in-unilateral-vestibular-hypofunction-a-randomized-controlled-pilot-trial
#17
Alessandro Micarelli, Andrea Viziano, Ivan Augimeri, Domenico Micarelli, Marco Alessandrini
Considering the emerging advantages related to virtual reality implementation in clinical rehabilitation, the aim of the present study was to discover possible (i) improvements achievable in unilateral vestibular hypofunction patients using a self-assessed head-mounted device (HMD)-based gaming procedure when combined with a classical vestibular rehabilitation protocol (HMD group) as compared with a group undergoing only vestibular rehabilitation and (ii) HMD procedure-related side effects. Therefore, 24 vestibular rehabilitation and 23-matched HMD unilateral vestibular hypofunction individuals simultaneously underwent a 4-week rehabilitation protocol...
July 18, 2017: International Journal of Rehabilitation Research. Revue Internationale de Recherches de Réadaptation
https://www.readbyqxmd.com/read/28712015/mechanisms-contributing-to-reduced-knee-stiffness-during-movement
#18
Daniel Ludvig, Maciej Plocharski, Piotr Plocharski, Eric J Perreault
The ability to modulate the mechanical properties of our limbs contributes to our ability to interact with the physical world in a consistent and predictable manner. An individual joint's contributions to whole limb mechanics can be quantified by its joint impedance, which characterizes the torque generated about a joint in response to external perturbations of position. A number of studies have estimated joint impedance during movement and have shown that it can be much lower than it is during posture. However, the mechanisms contributing to these differences remain unknown partly because conditions known to affect impedance, including muscle activation and joint angles, have not been carefully controlled across studies...
July 15, 2017: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
https://www.readbyqxmd.com/read/28649196/estimation-of-time-varying-intrinsic-and-reflex-dynamic-joint-stiffness-during-movement-application-to-the-ankle-joint
#19
Diego L Guarín, Robert E Kearney
Dynamic joint stiffness determines the relation between joint position and torque, and plays a vital role in the control of posture and movement. Dynamic joint stiffness can be quantified during quasi-stationary conditions using disturbance experiments, where small position perturbations are applied to the joint and the torque response is recorded. Dynamic joint stiffness is composed of intrinsic and reflex mechanisms that act and change together, so that nonlinear, mathematical models and specialized system identification techniques are necessary to estimate their relative contributions to overall joint stiffness...
2017: Frontiers in Computational Neuroscience
https://www.readbyqxmd.com/read/28638331/monosynaptic-stretch-reflex-fails-to-explain-the-initial-postural-response-to-sudden-lateral-perturbations
#20
Andreas Mühlbeier, Christian Puta, Kim J Boström, Heiko Wagner
Postural reflexes are essential for locomotion and postural stability, and may play an important role in the etiology of chronic back pain. It has recently been theoretically predicted, and with the help of unilateral perturbations of the trunk experimentally confirmed that the sensorimotor control must lower the reflex amplitude for increasing reflex delays to maintain spinal stability. The underlying neuromuscular mechanism for the compensation of postural perturbations, however, is not yet fully understood...
2017: Frontiers in Human Neuroscience
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