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1.
PLoS One ; 15(11): e0241969, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33175905

RESUMO

Goal-kicking is an important skill in Australian Football (AF). This study examined whether kinematic differences exist between accurate and inaccurate goal-kicks and determined the relationships between technical factors and accuracy. Eighteen elite to sub-elite AF players performed 15 x 30 m goal-kicks on an AF training ground, with three-dimensional kinematics collected using the Xsens inertial measurement system (Xsens Technologies B.V., Enschede, the Netherlands). A general linear mixed modelling approach and regression-based statistics were employed to quantify differences between accurate and inaccurate goal kicks and the relationships between technical factors and accuracy. Accurate goal-kicks were characterised by a straighter approach line, with less kick-leg joint range of motion (knee and hip), lower linear velocity (centre of mass, foot speed), angular velocity (knee and shank), and less support-leg knee flexion during the kicking phase compared to inaccurate goal-kicks. At the end of the follow through, players produced greater ankle plantarflexion and a straighter-leg line in accurate goal-kicks. Findings in this research indicated that many factors interact with goal-kicking accuracy in AF, ranging from the players' approach line path, their support-leg mechanics, the kick-leg swing motion, to the final position of the kicker during their follow through.


Assuntos
Fenômenos Biomecânicos/fisiologia , Futebol Americano/fisiologia , Futebol/fisiologia , Adolescente , Tornozelo/fisiologia , Articulação do Tornozelo/fisiologia , Desempenho Atlético/fisiologia , Austrália , Pé/fisiologia , Humanos , Joelho/fisiologia , Articulação do Joelho/fisiologia , Perna (Membro)/fisiologia , Extremidade Inferior/fisiologia , Masculino , Movimento/fisiologia , Amplitude de Movimento Articular/fisiologia
2.
PLoS Biol ; 18(11): e3000882, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33141817

RESUMO

During active tactile exploration, the dynamic patterns of touch are transduced to electrical signals and transformed by the brain into a mental representation of the object under investigation. This transformation from sensation to perception is thought to be a major function of the mammalian cortex. In primary somatosensory cortex (S1) of mice, layer 5 (L5) pyramidal neurons are major outputs to downstream areas that influence perception, decision-making, and motor control. We investigated self-motion and touch representations in L5 of S1 with juxtacellular loose-seal patch recordings of optogenetically identified excitatory neurons. We found that during rhythmic whisker movement, 54 of 115 active neurons (47%) represented self-motion. This population was significantly more modulated by whisker angle than by phase. Upon active touch, a distinct pattern of activity was evoked across L5, which represented the whisker angle at the time of touch. Object location was decodable with submillimeter precision from the touch-evoked spike counts of a randomly sampled handful of these neurons. These representations of whisker angle during self-motion and touch were independent, both in the selection of which neurons were active and in the angle-tuning preference of coactive neurons. Thus, the output of S1 transiently shifts from a representation of self-motion to an independent representation of explored object location during active touch.


Assuntos
Córtex Somatossensorial/fisiologia , Percepção do Tato/fisiologia , Tato/fisiologia , Potenciais de Ação/fisiologia , Animais , Encéfalo/fisiologia , Córtex Cerebral/fisiologia , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Movimento/fisiologia , Neurônios/fisiologia , Vibrissas/fisiologia
3.
Artigo em Inglês | MEDLINE | ID: mdl-33233328

RESUMO

OBJECTIVE: To assess whether a slackline intervention program improves postural control in children/adolescents with spastic cerebral palsy (CP). DESIGN: Randomized controlled trial. SETTING: Patients' association. PARTICIPANTS: Twenty-seven children/adolescents with spastic CP (9-16 years) were randomly assigned to a slackline intervention (n = 14, 13 ± 3 years) or control group (n = 13, 12 ± 2 years). INTERVENTION: Three slackline sessions per week (30 min/session) for 6 weeks. MAIN OUTCOME MEASURES: The primary outcome was static posturography (center of pressure-CoP-parameters). The secondary outcomes were surface myoelectrical activity of the lower-limb muscles during the posturography test and jump performance (countermovement jump test and Abalakov test). Overall (RPE, >6-20 scale) rating of perceived exertion was recorded at the end of each intervention session. RESULTS: The intervention was perceived as "very light" (RPE = 7.6 ± 0.6). The intervention yielded significant benefits on static posturography (a significant group by time interaction on Xspeed, p = 0.006) and jump performance (a significant group by time interaction on Abalakov test, p = 0.015). CONCLUSIONS: Slackline training improved static postural control and motor skills and was perceived as non-fatiguing in children/adolescents with spastic CP.


