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1.
Artigo em Inglês | MEDLINE | ID: mdl-33804915

RESUMO

This study aimed to investigate the visual biofeedback effect of a sensorized system for plantar pressure dynamic evaluation of in patients with a total hip replacement. Experimental group followed the rehabilitation training wearing sensorized insoles that provided images on three monitors. The control group followed the verbal instructions of physiotherapists during training. Weight bearing percentage healthy limb (WBPH), weight bearing percentage surgical limb (WBPS), swing healthy limb (SWH) and swing surgical limb (SWS) improved significantly more in the experimental group. The results underline the effectiveness of visual biofeedback based on sensorized system with dynamic evaluation of the plantar pressure.


Assuntos
Artroplastia de Quadril , Biorretroalimentação Psicológica , Retroalimentação Sensorial , Humanos , Sapatos , Suporte de Carga
2.
Artigo em Inglês | MEDLINE | ID: mdl-33668438

RESUMO

Increasingly, refined virtual reality (VR) techniques allow for the simultaneous and coherent stimulation of multiple sensory and motor domains. In some clinical interventions, such as those related to spinal cord injuries (SCIs), the impact of VR on people's multisensory perception, movements, attitudes, and even modulations of socio-cognitive aspects of their behavior may influence every phase of their rehabilitation treatment, from the acute to chronic stages. This work describes the potential advantages of using first-person-perspective VR to treat SCIs and its implications for manipulating sensory-motor feedback to alter body signals. By situating a patient with SCI in a virtual environment, sensorial perceptions and motor intention can be enriched into a more coherent bodily experience that also promotes processes of neural regeneration and plasticity. In addition to the great potential of research, the most significant areas of interest concern is managing neuropathic pain, motor rehabilitation, and psychological well-being.


Assuntos
Traumatismos da Medula Espinal , Terapia de Exposição à Realidade Virtual , Realidade Virtual , Retroalimentação Sensorial , Humanos , Traumatismos da Medula Espinal/terapia
3.
Artigo em Inglês | MEDLINE | ID: mdl-33670474

RESUMO

The aim of this study was to assess the efficacy of using real-time visual feedback (VF) during a one-week balance training intervention on postural sway parameters in young karatekas. Twenty-six young male karatekas (age = 14.0 ± 2.3 years) were randomly divided into two groups: real-time VF training (VFT; n = 14) and control (CTRL; n = 12). Their center of pressure (COP) displacement (path length, COPpl; distance from origin, COPod) was assessed pre- and post-training on a Wii Balance Board platform in two positions (Flex: knee of the supporting leg slightly bent, maximum hip and leg flexion of the other leg; Kick: knee of the supporting leg slightly bent, mawashi-geri posture for the kicking leg). Both groups trained twice a day for seven days, performing a one-legged stance on the non-dominant limb in the Kick position. During the training, VFT received real-time VF of COP displacement, while CTRL looked at a fixed point. No interaction effect was found (p > 0.05). VFT exhibited greater changes pre- and post-training in Flex COPpl (-25.2%, g = 1.5), Kick COPpl (-24.1%, g = 1.3), and Kick COPod (-44.1%, g = 1.0) compared to CTRL (-0.9--13.0%, g-range: 0.1-0.7). It is possible that superimposing real-time VF to a week-long balance training intervention could induce a greater sport-specific balance-training effect in young karatekas.


