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neuromechanics

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https://www.readbyqxmd.com/read/28427305/neuromechanical-adaptations-during-a-robotic-powered-exoskeleton-assisted-walking-session
#1
Arvind Ramanujam, Christopher M Cirnigliaro, Erica Garbarini, Pierre Asselin, Rakesh Pilkar, Gail F Forrest
OBJECTIVE: To evaluate gait parameters and neuromuscular profiles of exoskeleton-assisted walking under Max Assist condition during a single-session for; (i) able bodied (AB) individuals walking assisted with (EXO) and without (non-EXO) a powered exoskeleton, (ii) non-ambulatory SCI individuals walking assisted with a powered exoskeleton. DESIGN: Single-session. SETTING: Motion analysis laboratory. PARTICIPANTS: Four AB individuals and four individuals with SCI...
April 20, 2017: Journal of Spinal Cord Medicine
https://www.readbyqxmd.com/read/28396411/mechanosensation-is-evolutionarily-tuned-to-locomotor-mechanics
#2
Brett R Aiello, Mark W Westneat, Melina E Hale
The biomechanics of animal limbs has evolved to meet the functional demands for movement associated with different behaviors and environments. Effective movement relies not only on limb mechanics but also on appropriate mechanosensory feedback. By comparing sensory ability and mechanics within a phylogenetic framework, we show that peripheral mechanosensation has evolved with limb biomechanics, evolutionarily tuning the neuromechanical system to its functional demands. We examined sensory physiology and mechanics of the pectoral fins, forelimb homologs, in the fish family Labridae...
April 10, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28381996/evaluation-of-a-neuromechanical-walking-control-model-using-disturbance-experiments
#3
Seungmoon Song, Hartmut Geyer
Neuromechanical simulations have been used to study the spinal control of human locomotion which involves complex mechanical dynamics. So far, most neuromechanical simulation studies have focused on demonstrating the capability of a proposed control model in generating normal walking. As many of these models with competing control hypotheses can generate human-like normal walking behaviors, a more in-depth evaluation is required. Here, we conduct the more in-depth evaluation on a spinal-reflex-based control model using five representative gait disturbances, ranging from electrical stimulation to mechanical perturbation at individual leg joints and at the whole body...
2017: Frontiers in Computational Neuroscience
https://www.readbyqxmd.com/read/28351197/the-human-central-pattern-generator-for-locomotion
#4
Karen Minassian, Ursula S Hofstoetter, Florin Dzeladini, Pierre A Guertin, Auke Ijspeert
The ability of dedicated spinal circuits, referred to as central pattern generators (CPGs), to produce the basic rhythm and neural activation patterns underlying locomotion can be demonstrated under specific experimental conditions in reduced animal preparations. The existence of CPGs in humans is a matter of debate. Equally elusive is the contribution of CPGs to normal bipedal locomotion. To address these points, we focus on human studies that utilized spinal cord stimulation or pharmacological neuromodulation to generate rhythmic activity in individuals with spinal cord injury, and on neuromechanical modeling of human locomotion...
March 1, 2017: Neuroscientist: a Review Journal Bringing Neurobiology, Neurology and Psychiatry
https://www.readbyqxmd.com/read/28282755/the-acute-effects-of-an-intense-stretch-shortening-cycle-fatigue-protocol-on-the-neuromechanical-parameters-of-lower-limbs-in-men-and-prepubescent-boys
#5
Savvas Lazaridis, Dimitrios A Patikas, Eleni Bassa, Themistoklis Tsatalas, Konstantinos Hatzikotoulas, Christos Ftikas, Christos Kotzamanidis
The study examined the differences between boys and adults after an intense stretch-shortening cycle fatigue protocol on neuromechanical parameters of the lower limb. Thirteen boys (9-11 years old) and 13 adult men (22-28 years old) were tested for maximal isometric voluntary knee extension torque and drop jump (DJ) performance from 30 cm before and immediately after a fatigue protocol, consisted of 10 × 10 maximum effort vertical jumps. Three-dimensional kinematics, kinetics and electromyographic (EMG) parameters of the lower extremities muscles were recorded during DJs before and after the fatigue test...