Assuntos
Paralisia Cerebral/reabilitação , Transtornos Motores/reabilitação , Movimento/fisiologia , Espasticidade Muscular/reabilitação , Equilíbrio Postural/fisiologia , Treinamento de Resistência/métodos , Adolescente , Criança , Eletromiografia , Exercício Físico , Feminino , Humanos , Masculino , Transtornos Motores/etiologia , Destreza Motora/fisiologia , Resultado do Tratamento
4.
PLoS One ; 15(11): e0242416, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33216756

RESUMO

INTRODUCTION: Illusion of movement induced by tendon vibration is an effective approach for motor and sensory rehabilitation in case of neurological impairments. The aim of our study was to investigate which modality of visual feedback in Virtual Reality (VR) associated with tendon vibration of the wrist could induce the best illusion of movement. METHODS: We included 30 healthy participants in the experiment. Tendon vibration inducing illusion of movement (wrist extension, 100Hz) was applied on their wrist during 3 VR visual conditions (10 times each): a moving virtual hand corresponding to the movement that the participants could feel during the tendon vibration (Moving condition), a static virtual hand (Static condition), or no virtual hand at all (Hidden condition). After each trial, the participants had to quantify the intensity of the illusory movement on a Likert scale, the subjective degree of extension of their wrist and afterwards they answered a questionnaire. RESULTS: There was a significant difference between the 3 visual feedback conditions concerning the Likert scale ranking and the degree of wrist's extension (p<0.001). The Moving condition induced a higher intensity of illusion of movement and a higher sensation of wrist's extension than the Hidden condition (p<0.001 and p<0.001 respectively) than that of the Static condition (p<0.001 and p<0.001 respectively). The Hidden condition also induced a higher intensity of illusion of movement and a higher sensation of wrist's extension than the Static condition (p<0.01 and p<0.01 respectively). The preferred condition to facilitate movement's illusion was the Moving condition (63.3%). CONCLUSIONS: This study demonstrated the importance of carefully selecting a visual feedback to improve the illusion of movement induced by tendon vibration, and the increase of illusion by adding VR visual cues congruent to the illusion of movement. Further work will consist in testing the same hypothesis with stroke patients.


Assuntos
Retroalimentação Sensorial/fisiologia , Ilusões/fisiologia , Movimento/fisiologia , Tendões/fisiologia , Realidade Virtual , Adulto , Idoso , Idoso de 80 Anos ou mais , Sinais (Psicologia) , Voluntários Saudáveis , Humanos , Pessoa de Meia-Idade , Reabilitação do Acidente Vascular Cerebral , Vibração , Adulto Jovem
6.
PLoS One ; 15(10): e0241087, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33095827

RESUMO

An internal model of self-motion provides a fundamental basis for action in our daily lives, yet little is known about its development. The ability to control self-motion develops in youth and often deteriorates with advanced age. Self-motion generates relative motion between the viewer and the environment. Thus, the smoothness of the visual motion created will vary as control improves. Here, we study the influence of the smoothness of visually simulated self-motion on an observer's ability to judge how far they have travelled over a wide range of ages. Previous studies were typically highly controlled and concentrated on university students. But are such populations representative of the general public? And are there developmental and sex effects? Here, estimates of distance travelled (visual odometry) during visually induced self-motion were obtained from 466 participants drawn from visitors to a public science museum. Participants were presented with visual motion that simulated forward linear self-motion through a field of lollipops using a head-mounted virtual reality display. They judged the distance of their simulated motion by indicating when they had reached the position of a previously presented target. The simulated visual motion was presented with or without horizontal or vertical sinusoidal jitter. Participants' responses indicated that they felt they travelled further in the presence of vertical jitter. The effectiveness of the display increased with age over all jitter conditions. The estimated time for participants to feel that they had started to move also increased slightly with age. There were no differences between the sexes. These results suggest that age should be taken into account when generating motion in a virtual reality environment. Citizen science studies like this can provide a unique and valuable insight into perceptual processes in a truly representative sample of people.


