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Fuchs, Susanne, and Pascal Perrier. "On the complex nature of speech kinematics." ZAS Papers in Linguistics 42 (January 1, 2005): 137–65. http://dx.doi.org/10.21248/zaspil.42.2005.276.
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Studying kinematic behavior in speech production is an indispensable and fruitful methodology in order to describe for instance phonemic contrasts, allophonic variations, prosodic effects in articulatory movements. More intriguingly, it is also interpreted with respect to its underlying control mechanisms. Several interpretations have been borrowed from motor control studies of arm, eye, and limb movements. They do either explain kinematics with respect to a fine tuned control by the Central Nervous System (CNS) or they take into account a combination of influences arising from motor control strategies at the CNS level and from the complex physical properties of the peripheral speech apparatus. We assume that the latter is more realistic and ecological. The aims of this article are: first, to show, via a literature review related to the so called '1/3 power law' in human arm motor control, that this debate is of first importance in human motor control research in general. Second, to study a number of speech specific examples offering a fruitful framework to address this issue. However, it is also suggested that speech motor control differs from general motor control principles in the sense that it uses specific physical properties such as vocal tract limitations, aerodynamics and biomechanics in order to produce the relevant sounds. Third, experimental and modelling results are described supporting the idea that the three properties are crucial in shaping speech kinematics for selected speech phenomena. Hence, caution should be taken when interpreting kinematic results based on experimental data alone.
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Tian, Jing, Amit Satpathy, Ee Sin Ng, Soh Guat Ong, Wei Cheng, Jean-Marc Burgunder, and Walter Hunziker. "Motion analytics of zebrafish using fine motor kinematics and multi-view trajectory." Multimedia Systems 22, no. 6 (December 18, 2014): 713–23. http://dx.doi.org/10.1007/s00530-014-0441-6.
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Taverna, Livia, Marta Tremolada, Barbara Tosetto, Liliana Dozza, and Zanin Scaratti Renata. "Impact of Psycho-Educational Activities on Visual-Motor Integration, Fine Motor Skills and Name Writing among First Graders: A Kinematic Pilot Study." Children 7, no. 4 (April 2, 2020): 27. http://dx.doi.org/10.3390/children7040027.
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This pilot study presents the effects on acquisition of pre-writing skills of educational activities targeting visual-motor integration and fine motor skills on a convenient sample of first graders. After a 10-week intervention program, visual perceptual skills and fine motor control were tested on 13 six-year-old aged children. Participants completed the Beery-Buktenica VMI and the manual dexterity scale of the Movement ABC-2 at baseline (T1), after the intervention program (T2), and one month after the end of the educational activities (T3). Children’s writing pressure, frequency, and automaticity were measured using a digitizer during the administration of name writing test at T1, T2, and T3. The purpose of the study was to investigate changes in visual-perceptual abilities and fine motor skills after the intervention program and examine correlational effects on children’s kinematic writing performances. Findings reveal that educational activities impacted positively on children’s visual motor coordination component of writing improving VMI scores. No statistically significant difference was detected across the three time points on students’ manual dexterity skills. Measurement of writing kinematics allows to report and document variations in children’s writing during intervention. This pilot study discusses these findings and their implications for the field on early childhood acquisition of foundational skills for handwriting. It also proposes potential topics for future research on this field.
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Pizzimenti, Marc A., Warren G. Darling, Diane L. Rotella, David W. McNeal, James L. Herrick, Jizhi Ge, Kimberly S. Stilwell-Morecraft, and Robert J. Morecraft. "Measurement of Reaching Kinematics and Prehensile Dexterity in Nonhuman Primates." Journal of Neurophysiology 98, no. 2 (August 2007): 1015–29. http://dx.doi.org/10.1152/jn.00354.2007.
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A modified “Klüver” or dexterity board was developed to assess fine control of hand and digit movements by nonhuman primates during the acquisition of small food pellets from wells of different diameter. The primary advantages of the new device over those used previously include standardized positioning of target food pellets and controlled testing of each hand without the need for restraints, thereby allowing the monkey to move freely about the cage. Three-dimensional video analysis of hand motion was used to provide measures of reaching accuracy and grip aperture, as well as temporal measures of reach duration and food-pellet manipulation. We also present a validated performance score based on these measures, which serves as an indicator of successful food-pellet retrieval. Tests in three monkeys show that the performance score is an effective measure with which to study fine motor control associated with learning and handedness. We also show that the device and performance scores are effective for differentiating the effects of localized injury to motor areas of the cerebral cortex.