February 8, 2017: Journal of Sports Sciences
https://www.readbyqxmd.com/read/28280881/tryptophan-depletion-affects-compulsive-behaviour-in-rats-strain-dependent-effects-and-associated-neuromechanisms
#6
A Merchán, S V Navarro, A B Klein, S Aznar, L Campa, C Suñol, M Moreno, P Flores
RATIONALE: Compulsive behaviour, present in different psychiatric disorders, such as obsessive-compulsive disorder, schizophrenia and drug abuse, is associated with altered levels of monoamines, particularly serotonin (5-hydroxytryptamine) and its receptor system. OBJECTIVES: The present study investigated whether 5-HT manipulation, through a tryptophan (TRP) depletion by diet in Wistar and Lister Hooded rats, modulates compulsive drinking in schedule-induced polydipsia (SIP) and locomotor activity in the open-field test...
April 2017: Psychopharmacology
https://www.readbyqxmd.com/read/28279574/activity-patterns-of-extrinsic-finger-flexors-and-extensors-during-movements-of-instructed-and-non-instructed-fingers
#7
Nathalie van Beek, Dick F Stegeman, Josien C van den Noort, DirkJan H E J Veeger, Huub Maas
The fingers of the human hand cannot be controlled fully independently. This phenomenon may have a neurological as well as a mechanical basis. Despite previous studies, the neuromechanics of finger movements are not fully understood. The aims of this study were (1) to assess the activation and coactivation patterns of finger specific flexor and extensor muscle regions during instructed single finger flexion and (2) to determine the relationship between enslaved finger movements and respective finger muscle activation...
February 21, 2017: Journal of Electromyography and Kinesiology
https://www.readbyqxmd.com/read/28269975/effects-of-detraining-on-neuromuscular-performance-in-a-selected-group-of-elite-women-pole-vaulters-a-case-study
#8
Irineu Loturco, Lucas A Pereira, Ronaldo Kobal, Henrique C Martins, Katia Kitamura, Cesar C Abad, Fabio Y Nakamura
The aim of this paper was to determine the effects of 28 days of inactivity on neuromuscular performance of elite women pole-vaulters. Four athletes undertook measurements of rate of force development (RFD), unloaded and loaded vertical jump tests, drop jumps and a 45 m sprint test before and after a transition period of planned inactivity. The RFD, the ability to accelerate over very short distances (5 m) and sprinting capacity improved after training cessation. Acceleration over longer distances (5-45 m) was impaired, while unloaded and loaded vertical jump tests suffered trivial to small changes...
April 2017: Journal of Sports Medicine and Physical Fitness
https://www.readbyqxmd.com/read/28268271/a-model-based-exploration-of-the-role-of-pattern-generating-circuits-during-locomotor-adaptation
#9
Ali Marjaninejad, James M Finley
In this study, we used a model-based approach to explore the potential contributions of central pattern generating circuits (CPGs) during adaptation to external perturbations during locomotion. We constructed a neuromechanical modeled of locomotion using a reduced-phase CPG controller and an inverted pendulum mechanical model. Two different forms of locomotor adaptation were examined in this study: split-belt treadmill adaptation and adaptation to a unilateral, elastic force field. For each simulation, we first examined the effects of phase resetting and varying the model's initial conditions on the resulting adaptation...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28259465/contribution-of-muscle-short-range-stiffness-to-initial-changes-in-joint-kinetics-and-kinematics-during-perturbations-to-standing-balance-a-simulation-study
#10
Friedl De Groote, Jessica L Allen, Lena H Ting
Simulating realistic musculoskeletal dynamics is critical to understanding neural control of muscle activity evoked in sensorimotor feedback responses that have inherent neural transmission delays. Thus, the initial mechanical response of muscles to perturbations in the absence of any change in muscle activity determines which corrective neural responses are required to stabilize body posture. Muscle short-range stiffness, a history-dependent property of muscle that causes a rapid and transient rise in muscle force upon stretch, likely affects musculoskeletal dynamics in the initial mechanical response to perturbations...