Assuntos
Percepção de Movimento/fisiologia , Movimento/fisiologia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estimulação Luminosa/métodos , Tempo de Reação/fisiologia , Fatores Sexuais , Fatores de Tempo , Realidade Virtual , Adulto Jovem
7.
PLoS One ; 15(10): e0241479, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33119679

RESUMO

Virtual reality (VR) technology is commonly used in balance research due to its ability to simulate real world experiences under controlled experimental conditions. However, several studies reported considerable differences in balance behavior in real world environments as compared to virtual environments presented in a head mounted display. Most of these studies were conducted more than a decade ago, at a time when VR was still struggling with major technical limitations (delays, limited field-of-view, etc.). In the meantime, VR technology has progressed considerably, enhancing its capacity to induce the feeling of presence and behavioural realism. In this study, we addressed two questions: Has VR technology now reached a point where balance is similar in real and virtual environments? And does the integration of visual cues for balance depend on the subjective experience of presence? We used a state-of-the-art head mounted VR system and a custom-made balance platform to compare balance when viewing (1) a real-world environment, (2) a photo-realistic virtual copy of the real-world environment, (3) an abstract virtual environment consisting of only spheres and bars ('low presence' VR condition), and, as reference, (4) a condition with eyes closed. Body sway of ten participants was measured in three different support surface conditions: (A) quiet stance, (B) stance on a sway referenced surface, and (C) surface tilting following a pseudo-random sequence. A 2-level repeated measures ANOVA and PostHoc analyses revealed no significant differences in body sway between viewing the real world environment and the photo-realistic virtual copy. In contrast, body sway was increased in the 'low presence' abstract scene and further increased with eyes closed. Results were consistent across platform conditions. Our results support the hypothesis that state of the art VR reached a point of behavioural realism in which balance in photo-realistic VR is similar to balance in a real environment. Presence was lower in the abstract virtual condition as compared to the photo-realistic condition as measured by the IPQ presence questionnaire. Thus, our results indicate that spatial presence may be a moderating factor, but further research is required to confirm this notion. We conceive that virtual reality is a valid tool for balance research, but that the properties of the virtual environment affects results.


Assuntos
Movimento/fisiologia , Equilíbrio Postural , Pesquisa , Realidade Virtual , Adulto , Calibragem , Feminino , Humanos , Masculino
8.
Sci Rep ; 10(1): 18053, 2020 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-33093497

RESUMO

While large scale mobility data has become a popular tool to monitor the mobility patterns during the COVID-19 pandemic, the impacts of non-compulsory measures in Tokyo, Japan on human mobility patterns has been under-studied. Here, we analyze the temporal changes in human mobility behavior, social contact rates, and their correlations with the transmissibility of COVID-19, using mobility data collected from more than 200K anonymized mobile phone users in Tokyo. The analysis concludes that by April 15th (1 week into state of emergency), human mobility behavior decreased by around 50%, resulting in a 70% reduction of social contacts in Tokyo, showing the strong relationships with non-compulsory measures. Furthermore, the reduction in data-driven human mobility metrics showed correlation with the decrease in estimated effective reproduction number of COVID-19 in Tokyo. Such empirical insights could inform policy makers on deciding sufficient levels of mobility reduction to contain the disease.


Assuntos
Infecções por Coronavirus/patologia , Movimento/fisiologia , Pneumonia Viral/patologia , Comportamento , Betacoronavirus/isolamento & purificação , Uso do Telefone Celular/estatística & dados numéricos , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/virologia , Humanos , Pandemias , Pneumonia Viral/epidemiologia , Pneumonia Viral/virologia , Fatores de Tempo , Tóquio/epidemiologia
9.
Proc Natl Acad Sci U S A ; 117(44): 27655-27666, 2020 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-33060294

