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1.
Sportis (A Coruña) ; 6(3): 517-532, sept. 2020. ilus, graf, tab
Artigo em Inglês | IBECS | ID: ibc-197062

RESUMO

The purpose of this study is to determine the effect of an acute local vibration exercise on the visual reaction time of a fencer's upper body extremities. Twenty-six male fencers between the ages of 15 and 23 (mean age, 17.38 ± 2.13 years, height: 173.6±9.1 cm, body mass: 70.2 ±14.1 kg) volunteered for this study. The reaction time test was applied before and after the vibration exercise (applied for 30 seconds in 27 Hz with a 2-mm amplitude). After 25 min. standard warming up, fencers were informed about the test, and three repeated reaction tests were performed to provide familiarization. The fencers started the reaction test in the standard fencing guard position. According to five signals coming at two to five second intervals from the target monitor, the fencers made touché by bending (attacking). The reaction time test had five trials. The average reaction time values pre-vibration, and post-vibration were compared. The visual reaction time measured pre-vibration were significantly longer than those measured post-vibration (p < 0.001). Acute local vibration exercise applied to fencers shortened the visual reaction time. Given the fact that vibration can improve RT, the use of vibration in training has the potential to provide an advantage to fencers


El propósito de este estudio es determinar el efecto de un ejercicio de vibración local aguda en el tiempo de reacción visual de las extremidades superiores de un esgrimidor. Veintiséis esgrimidores masculinos entre las edades de 15 y 23 (edad media, 17.38 ± 2.13 años, altura: 173.6 ± 9.1 cm, masa corporal: 70.2 ± 14.1 kg) se ofrecieron como voluntarios para este estudio. La prueba del tiempo de reacción se aplicó antes y después del ejercicio de vibración (aplicado durante 30 segundos en 27 Hz con una amplitud de 2 mm). Después de 25 min. calentamiento estándar, se informó a los esgrimidores sobre la prueba y se realizaron tres pruebas de reacción repetidas para proporcionar familiarización. Los esgrimidores comenzaron la prueba de reacción en la posición estándar de protección de esgrima. De acuerdo con cinco señales que vienen a intervalos de dos a cinco segundos desde el monitor objetivo, los esgrimistas hicieron un toque al doblarse (atacar). La prueba del tiempo de reacción tuvo cinco ensayos. Se compararon los valores promedio de tiempo de reacción pre-vibración y post-vibración. El tiempo de reacción visual medido antes de la vibración fue significativamente mayor que el medido después de la vibración (p <0.001). El ejercicio de vibración local aguda aplicado a los esgrimidores acortó el tiempo de reacción visual. Dado que la vibración puede mejorar la RT, el uso de la vibración en el entrenamiento tiene el potencial de proporcionar una ventaja a los esgrimidores


Assuntos
Humanos , Masculino , Adolescente , Adulto Jovem , Adulto , Vibração , Visão Ocular/fisiologia , Esportes/fisiologia , Tempo de Reação/fisiologia , Desempenho Atlético/fisiologia , Desempenho Psicomotor/fisiologia , Percepção Espacial/fisiologia , Reflexo/fisiologia , Movimentos Oculares/fisiologia , Orientação/fisiologia , Software , Antropometria
2.
Am J Physiol Regul Integr Comp Physiol ; 319(3): R358-R365, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32726156

RESUMO

Studies have shown that early-stage type 1 diabetes mellitus (T1DM) leads to an exaggerated reflex pressor response to both static muscle contraction and tendon stretch. However, whether similar responses are present during dynamic exercise (i.e., intermittent contraction) is not known. Therefore, the purpose of this study was to determine whether T1DM leads to an exaggerated reflex pressor response to intermittent muscle contraction. We measured the exercise pressor reflex in unanesthetized, decerebrated T1DM (50 mg/kg streptozotocin; STZ) and healthy control (CTL) Sprague-Dawley rats by intermittently contracting the hindlimb muscles for 30 s while measuring mean arterial pressure (MAP), renal sympathetic nerve activity (RSNA), and heart rate (HR). Intermittently contracting the hindlimb muscles evoked exaggerated mean RSNA (STZ: Δ109 ± 21%, n = 4 rats; CTL: Δ61 ± 8%, n = 5 rats, P < 0.05), peak MAP (STZ: Δ32 ± 2 mmHg, n = 9 rats; CTL: Δ12 ± 2 mmHg, n = 6 rats, P < 0.05), blood pressure index (STZ: Δ625 ± 60 mmHg/s, n = 9 rats; CTL: Δ241 ± 46 mmHg/s, n = 6 rats, P < 0.05), and HR (STZ: Δ24 ± 3 beats/min, n = 9 rats; CTL: Δ9 ± 3 beats/min, n = 6 rats, P < 0.05) responses to similar developed tensions (P > 0.05) in T1DM compared with CTL rats. T1DM rats also exhibited exaggerated early-onset sympathetic (onset: 1 s) and pressor (onset: 5 s) responses. These data show that early-stage T1DM leads to an exaggerated pressor reflex evoked by intermittent muscle contraction. The early onset and greater blood pressure index suggest that cardiovascular strain during dynamic exercise may be significantly higher in individuals with T1DM.NEW & NOTEWORTHY This is the first study to provide evidence that early-stage type 1 diabetes mellitus (T1DM) leads to an exaggerated exercise pressor reflex evoked by intermittent muscle contraction, resulting in substantially higher cardiovascular strain. These findings are significant as they indicate that interventions targeting the exercise pressor reflex may work to alleviate the increased cardiovascular strain and overall burden during exercise in T1DM.


