RESUMEN
BACKGROUND: In daily life tasks of the upper limb, we must make quick corrections with our hands in unstable postural situations. Postural and reaching control mechanisms are involved in the accurate execution of upper-limb tasks. RESEARCH QUESTION: This research aimed to determine the effect of different postural stability conditions on the motor performance of the upper limb in a reaching task with non-static targets. METHODOLOGY: 19 young participants performed a reaching task toward targets that exhibited a change in position (at 200 or 600â¯ms) in different postural conditions (bipedal-firm, bipedal-foam, and unipedal-foam surface). Performance on the screen (motion time and spatial error), balance (center of pressure displacements, CoP), and index finger movements were recorded during the reaching task. RESULTS: The instability affects the finger kinematic (displacements) and CoP kinematic (displacements, speed, and smoothness) without affecting the performance on the screen (precision and duration). The timing of target change affects the performance on the screen, finger kinematic (speed and smoothness), and CoP kinematic (displacements, speed, and smoothness). SIGNIFICANCE: Postural and reaching control systems enable accurate hand motions in less stable situations, even in reaching tasks with non-static targets. The postural and reaching control systems can protect the end-effector performance during unstable conditions but not during trials with less time to correct the motion.
Asunto(s)
Equilibrio Postural , Desempeño Psicomotor , Humanos , Equilibrio Postural/fisiología , Fenómenos Biomecánicos , Masculino , Femenino , Adulto Joven , Desempeño Psicomotor/fisiología , Dedos/fisiología , Adulto , Movimiento/fisiología , Extremidad Superior/fisiologíaRESUMEN
This paper presents the development of an intelligent soft-sensor system to add haptic perception to the underactuated hand prosthesis PrHand. Two sensors based on optical fiber were constructed, one for finger joint angles and the other for fingertips' contact force. Three sensor fabrications were tested for the angle sensor by axially rotating the sensors in four positions. The configuration with the most similar response in the four rotations was chosen. The chosen sensors presented a polynomial response with R2 higher than 92%. The tactile force sensors tracked the force made over the objects. Almost all sensors presented a polynomial response with R2 higher than 94%. The system monitored the prosthesis activity by recognizing grasp types. Six machine learning algorithms were tested: linear regression, k-nearest neighbor, support vector machine, decision tree, k-means clustering, and hierarchical clustering. To validate the algorithms, a k-fold test was used with a k = 10, and the accuracy result for k-nearest neighbor was 98.5%, while that for decision tree was 93.3%, enabling the classification of the eight grip types.
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Dedos , Mano , Mano/fisiología , Dedos/fisiología , Prótesis e Implantes , Algoritmos , Fuerza de la Mano/fisiologíaRESUMEN
This study aimed to determine by ultrasonography, and cadaveric dissection, whether the firm cords felt by palpation at the sides of the proximal phalanx (PP), actively flexing, and extending the proximal interphalangeal (PIP) joint while keeping the metacarpophalangeal (MCP) joint extended are the lateral bands (LBs) of the extensor apparatus. If so, palpation of the LBs could help evaluate hand conditions that impact the digits' intrinsic muscles. To this end, the PP of the middle and ring fingers of the dominant hand of seven subjects were studied by palpation on both sides. Ultrasonography (US) was performed with a hockey-stick transducer placed on the ulnar side. Five cadaveric hands were dissected, exposing the dorsal extensor apparatus. On palpation, a firm cord was consistently felt at the PP's sides in all subjects. These cords moved widely forward on PIP flexion and backward with PIP extension. By US scanning, the cords corresponded to the LBs. However, the forward movement had only a median of 1.8 mm (range 0.7-3 mm) in the middle finger and a median of 1.1 mm (range 0.3-2.7 mm) in the ring finger compared with an estimated 5-10 mm upon palpation. Cadaveric dissection confirmed the forward movement of the LBs in PIP flexion. We concluded that the firm cords felt at the PP sides are the LBs of the extensor apparatus. We confirmed their movement with the active flexion/extension of the PIP joint. Comparing the wide palpatory and the meager US motion, a haptic illusion of motion may be present.