RESUMO

Modular organization of the spinal motor system is thought to reduce the cognitive complexity of simultaneously controlling the large number of muscles and joints in the human body. Although modular organization has been confirmed in the hindlimb control system of several animal species, it has yet to be established in the forelimb motor system or in primates. Expanding upon experiments originally performed in the frog lumbar spinal cord, we examined whether costimulation of two sites in the macaque monkey cervical spinal cord results in motor activity that is a simple linear sum of the responses evoked by stimulating each site individually. Similar to previous observations in the frog and rodent hindlimb, our analysis revealed that in most cases (77% of all pairs) the directions of the force fields elicited by costimulation were highly similar to those predicted by the simple linear sum of those elicited by stimulating each site individually. A comparable simple summation of electromyography (EMG) output, especially in the proximal muscles, suggested that this linear summation of force field direction was produced by a spinal neural mechanism whereby the forelimb motor output recruited by costimulation was also summed linearly. We further found that the force field magnitudes exhibited supralinear (amplified) summation, which was also observed in the EMG output of distal forelimb muscles, implying a novel feature of primate forelimb control. Overall, our observations support the idea that complex movements in the primate forelimb control system are made possible by flexibly combined spinal motor modules.


Assuntos
Braço/fisiologia , Medula Cervical/fisiologia , Movimento/fisiologia , Músculo Esquelético/fisiologia , Animais , Braço/inervação , Estimulação Elétrica/instrumentação , Eletrodos Implantados , Eletromiografia/instrumentação , Potencial Evocado Motor/fisiologia , Macaca , Masculino , Músculo Esquelético/inervação
10.
Proc Natl Acad Sci U S A ; 117(45): 28433-28441, 2020 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-33106395

RESUMO

Many parts of the visuomotor system guide daily hand actions, like reaching for and grasping objects. Do these regions depend exclusively on the hand as a specific body part whose movement they guide, or are they organized for the reaching task per se, for any body part used as an effector? To address this question, we conducted a neuroimaging study with people born without upper limbs-individuals with dysplasia-who use the feet to act, as they and typically developed controls performed reaching and grasping actions with their dominant effector. Individuals with dysplasia have no prior experience acting with hands, allowing us to control for hand motor imagery when acting with another effector (i.e., foot). Primary sensorimotor cortices showed selectivity for the hand in controls and foot in individuals with dysplasia. Importantly, we found a preference based on action type (reaching/grasping) regardless of the effector used in the association sensorimotor cortex, in the left intraparietal sulcus and dorsal premotor cortex, as well as in the basal ganglia and anterior cerebellum. These areas also showed differential response patterns between action types for both groups. Intermediate areas along a posterior-anterior gradient in the left dorsal premotor cortex gradually transitioned from selectivity based on the body part to selectivity based on the action type. These findings indicate that some visuomotor association areas are organized based on abstract action functions independent of specific sensorimotor parameters, paralleling sensory feature-independence in visual and auditory cortices in people born blind and deaf. Together, they suggest association cortices across action and perception may support specific computations, abstracted from low-level sensorimotor elements.


Assuntos
Encéfalo/fisiologia , Mãos/fisiologia , Córtex Motor/fisiologia , Córtex Sensório-Motor/fisiologia , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , , Lateralidade Funcional/fisiologia , Força da Mão/fisiologia , Humanos , Imagem por Ressonância Magnética , Movimento/fisiologia , Plasticidade Neuronal , Lobo Parietal/fisiologia , Desempenho Psicomotor/fisiologia
11.
Nat Commun ; 11(1): 5365, 2020 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-33097711

RESUMO

Whereas self-propelled hard discs undergo motility-induced phase separation, self-propelled rods exhibit a variety of nonequilibrium phenomena, including clustering, collective motion, and spatio-temporal chaos. In this work, we present a theoretical framework representing active particles by continuum fields. This concept combines the simplicity of alignment-based models, enabling analytical studies, and realistic models that incorporate the shape of self-propelled objects explicitly. By varying particle shape from circular to ellipsoidal, we show how nonequilibrium stresses acting among self-propelled rods destabilize motility-induced phase separation and facilitate orientational ordering, thereby connecting the realms of scalar and vectorial active matter. Though the interaction potential is strictly apolar, both, polar and nematic order may emerge and even coexist. Accordingly, the symmetry of ordered states is a dynamical property in active matter. The presented framework may represent various systems including bacterial colonies, cytoskeletal extracts, or shaken granular media.