Assuntos
Fenômenos Fisiológicos Cardiovasculares , Diabetes Mellitus Tipo 1/fisiopatologia , Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Condicionamento Físico Animal/fisiologia , Animais , Sistema Cardiovascular , Ratos Sprague-Dawley , Reflexo/fisiologia , Sistema Nervoso Simpático/fisiopatologia
4.
J Electromyogr Kinesiol ; 53: 102442, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32659610

RESUMO

The monoaminergic bulbospinal pathways from the brainstem are central to motor functions by regulating the gains of spinal motoneurons and represent, in that respect, probably the primary control system for motoneuron excitability. Yet, the efficiency of this system is few, if not never, assessed in the fields of sports and exercise sciences. In this review paper, we propose a methodological approach intended to assess how this neuromodulatory system affects motoneuron excitability. This approach is based on the use of tendon vibration which can, in certain circumstances, induce the generation of the so-called tonic vibration reflex through the stimulation of muscle spindles. Force and EMG responses to tendon vibration are indeed indicative of how this descending system modulates the gain of the ionotropic inputs from Ia afferents and thus of the strength of the monoaminergic drive. After a brief presentation of the neuromodulatory system and of the mechanisms involved in the generation of the tonic vibration reflex, we address some important methodological considerations regarding the use of the TVR to probe this neuromodulatory gain control system. Hopefully, this paper will encourage sports and exercise scientists to investigate this system.


Assuntos
Exercício Físico/fisiologia , Neurônios Motores/fisiologia , Tratos Piramidais/fisiologia , Esportes/fisiologia , Eletromiografia/métodos , Eletromiografia/tendências , Humanos , Contração Muscular/fisiologia , Fusos Musculares/fisiologia , Músculo Esquelético/fisiologia , Reflexo/fisiologia
5.
Am J Physiol Regul Integr Comp Physiol ; 319(2): R142-R147, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32663039

RESUMO

Earlier reports suggest that limb venous distension evokes reflex increases in muscle sympathetic nerve activity (MSNA) and blood pressure (BP) (i.e., venous distension reflex). Our recent report also shows that suction of arterially occluded limb evokes venous distension reflex. We postulate that the venous distension reflex contributes to autonomic responses to orthostatic stress. In this study, we hypothesized that orthostatic tolerance would be linked to the MSNA response seen with lower limb suction. Fifteen healthy subjects were tested in the supine position. Negative pressure (-100 mmHg) was applied on an arterially occluded lower limb for 2 min. MSNA from the peroneal nerve in the limb not exposed to suction, ECG, and BP (Finometer) was recorded throughout the study. Limb occlusion without suction was used as a control trial. In a separate visit, the individual's orthostatic tolerance was assessed using a graded lower body negative pressure (LBNP) tolerance test. Mean arterial BP and MSNA (18.6 ± 1.9 to 23.6 ± 2.0 bursts/min) significantly (both P < 0.05) increased during limb suction. Orthostatic tolerance index positively correlated (R = 0.636, P = 0.011) with the MSNA response seen with suction during occlusion. Since the venous distension reflex strength correlates with the level of orthostatic tolerance, we speculate that lower-limb venous distension reflex engagement increases the sympathetic responses during orthostatic challenge and serves to maintain BP with postural stress.