Assuntos
Retroalimentação Sensorial , Equilíbrio Postural , Adolescente , Criança , Humanos , Joelho , Masculino , Postura , Amplitude de Movimento Articular
4.
Sensors (Basel) ; 21(4)2021 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-33562342

RESUMO

Sensory feedback from wearables can be effective to learn better movement through enhanced information and engagement. Facilitating greater user cognition during movement practice is critical to accelerate gains in motor function during rehabilitation following brain or spinal cord trauma. This preliminary study presents an approach using an instrumented glove to leverage sense of agency, or perception of control, to provide training feedback for functional grasp. Seventeen able-bodied subjects underwent training and testing with a custom-built sensor glove prototype from our laboratory. The glove utilizes onboard force and flex sensors to provide inputs to an artificial neural network that predicts achievement of "secure" grasp. Onboard visual and audio feedback was provided during training with progressively shorter time delay to induce greater agency by intentional binding, or perceived compression in time between an action (grasp) and sensory consequence (feedback). After training, subjects demonstrated a significant reduction (p < 0.05) in movement pathlength and completion time for a functional task involving grasp-move-place of a small object. Future work will include a model-based algorithm to compute secure grasp, virtual reality immersion, and testing with clinical populations.


Assuntos
Força da Mão , Mãos , Retroalimentação , Retroalimentação Sensorial , Humanos , Movimento
5.
Neuron ; 109(7): 1188-1201.e7, 2021 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-33577748

RESUMO

Proprioception is essential for behavior and provides a sense of our body movements in physical space. Proprioceptor organs are thought to be only in the periphery. Whether the central nervous system can intrinsically sense its own movement remains unclear. Here we identify a segmental organ of proprioception in the adult zebrafish spinal cord, which is embedded by intraspinal mechanosensory neurons expressing Piezo2 channels. These cells are late-born, inhibitory, commissural neurons with unique molecular and physiological profiles reflecting a dual sensory and motor function. The central proprioceptive organ locally detects lateral body movements during locomotion and provides direct inhibitory feedback onto rhythm-generating interneurons responsible for the central motor program. This dynamically aligns central pattern generation with movement outcome for efficient locomotion. Our results demonstrate that a central proprioceptive organ monitors self-movement using hybrid neurons that merge sensory and motor entities into a unified network.


Assuntos
Retroalimentação Sensorial/fisiologia , Movimento/fisiologia , Propriocepção/fisiologia , Peixe-Zebra/fisiologia , Animais , Geradores de Padrão Central/fisiologia , Feminino , Interneurônios/fisiologia , Canais Iônicos/fisiologia , Locomoção/fisiologia , Masculino , Mecanotransdução Celular , Neurônios Motores/fisiologia , Rede Nervosa/citologia , Rede Nervosa/fisiologia , RNA/genética , Células Receptoras Sensoriais/fisiologia , Medula Espinal/diagnóstico por imagem , Medula Espinal/fisiologia , Tomografia Computadorizada por Raios X , Proteínas de Peixe-Zebra/fisiologia
6.
Biol Psychol ; 160: 108048, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33596460

RESUMO

The present study investigated whether auditory stimuli with different contents affect right laterality and the components of stimulus-preceding negativity (SPN). A time-estimation task was performed under voice, rhythm, beep, and control conditions. The SPN interval during which participants anticipated the stimulus was divided into quarters to define early and late SPNs. Early and late components of SPN were also extracted using a principal component analysis. The anticipation of voice sounds enhanced the early SPN and the early component, which reflected the anticipation of language processing. Beep sounds elicited the right hemisphere preponderance of the early component, the early SPN, and the late SPN. The rhythmic sound tended to attenuate the amplitude compared with the two other stimuli. These findings further substantiate the existence of separate early and late components of the SPN. In addition, they suggest that the early component reflects selective anticipatory attention toward differing types of auditory feedback.


Assuntos
Atenção , Nomes , Eletroencefalografia , Retroalimentação Sensorial , Humanos , Idioma
7.
Nat Commun ; 12(1): 1026, 2021 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-33589589

RESUMO

Proprioceptive neurons (PNs) are essential for the proper execution of all our movements by providing muscle sensory feedback to the central motor network. Here, using deep single cell RNAseq of adult PNs coupled with virus and genetic tracings, we molecularly identify three main types of PNs (Ia, Ib and II) and find that they segregate into eight distinct subgroups. Our data unveil a highly sophisticated organization of PNs into discrete sensory input channels with distinct spatial distribution, innervation patterns and molecular profiles. Altogether, these features contribute to finely regulate proprioception during complex motor behavior. Moreover, while Ib- and II-PN subtypes are specified around birth, Ia-PN subtypes diversify later in life along with increased motor activity. We also show Ia-PNs plasticity following exercise training, suggesting Ia-PNs are important players in adaptive proprioceptive function in adult mice.


