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1.
Exp Neurol ; 347: 113886, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34624327

RESUMO

Children with low physical activity and interactions with environment experience atypical sensorimotor development and maturation leading to anatomical and functional disorganization of the sensorimotor circuitry and also to enduring altered motor function. Previous data have shown that postnatal movement restriction in rats results in locomotor disturbances, functional disorganization and hyperexcitability of the hind limb representations in the somatosensory and motor cortices, without apparent brain damage. Due to the reciprocal interplay between the nervous system and muscle, it is difficult to determine whether muscle alteration is the cause or the result of the altered sensorimotor behavior (Canu et al., 2019). In the present paper, our objectives were to evaluate the impact of early movement restriction leading to sensorimotor restriction (SMR) during development on the postural soleus muscle and on sensorimotor performance in rats, and to determine whether changes were reversed when typical activity was resumed. Rats were submitted to SMR by hind limb immobilization for 16 h / day from birth to postnatal day 28 (PND28). In situ isometric contractile properties of soleus muscle, fiber cross sectional area (CSA) and myosin heavy chain content (MHC) were studied at PND28 and PND60. In addition, the motor function was evaluated weekly from PND28 to PND60. At PND28, SMR rats presented a severe atrophy of soleus muscle, a decrease in CSA and a force loss. The muscle maturation appeared delayed, with persistence of neonatal forms of MHC. Changes in kinetic properties were moderate or absent. The Hoffmann reflex provided evidence for spinal hyperreflexia and signs of spasticity. Most changes were reversed at PND60, except muscle atrophy. Functional motor tests that require a good limb coordination, i.e. rotarod and locomotion, showed an enduring alteration related to SMR, even after one month of 'typical' activity. On the other hand, paw withdrawal test and grip test were poorly affected by SMR whereas spontaneous locomotor activity increased over time. Our results support the idea that proprioceptive feedback is at least as important as the amount of motor activity to promote a typical development of motor function. A better knowledge of the interplay between hypoactivity, muscle properties and central motor commands may offer therapeutic perspectives for children suffering from neurodevelopmental disorders.


Assuntos
Retroalimentação Sensorial/fisiologia , Elevação dos Membros Posteriores/efeitos adversos , Atividade Motora/fisiologia , Músculo Esquelético/fisiopatologia , Animais , Feminino , Masculino , Movimento/fisiologia , Atrofia Muscular/patologia , Ratos , Ratos Sprague-Dawley
2.
PLoS One ; 16(12): e0261735, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34965256

RESUMO

In joint action literature it is often assumed that acting together is driven by pervasive and automatic process of co-representation, that is, representing the co-actor's part of the task in addition to one's own. Much of this research employs joint stimulus-response compatibility tasks varying the stimuli employed or the physical and social relations between participants. In this study we test the robustness of co-representation effects by focusing instead on variation in response modality. Specifically, we implement a mouse-tracking version of a Joint Simon Task in which participants respond by producing continuous movements with a computer mouse rather than pushing discrete buttons. We have three key findings. First, in a replication of an earlier study we show that in a classical individual Simon Task movement trajectories show greater curvature on incongruent trials, paralleling longer response times. Second, this effect largely disappears in a Go-NoGo Simon Task, in which participants respond to only one of the cues and refrain from responding to the other. Third, contrary to previous studies that use button pressing responses, we observe no overall effect in the joint variants of the task. However, we also detect a notable diversity in movement strategies adopted by the participants, with some participants showing the effect on the individual level. Our study casts doubt on the pervasiveness of co-representation, highlights the usefulness of mouse-tracking methodology and emphasizes the need for looking at individual variation in task performance.