Assuntos
Barorreflexo/fisiologia , Pressão Sanguínea/fisiologia , Extremidade Inferior/fisiologia , Reflexo/fisiologia , Sistema Nervoso Simpático/fisiologia , Adulto , Feminino , Frequência Cardíaca/fisiologia , Humanos , Pressão Negativa da Região Corporal Inferior , Masculino , Fluxo Sanguíneo Regional
6.
J Electromyogr Kinesiol ; 53: 102436, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32505988

RESUMO

This systematic review and meta-analysis examined differences in lower extremity neural excitability between ankles with and without chronic ankle instability (CAI). We searched the literature for studies that compared corticomotor or spinal reflexive excitability between a CAI group and controls or copers, or between limbs of a CAI group. Random effects meta-analyses calculated pooled effect sizes for each outcome. Nineteen studies were included. Meta-analyses of motor thresholds of the fibularis longus (Z = 1.17, P = 0.24) and soleus (Z = 0.47, P = 0.64) exhibited no differences between ankles with and without CAI. Pooled data indicate that ankles with CAI had reduced soleus spinal reflexive excitability (Z = 2.18, P = 0.03) and significantly less modulation of the soleus (Z = 6.96, P < 0.01) and fibularis longus (Z = 4.75, P < 0.01) spinal reflexive excitability when transitioning to more challenging stances. Pre-synaptic inhibition was facilitated in ankles with CAI (Z = 4.05, P < 0.01), but no difference in recurrent inhibition existed (Z = 1.50, P = 0.13). Soleus spinal reflexive activity is reduced in those with CAI. Reduced ability of ankles with CAI to modulate soleus and fibularis longus reflexive activity may contribute to impaired balance.


Assuntos
Articulação do Tornozelo/fisiologia , Potencial Evocado Motor/fisiologia , Instabilidade Articular/fisiopatologia , Extremidade Inferior/fisiologia , Músculo Esquelético/fisiologia , Traumatismos do Tornozelo/diagnóstico , Traumatismos do Tornozelo/fisiopatologia , Estudos de Casos e Controles , Humanos , Instabilidade Articular/diagnóstico , Reflexo/fisiologia , Estimulação Magnética Transcraniana/métodos
7.
Anim Sci J ; 91(1): e13373, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32301197

RESUMO

The difference in the frequency of the occurrence of reflexes/reactions in 355 cows (average weight 505.5 ± 7.9 kg) and 262 bulls (average weight 735.6 ± 8.4 kg) following stunning with a Matador SS 3,000 B trigger-activated captive bolt gun (Termet) was determined. The stun shot more than 2 cm from the ideal position was found in 79.6% of animals. Vocalization, corneal reflex, rhythmic breathing, blinking, eyeball rotation and the absence of tongue protrusion occurred more frequently in bulls (p < .05). Spontaneous limb movements and nystagmus occurred more frequently in cows (p < .05). No difference between bulls and cows was determined in the occurrence of a response to painful stimuli or attempts to regain normal posture. No dependency was determined between the frequency of the occurrence of a reflex/reaction and the distance of the stun shot from the ideal point on the skull for any of the monitored signs. This study shows that the occurrence of reflexes/reactions following the stunning of cattle with a captive bolt is not only dependent on the position of the shot if placed within a 9 cm radius from the ideal point on the cattle skull.


Assuntos
Matadouros , Criação de Animais Domésticos/métodos , Bovinos/fisiologia , Eletrochoque/efeitos adversos , Eletrochoque/veterinária , Reflexo/fisiologia , Animais , Piscadela/fisiologia , Córnea/fisiologia , Movimentos Oculares/fisiologia , Feminino , Masculino , Respiração , Vocalização Animal/fisiologia
8.
Am J Physiol Regul Integr Comp Physiol ; 319(1): R1-R10, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32348680

RESUMO

Dynamic exercise elicits robust increases in sympathetic activity in part due to muscle metaboreflex activation (MMA), a pressor response triggered by activation of skeletal muscle afferents. MMA during dynamic exercise increases arterial pressure by increasing cardiac output via increases in heart rate, ventricular contractility, and central blood volume mobilization. In heart failure, ventricular function is compromised, and MMA elicits peripheral vasoconstriction. Ventricular-vascular coupling reflects the efficiency of energy transfer from the left ventricle to the systemic circulation and is calculated as the ratio of effective arterial elastance (Ea) to left ventricular maximal elastance (Emax). The effect of MMA on Ea in normal subjects is unknown. Furthermore, whether muscle metaboreflex control of Ea is altered in heart failure has not been investigated. We utilized two previously published methods of evaluating Ea [end-systolic pressure/stroke volume (EaPV)] and [heart rate × vascular resistance (EaZ)] during rest, mild treadmill exercise, and MMA (induced via partial reductions in hindlimb blood flow imposed during exercise) in chronically instrumented conscious canines before and after induction of heart failure via rapid ventricular pacing. In healthy animals, MMA elicits significant increases in effective arterial elastance and stroke work that likely maintains ventricular-vascular coupling. In heart failure, Ea is high, and MMA-induced increases are exaggerated, which further exacerbates the already uncoupled ventricular-vascular relationship, which likely contributes to the impaired ability to raise stroke work and cardiac output during exercise in heart failure.