Assuntos
Fenômenos Fisiológicos Bacterianos , Movimento (Física) , Análise por Conglomerados , Simulação por Computador , Modelos Biológicos , Modelos Teóricos , Movimento/fisiologia , Termodinâmica
12.
PLoS One ; 15(10): e0240998, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33112886

RESUMO

It has been reported that the cerebellar vermis is equally involved in both motor imagery about axial movement and the actual execution of postural balance in healthy human subjects, but this finding is yet to be explored in Parkinson's disease (PD). We therefore investigated the neuronal responses during observation of standing posture, imagination of standing and the assumption of an upright posture in ten drug-naïve PD patients using positron emission tomography (PET) with [15O]H2O and evaluated dopamine dysfunction by measuring the level of dopamine transporter binding of [11C]CFT. Within-group statistical parametric mapping (SPM) analysis showed similar cerebellar activation during imagination of standing and its real execution between the PD and control groups (12 healthy subjects); i.e., increases in regional cerebral blood flow (rCBF) were observed in the anterior cerebellar vermis during motor imagination and the posterior vermis during standing. A comparison between the groups showed that the motor execution of standing significantly activated the superior part of the posterior vermis (declive VI) and the paracentral sulcus region in the PD patients, while the prefrontal cortices were deactivated during standing (p<0.001 uncorrected). Correlation analysis within the PD group revealed that the postural rCBF increases in the cerebellar vermis (pyramis) were negatively correlated with putaminal [11C]CFT binding (p<0.01, r = 0.94) and that the postural rCBF reductions in the orbitofrontal cortex were positively correlated with caudate [11C]CFT binding (p<0.05, r = 0.70). These results suggest that while the neural circuits for postural imagery and execution are intact in PD, standing performance, which requires more recruitment of dopaminergic control, may result in compensatory overstimulation of the cerebellar vermis and paracentral foot area in PD patients. Hyperactivity in these areas along with mesocortical hypofunction may be pathophysiological aspects of postural control in PD patients. Hence, our findings would help understand the modifications observed within the neural networks in relationship with postural performance, and possible compensatory mechanisms in PD.


Assuntos
Dopamina/metabolismo , Neurônios/metabolismo , Neurônios/fisiologia , Doença de Parkinson/metabolismo , Doença de Parkinson/fisiopatologia , Cerebelo/metabolismo , Cerebelo/fisiopatologia , Corpo Estriado/metabolismo , Corpo Estriado/fisiopatologia , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Feminino , Lobo Frontal/metabolismo , Lobo Frontal/fisiopatologia , Humanos , Processamento de Imagem Assistida por Computador/métodos , Imaginação/fisiologia , Masculino , Pessoa de Meia-Idade , Movimento/fisiologia , Tomografia por Emissão de Pósitrons/métodos , Tomografia Computadorizada por Raios X/métodos
13.
PLoS One ; 15(10): e0238486, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33031372

RESUMO

OBJECTIVE: We aim to propose a novel method of evaluating the degree of rhythmic irregularity during repetitive tasks in Parkinson's disease (PD) by using autocorrelation to extract serial perturbation in the periodicity of body part movements as recorded by objective devices. METHODS: We used publicly distributed sequential joint movement data recorded during a leg agility task or pronation-supination task. The sequences of body part trajectory were processed to extract their short-time autocorrelation (STACF) matrices; the sequences of single task conducted by participants were then divided into two clusters according to their similarity in terms of their STACF representation. The Unified Parkinson's Disease Rating Scale sub-score rated for each task was compared with cluster membership to obtain the area under the curve (AUC) to evaluate the discrimination performance of the clustering. We compared the AUC with those obtained from the clustering of the raw sequence or short-time Fourier transform (STFT). RESULTS: In classifying the pose estimator-based trajectory data of the knee during the leg agility task, the AUC was the highest when the STACF sequence was used for clustering instead of other types of sequences with up to 0.815, being comparable to the results reported in the original analysis of the data using an approach different from ours. In addition, in classifying another dataset of accelerometer-based trajectory data of the wrist during a pronation-supination task, the AUC was again highest up to 0.785 when clustering was performed using the STACF rather than other types of sequence. CONCLUSION: Our autocorrelation-based method achieved a fair performance in detecting sequences with irregular rhythm, suggesting that it might be used as another evaluation strategy that is potentially widely applicable to qualify the disordered rhythm of PD regardless of the kinds of task or the modality of devices, although further refinement is needed.