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Articulaciones de los Dedos/anatomía & histología , Dedos/anatomía & histología , Articulación Metacarpofalángica/anatomía & histología , Rango del Movimiento Articular/fisiología , Articulaciones de los Dedos/diagnóstico por imagen , Articulaciones de los Dedos/fisiología , Dedos/diagnóstico por imagen , Dedos/fisiología , Humanos , Articulación Metacarpofalángica/diagnóstico por imagen , Articulación Metacarpofalángica/fisiología , Palpación , UltrasonografíaRESUMEN
OBJECTIVES: Cuncaicha, a rockshelter site in the southern Peruvian Andes, has yielded archaeological evidence for human occupation at high elevation (4,480 masl) during the Terminal Pleistocene (12,500-11,200 cal BP), Early Holocene (9,500-9,000 cal BP), and later periods. One of the excavated human burials (Feature 15-06), corresponding to a middle-aged female dated to ~8,500 cal BP, exhibits skeletal osteoarthritic lesions previously proposed to reflect habitual loading and specialized crafting labor. Three small tools found in association with this burial are hypothesized to be associated with precise manual dexterity. MATERIALS AND METHODS: Here, we tested this functional hypothesis through the application of a novel multivariate methodology for the three-dimensional analysis of muscle attachment surfaces (entheses). This original approach has been recently validated on both lifelong-documented anthropological samples as well as experimental studies in nonhuman laboratory samples. Additionally, we analyzed the three-dimensional entheseal shape and resulting moment arms for muscle opponens pollicis. RESULTS: Results show that Cuncaicha individual 15-06 shows a distinctive entheseal pattern associated with habitual precision grasping via thumb-index finger coordination, which is shared exclusively with documented long-term precision workers from recent historical collections. The separate geometric morphometric analysis revealed that the individual's opponens pollicis enthesis presents a highly projecting morphology, which was found to strongly correlate with long joint moment arms (a fundamental component of force-producing capacity), closely resembling the form of Paleolithic hunter-gatherers from diverse geo-chronological contexts of Eurasia and North Africa. DISCUSSION: Overall, our findings provide the first biocultural evidence to confirm that the lifestyle of some of the earliest Andean inhabitants relied on habitual and forceful precision grasping tasks.
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Huesos de la Mano/anatomía & histología , Huesos de la Mano/fisiología , Indígenas Sudamericanos/historia , Tecnología/historia , Altitud , Antropología Física , Femenino , Dedos/anatomía & histología , Dedos/fisiología , Historia Antigua , Actividades Humanas/historia , Humanos , Persona de Mediana Edad , Fenómenos Fisiológicos Musculoesqueléticos , PerúRESUMEN
A previously introduced Bayesian non-parametric multi-scale technique, called iterated Multigrid Priors (iMGP) method, is used to map the topographic organization of human primary somatosensory cortex (S1). We analyze high spatial resolution fMRI data acquired at ultra-high field (UHF, 7T) in individual subjects during vibrotactile stimulation applied to each distal phalange of the left hand digits using both a travelling-wave (TW) and event-related (ER) paradigm design. We compare the somatotopic digit representations generated in S1 using the iMGP method with those obtained using established fMRI paradigms and analysis techniques: Fourier-based analysis of travelling-wave data and General Linear Model (GLM) analysis of event-related data. Maps derived with the iMGP method are similar to those derived with the standard analysis, but in contrast to the Fourier-based analysis, the iMGP method reveals overlap of activity from adjacent digit representations in S1. These findings validate the use of the iMGP method as an alternative to study digit representations in S1, particularly with the TW design as an attractive means to study cortical reorganization in patient populations such dystonia and carpal tunnel syndrome, where the degree of spatial overlap of cortical finger representations is of interest.
Asunto(s)
Imagen por Resonancia Magnética/métodos , Corteza Somatosensorial/fisiología , Adulto , Teorema de Bayes , Mapeo Encefálico/métodos , Femenino , Dedos/fisiología , Análisis de Fourier , Humanos , Modelos Lineales , MasculinoRESUMEN
The purpose of this study was to determine whether the contribution of bimanual light touch varies according to the difficulty level of postural tasks (e.g., vision occlusion, height of support surface). Fourteen healthy young adults each were asked to stand in a tandem position, on a 20-cm height balance beam. Postural tasks included light touch and no touch conditions in two vision conditions, nonvision and full vision. The root mean square of amplitude of oscillation (mediolateral), mean velocity, ellipse area, and path length of the center of pressure revealed that touch conditions reduced sway to a greater extent in the elevated support surface, nonvision condition. Highly unstable balance tasks increase the optimization of light touch and affect the attenuation of postural sway.