Assuntos
Artérias/fisiopatologia , Insuficiência Cardíaca/fisiopatologia , Músculo Esquelético/metabolismo , Condicionamento Físico Animal , Animais , Artérias/inervação , Cães , Elasticidade , Feminino , Frequência Cardíaca , Membro Posterior/irrigação sanguínea , Masculino , Músculo Esquelético/inervação , Neurônios Aferentes , Reflexo/fisiologia , Volume Sistólico , Resistência Vascular
9.
Int J Mol Sci ; 21(4)2020 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-32085403

RESUMO

The neurotransmitter levels of representatives from five different diagnosis groups were tested before and after participation in the MNRI®-Masgutova Neurosensorimotor Reflex Intervention. The purpose of this study was to ascertain neurological impact on (1) Developmental disorders, (2) Anxiety disorders/OCD (Obsessive Compulsive Disorder), PTSD (Post-Traumatic Stress disorder), (3) Palsy/Seizure disorders, (4) ADD/ADHD (Attention Deficit Disorder/Attention Deficit Disorder Hyperactive Disorder), and (5) ASD (Autism Spectrum Disorder) disorders. Each participant had a form of neurological dysregulation and typical symptoms respective to their diagnosis. These diagnoses have a severe negative impact on the quality of life, immunity, stress coping, cognitive skills, and social assimilation. This study showed a trend towards optimization and normalization of neurological and immunological functioning, thus supporting the claim that the MNRI method is an effective non-pharmacological neuromodulation treatment of neurological disorders. The effects of MNRI on inflammation have not yet been assessed. The resulting post-MNRI changes in participants' neurotransmitters show significant adjustments in the regulation of the neurotransmitter resulting in being calmer, a decrease of hypervigilance, an increase in stress resilience, behavioral and emotional regulation improvements, a more positive emotional state, and greater control of cognitive processes. In this paper, we demonstrate that the MNRI approach is an intervention that reduces inflammation. It is also likely to reduce oxidative stress and encourage homeostasis of excitatory neurotransmitters. MNRI may facilitate neurodevelopment, build stress resiliency, neuroplasticity, and optimal learning opportunity. There have been no reported side effects of MNRI treatments.


Assuntos
Inflamação/patologia , Neurotransmissores/metabolismo , Adolescente , Adulto , Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Transtorno do Deficit de Atenção com Hiperatividade/terapia , Transtorno do Espectro Autista/fisiopatologia , Transtorno do Espectro Autista/terapia , Dopamina/metabolismo , Epinefrina/biossíntese , Histamina/metabolismo , Humanos , Reflexo/fisiologia , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo , Adulto Jovem
10.
J Neurosci ; 40(13): 2680-2694, 2020 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-32066584

RESUMO

The spinal cord can appropriately generate diverse movements, even without brain input and movement-related sensory feedback, using a combination of multifunctional and behaviorally specialized interneurons. The adult turtle spinal cord can generate motor patterns underlying forward swimming, three forms of scratching, and limb withdrawal (flexion reflex). We previously described turtle spinal interneurons activated during both scratching and swimming (multifunctional interneurons), interneurons activated during scratching but not swimming (scratch-specialized interneurons), and interneurons activated during flexion reflex but not scratching or swimming (flexion reflex-selective interneurons). How multifunctional and behaviorally specialized turtle spinal interneurons affect downstream neurons was unknown. Here, we recorded intracellularly from spinal interneurons activated during these motor patterns in turtles of both sexes in vivo and filled each with dyes. We labeled motoneurons using choline acetyltransferase antibodies or earlier intraperitoneal FluoroGold injection and used immunocytochemistry of interneuron axon terminals to identify their neurotransmitter(s) and putative synaptic contacts with motoneurons. We found that multifunctional interneurons are heterogeneous with respect to neurotransmitter, with some glutamatergic and others GABAergic or glycinergic, and can directly contact motoneurons. Also, scratch-specialized interneurons are heterogeneous with respect to neurotransmitter and some directly contact motoneurons. Thus, scratch-specialized interneurons might directly excite motoneurons that are more strongly activated during scratching than forward swimming, such as hip-flexor motoneurons. Finally, and surprisingly, we found that some motoneurons are behaviorally specialized, for scratching or flexion reflex. Thus, either some limb muscles are only used for a subset of limb behaviors or some limb motoneurons are only recruited during certain limb behaviors.SIGNIFICANCE STATEMENT Both multifunctional and behaviorally specialized spinal cord interneurons have been described in turtles, but their outputs are unknown. We studied responses of multifunctional interneurons (activated during swimming and scratching) and scratch-specialized interneurons, filled each with dyes, and used immunocytochemistry to determine their neurotransmitters and contacts with motoneurons. We found that both multifunctional and scratch-specialized interneurons are heterogeneous with respect to neurotransmitter, with some excitatory and others inhibitory. We found that some multifunctional and some scratch-specialized interneurons directly contact motoneurons. Scratch-specialized interneurons may excite motoneurons that are more strongly activated during scratching than swimming, such as hip-flexor motoneurons, or inhibit their antagonists, hip-extensor motoneurons. Surprisingly, we also found that some motoneurons are behaviorally specialized, for scratching or for flexion reflex.