Assuntos
Retroalimentação Sensorial/fisiologia , Gânglios Espinais/metabolismo , Neurônios Motores/metabolismo , Propriocepção/fisiologia , Células Receptoras Sensoriais/metabolismo , Animais , Calbindina 1/genética , Calbindina 1/metabolismo , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas Correpressoras/genética , Proteínas Correpressoras/metabolismo , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , Subunidade alfa 3 de Fator de Ligação ao Core/genética , Subunidade alfa 3 de Fator de Ligação ao Core/metabolismo , Gânglios Espinais/citologia , Expressão Gênica , Proteínas com Domínio LIM/genética , Proteínas com Domínio LIM/metabolismo , Lectinas Tipo C/genética , Lectinas Tipo C/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neurônios Motores/classificação , Neurônios Motores/citologia , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Condicionamento Físico Animal , Células Receptoras Sensoriais/classificação , Células Receptoras Sensoriais/citologia , Análise de Célula Única , Medula Espinal/citologia , Medula Espinal/metabolismo
8.
Sensors (Basel) ; 21(2)2021 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-33478053

RESUMO

In this research, we focused on Human-Robot collaboration. There were two goals: (1) to develop and evaluate a real-time Human-Robot collaborative system, and (2) to achieve concrete tasks such as collaborative peg-in-hole using the developed system. We proposed an algorithm for visual sensing and robot hand control to perform collaborative motion, and we analyzed the stability of the collaborative system and a so-called collaborative error caused by image processing and latency. We achieved collaborative motion using this developed system and evaluated the collaborative error on the basis of the analysis results. Moreover, we aimed to realize a collaborative peg-in-hole task that required a system with high speed and high accuracy. To achieve this goal, we analyzed the conditions required for performing the collaborative peg-in-hole task from the viewpoints of geometric, force and posture conditions. Finally, in this work, we show the experimental results and data of the collaborative peg-in-hole task, and we examine the effectiveness of our collaborative system.


Assuntos
Retroalimentação Sensorial , Robótica , Algoritmos , Mãos , Humanos , Movimento (Física) , Análise e Desempenho de Tarefas
9.
Nat Commun ; 12(1): 228, 2021 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-33431862

RESUMO

The sensory neocortex consists of hierarchically-organized areas reciprocally connected via feedforward and feedback circuits. Feedforward connections shape the receptive field properties of neurons in higher areas within parallel streams specialized in processing specific stimulus attributes. Feedback connections have been implicated in top-down modulations, such as attention, prediction and sensory context. However, their computational role remains unknown, partly because we lack knowledge about rules of feedback connectivity to constrain models of feedback function. For example, it is unknown whether feedback connections maintain stream-specific segregation, or integrate information across parallel streams. Using viral-mediated labeling of feedback connections arising from specific cytochrome-oxidase stripes of macaque visual area V2, here we show that feedback to the primary visual cortex (V1) is organized into parallel streams resembling the reciprocal feedforward pathways. This suggests that functionally-specialized V2 feedback channels modulate V1 responses to specific stimulus attributes, an organizational principle potentially extending to feedback pathways in other sensory systems.