Assuntos
Doença de Parkinson/diagnóstico , Doença de Parkinson/fisiopatologia , Análise e Desempenho de Tarefas , Acelerometria , Área Sob a Curva , Fenômenos Biomecânicos , Análise por Conglomerados , Bases de Dados Factuais , Diagnóstico por Computador , Análise de Fourier , Humanos , Articulação do Joelho/fisiopatologia , Movimento/fisiologia , Doença de Parkinson/classificação , Pronação/fisiologia , Estudos Retrospectivos , Análise Espacial , Supinação/fisiologia
14.
Artigo em Inglês | MEDLINE | ID: mdl-32992943

RESUMO

There are many adolescent patients complaining of low back pain, but research on it is lacking. The purpose of this study was to investigate the effects of trunk stabilization exercise combined with vibration on the pain, proprioception, and kinematics of the lumbar spine (LS) during sit to stand (STS) in adolescent patients with nonspecific low back pain (LBP). Fifty LBP patients were recruited and were randomly divided into two groups: Vibration group (n = 25) and placebo group (n = 25). All participants underwent 36-sessions of training consisting of six exercises. The Vibration group provided vibration stimulation during exercise, but the placebo group did not. The Numeric Pain Rating Scale (NPRS) and digital dual inclinometer were used to measure pain intensity and proprioception. The kinematics of the lumbar spine during STS were measured by motion capture system. After training, the pain and proprioception in the vibration group improved significantly greater than the placebo group (p < 0.05). The mobility of LS (maximum range of motion, angular velocity, lumbar to hip movement ratios) and lumbar-hip coordination during STS in the vibration group were significantly improved compared to the placebo group (p < 0.05). Thus, trunk stabilization exercise combined with vibration may be used to improve the pain, proprioception, and kinematic of the lumbar spine during sit to stand in adolescent patients with LBP.


Assuntos
Terapia por Exercício/métodos , Dor Lombar/diagnóstico , Dor Lombar/terapia , Vértebras Lombares/fisiologia , Movimento/fisiologia , Vibração/uso terapêutico , Adolescente , Feminino , Humanos , Dor Lombar/fisiopatologia , Região Lombossacral , Masculino , Amplitude de Movimento Articular , Resultado do Tratamento
15.
Sci Rep ; 10(1): 14726, 2020 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-32895449

RESUMO

The aim of this work was to critically assess if functional near infrared spectroscopy (fNIRS) can be profitably used as a tool for noninvasive recording of brain functions and emotions in sheep. We considered an experimental design including advances in instrumentation (customized wireless multi-distance fNIRS system), more accurate physical modelling (two-layer model for photon diffusion and 3D Monte Carlo simulations), support from neuroanatomical tools (positioning of the fNIRS probe by MRI and DTI data of the very same animals), and rigorous protocols (motor task, startling test) for testing the behavioral response of freely moving sheep. Almost no hemodynamic response was found in the extra-cerebral region in both the motor task and the startling test. In the motor task, as expected we found a canonical hemodynamic response in the cerebral region when sheep were walking. In the startling test, the measured hemodynamic response in the cerebral region was mainly from movement. Overall, these results indicate that with the current setup and probe positioning we are primarily measuring the motor area of the sheep brain, and not probing the too deeply located cortical areas related to processing of emotions.


Assuntos
Encéfalo/fisiologia , Emoções/fisiologia , Imagem por Ressonância Magnética/métodos , Ovinos/fisiologia , Animais , Hemodinâmica/fisiologia , Córtex Motor/fisiologia , Movimento/fisiologia , Reprodutibilidade dos Testes
16.
Phys Ther ; 100(12): 2134-2143, 2020 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-32936920