Assuntos
Braço/fisiologia , Articulações/fisiologia , Movimento/fisiologia , Desempenho Psicomotor/fisiologia , Adulto , Comportamento de Escolha , Feminino , Humanos , Testes Neuropsicológicos , Tempo de Reação , Adulto Jovem
3.
PLoS One ; 16(12): e0259862, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34905546

RESUMO

Parkinson's disease (PD) can produce postural abnormalities of the standing body position such as kyphosis. We investigated the effects of PD, deep brain stimulation (DBS) in the subthalamic nucleus (STN), vision and adaptation on body position in a well-defined group of patients with PD in quiet standing and during balance perturbations. Ten patients with PD and 25 young and 17 old control participants were recruited. Body position was measured with 3D motion tracking of the ankle, knee, hip, shoulder and head. By taking the ankle as reference, we mapped the position of the joints during quiet standing and balance perturbations through repeated calf muscle vibration. We did this to explore the effect of PD, DBS in the STN, and vision on the motor learning process of adaptation in response to the repeated stimulus. We found that patients with PD adopt a different body position with DBS ON vs. DBS OFF, to young and old controls, and with eyes open vs. eyes closed. There was an altered body position in PD with greater flexion of the head, shoulder and knee (p≤0.042) and a posterior position of the hip with DBS OFF (p≤0.014). With DBS ON, body position was brought more in line with the position taken by control participants but there was still evidence of greater flexion at the head, shoulder and knee. The amplitude of movement during the vibration period decreased in controls at all measured sites with eyes open and closed (except at the head in old controls with eyes open) showing adaptation which contrasted the weaker adaptive responses in patients with PD. Our findings suggest that alterations of posture and greater forward leaning with repeated calf vibration, are independent from reduced movement amplitude changes. DBS in the STN can significantly improve body position in PD although the effects are not completely reversed. Patients with PD maintain adaptive capabilities by leaning further forward and reducing movement amplitude despite their kyphotic posture.


Assuntos
Adaptação Fisiológica , Estimulação Encefálica Profunda/métodos , Cifose/terapia , Doença de Parkinson/terapia , Equilíbrio Postural/fisiologia , Idoso , Articulação do Tornozelo/fisiologia , Estudos de Casos e Controles , Feminino , Globo Pálido/fisiopatologia , Cabeça/fisiologia , Articulação do Quadril/fisiologia , Humanos , Articulação do Joelho/fisiologia , Cifose/etiologia , Cifose/fisiopatologia , Masculino , Pessoa de Meia-Idade , Movimento/fisiologia , Doença de Parkinson/complicações , Doença de Parkinson/fisiopatologia , Postura/fisiologia , Articulação do Ombro/fisiologia , Núcleo Subtalâmico/fisiopatologia
4.
J Occup Health ; 63(1): e12295, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34780083

RESUMO

OBJECTIVES: To evaluate whether the grip strength ratio of three wrist positions could determine sincerity of effort (SOE), by differentiating between maximal effort (ME) and submaximal effort (SE), in individuals with upper extremity musculoskeletal disorders (MSDs). METHODS: A total of 19 volunteers with unilateral upper extremity MSDs (9 males, 10 females) participated in this study. Participants performed grip strength tests in neutral, full flexion, and full extension wrist positions for both hands. In each wrist position, they exerted grip force with their ME and preferred SE for three times. RESULTS: Significant main effects of type of effort, wrist position (P < .001), and hand (P = .005) were observed. The results also showed significant interactions for type of effort × wrist position (P < .001) and wrist positions × hand (P = .001). Moreover, the grip strength ratios of neutral/flexion (N/F) and neutral/extension (N/E) between ME and SE differed significantly (P < .001). CONCLUSION: This study suggests that the N/F and N/E grip strength ratios can discriminate between ME and SE in individuals with upper extremity MSDs. Thus, this test might be applicable to use for identifying SOE in clinical setting.


Assuntos
Força da Mão/fisiologia , Movimento/fisiologia , Doenças Musculoesqueléticas/diagnóstico , Esforço Físico/fisiologia , Punho/fisiologia , Adulto , Feminino , Humanos , Masculino , Dinamômetro de Força Muscular , Amplitude de Movimento Articular , Extremidade Superior/patologia
5.
J Orthop Sports Phys Ther ; 51(10): 492-502, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34592828