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Equilibrio Postural/fisiología , Percepción del Tacto/fisiología , Femenino , Dedos/fisiología , Humanos , Masculino , Percepción Visual , Adulto JovenRESUMEN
Activity recognition, a key component in pervasive healthcare monitoring, relies on classification algorithms that require labeled data of individuals performing the activity of interest to train accurate models. Labeling data can be performed in a lab setting where an individual enacts the activity under controlled conditions. The ubiquity of mobile and wearable sensors allows the collection of large datasets from individuals performing activities in naturalistic conditions. Gathering accurate data labels for activity recognition is typically an expensive and time-consuming process. In this paper we present two novel approaches for semi-automated online data labeling performed by the individual executing the activity of interest. The approaches have been designed to address two of the limitations of self-annotation: (i) The burden on the user performing and annotating the activity, and (ii) the lack of accuracy due to the user labeling the data minutes or hours after the completion of an activity. The first approach is based on the recognition of subtle finger gestures performed in response to a data-labeling query. The second approach focuses on labeling activities that have an auditory manifestation and uses a classifier to have an initial estimation of the activity, and a conversational agent to ask the participant for clarification or for additional data. Both approaches are described, evaluated in controlled experiments to assess their feasibility and their advantages and limitations are discussed. Results show that while both studies have limitations, they achieve 80% to 90% precision.
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Atención a la Salud/métodos , Dedos/fisiología , Gestos , Reconocimiento de Normas Patrones Automatizadas/métodos , Algoritmos , HumanosRESUMEN
In the present study, we investigated motor cortex (M1) and a small portion of premotor and parietal cortex using intracortical microstimulation in anesthetized capuchin monkeys. Capuchins are the only New World monkeys that have evolved an opposable thumb and use tools in the wild. Like most Old World monkeys and humans, capuchin monkeys have highly dexterous hands. We surveyed a large extent of M1 and found that ~22% of all evoked movements in M1 involved the digits, and the majority of these consisted of finger flexions and extensions. Different subtypes of movements could be identified, including opposable movements of digits 1 and 2 (D1 and D2). Interestingly, the pattern of such movements varied between animals. In one case, movements involved the adduction of the medial surface of D1 toward the lateral surface of D2, whereas in the other case, the tips of D1 and D2 came in contact. Unlike other primates examined, we also found extensive representations of the prehensile foot and tail. We propose that the manual behavioral repertoire of capuchin monkeys, which includes the use of tools in the wild, is well represented within the motor cortex in the form of muscle synergies between different body parts that compose these larger, complex behaviors.SIGNIFICANCE STATEMENT The ability to use tools is a milestone in human evolution. Capuchin monkeys are one of the few non-human primates that use tools in the wild. The present study is the first detailed exploration of the motor cortex of these primates using long-train intracortical microstimulation. Within primary motor cortex, we evoked finger movements involving flexions and extensions of multiple digits, or of the first and second digits alone. Interestingly, flexion of tail and toes could also be evoked. Together, these results suggest that the functional organization of the motor cortex represents not just muscles of the body, but muscle synergies that form the building blocks of the complex behavioral repertoire of these animals.
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Dedos/fisiología , Fuerza de la Mano/fisiología , Corteza Motora/fisiología , Movimiento/fisiología , Animales , Mapeo Encefálico , Cebus , Femenino , Lateralidad Funcional/fisiología , Masculino , Músculo Esquelético/inervación , Músculo Esquelético/fisiología , Lóbulo Parietal/fisiología , Pulgar , Comportamiento del Uso de la HerramientaRESUMEN
We used force-matching tasks between the two hands to test predictions of the recently introduced scheme of perception based on the concept of iso-perceptual manifold (IPM) in the combined afferent-efferent space of neural signals. The main hypothesis was that accuracy and variability of individual finger force matching would be worse in a four-finger task compared to one-finger tasks. The subjects produced accurate force levels under visual feedback by pressing with either all four fingers or by one of the fingers of a hand (task-hand). They tried to match the total four-finger force or individual finger forces by pressing with the other hand (match-hand, no visual feedback). The match-hand consistently overshot the task-hand force during single-finger matching episodes. It showed higher inter-trial force variability during single-finger matching when the task-hand performed the four-finger task compared to trials when the task-hand performed single-finger tasks. These findings confirm our main hypothesis by showing that perception of individual finger forces can vary in multi-finger tasks within a space (IPM) corresponding to veridical perception of total force. Matching hypothetical commands to fingers, rather than finger forces, could be responsible for the consistent force overshoots. Indices of inter-trial variance affecting and unaffecting total force showed strong stabilization of total force in the task-hand but not in the match-hand in support of an earlier hypothesis on the importance of visual feedback for force stabilization. No differences were seen between the right and left hands suggesting that the dynamic dominance hypothesis may not be generalizable to perceptual phenomena.