RESUMO

OBJECTIVE: Obesity reduces voluntary recruitment of quadriceps during single-joint exercises, but the effects of obesity on quadriceps femoris muscle activation during dynamic daily living tasks, such as sit-to-stand (STS), are largely unknown. The purpose of this study was to determine how obesity affects quadriceps muscle recruitment during STS. METHODS: In this cross-sectional study, 10 women who were lean and 17 women who were obese completed STS from a chair with arms crossed over the chest. Three-dimensional motion analysis was used to define 3 distinct phases (I-III) of the STS cycle. The electromyographic (EMG) activity of the vastus medialis, vastus lateralis, and semitendinosus was measured. RESULTS: STS duration was greater (3.02 [SD = 0.75] seconds vs 1.67 [SD = 0.28] seconds) and peak trunk flexion angle was lower (28.9 degrees [SD = 10.4 degrees] vs 35.8 degrees [SD = 10.1 degrees]) in the women who were obese than in the women who were lean. The mean EMG activity of the knee extensors increased from phase I to phase II in both groups; however, the mean EMG activities of both the vastus medialis (32.1% [SD = 16.6%] vs 47.3% [SD = 19.6%] maximal voluntary isometric contraction) and the vastus lateralis (31.8% [SD = 19.4%] vs 47.5% [SD = 19.6%] maximal voluntary isometric contraction) were significantly lower during phase II in the women who were obese. The mean EMG activity of the semitendinosus increased throughout STS but was not significantly different between the 2 groups. Coactivation of the semitendinosus and knee extensors tended to be greater in the women who were obese but failed to reach statistical significance. CONCLUSIONS: Knee extensor EMG amplitude was reduced in women who were obese during STS, despite reduced trunk flexion. IMPACT: Reduced knee extensor recruitment during STS in obesity may redistribute forces needed to complete this task to other joints. Functional movement training may help improve knee extensor recruitment during STS in people who are obese. LAY SUMMARY: People with obesity often have low quadriceps muscle strength and impaired mobility during daily activities. This study shows that women who are obese have lower voluntary recruitment of quadriceps when rising from a chair than women who are lean do, which could increase workload on hip or ankle muscles during this important daily task. Quadriceps strengthening exercises might improve the ability to rise from sitting to standing.


Assuntos
Movimento/fisiologia , Obesidade/fisiopatologia , Músculo Quadríceps/fisiologia , Postura Sentada , Posição Ortostática , Adulto , Estudos Transversais , Eletromiografia/métodos , Feminino , Humanos , Contração Isométrica/fisiologia , Extremidade Inferior/fisiopatologia , Pessoa de Meia-Idade , Recrutamento Neurofisiológico/fisiologia , Magreza/fisiopatologia , Fatores de Tempo , Adulto Jovem
17.
Sci Rep ; 10(1): 15554, 2020 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-32968191

RESUMO

In joint performances spanning from jazz improvisation to soccer, expert performers synchronize their movements in ways that novices cannot. Particularly, experts can align the velocity profiles of their movements in order to achieve synchrony on a fine-grained time scale, compared to novices who can only synchronize the duration of their movement intervals. This study investigated how experts' ability to engage in velocity-based synchrony affects observers' perception of coordination and their aesthetic experience of joint performances. Participants observed two moving dots on a screen and were told that these reflect the hand movements of two performers engaging in joint improvisation. The dots were animated to reflect the velocity-based synchrony characteristic of expert performance (in terms of jitter of the velocity profile: Experiment 1, or through aligning sharpness of the velocity profile: Experiment 2) or contained only interval-based synchrony. Performances containing velocity-based synchrony were judged as more coordinated with performers rated as liking each other more, and were rated as more beautiful, providing observers with a stronger aesthetic experience. These findings demonstrate that subtle timing cues fundamentally shape the experience of watching joint actions, directly influencing how beautiful and enjoyable we find these interactions, as well as our perception of the relationship between co-actors.


Assuntos
Comportamento Cooperativo , Movimento/fisiologia , Desempenho Psicomotor/fisiologia , Adulto , Feminino , Humanos , Masculino , Percepção/fisiologia
18.
J Sports Med Phys Fitness ; 60(8): 1081-1088, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32955834