April 11, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28226428/a-model-based-exploration-of-the-role-of-pattern-generating-circuits-during-locomotor-adaptation
#11
Ali Marjaninejad, James M Finley, Ali Marjaninejad, James M Finley, Ali Marjaninejad, James M Finley
In this study, we used a model-based approach to explore the potential contributions of central pattern generating circuits (CPGs) during adaptation to external perturbations during locomotion. We constructed a neuromechanical modeled of locomotion using a reduced-phase CPG controller and an inverted pendulum mechanical model. Two different forms of locomotor adaptation were examined in this study: split-belt treadmill adaptation and adaptation to a unilateral, elastic force field. For each simulation, we first examined the effects of phase resetting and varying the model's initial conditions on the resulting adaptation...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28224266/design-process-and-tools-for-dynamic-neuromechanical-models-and-robot-controllers
#12
Nicholas S Szczecinski, Alexander J Hunt, Roger D Quinn
We present a serial design process with associated tools to select parameter values for a posture and locomotion controller for simulation of a robot. The controller is constructed from dynamic neuron and synapse models and simulated with the open-source neuromechanical simulator AnimatLab 2. Each joint has a central pattern generator (CPG), whose neurons possess persistent sodium channels. The CPG rhythmically inhibits motor neurons that control the servomotor's velocity. Sensory information coordinates the joints in the leg into a cohesive stepping motion...
February 2017: Biological Cybernetics
https://www.readbyqxmd.com/read/28220377/altered-functional-connectivity-architecture-of-the-brain-in-medication-overuse-headache-using-resting-state-fmri
#13
Zhiye Chen, Xiaoyan Chen, Mengqi Liu, Zhao Dong, Lin Ma, Shengyuan Yu
BACKGROUND: Functional connectivity density (FCD) could identify the abnormal intrinsic and spontaneous activity over the whole brain, and a seed-based resting-state functional connectivity (RSFC) could further reveal the altered functional network with the identified brain regions. This may be an effective assessment strategy for headache research. This study is to investigate the RSFC architecture changes of the brain in the patients with medication overuse headache (MOH) using FCD and RSFC methods...
December 2017: Journal of Headache and Pain
https://www.readbyqxmd.com/read/28116559/altered-functional-connectivity-of-amygdala-underlying-the-neuromechanism-of-migraine-pathogenesis
#14
Zhiye Chen, Xiaoyan Chen, Mengqi Liu, Zhao Dong, Lin Ma, Shengyuan Yu
BACKGROUND: The amygdala is a large grey matter complex in the limbic system, and it may contribute in the neurolimbic pain network in migraine. However, the detailed neuromechanism remained to be elucidated. The objective of this study is to investigate the amygdala structural and functional changes in migraine and to elucidate the mechanism of neurolimbic pain-modulating in the migraine pathogenesis. METHODS: Conventional MRI, 3D structure images and resting state functional MRI were performed in 18 normal controls (NC), 18 patients with episodic migraine (EM), and 16 patients with chronic migraine (CM)...
December 2017: Journal of Headache and Pain
https://www.readbyqxmd.com/read/28113200/design-and-characterization-of-an-exoskeleton-for-perturbing-the-knee-during-gait
#15
Michael R Tucker, Camila Shirota, Olivier Lambercy, James Sulzer, Roger Gassert
OBJECTIVE: An improved understanding of mechanical impedance modulation in human joints would provide insights about the neuromechanics underlying functional movements. Experimental estimation of impedance requires specialized tools with highly reproducible perturbation dynamics and reliable measurement capabilities. This paper presents the design and mechanical characterization of the ETH Knee Perturbator: an actuated exoskeleton for perturbing the knee during gait. METHODS: A novel wearable perturbation device was developed based on specific experimental objectives...