Assuntos
Comportamento Animal/fisiologia , Interneurônios/fisiologia , Atividade Motora/fisiologia , Neurônios Motores/fisiologia , Medula Espinal/fisiologia , Potenciais de Ação/fisiologia , Animais , Feminino , Masculino , Reflexo/fisiologia , Natação/fisiologia , Tartarugas
11.
Exp Neurol ; 327: 113220, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32027928

RESUMO

Vagus nerve stimulation (VNS) has rapidly gained interest as a treatment for a variety of disorders. A number of methods have been employed to stimulate the vagus nerve, but the most common relies on a cuff electrode implanted around the cervical branch of the nerve. Recently, two non-invasive methods have increased in popularity: transcutaneous cervical VNS (tcVNS) and transcutaneous auricular VNS (taVNS). Despite promising clinical results, there has been little direct comparison of these methods to stimulation delivered via an implanted device. In this study, we directly compared both non-invasive strategies to stimulation with an implanted cuff electrode on activation of the Hering-Breuer (HB) reflex, a non-invasive biomarker of A-fiber activation in the vagus. Stimulation was delivered across a wide range of parameters using tcVNS, taVNS, and an implanted cuff electrode in female rats. Activation of the HB reflex, changes in heart rate, and neck muscle twitch force were recorded. Consistent with low thresholds reported in previous studies, we found that the threshold to activate the HB reflex using an implanted cuff electrode was 0.406 ± 0.066 mA. tcVNS was capable of activating the HB reflex, but the threshold was 34.18 ± 1.86 mA, over 15 fold higher than the stimulation intensity that caused twitching of the neck muscles (2.09 ± 0.16 mA). No activation of the HB reflex was observed with taVNS at any parameters. These results describe activation of the HB reflex with each strategy and provide initial evidence regarding differences in the activation of the vagus nerve with invasive and non-invasive methods.


Assuntos
Frequência Cardíaca/fisiologia , Músculos do Pescoço/fisiologia , Fibras Nervosas Mielinizadas/fisiologia , Reflexo/fisiologia , Estimulação do Nervo Vago/métodos , Nervo Vago/fisiologia , Animais , Feminino , Contração Muscular/fisiologia , Ratos , Ratos Sprague-Dawley
12.
Neurology ; 94(10): e1085-e1093, 2020 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-32029547

RESUMO

OBJECTIVE: The trigeminal autonomic reflex is a physiologic reflex that plays a crucial role in primary headache and particularly in trigeminal autonomic cephalalgias, such as cluster headache. Previous studies have shown that this reflex can be modulated by the vagus nerve, leading to an inhibition of the parasympathetic output of the reflex in healthy participants. The aim of the present study was to characterize neural correlates of the modulatory effect of noninvasive vagus nerve stimulation (nVNS) on the trigeminal autonomic reflex. METHODS: Twenty-one healthy participants were included in a 2-day, randomized, single-blind, within-subject design. The reflex was activated inside the MRI scanner using kinetic oscillation stimulation placed in the left nostril, resulting in an increase in lacrimation. After the first fMRI session, the participants received either sham vagus nerve stimulation or nVNS outside the scanner and underwent a subsequent fMRI session. RESULTS: nVNS prompted an increase in activation of the left pontine nucleus and a decreased activation of the right parahippocampal gyrus. Psychophysiologic interaction analyses revealed an increased functional connectivity between the left pontine nucleus and the right hypothalamus and a decreased functional connectivity between the right parahippocampal gyrus and the bilateral spinal trigeminal nuclei (sTN). CONCLUSIONS: These findings indicate a complex network involved in the modulatory effect of nVNS including the hypothalamus, the sTN, the pontine nucleus, and the parahippocampal gyrus.