RESUMO

BACKGROUND: Declines in muscle morphology and function are commonly reported as a consequence of aging. However, few studies have investigated the influence of age on a comprehensive set of muscle function-related measures (i.e., reactive strength, power, etc.) that focuses on a dynamic performance task such as the vertical jump across the adult life span. This study aimed to examine the effects of age on muscle morphology characteristics (muscle cross-sectional area [CSA] and echo intensity [EI]) and vertical jump height, power, and reactive strength index (RSI) in females. METHODS: Twenty-six young (22±2 years), 30 middle-aged (36±5 years), and 23 older (71±5 years) females participated in this study. Muscle CSA and EI were determined from ultrasound scans of the vastus lateralis. Countermovement jumps were used to assess jump height, RSI, movement time, and peak power (Pmax). RESULTS: Muscle CSA, jump height, and Pmax were higher for the young compared to the old and middle-aged (P≤0.027) and for the middle-aged compared to the old (P<0.001). Movement time and EI values were lower (P≤0.004) and RSI values were higher (P<0.001) for the young and middle-aged compared to the old; however, no differences were observed between the young and middle-aged (P=0.367-0.620). CONCLUSIONS: Of all the variables assessed in this study, RSI exhibited the greatest decline (76%) between the young and old females. Such findings highlight the importance of reactive strength when assessing age-related changes in neuromuscular performance.


Assuntos
Envelhecimento/fisiologia , Força Muscular/fisiologia , Exercício Pliométrico , Músculo Quadríceps/anatomia & histologia , Músculo Quadríceps/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Desempenho Atlético/fisiologia , Feminino , Humanos , Pessoa de Meia-Idade , Movimento/fisiologia , Músculo Quadríceps/diagnóstico por imagem , Análise e Desempenho de Tarefas , Ultrassonografia , Adulto Jovem
19.
Phys Rev Lett ; 125(9): 098002, 2020 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-32915620

RESUMO

Many biological systems display intriguing chiral patterns and dynamics. Here, we present an active nematic theory accounting for individual spin to explore the collective handedness in chiral rod-shaped aggregations. We show that coordinated individual spin and motility can engender a vortex-array pattern with chirality and drive ordering of topological defects. During this chiral process, the stationary trefoil-like defects self-organize into a periodic, hexagon-dominated polygonal network, which segregates persistently rotating cometlike defects in pairs within each polygon, leading to a translation symmetry at the global scale while a broken reflection symmetry at the local scale. Such defect ordering agrees exactly with the Voronoi tiling of two-dimensional space and the emergence of the hexagonal symmetry is deciphered in analogy with topological charge neutralization. We calculate energy barriers to the topological transition of the defect ordering and explain the existing metastable states with nonhexagonal polygons. Our findings shed light on the chiral morphodynamics in life processes and also suggest a potential route towards tuning self-organization in active materials.


Assuntos
Flagelos/fisiologia , Modelos Biológicos , Espermatozoides/fisiologia , Animais , Fenômenos Fisiológicos Bacterianos , Masculino , Movimento/fisiologia , Ouriços-do-Mar
20.
Sci Rep ; 10(1): 15085, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32934249

RESUMO

This study was designed to investigate the effects of anxiety and dual-task on reach and grasp motor control in chronic stroke survivors compared with age- and sex-matched healthy subjects (HC). Reach and grasp kinematic data of 68 participants (high-anxiety stroke (HA-stroke), n = 17; low-anxiety stroke (LA-stroke), n = 17; low-anxiety HC, n = 17; and high-anxiety HC, n = 17) were recorded under single- and dual-task conditions. Inefficient reach and grasp of stroke participants, especially HA-stroke were found compared with the control groups under single- and dual-task conditions as evidenced by longer movement time (MT), lower and earlier peak velocity (PV) as well as delayed and smaller hand opening. The effects of dual-task on reach and grasp kinematic measures were similar between HCs and stroke participants (i.e., increased MT, decreased PV that occurred earlier, and delayed and decreased hand opening), with greater effect in stroke groups than HCs, and in HA-stroke group than LA-stroke group. The results indicate that performing a well-learned upper limb movement with concurrent cognitive task leads to decreased efficiency of motor control in chronic stroke survivors compared with HCs. HA-stroke participants were more adversely affected by challenging dual-task conditions, underlying importance of assessing anxiety and designing effective interventions for it in chronic stroke survivors.


Assuntos
Ansiedade/fisiopatologia , Ansiedade/psicologia , Córtex Motor/fisiopatologia , Acidente Vascular Cerebral/fisiopatologia , Acidente Vascular Cerebral/psicologia , Extremidade Superior/fisiopatologia , Adulto , Idoso , Fenômenos Biomecânicos/fisiologia , Feminino , Força da Mão/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Movimento/fisiologia , Recuperação de Função Fisiológica/fisiologia , Reabilitação do Acidente Vascular Cerebral/psicologia , Sobreviventes
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