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Lee, Seungjae, Hyejeong Lee, Jongshill Lee, Hokyoung Ryu, In Young Kim, and Jieun Kim. "Clip-On IMU System for Assessing Age-Related Changes in Hand Functions." Sensors 20, no. 21 (November 5, 2020): 6313. http://dx.doi.org/10.3390/s20216313.
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Hand functions affect the instrumental activities of daily living. While functional outcome measures, such as a targeted box and block test, have been widely used in clinical settings and provide a useful measure of overall performance, the advent of a wearable Inertial Measurement Unit(IMU)-based system enables the examination of the specific performance and kinematic parameters of hand movements. This study proposed a novel clip-on IMU system to facilitate the clinically fitted measurements of fine-motor finger and wrist joint movements. Clinical validation was conducted with the aim of characterising age-related changes in hand functions, namely grasping, transporting, and releasing blocks. Eighteen young (age 20–31) and sixteen healthy older adults (age 75–89) were evaluated during the box and block test. The results demonstrated that an older age was characterized by slower movements and higher variations and kinematic alterations in the hand functions, such as a larger range of motions at the fingers as well as kinematic trajectories. The proposed IMU system and subsequent validations highlight the value of the performance and kinematics parameters for a more comprehensive understanding of fine-motor finger and wrist movements that could shed light on further implementations in clinical and practical settings.
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Rong, Panying. "A Novel Hierarchical Framework for Measuring the Complexity and Irregularity of Multimodal Speech Signals and Its Application in the Assessment of Speech Impairment in Amyotrophic Lateral Sclerosis." Journal of Speech, Language, and Hearing Research 64, no. 8 (August 9, 2021): 2996–3014. http://dx.doi.org/10.1044/2021_jslhr-20-00743.
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Purpose The purposes of this study are to develop a novel multimodal framework for measuring variability at the muscular, kinematic, and acoustic levels of the motor speech hierarchy and evaluate the utility of this framework in detecting speech impairment in amyotrophic lateral sclerosis (ALS). Method The myoelectric activities of three bilateral jaw muscle pairs (masseter, anterior temporalis, and anterior belly of digastric), jaw kinematics, and speech acoustics were recorded in 13 individuals with ALS and 10 neurologically healthy controls during sentence reading. Thirteen novel measures (six muscular, three kinematic, four acoustic), which characterized two different but interrelated aspects of variability—complexity and irregularity—were derived using linear and nonlinear methods. Exploratory factor analysis was applied to identify the latent factors underlying these measures. Based on the latent factors, three supervised classifiers—support vector machine (SVM), random forest (RF), and logistic regression (Logit)—were used to differentiate between the speech samples for patients and controls. Results Four interpretable latent factors were identified, representing the complexity of jaw kinematics, the irregularity of jaw antagonists functioning, the irregularity of jaw agonists functioning, and the irregularity of subband acoustic signals, respectively. Based on these latent factors, the speech samples for patients and controls were classified with high accuracy (> 96% for SVM and RF; 88.64% for Logit), outperforming the unimodal measures. Two factors showed significant between-groups differences, as characterized by decreased complexity of jaw kinematics and increased irregularity of jaw antagonists functioning in patients versus controls. Conclusions Decreased complexity of jaw kinematics presumably reflects impaired fine control of jaw movement, while increased irregularity of jaw antagonists functioning could be attributed to reduced synchronization of motor unit firing in ALS. The findings provide preliminary evidence for the utility of the multimodal framework as a novel quantitative assessment tool for detecting speech impairment in ALS and (potentially) in other neuromotor disorders.
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Chen, Yuping, Sergio Garcia-Vergara, and Ayanna M. Howard. "Effect of a Home-Based Virtual Reality Intervention for Children with Cerebral Palsy Using Super Pop VR Evaluation Metrics: A Feasibility Study." Rehabilitation Research and Practice 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/812348.
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Objective.The purpose of this pilot study was to determine whether Super Pop VR, a low-cost virtual reality (VR) system, was a feasible system for documenting improvement in children with cerebral palsy (CP) and whether a home-based VR intervention was effective.Methods.Three children with CP participated in this study and received an 8-week VR intervention (30 minutes × 5 sessions/week) using the commercial EyeToy Play VR system. Reaching kinematics measured by Super Pop VR and two fine motor tools (Bruininks-Oseretsky Test of Motor Proficiency second edition, BOT-2, and Pediatric Motor Activity Log, PMAL) were tested before, mid, and after intervention.Results.All children successfully completed the evaluations using the Super Pop VR system at home where 85% of the reaches collected were used to compute reaching kinematics, which is compatible with literature using expensive motion analysis systems. Only the child with hemiplegic CP and more impaired arm function improved the reaching kinematics and functional use of the affected hand after intervention.Conclusion.Super Pop VR proved to be a feasible evaluation tool in children with CP.