Assuntos
Sistema Nervoso Autônomo/fisiologia , Hipotálamo/fisiologia , Rede Nervosa/fisiologia , Giro Para-Hipocampal/fisiologia , Reflexo/fisiologia , Nervo Trigêmeo/fisiologia , Estimulação do Nervo Vago , Nervo Vago/fisiologia , Adulto , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Método Simples-Cego , Adulto Jovem
13.
PLoS One ; 15(2): e0229456, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32101577

RESUMO

Using measures of reflex impairment and injury to quantify an aquatic organism's vitality have gained popularity as survival predictors of discarded non-target fisheries catch. To evaluate the robustness of this method with respect to 'rater' subjectivity, we tested inter- and intra-rater repeatability and the role of 'expectation bias'. From video clips, multiple raters determined impairment levels of four reflexes of beam-trawled common sole (Solea solea) intended for discard. Raters had a range of technical experience, including veterinary students, practicing veterinarians, and fisheries scientists. Expectation bias was evaluated by first assessing a rater's assumption about the effect of air exposure on vitality, then comparing their reflex ratings of the same fish, once when the true air exposure duration was indicated and once when the time was exaggerated (by either 15 or 30 min). Inter-rater repeatability was assessed by having multiple raters evaluate those clips with true air exposure information; and intra- and inter-rater repeatability was determined by having individual raters evaluate a series of duplicated clips, all with true air exposure. Results indicate that inter- and intra-rater repeatability were high (intra-class correlation coefficients of 74% for both), and were not significantly affected by background type nor expectation bias related to assumed impact from prolonged air exposure. This suggests that reflex impairment as a metric for predicting fish survival is robust to involving multiple raters with diverse backgrounds. Bias is potentially more likely to be introduced through subjective reflexes than raters, given that consistency in scoring differed for some reflexes based on rater experience type. This study highlights the need to provide ample training for raters, and that no prior experience is needed to become a reliable rater. Moreover, before implementing reflexes in a vitality study, it is important to evaluate whether the determination of presence/absence is subjective.


Assuntos
Comportamento Animal , Linguados/crescimento & desenvolvimento , Transtornos dos Movimentos/veterinária , Variações Dependentes do Observador , Reflexo/fisiologia , Gravação em Vídeo , Animais , Feminino , Linguados/fisiologia , Humanos , Masculino , Transtornos dos Movimentos/diagnóstico , Reprodutibilidade dos Testes , Inquéritos e Questionários
14.
Exp Brain Res ; 238(2): 295-304, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31897517

RESUMO

Somatosensory feedback plays important roles in regulating all animal movement. The effects of sensory feedback on spinally mediated neural excitability are widely studied using cutaneous electrical stimulation paradigms. Cutaneous reflex amplitudes are reduced when stimulation is self-triggered instead of externally triggered. Altered spinal excitability and motor output are also observed following sustained stimulation with various parameters. Our purpose was to probe for interactions between mode and duration by investigating muscle responses following enhanced cutaneous stimulation. Fifteen neurologically intact participants were recruited. Cutaneous reflexes in the extensor carpi radialis (ECR) were evoked with brief (15 ms, 300 Hz) or sustained (300 ms, 50 Hz) stimulation trains. Stimulation was applied to the superficial radial or median nerve at the wrist and triggered by: (1) a computer program (random-triggered); (2) muscle contraction (EMG-triggered); (3) the participant pressing a button themselves (button-triggered). During each condition, isometric contractions were performed with ECR muscle activity maintained at 10, 25, 35, and 50% of maximal voluntary contraction. Stronger inhibitory reflexes were found following brief superficial radial nerve stimulation was EMG-triggered suggesting that modulation of cutaneous reflex excitability is specific to the timing when sensory 'cues' are applied during muscle contraction. No difference was observed following sustained stimulation applied to the superficial radial nerve meaning that brief and sustained stimulation affect the cutaneous pathways differentially. Nerve-specific responses were found between superficial radial and median nerve stimulation, such that greater inhibition was induced by EMG-triggered sustained stimulation to the median nerve. These observations are critical in moving beyond pathway phenomenology toward targeted sensory enhancement and amplified motor output in rehabilitation and training.