RESUMO

OBJECTIVE: To report whether changes in knee joint movement parameters recorded during functional activities relate to change in activity limitation or pain after an exercise intervention in people with knee osteoarthritis (OA). DESIGN: Etiology systematic review. LITERATURE SEARCH: Four databases (MEDLINE, Embase, CINAHL, and AMED) were searched up to January 22, 2021. STUDY SELECTION CRITERIA: Randomized controlled trials or cohort studies of exercise interventions for people with knee OA that assessed change in knee joint movement parameters (moments, kinematics, or muscle activity) and clinical outcomes (activity limitation or pain). DATA SYNTHESIS: A descriptive synthesis of functional activities, movement parameters, and clinical outcomes. RESULTS: From 3182 articles, 22 studies met the inclusion criteria, and almost all were of low quality. Gait was the only investigated functional activity. After exercise, gait parameters changed 26% of the time, and clinical outcomes improved 90% of the time. A relationship between group-level changes in gait parameters and clinical outcomes occurred 24.5% of the time. Two studies directly investigated an individual-level relationship, reporting only 1 significant association out of 8 correlations tested. CONCLUSION: Most studies reported no change in gait-related movement parameters despite improvement in clinical outcomes, challenging the belief that changing movement parameters is always clinically important in people with knee OA. J Orthop Sports Phys Ther 2021;51(10):492-502. doi:10.2519/jospt.2021.10418.


Assuntos
Artralgia/fisiopatologia , Artralgia/reabilitação , Terapia por Exercício/métodos , Marcha/fisiologia , Movimento/fisiologia , Osteoartrite do Joelho/fisiopatologia , Osteoartrite do Joelho/reabilitação , Fenômenos Biomecânicos , Humanos , Medição da Dor
6.
Nat Commun ; 12(1): 5949, 2021 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-34642318

RESUMO

Directed motility enables swimming microbes to navigate their environment for resources via chemo-, photo-, and magneto-taxis. However, directed motility competes with fluid flow in porous microbial habitats, affecting biofilm formation and disease transmission. Despite this broad importance, a microscopic understanding of how directed motility impacts the transport of microswimmers in flows through constricted pores remains unknown. Through microfluidic experiments, we show that individual magnetotactic bacteria directed upstream through pores display three distinct regimes, whereby cells swim upstream, become trapped within a pore, or are advected downstream. These transport regimes are reminiscent of the electrical conductivity of a diode and are accurately predicted by a comprehensive Langevin model. The diode-like behavior persists at the pore scale in geometries of higher dimension, where disorder impacts conductivity at the sample scale by extending the trapping regime over a broader range of flow speeds. This work has implications for our understanding of the survival strategies of magnetotactic bacteria in sediments and for developing their use in drug delivery applications in vascular networks.


Assuntos
Alphaproteobacteria/fisiologia , Campos Magnéticos , Movimento/fisiologia , Resposta Táctica/fisiologia , Biofilmes/crescimento & desenvolvimento , Condutividade Elétrica , Técnicas Analíticas Microfluídicas , Porosidade , Reologia
7.
Clin Neurophysiol ; 132(11): 2870-2889, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34628342

RESUMO

Unperturbed human locomotion presumably results from feedforward shifts in stable body equilibrium in the environment, thus avoiding falling and subsequent catching considered in alternative theories of locomotion. Such shifts are achieved by relocation of the referent body configuration at which multiple muscle recruitment begins. Rather than being directly specified by a central pattern generator, multiple muscles are activated depending on the extent to which the body is deflected from the referent, threshold body configuration, as confirmed in previous studies. Based on the referent control theory of action and perception, solutions to classical problems in motor control are offered, including the previously unresolved problem of the integration of central and reflex influences on motoneurons and the problem of how posture and movement are related. The speed of locomotion depends on the rate of shifts in the referent body configuration. The transition from walking to running results from increasing the rate of referent shifts. It is emphasised that there is a certain hierarchy between reciprocal and co-activation of agonist and antagonist muscles during locomotion and other motor actions, which is also essential for the understanding of how locomotor speed is regulated. The analysis opens a new avenue in neurophysiological approaches to human locomotion with clinical implications.