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Dedos/fisiología , Destreza Motora/fisiología , Percepción/fisiología , Desempeño Psicomotor/fisiología , Adulto , Retroalimentación Sensorial , Femenino , Lateralidad Funcional , Fuerza de la Mano , Humanos , Cinestesia , Masculino , Contracción Muscular , Propiocepción , Percepción del TactoRESUMEN
We investigated the extent to which a complex finger sequence impacts on hand switching costs in a sequential action. Response component latencies (premotor, motor, and movement) were compared in no-switch (same finger performed the action of pressing and reaching) and switch conditions (pressing with one finger and completing the reaching action with the homologous finger from the other hand). Results showed that the switch condition presented longer latency for premotor and movement components. For the motor component, however, switch condition was faster. This expands the previous literature investigating switching costs using simple finger movements in more complex tasks. A mechanical explanation of the interplay between response subcomponents is provided to explain the inversion of response pattern for the motor component.
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Metabolismo Energético/fisiología , Lateralidad Funcional/fisiología , Mano/fisiología , Adulto , Fenómenos Biomecánicos/fisiología , Femenino , Dedos/fisiología , Humanos , Masculino , Desempeño Psicomotor/fisiología , Tiempo de Reacción/fisiología , Adulto JovenRESUMEN
Sport climbers frequently use campus board (CB) to improve their upper limb strength under similar conditions of high-difficulty sport climbing routes. The objective of this study was to assess the test-retest reliability of peak force and impulse measured using a CB instrumented with two load cells on starting holds. The same evaluator examined 22 climbers on two days with 48 h between the assessments. The participants performed five concentric lunges (CL) and five lunges with stretch-shortening cycle with 1 min intervals between repetitions and 10 min between exercises. All variables were associated with significant intraclass correlation coefficient (ICC) values (p = 0.001), and none variable showed systematic errors (p > 0.05). Peak force ICC was higher than 0.88, and the standard error of measurement (SEM%) was less than 5%. Impulse ICC for the CL was greater than 0.90, and the SEM% was less than 14%. We conclude that the kinetic variables measured using the CB were reliable. The ability of the hands to maintain contact with the holds (peak force) and the abilities of the arms and shoulders vertically move the centre of mass (impulse) should be taken into account by coaches on CB training prescription as well for further research.
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Montañismo/fisiología , Fuerza Muscular/fisiología , Acondicionamiento Físico Humano/instrumentación , Extremidad Superior/fisiología , Adulto , Brazo/fisiología , Fenómenos Biomecánicos , Dedos/fisiología , Humanos , Masculino , Reproducibilidad de los Resultados , Hombro/fisiología , Muñeca/fisiologíaRESUMEN
A number of analyses associated with the uncontrolled manifold (UCM) hypothesis have been used recently to investigate stability of actions across populations. We explored whether some of those methods have an advantage for clinical studies because they require fewer trials to achieve consistent findings. We compared the number of trials needed for the analysis of inter-trial variance, analysis of motor equivalence, and analysis in the space of referent coordinates. Young healthy adults performed four-finger accurate force production tasks under visual feedback with the right (dominant) and left hand over three days. Three methods [analytical (M1), experimental (M2), and cumulative mean (M3) methods] were used to define the minimal number of trials required to reach certain statistical criteria. Two of these methods, M1 and M2, showed qualitatively similar results. Fewer trials (M1: 5-13, M2: 4-10) were needed for analysis of motor equivalence compared to inter-trial variance analysis (M1: 14-24, M2: 10-14). The third method (M3) showed no major differences among the outcome variables. The index of synergy in the inter-trial variance analysis required a very small number of trials (M1, M2: 2-4). Variables related to referent coordinates required only a few trials (under 3), whereas the synergy index in this analysis required the largest number of trials (M1: 24-34, M2: 12-16). This is the first study to quantify the number of trials needed for UCM-based methods of assessing motor coordination broadly used in clinical studies. Clinical studies can take advantage of specific recommendations based on the current data regarding the number of trials needed for each analysis thus allowing minimizing the test session duration without compromising data reliability.