Assuntos
Braço/fisiologia , Retroalimentação Sensorial/fisiologia , Contração Isométrica/fisiologia , Músculo Esquelético/fisiologia , Reflexo/fisiologia , Adulto , Estimulação Elétrica , Eletromiografia , Humanos , Atividade Motora/fisiologia , Adulto Jovem
15.
Bioinspir Biomim ; 15(2): 026007, 2020 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-31968325

RESUMO

It has been shown that human-like hopping can be achieved by muscle reflex control in neuromechanical simulations. However, it is unclear if this concept is applicable and feasible for controlling a real robot. This paper presents a low-cost two-segmented robotic leg design and demonstrates the feasibility and the benefits of the bio-inspired neuromuscular reflex based control for hopping. Simulation models were developed to describe the dynamics of the real robot. Different neuromuscular reflex pathways were investigated with the simulation models. We found that stable hopping can be achieved with both positive muscle force and length feedback, and the hopping height can be controlled by modulating the muscle force feedback gains with the return maps. The force feedback neuromuscular reflex based controller is robust against body mass and ground impedance changes. Finally, we implemented the controller on the real robot to prove the feasibility of the proposed neuromuscular reflex based control idea. This paper demonstrates the neuromuscular reflex based control approach is feasible to implement and capable of achieving stable and robust hopping in a real robot. It provides a promising direction of controlling the legged robot to achieve robust dynamic motion in the future.


Assuntos
Perna (Membro)/fisiologia , Reflexo/fisiologia , Robótica/instrumentação , Materiais Biomiméticos , Simulação por Computador , Estudos de Viabilidade , Humanos , Modelos Biológicos , Movimento (Física)
16.
Nat Commun ; 11(1): 326, 2020 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-31949147

RESUMO

Bioinspired electronics are rapidly promoting advances in artificial intelligence. Emerging AI applications, e.g., autopilot and robotics, increasingly spur the development of power devices with new forms. Here, we present a strain-controlled power device that can directly modulate the output power responses to external strain at a rapid speed, as inspired by human reflex. By using the cantilever-structured AlGaN/AlN/GaN-based high electron mobility transistor, the device can control significant output power modulation (2.30-2.72 × 103 W cm-2) with weak mechanical stimuli (0-16 mN) at a gate bias of 1 V. We further demonstrate the acceleration-feedback-controlled power application, and prove that the output power can be effectively adjusted at real-time in response to acceleration changes, i.e., ▵P of 72.78-132.89 W cm-2 at an acceleration of 1-5 G at a supply voltage of 15 V. Looking forward, the device will have great significance in a wide range of AI applications, including autopilot, robotics, and human-machine interfaces.


Assuntos
Inteligência Artificial , Reflexo/fisiologia , Robótica/instrumentação , Robótica/métodos , Transistores Eletrônicos , Compostos de Alumínio/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Elétrons , Gálio/química , Humanos
18.
Int J Psychophysiol ; 147: 113-127, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31778726

RESUMO

Data from three published studies examining autonomic and ERP measures in variants of a dishabituation paradigm were re-analysed to clarify ambiguous novelty results. The three studies manipulated 1. Novelty, 2. Novelty and Intensity, and 3. Novelty and Significance, in auditory dishabituation paradigms at very long interstimulus intervals (ISIs). The question of whether any single ERP matches SCR as the benchmark for the phasic Orienting Reflex (OR) was also addressed. Finally, we aimed to align the re-analysed measures of this and the previous analyses with processes of Preliminary Process Theory (PPT). The SCR demonstrated decrement, recovery, and dishabituation. A summary temporal PCA extracted PN (Processing Negativity), P3a, P3b, Novelty P3, and classic SW for detailed analysis. P3b and SW showed decrement but no recovery at the change trial, while Respiratory pause (RP) and Novelty P3 demonstrated decrement and recovery, but no dishabituation. Post hoc exploration of observed power versus sample size for each of these findings confirmed their robustness. No decrement for PN was also confirmed. Five autonomic and ERP groupings emerged and aligned with modules of processing in PPT: ECR1 (cardiac deceleration), P1, N1-3, and PN - stimulus registration; RP and Novelty P3 - Novelty registration; Peripheral Vasoconstriction (PVC) and P3b - Intensity registration; and ECR2 (cardiac acceleration) and classic SW - Response system. The SCR was confirmed as the sole index of the phasic OR. The pattern of results for the Late Positive Complex (LPC) components (P3a, P3b, Novelty P3, and SW) suggests each is differentially sensitivity to selective determinants of the phasic OR, and consequently the summary LPC is presented as the most appropriate central index of the phasic OR.