Assuntos
Geradores de Padrão Central/fisiologia , Locomoção/fisiologia , Movimento/fisiologia , Músculo Esquelético/fisiologia , Equilíbrio Postural/fisiologia , Propriocepção/fisiologia , Humanos
8.
Medicine (Baltimore) ; 100(37): e27262, 2021 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-34664877

RESUMO

ABSTRACT: To explore the relationship between general movements (GMs) and neonatal behavior neurological assessment (NBNA)/cerebral magnetic resonance imaging (MRI) in preterm infants.Forty preterm infants were examined with GMs assessment before gestational age of 40 weeks; NBNA was performed at the age of 40 weeks; cerebral MRI was performed at the age of 42 weeks.Our experiment showed that preterm infants with poor GMs scores are more likely to have low NBNA scores (P = .001); preterm infants with abnormal cerebral MRI are more likely to have low NBNA scores (P = .002); preterm infants with poor GMs scores are more likely to have abnormal cerebral MRI (P = .012).GM assessment is correlated with NBNA and MRI results in preterm infants for neurological development.


Assuntos
Técnicas de Diagnóstico Neurológico/instrumentação , Recém-Nascido Prematuro/fisiologia , Movimento/fisiologia , Técnicas de Diagnóstico Neurológico/normas , Técnicas de Diagnóstico Neurológico/estatística & dados numéricos , Feminino , Humanos , Recém-Nascido , Imageamento por Ressonância Magnética/métodos , Imageamento por Ressonância Magnética/estatística & dados numéricos , Masculino , Triagem Neonatal
9.
PLoS One ; 16(10): e0250225, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34705848

RESUMO

The aim of this study was to analyze the influence of service tactic formation on players' movements and point outcome at two different performance levels. The sample contained 2,148 points corresponding to 18 matches from two male padel indoor tournaments. Players were classified according to their game level: high-level (N = 36; age = 33.3 ± 6.9 years) and beginner (N = 36; age = 35.4 ± 6.8 years). Variables pertaining to service tactic formation (conventional or Australian), point outcome and movement patterns were analysed from the matches through systematic observation. The results showed how high-level players used a significantly higher percentage of the Australian formation than beginners. Also, high-level players won a significantly higher percentage of points than recreational players when using both service tactics. According to movement variables, servers were significantly closer to the net and the side wall using a conventional formation when the returner hit the ball. Furthermore, servers had to move quicker when they used the Australian formation. Finally, the comparison of movement patterns of servers according to game level, showed how high-level players ran faster to the offensive position, covered a greater distance and spent less time between serve and return impacts than beginners.


Assuntos
Desempenho Atlético/fisiologia , Movimento/fisiologia , Tênis/fisiologia , Adulto , Austrália , Humanos , Masculino , Análise e Desempenho de Tarefas
10.
Nat Neurosci ; 24(11): 1555-1566, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34697455

RESUMO

Dopamine plays a central role in motivating and modifying behavior, serving to invigorate current behavioral performance and guide future actions through learning. Here we examine how this single neuromodulator can contribute to such diverse forms of behavioral modulation. By recording from the dopaminergic reinforcement pathways of the Drosophila mushroom body during active odor navigation, we reveal how their ongoing motor-associated activity relates to goal-directed behavior. We found that dopaminergic neurons correlate with different behavioral variables depending on the specific navigational strategy of an animal, such that the activity of these neurons preferentially reflects the actions most relevant to odor pursuit. Furthermore, we show that these motor correlates are translated to ongoing dopamine release, and acutely perturbing dopaminergic signaling alters the strength of odor tracking. Context-dependent representations of movement and reinforcement cues are thus multiplexed within the mushroom body dopaminergic pathways, enabling them to coordinately influence both ongoing and future behavior.