Assuntos
Retroalimentação Sensorial/fisiologia , Córtex Visual/fisiologia , Animais , Axônios/metabolismo , Feminino , Proteínas de Fluorescência Verde/metabolismo , Macaca fascicularis , Masculino , Modelos Biológicos
10.
NeuroRehabilitation ; 48(1): 29-37, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33386818

RESUMO

BACGROUND: Interventions addressing balance dysfunction after traumatic brain injury (TBI) only target compensatory aspects and do not investigate perceptual mechanisms such as sensory acuity. OBJECTIVE: To evaluate the efficacy of a novel intervention that integrates sensory acuity with a perturbation-based approach for improving the perception and functional balance after TBI. METHODS: A two-group design was implemented to evaluate the effect of a novel, perturbation-based balance intervention. The intervention group (n = 5) performed the intervention with the sinusoidal (0.33, 0.5, and 1 Hz) perturbations to the base of support with amplitudes derived using our novel outcome of sensory acuity - perturbation perception threshold (PPT). The efficacy is evaluated using changes in PPT and functional outcomes (Berg Balance Scale (BBS), Timed-up and Go (TUG), 5-meter walk test (5MWT), and 10-meter walk test (10MWT)). RESULTS: There was a significant post-intervention change in PPT for 0.33 Hz (p = 0.021). Additionally, clinically and statistically significant improvements in TUG (p = 0.03), 5MWT (p = 0.05), and 10MWT (p = 0.04) were observed. CONCLUSIONS: This study provides preliminary efficacy of a novel, near-sensory balance intervention for individuals with TBI. The use of PPT is suggested for a comprehensive understanding and treatment of balance dysfunction. The promising results support the investigation in a larger cohort.


Assuntos
Biorretroalimentação Psicológica/métodos , Biorretroalimentação Psicológica/fisiologia , Lesões Encefálicas Traumáticas/terapia , Retroalimentação Sensorial/fisiologia , Modalidades de Fisioterapia , Equilíbrio Postural/fisiologia , Adulto , Lesões Encefálicas Traumáticas/diagnóstico , Lesões Encefálicas Traumáticas/fisiopatologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Distribuição Aleatória
11.
PLoS One ; 16(1): e0245191, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33411838

RESUMO

Brain-machine interfaces (BMI) allows individuals to control an external device by controlling their own brain activity, without requiring bodily or muscle movements. Performing voluntary movements is associated with the experience of agency ("sense of agency") over those movements and their outcomes. When people voluntarily control a BMI, they should likewise experience a sense of agency. However, using a BMI to act presents several differences compared to normal movements. In particular, BMIs lack sensorimotor feedback, afford lower controllability and are associated with increased cognitive fatigue. Here, we explored how these different factors influence the sense of agency across two studies in which participants learned to control a robotic hand through motor imagery decoded online through electroencephalography. We observed that the lack of sensorimotor information when using a BMI did not appear to influence the sense of agency. We further observed that experiencing lower control over the BMI reduced the sense of agency. Finally, we observed that the better participants controlled the BMI, the greater was the appropriation of the robotic hand, as measured by body-ownership and agency scores. Results are discussed based on existing theories on the sense of agency in light of the importance of BMI technology for patients using prosthetic limbs.


Assuntos
Interfaces Cérebro-Computador , Encéfalo/fisiologia , Retroalimentação Sensorial/fisiologia , Mãos/fisiologia , Movimento/fisiologia , Eletroencefalografia , Feminino , Humanos , Masculino
12.
PLoS One ; 16(1): e0245184, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33428665