Assuntos
Percepção Auditiva/fisiologia , Sistema Nervoso Autônomo/fisiologia , Potenciais Evocados/fisiologia , Resposta Galvânica da Pele/fisiologia , Habituação Psicofisiológica/fisiologia , Orientação/fisiologia , Reflexo/fisiologia , Adolescente , Adulto , Eletroencefalografia , Potencial Evocado P300/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Componente Principal , Adulto Jovem
19.
Neurourol Urodyn ; 39(1): 447-454, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31770467

RESUMO

BACKGROUND: Anal acoustic reflectometry (AAR) is a technique for measuring the physiological profile of the anal canal, primarily the internal anal sphincter. Evaluation of a new continuous method, recently developed for the urethra, would enable its future application for investigation of rectal reflexes. METHODS: Patients aged 18 and over with fecal incontinence (FI) were included. Stepwise AAR parameters were compared with continuous opening pressure (Op, cmH2 O), opening elastance (Oe, cmH2 O/mm2 ), closing pressure (Cp, cmH2 O), closing elastance (Ce, cmH2 O/mm2 ), hysteresis (Hys, [%]), squeeze opening pressure (SqOp, cmH2 O), and squeeze opening elastance (SqOe, cmH2 O/mm2 ). Vaizey incontinence and Manchester Health Questionnaire scores were also collected. RESULTS: Thirty-two patients, 26 females were analyzed. Median age: 60 (range, 32-75). Median AAR parameters of Op (37.50 vs 35.15, P = .031), Oe (1.31 vs 0.84, P < .0001), Ce (1.11 vs 0.88, P < .0001), Hys (37.75 vs 19.04, P < .0001), and SqOe (1.27 vs 1.06, P = .005) were significantly higher with the continuous method. Cp (22.70 vs 27.22, P = .003) is lower and SqOp (96.87 vs 59.47, P = .71) not significantly different. The continuous technique had superior repeatability between cycles for all AAR parameters except Oe, which was equivalent and continuous SqOp had a stronger negative correlation with Vaizey score than stepwise (-0.46, P = .009 vs -0.37, P = .038). CONCLUSIONS: The differences seen between the two techniques are likely to be related to the rate of stretch. The continuous technique appears to represent a more physiological measurement of anal sphincter function than the stepwise technique particularly in the assessment of voluntary squeeze function.


Assuntos
Canal Anal/fisiopatologia , Doenças do Ânus/diagnóstico , Incontinência Fecal/fisiopatologia , Reflexo/fisiologia , Adulto , Idoso , Doenças do Ânus/fisiopatologia , Feminino , Humanos , Masculino , Manometria/métodos , Pessoa de Meia-Idade , Reto/fisiopatologia
20.
Proc Natl Acad Sci U S A ; 117(1): 698-707, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-31848242

RESUMO

Group III/IV muscle afferents transduce nociceptive signals and modulate exercise pressor reflexes (EPRs). However, the mechanisms governing afferent responsiveness to dually modulate these processes are not well characterized. We and others have shown that ischemic injury can induce both nociception-related behaviors and exacerbated EPRs in the same mice. This correlated with primary muscle afferent sensitization and increased expression of glial cell line-derived neurotrophic factor (GDNF) in injured muscle and increased expression of GDNF family receptor α1 (GFRα1) in dorsal root ganglia (DRG). Here, we report that increased GDNF/GFRα1 signaling to sensory neurons from ischemia/reperfusion-affected muscle directly modulated nociceptive-like behaviors and increased exercise-mediated reflexes and group III/IV muscle afferent sensitization. This appeared to have taken effect through increased cyclic adenosine monophosphate (cAMP) response element binding (CREB)/CREB binding protein-mediated expression of the purinergic receptor P2X5 in the DRGs. Muscle GDNF signaling to neurons may, therefore, play an important dual role in nociception and sympathetic reflexes and could provide a therapeutic target for treating complications from ischemic injuries.


Assuntos
Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Mialgia/etiologia , Nociceptividade/fisiologia , Reflexo/fisiologia , Traumatismo por Reperfusão/patologia , Animais , Proteína de Ligação a CREB/metabolismo , Sistema Cardiovascular/inervação , AMP Cíclico/metabolismo , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Modelos Animais de Doenças , Exercício Físico/fisiologia , Gânglios Espinais/metabolismo , Receptores de Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Frequência Cardíaca/fisiologia , Humanos , Masculino , Camundongos , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/inervação , Músculo Esquelético/metabolismo , Mialgia/patologia , Neurônios Aferentes/fisiologia , Receptores Purinérgicos P2X5/metabolismo , Traumatismo por Reperfusão/complicações , Transdução de Sinais/fisiologia
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