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Estudios Clínicos como Asunto/métodos , Interpretación Estadística de Datos , Retroalimentación Sensorial/fisiología , Dedos/fisiología , Actividad Motora/fisiología , Desempeño Psicomotor/fisiología , Proyectos de Investigación , Adulto , Humanos , Adulto JovenRESUMEN
Paced finger tapping is one of the simplest tasks to study sensorimotor synchronization. The subject is instructed to tap in synchrony with a periodic sequence of brief tones, and the time difference (called asynchrony) between each response and the corresponding stimulus is recorded. Despite its simplicity, this task helps to unveil interesting features of the underlying neural system and the error-correction mechanism responsible for synchronization. Perturbation experiments are usually performed to probe the subject's response, for example, in the form of a "step change," i.e., an unexpected change in tempo. The asynchrony is the usual observable in such experiments and it is chosen as the main variable in many mathematical models that attempt to describe the phenomenon. In this work we show that although asynchrony can be perfectly described in operational terms, it is not well defined as a model variable when tempo perturbations are considered. We introduce an alternative variable and a mathematical model that intrinsically takes into account the perturbation and make theoretical predictions about the response to novel perturbations based on the geometrical organization of the trajectories in phase space. Our proposal is relevant to understand interpersonal synchronization and the synchronization to nonperiodic stimuli.
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Retroalimentación Sensorial , Dedos/fisiología , Modelos Teóricos , Movimiento/fisiología , Humanos , Modelos BiológicosRESUMEN
This study analyzed the finger temperatures of poultry slaughterhouse workers and its association with personal and organizational variables, bodily discomfort perception, and cold thermal sensation. The study included 143 poultry slaughterhouse workers. A thermograph was used to measure finger temperature and an interview to collect worker data. There were two groups: workers who used a tool and those without. The binary logistic regression, Friedman and Wilcoxon tests were used (p ≤ 0.05). Most workers presented at least one finger with an average temperature ≤15 °C (66.4%) and ≤24 °C (99.3%), perceived their cold hands, and wore three overlapping gloves (57.3%). There were no associations between finger temperatures (≤15 °C) and the analyzed variables. The chance of feeling cold for a worker who used a tool was greater than for a worker who did not (OR = 3.19, 95% CI 1.46; 6.94). There was a difference between the finger temperatures of each hand on both surfaces and the analyzed groups (p < 0.01). The temperature of each finger with its respective contralateral was different in the little fingers (no tool), index, middle, ring, and little fingers (using a tool) (p < 0.05). The use of several overlapping gloves was not sufficient to promote thermal insulation of the hands.
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Frío , Dedos/fisiología , Exposición Profesional/análisis , Salud Laboral , Equipo de Protección Personal/estadística & datos numéricos , Sensación Térmica , Mataderos/estadística & datos numéricos , Adulto , Animales , Femenino , Humanos , Masculino , Aves de Corral , Temperatura CutáneaRESUMEN
BACKGROUND: The production of finger force control is essential for a large number of daily activities. There is evidence that deficits in the mechanisms of accuracy and control of finger force tasks are associated with children's motor difficulties. OBJECTIVE: To compare the effect of practice of an isometric finger force/torque task between children with significant movement difficulty and those with no difficulty movement. METHODS: Twenty-four children aged between 9 and 10 years (12 at risk of developmental coordination disorder and 12 with no movement difficulty - typically developing children) were asked to produce finger force/torque control in a continuous and constant 25% of maximum voluntary torque with visual feedback during 15s. Practice was given during five consecutive days with 15 trials per day. After the practice with visual feedback, children were asked to perform five trials without visual feedback. In these trials, feedback was removed 5s after the start of the trial. RESULTS: Typically developing children were consistently more accurate in maintaining finger force/torque control than those children at risk of developmental coordination disorder. Children from both groups improved the performance in the task according to practice sessions. Also, children at risk of developmental coordination disorder poorly performed the task without visual feedback as they did when visual feedback was available. CONCLUSION: The present study give support to the idea that movement difficulty is associated with finger force/torque control and children at risk of developmental coordination disorder can improve finger force/torque control with practice when visual feedback is available.