Assuntos
Dopamina/metabolismo , Neurônios Dopaminérgicos/metabolismo , Movimento/fisiologia , Corpos Pedunculados/metabolismo , Reforço Psicológico , Olfato/fisiologia , Animais , Neurônios Dopaminérgicos/química , Drosophila , Feminino , Microscopia de Fluorescência por Excitação Multifotônica/métodos , Corpos Pedunculados/química , Odorantes , Transdução de Sinais/fisiologia
11.
Neuron ; 109(19): 3164-3177.e8, 2021 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-34499856

RESUMO

Modern brain-machine interfaces can return function to people with paralysis, but current upper extremity brain-machine interfaces are unable to reproduce control of individuated finger movements. Here, for the first time, we present a real-time, high-speed, linear brain-machine interface in nonhuman primates that utilizes intracortical neural signals to bridge this gap. We created a non-prehensile task that systematically individuates two finger groups, the index finger and the middle-ring-small fingers combined. During online brain control, the ReFIT Kalman filter could predict individuated finger group movements with high performance. Next, training ridge regression decoders with individual movements was sufficient to predict untrained combined movements and vice versa. Finally, we compared the postural and movement tuning of finger-related cortical activity to find that individual cortical units simultaneously encode multiple behavioral dimensions. Our results suggest that linear decoders may be sufficient for brain-machine interfaces to execute high-dimensional tasks with the performance levels required for naturalistic neural prostheses.


Assuntos
Interfaces Cérebro-Computador , Dedos/fisiologia , Movimento/fisiologia , Próteses Neurais , Algoritmos , Animais , Fenômenos Biomecânicos , Eletrodos Implantados , Dedos/inervação , Previsões , Modelos Lineares , Macaca mulatta , Masculino , Microeletrodos , Córtex Motor/fisiologia , Postura/fisiologia , Desenho de Prótese , Desempenho Psicomotor
12.
Nat Commun ; 12(1): 5662, 2021 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-34580314

RESUMO

Using multi-color visible lights for independent optogenetic manipulation of multiple neuronal populations offers the ability for sophisticated brain functions and behavior dissection. To mitigate invasive fiber insertion, infrared light excitable upconversion nanoparticles (UCNPs) with deep tissue penetration have been implemented in optogenetics. However, due to the chromatic crosstalk induced by the multiple emission peaks, conventional UCNPs or their mixture cannot independently activate multiple targeted neuronal populations. Here, we report NIR multi-color optogenetics by the well-designed trichromatic UCNPs with excitation-specific luminescence. The blue, green and red color emissions can be separately tuned by switching excitation wavelength to match respective spectral profiles of optogenetic proteins ChR2, C1V1 and ChrimsonR, which enables selective activation of three distinct neuronal populations. Such stimulation with tunable intensity can not only activate distinct neuronal populations selectively, but also achieve transcranial selective modulation of the motion behavior of awake-mice, which opens up a possibility of multi-color upconversion optogenetics.


Assuntos
Encéfalo/fisiologia , Estimulação Encefálica Profunda/métodos , Raios Infravermelhos , Nanopartículas/efeitos da radiação , Optogenética/métodos , Animais , Encéfalo/citologia , Encéfalo/efeitos da radiação , Cor , Masculino , Camundongos , Microscopia Eletrônica de Transmissão , Modelos Animais , Movimento/fisiologia , Neurônios/fisiologia , Neurônios/efeitos da radiação , Técnicas de Patch-Clamp , Imagem Individual de Molécula/métodos , Técnicas Estereotáxicas
13.
Clin Neurophysiol ; 132(11): 2840-2850, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34592561

RESUMO

OBJECTIVE: To develop methods for recording and analysing infant's proximal muscle activations. METHODS: Surface electromyography (sEMG) of truncal muscles was recorded in three months old infants (N = 18) during spontaneous movement and controlled postural changes. The infants were also divided into two groups according to motor performance. We developed an efficient method for removing dynamic cardiac artefacts to allow i) accurate estimation of individual muscle activations, as well as ii) quantitative characterization of muscle networks. RESULTS: The automated removal of cardiac artefacts allowed quantitation of truncal muscle activity, which showed predictable effects during postural changes, and there were differences between high and low performing infants.The muscle networks showed consistent change in network density during spontaneous movements between supine and prone position. Moreover, activity correlations in individual pairs of back muscles linked to infant́s motor performance. CONCLUSIONS: The hereby developed sEMG analysis methodology is feasible and may disclose differences between high and low performing infants. Analysis of the muscle networks may provide novel insight to central control of motility. SIGNIFICANCE: Quantitative analysis of infant's muscle activity and muscle networks holds promise for an objective neurodevelopmental assessment of motor system.