RESUMO

Reaching with a visuomotor distortion in a virtual environment leads to reach adaptation in the trained hand, and in the untrained hand. In the current study we asked if reach adaptation in the untrained (right) hand is due to transfer of explicit adaptation (EA; strategic changes in reaches) and/or implicit adaptation (IA; unconscious changes in reaches) from the trained (left) hand, and if this transfer changes depending on instructions provided. We further asked if EA and IA are retained in both the trained and untrained hands. Participants (n = 60) were divided into 3 groups (Instructed (provided with instructions on how to counteract the visuomotor distortion), Non-Instructed (no instructions provided), and Control (EA not assessed)). EA and IA were assessed in both the trained and untrained hands immediately following rotated reach training with a 40° visuomotor distortion, and again 24 hours later by having participants reach in the absence of cursor feedback. Participants were to reach (1) so that the cursor landed on the target (EA + IA), and (2) so that their hand landed on the target (IA). Results revealed that, while initial EA observed in the trained hand was greater for the Instructed versus Non-Instructed group, the full extent of EA transferred between hands for both groups and was retained across days. IA observed in the trained hand was greatest in the Non-Instructed group. However, IA did not significantly transfer between hands for any of the three groups. Limited retention of IA was observed in the trained hand. Together, these results suggest that while initial EA and IA in the trained hand are dependent on instructions provided, transfer and retention of visuomotor adaptation to a large visuomotor distortion are driven almost exclusively by EA.


Assuntos
Adaptação Fisiológica , Retroalimentação Sensorial/fisiologia , Propriocepção/fisiologia , Desempenho Psicomotor/fisiologia , Percepção Visual/fisiologia , Adulto , Feminino , Humanos , Masculino
13.
Sensors (Basel) ; 21(2)2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33467611

RESUMO

It is important to operate devices with control panels and touch screens assisted by haptic feedback in mobile environments such as driving automobiles and electric power wheelchairs. A lot of consideration is needed to give accurate haptic feedback, especially, presenting clear touch feedback to the elderly and people with reduced sensation is a very critical issue from healthcare and safety perspectives. In this study, we aimed to identify the perceptual characteristics for the frequency and direction of haptic vibration on the touch screen with vehicle-driving vibration and to propose an efficient haptic system based on these characteristics. As a result, we demonstrated that the detection threshold shift decreased at frequencies above 210 Hz due to the contact pressure during active touch, but the detection threshold shift increased at below 210 Hz. We found that the detection thresholds were 0.30-0.45 gpeak with similar sensitivity in the 80-270 Hz range. The haptic system implemented by reflecting the experimental results achieved characteristics suitable for use scenarios in automobiles. Ultimately, it could provide practical guidelines for the development of touch screens to give accurate touch feedback in the real-world environment.


Assuntos
Retroalimentação Sensorial , Retroalimentação , Interface Usuário-Computador , Idoso , Desenho de Equipamento , Humanos , Estimulação Física , Vibração
14.
Neuron ; 109(4): 677-689.e4, 2021 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-33357383

RESUMO

Intentional control over external objects is informed by our sensory experience of them. To study how causal relationships are learned and effected, we devised a brain machine interface (BMI) task using wide-field calcium signals. Mice learned to entrain activity patterns in arbitrary pairs of cortical regions to guide a visual cursor to a target location for reward. Brain areas that were normally correlated could be rapidly reconfigured to exert control over the cursor in a sensory-feedback-dependent manner. Higher visual cortex was more engaged when expert but not naive animals controlled the cursor. Individual neurons in higher visual cortex responded more strongly to the cursor when mice controlled it than when they passively viewed it, with the greatest response boosting as the cursor approached the target location. Thus, representations of causally controlled objects are sensitive to intention and proximity to the subject's goal, potentially strengthening sensory feedback to allow more fluent control.


Assuntos
Interfaces Cérebro-Computador , Retroalimentação Sensorial/fisiologia , Desempenho Psicomotor/fisiologia , Recompensa , Córtex Visual/fisiologia , Animais , Teste de Esforço/métodos , Teste de Esforço/psicologia , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos
15.
Neurosci Lett ; 743: 135557, 2021 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-33352280