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Boulenger, Véronique, Alice C. Roy, Yves Paulignan, Viviane Deprez, Marc Jeannerod, and Tatjana A. Nazir. "Cross-talk between Language Processes and Overt Motor Behavior in the First 200 msec of Processing." Journal of Cognitive Neuroscience 18, no. 10 (October 2006): 1607–15. http://dx.doi.org/10.1162/jocn.2006.18.10.1607.
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A recently emerging view sees language understanding as closely linked to sensory and motor processes. The present study investigates this issue by examining the influence of processing action verbs and concrete nouns on the execution of a reaching movement. Fine-grained analyses of movement kinematics revealed that relative to nouns, processing action verbs significantly affects overt motor performance. Within 200 msec after onset, processing action verbs interferes with a concurrent reaching movement. By contrast, the same words assist reaching movement when processed before movement onset. The cross-talk between language processes and overt motor behavior provides unambiguous evidence that action words and motor action share common cortical representations and could thus suggest that cortical motor regions are indeed involved in action word retrieval.
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Oota, Satoshi, Yosuke Ikegami, Koh Ayusawa, Nobunori Kakusho, Hirotaka Imagawa, Hiroyuki Hishida, Hiromasa Suzuki, et al. "Fine-grained phenotypic analyses of motor functions for laboratory mice: The inverse kinematics of mouse gait patterns." Neuroscience Research 71 (September 2011): e244. http://dx.doi.org/10.1016/j.neures.2011.07.1067.
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Chen, Yu-Ping, Lin-Ju Kang, Tien-Yow Chuang, Ji-Liang Doong, Shwn-Jan Lee, Mei-Wun Tsai, Suh-Fang Jeng, and Wen-Hsu Sung. "Use of Virtual Reality to Improve Upper-Extremity Control in Children With Cerebral Palsy: A Single-Subject Design." Physical Therapy 87, no. 11 (November 1, 2007): 1441–57. http://dx.doi.org/10.2522/ptj.20060062.
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Background and Purpose Virtual reality (VR) creates an exercise environment in which the intensity of practice and positive feedback can be systematically manipulated in various contexts. The purpose of this study was to investigate the training effects of a VR intervention on reaching behaviors in children with cerebral palsy (CP). Participants Four children with spastic CP were recruited. Method A single-subject design (A-B with follow-up) was used. All children were evaluated with 3 baseline, 4 intervention, and 2 follow-up measures. A 4-week individualized VR training program (2 hours per week) with 2 VR systems was applied to all children. The outcome measures included 4 kinematic parameters (movement time, path length, peak velocity, and number of movement units) for mail-delivery activities in 3 directions (neutral, outward, and inward) and the Fine Motor Domain of the Peabody Developmental Motor Scales–Second Edition (PDMS-2). Visual inspection and the 2-standard-deviation–band method were used to compare the outcome measures. Results Three children who had normal cognition showed improvements in some aspects of reaching kinematics, and 2 children’s change scores on the PDMS-2 reached the minimal detectable change during the intervention. The improvements in kinematics were partially maintained during follow-up. Discussion and Conclusion A 4-week individualized VR training program appeared to improve the quality of reaching in children with CP, especially in children with normal cognition and good cooperation. The training effects were retained in some children after the intervention.
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Shen, Cheng, Ning Chen, Ruoyu Tan, Shixun Fan, and Dapeng Fan. "Modeling and Stability Analysis of Coarse–Fine Composite Mechatronic System in UAV Multi-Gimbal Electro-Optical Pod." Electronics 9, no. 5 (May 7, 2020): 769. http://dx.doi.org/10.3390/electronics9050769.
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Coarse–fine composite mechatronic systems face numerous challenges due to the structural complexity and diversification of multi-gimbals. The core goal of this manuscript is to address the issue of the coarse-fine composite mechatronic system stability of a UAV (unmanned aerial vehicle) multi-gimbal electro-optical pod using USM-VCM (ultrasonic motor and voice coil motor) mechatronic design, Euler dynamics modeling, and stability DOB (disturbance observer) control. In response to this problem, a Hall effect electromagnetic circuit and USM-VCM drive acquisition circuit are designed. A Euler dynamics model in the Cartesian coordinate system is built to derive the kinematics coupling compensation matrix and mechanical parameter optimization method between the gimbals. Finally, the model is substituted into the DOB suppression control, which can monitor and compensate the motion coupling between the coarse–fine composite mechatronic systems in real time. Results show that the disturbance suppression impact of the DOB method with the Euler optimization model and USM-VCM mechatronic design is increased by up to 90% compared to the PID (proportion integration differentiation) method and 20% better than the traditional DOB method.