Assuntos
Desenvolvimento Infantil/fisiologia , Eletromiografia/métodos , Movimento/fisiologia , Músculo Esquelético/crescimento & desenvolvimento , Postura/fisiologia , Feminino , Humanos , Lactente , Masculino
14.
Clin Neurophysiol ; 132(10): 2558-2566, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34479133

RESUMO

OBJECTIVE: Only few studies investigated voluntary movement abnormalities in patients with motoneuron diseases (MNDs) or their neurophysiological correlates. We aimed to kinematically assess finger tapping abnormalities in patients with amyotrophic lateral sclerosis (ALS) and primary lateral sclerosis (PLS), as compared to healthy controls (HCs), and their relationship with motoneuron involvement. METHODS: Fourteen ALS and 5 PLS patients were enrolled. Finger tapping was assessed by a motion analysis system. Patients underwent a central motor conduction time assessment, a motor nerve conduction study, and needle electromyography. Data were compared to those of 79 HCs using non-parametric tests. Possible relationships between clinical, kinematic, and neurophysiological data were assessed in patients. RESULTS: As a major finding, ALS and PLS patients performed finger tapping slower than HCs. In both conditions, movement slowness correlated with muscle strength. In ALS, movement slowness also correlated with the amplitude of the compound muscle action potential recorded from the muscles involved in the task and with denervation activity. No correlations were found between slowness, measures of upper motoneuron involvement, and other clinical and neurophysiological data. CONCLUSIONS: This study provides novel information on voluntary movement abnormalities in MNDs. SIGNIFICANCE: The results highlight the pathophysiological role of motoneurons in generating movement slowness.


Assuntos
Hipocinesia/epidemiologia , Hipocinesia/fisiopatologia , Doença dos Neurônios Motores/epidemiologia , Doença dos Neurônios Motores/fisiopatologia , Neurônios Motores/fisiologia , Potenciais de Ação/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Esclerose Amiotrófica Lateral/diagnóstico , Esclerose Amiotrófica Lateral/epidemiologia , Esclerose Amiotrófica Lateral/fisiopatologia , Feminino , Humanos , Hipocinesia/diagnóstico , Masculino , Pessoa de Meia-Idade , Córtex Motor/fisiopatologia , Doença dos Neurônios Motores/diagnóstico , Movimento/fisiologia
15.
PLoS One ; 16(9): e0256608, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34570774

RESUMO

Advances in bio-logging technology for wildlife monitoring have expanded our ability to study space use and behavior of many animal species at increasingly detailed scales. However, such data can be challenging to analyze due to autocorrelation of GPS positions. As a case study, we investigated spatiotemporal movements and habitat selection in the little owl (Athene noctua), a bird species that is declining in central Europe and verges on extinction in Denmark. We equipped 6 Danish food-supplemented little owls and 6 non-supplemented owls in the Czech Republic with high-resolution GPS loggers that recorded one position per minute. Nightly space use, measured as 95% kernel density estimates, of Danish male owls were on average 62 ha (± 64 SD, larger than any found in previous studies) compared to 2 ha (± 1) in females, and to 3 ± 1 ha (males) versus 3 ± 5 ha (females) in the Czech Republic. Foraging Danish male owls moved on average 4-fold further from their nest and at almost double the distance per hour than Czech males. To create availability data for the habitat selection analysis, we accounted for high spatiotemporal autocorrelation of the GPS data by simulating correlated random walks with the same autocorrelation structure as the actual little owl movement trajectories. We found that habitat selection was similar between Danish and Czech owls, with individuals selecting for short vegetation and areas with high structural diversity. Our limited sample size did not allow us to infer patterns on a population level, but nevertheless demonstrates how high-resolution GPS data can help to identify critical habitat requirements to better formulate conservation actions on a local scale.