RESUMO

Among the techniques used to reduce spatial neglect's symptoms, left neck muscle vibration (NMV) is alluring because it does not require the patient's attentional co-operation. The aim of this study was to determine the type of NMV-associated feedback that induced the most intense and longest-lasting egocentric post-effects. Eighty-seven healthy individuals were randomly assigned to four intervention groups: "neck muscle vibration, blindfolded" (NMV), "neck muscle vibration with vision" (NMV + V), "neck muscle vibration and visual finger-pointing" (NMV + P), and "visual finger-pointing" (P). An eyes-closed finger-pointing subjective straight-ahead (SSA) test was carried out before the intervention, immediately afterwards, and 30 min afterwards. The results showed that only the NMV + P intervention induced a lasting leftward bias of SSA. In addition, the deviation reported in this intervention group differed significantly from those observed in the other interventions. The combination of visuo-haptic feedback and neck-somatosensory stimulation may enable a full, lasting intermodal recalibration, which could be potentiated by the attention level engaged during voluntary pointing. These outcomes highlighted that the NMV technique could easily integrate into routine occupational therapy sessions for treating various aspects of neglect disorders.


Assuntos
Agnosia/terapia , Retroalimentação Sensorial/fisiologia , Músculos do Pescoço/fisiologia , Processamento Espacial/fisiologia , Percepção do Tato/fisiologia , Vibração/uso terapêutico , Agnosia/fisiopatologia , Feminino , Humanos , Masculino , Transtornos da Percepção/fisiopatologia , Transtornos da Percepção/terapia , Distribuição Aleatória , Adulto Jovem
16.
Proc Biol Sci ; 287(1941): 20201774, 2020 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-33323088

RESUMO

Animals rapidly collect and act on incoming information to navigate complex environments, making the precise timing of sensory feedback critical in the context of neural circuit function. Moreover, the timing of sensory input determines the biomechanical properties of muscles that undergo cyclic length changes, as during locomotion. Both of these issues come to a head in the case of flying insects, as these animals execute steering manoeuvres at timescales approaching the upper limits of performance for neuromechanical systems. Among insects, flies stand out as especially adept given their ability to execute manoeuvres that require sub-millisecond control of steering muscles. Although vision is critical, here I review the role of rapid, wingbeat-synchronous mechanosensory feedback from the wings and structures unique to flies, the halteres. The visual system and descending interneurons of the brain employ a spike rate coding scheme to relay commands to the wing steering system. By contrast, mechanosensory feedback operates at faster timescales and in the language of motor neurons, i.e. spike timing, allowing wing and haltere input to dynamically structure the output of the wing steering system. Although the halteres have been long known to provide essential input to the wing steering system as gyroscopic sensors, recent evidence suggests that the feedback from these vestigial hindwings is under active control. Thus, flies may accomplish manoeuvres through a conserved hindwing circuit, regulating the firing phase-and thus, the mechanical power output-of the wing steering muscles.


Assuntos
Dípteros/fisiologia , Voo Animal/fisiologia , Músculos/fisiologia , Animais , Fenômenos Biomecânicos , Retroalimentação Sensorial , Mecanorreceptores , Neurônios Motores , Asas de Animais/fisiologia
17.
Sci Rep ; 10(1): 22427, 2020 12 30.
Artigo em Inglês | MEDLINE | ID: mdl-33380732

RESUMO

It has been shown that mere observation of body discontinuity leads to diminished body ownership. However, the impact of body discontinuity has mainly been investigated in conditions where participants observe a collocated static virtual body from a first-person perspective. This study explores the influence of body discountinuity on the sense of embodiment, when rich visuomotor correlations between a real and an artificial virtual body are established. In two experiments, we evaluated body ownership and motor performance, when participants interacted in virtual reality either using virtual hands connected or disconnected from a body. We found that even under the presence of congruent visuomotor feedback, mere observation of body discontinuity resulted in diminished embodiment. Contradictory evidence was found in relation to motor performance, where further research is needed to understand the role of visual body discontinuity in motor tasks. Preliminary findings on physiological reactions to a threat were also assessed, indicating that body visual discontinuity does not differently impact threat-related skin conductance responses. The present results are in accordance with past evidence showing that body discontinuity negatively impacts embodiment. However, further research is needed to understand the influence of visuomotor feedback and body morphological congruency on motor performance and threat-related physiological reactions.