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Kotani, Shuntaro, and Shinichi Furuya. "State anxiety disorganizes finger movements during musical performance." Journal of Neurophysiology 120, no. 2 (August 1, 2018): 439–51. http://dx.doi.org/10.1152/jn.00813.2017.
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Skilled performance, in many situations, exposes an individual to psychological stress and fear, thus triggering state anxiety and compromising motor dexterity. Suboptimal skill execution in people under pressure affects the future career prospects of trained individuals, such as athletes, clinicians, and musicians. However, it has not been elucidated in what manner state anxiety affects multijoint movements and thereby degrades fine motor control. Using principal component analysis of hand kinematics recorded by a data glove during piano performances, we tested whether state anxiety affects the organization of movements of multiple joints or merely constrains the amplitude of the individual joints without affecting joint movement coordination. The result demonstrated changes in the coordination of movements across joints in piano performances by experts under psychological stress. Overall, the change was characterized by reduction of synergistic movements between the finger responsible for the keypress and its adjacent fingers. A regression analysis further identified that the attenuation of the movement covariation between the fingers was associated with an increase in temporal error during performance under pressure. In contrast, neither the maximum nor minimum angles of the individual joints of the hand were susceptible to induced anxiety. These results suggest that degradation of fine motor control under pressure is mediated by incoordination of movements between the fingers in skilled piano performances. NEW & NOTEWORTHY A key issue in neuromuscular control of coordinated movements is how the nervous system organizes multiple degrees of freedom for production of skillful motor behaviors. We found that state anxiety disorchestrates the organization of finger movements so as to decrease synergistic motions between the fingers in musical performance, which degrades fine motor control. The findings are important to shed light on mechanisms underlying loss of motor dexterity under pressure.
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Buonocore, Antimo, Chih-Yang Chen, Xiaoguang Tian, Saad Idrees, Thomas A. Münch, and Ziad M. Hafed. "Alteration of the microsaccadic velocity-amplitude main sequence relationship after visual transients: implications for models of saccade control." Journal of Neurophysiology 117, no. 5 (May 1, 2017): 1894–910. http://dx.doi.org/10.1152/jn.00811.2016.
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Microsaccades occur during gaze fixation to correct for miniscule foveal motor errors. The mechanisms governing such fine oculomotor control are still not fully understood. In this study, we explored microsaccade control by analyzing the impacts of transient visual stimuli on these movements’ kinematics. We found that such kinematics can be altered in systematic ways depending on the timing and spatial geometry of visual transients relative to the movement goals. In two male rhesus macaques, we presented peripheral or foveal visual transients during an otherwise stable period of fixation. Such transients resulted in well-known reductions in microsaccade frequency, and our goal was to investigate whether microsaccade kinematics would additionally be altered. We found that both microsaccade timing and amplitude were modulated by the visual transients, and in predictable manners by these transients’ timing and geometry. Interestingly, modulations in the peak velocity of the same movements were not proportional to the observed amplitude modulations, suggesting a violation of the well-known “main sequence” relationship between microsaccade amplitude and peak velocity. We hypothesize that visual stimulation during movement preparation affects not only the saccadic “Go” system driving eye movements but also a “Pause” system inhibiting them. If the Pause system happens to be already turned off despite the new visual input, movement kinematics can be altered by the readout of additional visually evoked spikes in the Go system coding for the flash location. Our results demonstrate precise control over individual microscopic saccades and provide testable hypotheses for mechanisms of saccade control in general. NEW & NOTEWORTHY Microsaccadic eye movements play an important role in several aspects of visual perception and cognition. However, the mechanisms for microsaccade control are still not fully understood. We found that microsaccade kinematics can be altered in a systematic manner by visual transients, revealing a previously unappreciated and exquisite level of control by the oculomotor system of even the smallest saccades. Our results suggest precise temporal interaction between visual, motor, and inhibitory signals in microsaccade control.
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DeLozier, Katherine R., Francois D. H. Gould, Jocelyn Ohlemacher, Allan J. Thexton, and Rebecca Z. German. "Impact of recurrent laryngeal nerve lesion on oropharyngeal muscle activity and sensorimotor integration in an infant pig model." Journal of Applied Physiology 125, no. 1 (July 1, 2018): 159–66. http://dx.doi.org/10.1152/japplphysiol.00963.2017.