Assuntos
Migração Animal/fisiologia , Comportamento Animal/fisiologia , Movimento/fisiologia , Estrigiformes/fisiologia , Animais , Monitoramento Biológico , República Tcheca , Ecossistema , Feminino , Masculino
16.
PLoS One ; 16(9): e0257159, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34520496

RESUMO

INTRODUCTION: Stair falls can be caused by inconsistent stair dimensions. During ascent, inconsistently taller stair risers lead to reduced foot clearances as the inconsistency goes unnoticed. A stair horizontal-vertical illusion increases perceived riser heights and foot clearance and could offset reduced foot clearances over inconsistently taller risers, though this might impact other stair safety measures. METHOD: Twelve participants (age: 22 (3) years) ascended a seven-step staircase under three conditions: i) all steps consistent in riser height (consistent), ii) a 1cm increase in step 5 riser height (inconsistent) and iii) a 1cm increase in step 5 riser height, superimposed with a stair horizontal-vertical illusion (illusion). Vertical foot clearance, foot overhang, and margins of stability were assessed over step 4, 5 and 6. Perceived riser height due to the illusion was determined through a computer perception test. A One-Way Repeated Measures ANOVA compared biomechanical variables between conditions. A One Sample t test compared perceived riser height to the true height. RESULTS: Over the inconsistent step 5, foot clearance reduced by 0.8cm compared to consistent. Illusion increased foot clearance by 1.1cm and decreased foot overhang by 4% compared to inconsistent. On step 4 the illusion led to more anterior instability compared to inconsistent. Illusion and inconsistent led to more mediolateral stability compared to consistent. The illusion increased perceived riser height by 12%. DISCUSSION: Foot clearance reductions over inconsistently taller risers can be offset by a stair horizontal-vertical illusion. Additional benefits included a safer foot overhang and unaffected stability over the inconsistent riser. Changes to step 4 stability might have resulted from leaning forward to look at the step 5 illusion. The stair horizontal-vertical illusion could be a practical solution for inconsistently taller stair risers, where a rebuild is usually the only solution.


Assuntos
Pé/fisiologia , Ilusões , Feminino , Humanos , Masculino , Movimento/fisiologia , Avaliação de Resultados em Cuidados de Saúde , Adulto Jovem
17.
PLoS One ; 16(9): e0257652, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34534253

RESUMO

Vibroarthrography measures joint sounds caused by sliding of the joint surfaces over each other. and can be affected by joint health, load and type of movement. Since both warm-up and muscle fatigue lead to local changes in the knee joint (e.g., temperature increase, lubrication of the joint, muscle activation), these may impact knee joint sounds. Therefore, this study investigates the effects of warm-up and muscle fatiguing exercise on knee joint sounds during an activity of daily living. Seventeen healthy, physically active volunteers (25.7 ± 2 years, 7 males) performed a control and an intervention session with a wash-out phase of one week. The control session consisted of sitting on a chair, while the intervention session contained a warm-up (walking on a treadmill) followed by a fatiguing exercise (modified sit-to-stand) protocol. Knee sounds were recorded by vibroarthrography (at the medial tibia plateau and at the patella) at three time points in each session during a sit-to-stand movement. The primary outcome was the mean signal amplitude (MSA, dB). Differences between sessions were determined by repeated measures ANOVA with intra-individual pre-post differences for the warm-up and for the muscle fatigue effect. We found a significant difference for MSA at the medial tibia plateau (intervention: mean 1.51 dB, standard deviation 2.51 dB; control: mean -1.28 dB, SD 2.61 dB; F = 9.5; p = .007; η2 = .37) during extension (from sit to stand) after the warm-up. There was no significant difference for any parameter after the muscle fatiguing exercise (p > .05). The increase in MSA may mostly be explained by an increase in internal knee load and joint friction. However, neuromuscular changes may also have played a role. It appears that the muscle fatiguing exercise has no impact on knee joint sounds in young, active, symptom-free participants during sit to stand.