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Dedos/fisiología , Trastornos de la Destreza Motora/fisiopatología , Desempeño Psicomotor/fisiología , Niño , Humanos , TorqueRESUMEN
We used the framework of the uncontrolled manifold (UCM) hypothesis and explored the reliability of several outcome variables across different spaces of analysis during a very simple four-finger accurate force production task. Fourteen healthy, young adults performed the accurate force production task with each hand on 3 days. Small spatial finger perturbations were generated by the "inverse piano" device three times per trial (lifting the fingers 1 cm/0.5 s and lowering them). The data were analyzed using the following main methods: (1) computation of indices of the structure of inter-trial variance and motor equivalence in the space of finger forces and finger modes, and (2) analysis of referent coordinates and apparent stiffness values for the hand. Maximal voluntary force and the index of enslaving (unintentional finger force production) showed good to excellent reliability. Strong synergies stabilizing total force were reflected in both structure of variance and motor equivalence indices. Variance within the UCM and the index of motor equivalent motion dropped over the trial duration and showed good to excellent reliability. Variance orthogonal to the UCM and the index of non-motor equivalent motion dropped over the 3 days and showed poor to moderate reliability. Referent coordinate and apparent stiffness indices co-varied strongly and both showed good reliability. In contrast, the computed index of force stabilization showed poor reliability. The findings are interpreted within the scheme of neural control with referent coordinates involving the hierarchy of two basic commands, the r-command and c-command. The data suggest natural drifts in the finger force space, particularly within the UCM. We interpret these drifts as reflections of a trade-off between stability and optimization of action. The implications of these findings for the UCM framework and future clinical applications are explored in the discussion. Indices of the structure of variance and motor equivalence show good reliability and can be recommended for applied studies.
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Fenómenos Biomecánicos/fisiología , Investigación Biomédica/métodos , Interpretación Estadística de Datos , Dedos/fisiología , Actividad Motora/fisiología , Desempeño Psicomotor/fisiología , Adulto , Análisis de Varianza , Femenino , Humanos , Masculino , Reproducibilidad de los Resultados , Adulto JovenRESUMEN
Sensorimotor synchronization (SMS) is a form of referential behavior in which an action is coordinated with a predictable external stimulus. The neural bases of the synchronization ability remain unknown, even in the simpler, paradigmatic task of finger tapping to a metronome. In this task the subject is instructed to tap in synchrony with a periodic sequence of brief tones, and the time difference between each response and the corresponding stimulus tone (asynchrony) is recorded. We make a step towards the identification of the neurophysiological markers of SMS by recording high-density EEG event-related potentials and the concurrent behavioral response-stimulus asynchronies during an isochronous paced finger-tapping task. Using principal component analysis, we found an asymmetry between the traces for advanced and delayed responses to the stimulus, in accordance with previous behavioral observations from perturbation studies. We also found that the amplitude of the second component encodes the higher-level percept of asynchrony 100 ms after the current stimulus. Furthermore, its amplitude predicts the asynchrony of the next step, past 300 ms from the previous stimulus, independently of the period length. Moreover, the neurophysiological processing of synchronization errors is performed within a fixed-duration interval after the stimulus. Our results suggest that the correction of a large asynchrony in a periodic task and the recovery of synchrony after a perturbation could be driven by similar neural processes.
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Potenciales Evocados/fisiología , Dedos/fisiología , Desempeño Psicomotor/fisiología , Adulto , Femenino , Humanos , Masculino , Tiempo de Reacción/fisiología , Adulto JovenRESUMEN
OBJECTIVE: In this work we propose the use of conditional random fields with long-range dependencies for the classification of finger movements from electrocorticographic recordings. APPROACH: The proposed method uses long-range dependencies taking into consideration time-lags between the brain activity and the execution of the motor task. In addition, the proposed method models the dynamics of the task executed by the subject and uses information about these dynamics as prior information during the classification stage. MAIN RESULTS: The results show that incorporating temporal information about the executed task as well as incorporating long-range dependencies between the brain signals and the labels effectively increases the system's classification performance compared to methods in the state of art. SIGNIFICANCE: The method proposed in this work makes use of probabilistic graphical models to incorporate temporal information in the classification of finger movements from electrocorticographic recordings. The proposed method highlights the importance of including prior information about the task that the subjects execute. As the results show, the combination of these two features effectively produce a significant improvement of the system's classification performance.