Assuntos
Retroalimentação Sensorial/fisiologia , Mãos , Desempenho Psicomotor/fisiologia , Realidade Virtual , Adulto , Imagem Corporal/psicologia , Feminino , Humanos , Masculino , Estimulação Luminosa/métodos , Psicofisiologia , Percepção Visual/fisiologia , Adulto Jovem
18.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 2942-2945, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018623

RESUMO

Multisensory integration is the process by which information from different sensory modalities is integrated by the nervous system. Understanding this process is important not only from a basic science perspective but also for translational reasons, e.g. for the development of closed-loop neural prosthetic systems. Here we describe a versatile virtual reality platform which can be used to study the neural mechanisms of multisensory integration for the upper limb and could potentially be incorporated into systems for training of robust neural prosthetic control. The platform involves the interaction of multiple computers and programs and allows for selection of different avatar arms and for modification of a selected arm's visual properties. The system was tested with two non-human primates (NHP) that were trained to reach to multiple targets on a tabletop. Reliability of arm visual feedback was altered by applying different levels of blurring to the arm. In addition, tactile feedback was altered by adding or removing physical targets from the environment. We observed differences in movement endpoint distributions that varied between animals and visual feedback conditions, as well as across targets. The results indicate that the system can be used to study multisensory integration in a well-controlled manner.


Assuntos
Realidade Virtual , Animais , Retroalimentação , Retroalimentação Sensorial , Movimento , Reprodutibilidade dos Testes
19.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3114-3117, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018664

RESUMO

Identifying balance deficits associated with aging is critical to preventing falls in elderly people. The purpose of this study was to investigate the effects of aging on the multi-muscle synergy in lower extremities during standing on sloped surfaces. Eighteen healthy elderly subjects and 18 healthy young subjects were recruited in the experiment. Subjects were required to stand quietly on slopes at 5 different angles for 30 s with and without visual feedback. Surface electromyography signals of muscles in the lower limbs were collected simultaneously during standing. The muscle synergy of synergistic muscles and of antagonistic muscles were quantified by the parameters of multidimensional recurrence quantification analysis (MdRQA). The results showed that the dynamical synergies in synergistic and antagonistic muscle groups were significantly enhanced in elderly group, especially during standing on sloped surfaces (p < 0.05). The MdRQA parameters were significantly increased when standing without visual feedback than with visual feedback (p < 0.05). The aging and the absence of visual feedback led to more deterministic structures in the dynamical coupling of muscle activations, indicating strengthened synergistic contractions of muscles. These changes in elderly may increase the restriction on balance control and reduce the adaptability of motor system to potential external perturbations. This study shed light on the effects of aging on standing balance control and may facilitate to develop novel strategies for evaluation of aging and predication of falls.


Assuntos
Equilíbrio Postural , Posição Ortostática , Idoso , Eletromiografia , Retroalimentação Sensorial , Humanos , Músculo Esquelético , Adulto Jovem
20.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3232-3235, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018693

RESUMO

Movement control process can be considered to take place on at least two different levels: a high, more cognitive level and a low, sensorimotor level. On a high level processing a motor command is planned accordingly to the desired goal and the sensory afference, mainly proprioception, is used to determine the necessary adjustments in order to minimize any discrepancy between predicted and executed action. On a lower level processing, the proprioceptive feedback later employed in high level regulations, is generated by Ia sensory fibers positioned in muscle main proprioceptors: muscle spindles. By entraining the activity of these spindle fibers through 80Hz vibration of triceps distal tendon, we show the intriguing possibility of inducing kinematics adjustments due to negative feedback corrections, during a lifting task.


Assuntos
Retroalimentação Sensorial , Remoção , Fenômenos Biomecânicos , Movimento , Propriocepção
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