Assuntos
Técnicas de Imagem por Elasticidade/métodos , Articulação do Joelho/fisiologia , Fadiga Muscular/fisiologia , Exercício de Aquecimento/fisiologia , Adulto , Estudos Cross-Over , Feminino , Humanos , Articulação do Joelho/diagnóstico por imagem , Masculino , Movimento/fisiologia
18.
Neuron ; 109(18): 2981-2994.e5, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34534455

RESUMO

The role of the cerebellum in predictive motor control and coordination has been thoroughly studied during movements of a single body part. In the real world, however, actions are often more complex. Here, we show that a small area in the rostral anterior interpositus nucleus (rAIN) of the mouse cerebellum is responsible for generating a predictive motor synergy that serves to protect the eye by precisely coordinating muscles of the eyelid, neck, and forelimb. Within the rAIN region, we discovered a new functional category of neurons with unique properties specialized for control of motor synergies. These neurons integrated inhibitory cutaneous inputs from multiple parts of the body, and their activity was correlated with the vigor of the defensive motor synergy on a trial-by-trial basis. We propose that some regions of the cerebellum are organized in poly-somatotopic "action maps" to reduce dimensionality and simplify motor control during ethologically relevant behaviors.


Assuntos
Piscadela/fisiologia , Núcleos Cerebelares/química , Núcleos Cerebelares/fisiologia , Extremidades/fisiologia , Movimento/fisiologia , Animais , Núcleos Cerebelares/citologia , Cerebelo/química , Cerebelo/citologia , Cerebelo/fisiologia , Previsões , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Optogenética/métodos , Gravação em Vídeo/métodos
19.
Biochem Biophys Res Commun ; 577: 64-70, 2021 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-34507067

RESUMO

To detect a small amount of Period1 (Per1) expression, we developed a micro-photomultiplier tube (µPMT) system which can be used both in vivo and in vitro. Using this system, we succeeded in detecting Per1 gene expression in the skin of freely moving mice over 240 times higher compared with that of the tissue contact optical sensor (TCS) as previously reported. For in vitro studies, we succeeded in detecting elevated Per1 expression by streptozotocin (STZ) treatment in the scalp hairs at an early stage of diabetes, when glucose content in the blood was still normal. In addition, we could detect elevated Per1 expression in a single whisker hair at the time of diabetes onset. These results show that our µPMT system responds to minute changes in gene expression in freely moving mice in vivo and in mice hair follicles in vitro. Furthermore, Per1 in the hair can be used for a marker of diabetic aggravation.


Assuntos
Expressão Gênica , Luciferases/genética , Medições Luminescentes/métodos , Proteínas Circadianas Period/genética , Animais , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , Cabelo/metabolismo , Luciferases/metabolismo , Medições Luminescentes/instrumentação , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Atividade Motora/fisiologia , Movimento/fisiologia , Proteínas Circadianas Period/metabolismo , Reprodutibilidade dos Testes , Couro Cabeludo/metabolismo , Pele/citologia , Pele/metabolismo , Vibrissas/metabolismo
20.
Nat Commun ; 12(1): 5390, 2021 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-34508073

RESUMO

The smooth conduct of movements requires simultaneous motor planning and execution according to internal goals. So far it remains unknown how such movement plans are modified without interfering with ongoing movements. Previous studies have isolated planning and execution-related neuronal activity by separating behavioral planning and movement periods in time by sensory cues. Here, we separate continuous self-paced motor planning from motor execution statistically, by experimentally minimizing the repetitiveness of the movements. This approach shows that, in the rat sensorimotor cortex, neuronal motor planning processes evolve with slower dynamics than movement-related responses. Fast-evolving neuronal activity precees skilled forelimb movements and is nested within slower dynamics. We capture this effect via high-pass filtering and confirm the results with optogenetic stimulations. The various dynamics combined with adaptation-based high-pass filtering provide a simple principle for separating concurrent motor planning and execution.


Assuntos
Destreza Motora/fisiologia , Movimento/fisiologia , Neurônios/fisiologia , Córtex Sensório-Motor/fisiologia , Animais , Técnicas de Observação do Comportamento , Comportamento Animal/fisiologia , Membro Anterior/fisiologia , Masculino , Modelos Animais , Optogenética , Ratos , Ratos Long-Evans , Técnicas Estereotáxicas
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