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Electrocorticografía/métodos , Dedos/fisiología , Movimiento/fisiología , Algoritmos , Encéfalo/fisiología , Mapeo Encefálico , Interfaces Cerebro-Computador , Humanos , Modelos Estadísticos , Desempeño Psicomotor , Procesamiento de Señales Asistido por ComputadorRESUMEN
OBJECTIVE: To investigate the feasibility of using free gracilis muscle transfer along with the brachialis muscle branch of the musculocutaneous nerve to restore finger and thumb flexion in lower trunk brachial plexus injury according to an anatomical study and a case report. METHODS: Thirty formalin-fixed upper extremities from 15 adult cadavers were used in this study. The distance from the point at which the brachialis muscle branch of the musculocutaneous nerve originates to the midpoint of the humeral condylar was measured, as well as the length, diameter, course and branch type of the brachialis muscle branch of the musculocutaneous nerve. An 18-year-old male who sustained an injury to the left brachial plexus underwent free gracilis transfer using the brachialis muscle branch of the musculocutaneous nerve as the donor nerve to restore finger and thumb flexion. Elbow flexion power and hand grip strength were recorded according to British Medical Research Council standards. Postoperative measures of the total active motion of the fingers were obtained monthly. RESULTS: The mean length and diameter of the brachialis muscle branch of the musculocutaneous nerve were 52.66±6.45 and 1.39±0.09 mm, respectively, and three branching types were observed. For the patient, the first gracilis contraction occurred during the 4th month. A noticeable improvement was observed in digit flexion one year later; the muscle power was M4, and the total active motion of the fingers was 209°. CONCLUSIONS: Repairing injury to the lower trunk of the brachial plexus by transferring the brachialis muscle branch of the musculocutaneous nerve to the anterior branch of the obturator nerve using a tension-free direct suture is technically feasible, and the clinical outcome was satisfactory in a single surgical patient.
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Neuropatías del Plexo Braquial/cirugía , Plexo Braquial/lesiones , Dedos/fisiología , Músculo Grácil/inervación , Músculo Grácil/cirugía , Nervio Musculocutáneo/trasplante , Transferencia Tendinosa/métodos , Adolescente , Neuropatías del Plexo Braquial/fisiopatología , Cadáver , Estudios de Factibilidad , Fuerza de la Mano/fisiología , Humanos , Masculino , Transferencia de Nervios/métodos , Rango del Movimiento Articular/fisiología , Pulgar/fisiologíaRESUMEN
OBJECTIVE: To investigate the feasibility of using free gracilis muscle transfer along with the brachialis muscle branch of the musculocutaneous nerve to restore finger and thumb flexion in lower trunk brachial plexus injury according to an anatomical study and a case report. METHODS: Thirty formalin-fixed upper extremities from 15 adult cadavers were used in this study. The distance from the point at which the brachialis muscle branch of the musculocutaneous nerve originates to the midpoint of the humeral condylar was measured, as well as the length, diameter, course and branch type of the brachialis muscle branch of the musculocutaneous nerve. An 18-year-old male who sustained an injury to the left brachial plexus underwent free gracilis transfer using the brachialis muscle branch of the musculocutaneous nerve as the donor nerve to restore finger and thumb flexion. Elbow flexion power and hand grip strength were recorded according to British Medical Research Council standards. Postoperative measures of the total active motion of the fingers were obtained monthly. RESULTS: The mean length and diameter of the brachialis muscle branch of the musculocutaneous nerve were 52.66±6.45 and 1.39±0.09 mm, respectively, and three branching types were observed. For the patient, the first gracilis contraction occurred during the 4th month. A noticeable improvement was observed in digit flexion one year later; the muscle power was M4, and the total active motion of the fingers was 209°. CONCLUSIONS: Repairing injury to the lower trunk of the brachial plexus by transferring the brachialis muscle branch of the musculocutaneous nerve to the anterior branch of the obturator nerve using a tension-free direct suture is technically feasible, and the clinical outcome was satisfactory in a single surgical patient.