January 20, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28094764/neuromorphic-meets-neuromechanics-part-ii-the-role-of-fusimotor-drive
#16
Kian Jalaleddini, Chuanxin Minos Niu, Suraj Chakravarthi Raja, Won Joon Sohn, Gerald E Loeb, Terence D Sanger, Francisco J Valero-Cuevas
OBJECTIVE: We studied the fundamentals of muscle afferentation by building a Neuro-mechano-morphic system actuating a cadaveric finger. This system is a faithful implementation of the stretch reflex circuitry. It allowed the systematic exploration of the effects of different fusimotor drives to the muscle spindle on the closed-loop stretch reflex response. APPROACH: As in Part I of this work, sensory neurons conveyed proprioceptive information from muscle spindles (with static and dynamic fusimotor drive) to populations of α-motor neurons (with recruitment and rate coding properties)...
April 2017: Journal of Neural Engineering
https://www.readbyqxmd.com/read/28004255/robustness-flexibility-and-sensitivity-in-a-multifunctional-motor-control-model
#17
David N Lyttle, Jeffrey P Gill, Kendrick M Shaw, Peter J Thomas, Hillel J Chiel
Motor systems must adapt to perturbations and changing conditions both within and outside the body. We refer to the ability of a system to maintain performance despite perturbations as "robustness," and the ability of a system to deploy alternative strategies that improve fitness as "flexibility." Different classes of pattern-generating circuits yield dynamics with differential sensitivities to perturbations and parameter variation. Depending on the task and the type of perturbation, high sensitivity can either facilitate or hinder robustness and flexibility...
February 2017: Biological Cybernetics
https://www.readbyqxmd.com/read/27992539/kinetics-and-muscle-activity-patterns-during-unweighting-and-reloading-transition-phases-in-running
#18
Patrick Sainton, Caroline Nicol, Jan Cabri, Joëlle Barthèlemy-Montfort, Pascale Chavet
Amongst reduced gravity simulators, the lower body positive pressure (LBPP) treadmill is emerging as an innovative tool for both rehabilitation and fundamental research purposes as it allows running while experiencing reduced vertical ground reaction forces. The appropriate use of such a treadmill requires an improved understanding of the associated neuromechanical changes. This study concentrates on the runner's adjustments to LBPP-induced unweighting and reloading during running. Nine healthy males performed two running series of nine minutes at natural speed...
2016: PloS One
https://www.readbyqxmd.com/read/27884349/endotoxemia-accelerates-diaphragm-dysfunction-in-ventilated-rabbits
#19
Yi Yang, Tao Yu, Chun Pan, Federico Longhini, Ling Liu, Yingzi Huang, Fengmei Guo, Haibo Qiu
BACKGROUND: Ventilators may induce diaphragm dysfunction, and most of the septic population who are admitted to the intensive care unit require mechanical ventilation. However, there is no evidence that sepsis accelerates the onset of ventilator-induced diaphragm dysfunction or affects the microcirculation. Our study investigated whether lipopolysaccharide (LPS)-induced endotoxemia accelerated diaphragm dysfunction in ventilated rabbits by evaluating microcirculation, lipid accumulation, and diaphragm contractility...
December 2016: Journal of Surgical Research
https://www.readbyqxmd.com/read/27796733/nonspecific-periaqueductal-gray-lesions-on-t2wi-in-episodic-migraine
#20
Zhiye Chen, Xiaoyan Chen, Mengqi Liu, Shuangfeng Liu, Lin Ma, Shengyuan Yu
BACKGROUND: The specific periaqueductal gray (PAG) lesions with migraine-like headache were easily identified on conventional MR images in clinical practice, and the aim of this study is to investigate the nonspecific periaqueductal gray (PAG) lesions in episodic migraine (EM) patients based on T2 weighted imaging (T2WI). METHODS: T2WI images were obtained from 18 EM patients and 18 normal controls (NC) on 3.0 T MR system. The images were observed by two experienced radiologists, and the lesions were identified on T2WI by consensus by 2 experienced neuroradiologists blinded to the patient identity...
December 2016: Journal of Headache and Pain
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