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The successful performance of a swallow requires dynamic integration between a wide range of sensory inputs and muscle activities to produce the coordinated kinematics of oropharyngeal structures. Damage to the recurrent laryngeal nerve (RLN) produces dysphagia in infants, with food or liquid entering the airway despite this nerve having minimal direct sensory or motor connections to the act of swallowing, apart from vocal fold closure. Previous results have demonstrated that a complete RLN lesion disrupts both performance and kinematics before initiation of the pharyngeal swallow in infants. We tested the hypothesis that a RLN lesion produces changes in the normal activity of oral floor, tongue, and infrahyoid muscles during a swallow. We recorded swallowing in our validated infant pig model, with synchronous high-speed imaging and fine-wire, chronic electromyography. We found changes in the timing, duration, and amplitude of the motor pattern in an array of muscles that are supplied by several different cranial and cervical nerves. Some of these changes in muscle activity are associated with the preparatory aspects of bolus aggregation or movement and so occur before the pharyngeal swallow. Taken with previous biomechanical results, these patterns suggest an intricate brain stem sensorimotor integration that occurs as part of a swallow. In particular, the execution of oral motor function is changed as a result of this simple lesion. NEW & NOTEWORTHY Damage to the recurrent laryngeal nerve compromises swallowing despite an absent or minimal contribution to either the motor or sensory aspects of this function. This study documents EMG changes, following RLN lesion, to non-RLN innervated muscles that are active during swallowing in an infant model. Some of these muscles fire before the pharyngeal swallow and are associated with the preparatory aspects of bolus aggregation and movement, suggesting important sensorimotor integration at a brain stem level.
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Ekstrom, Laura J., Chris Panzini, and Gary B. Gillis. "Vision fine-tunes preparation for landing in the cane toad, Rhinella marina." Biology Letters 14, no. 9 (September 2018): 20180397. http://dx.doi.org/10.1098/rsbl.2018.0397.
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In toad hopping, the hindlimbs generate the propulsive force for take-off while the forelimbs resist the impact forces associated with landing. Preparing to perform a safe landing, in which impact forces are managed appropriately, likely involves the integration of multiple types of sensory feedback. In toads, vestibular and/or proprioceptive feedback is critical for coordinated landing; however, the role of vision remains unclear. To clarify this, we compare pre-landing forelimb muscle activation patterns before and after removing vision. Specifically, we recorded EMG activity from two antagonistic forelimb muscles, the anconeus and coracoradialis, which demonstrate distance-dependent onset timing and recruitment intensity, respectively. Toads were first recorded hopping normally and then again after their optic nerves were severed to remove visual feedback. When blind, toads exhibited hop kinematics and pre-landing muscle activity similar to when sighted. However, distance-dependent relationships for muscle activity patterns were more variable, if present at all. This study demonstrates that blind toads are still able to perform coordinated landings, reinforcing the importance of proprioceptive and/or vestibular feedback during hopping. But the increased variability in distance-dependent activity patterns indicates that vision is more responsible for fine-tuning the motor control strategy for landing.
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Shmuelof, Lior, John W. Krakauer, and Pietro Mazzoni. "How is a motor skill learned? Change and invariance at the levels of task success and trajectory control." Journal of Neurophysiology 108, no. 2 (July 15, 2012): 578–94. http://dx.doi.org/10.1152/jn.00856.2011.
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The public pays large sums of money to watch skilled motor performance. Notably, however, in recent decades motor skill learning (performance improvement beyond baseline levels) has received less experimental attention than motor adaptation (return to baseline performance in the setting of an external perturbation). Motor skill can be assessed at the levels of task success and movement quality, but the link between these levels remains poorly understood. We devised a motor skill task that required visually guided curved movements of the wrist without a perturbation, and we defined skill learning at the task level as a change in the speed–accuracy trade-off function (SAF). Practice in restricted speed ranges led to a global shift of the SAF. We asked how the SAF shift maps onto changes in trajectory kinematics, to establish a link between task-level performance and fine motor control. Although there were small changes in mean trajectory, improved performance largely consisted of reduction in trial-to-trial variability and increase in movement smoothness. We found evidence for improved feedback control, which could explain the reduction in variability but does not preclude other explanations such as an increased signal-to-noise ratio in cortical representations. Interestingly, submovement structure remained learning invariant. The global generalization of the SAF across a wide range of difficulty suggests that skill for this task is represented in a temporally scalable network. We propose that motor skill acquisition can be characterized as a slow reduction in movement variability, which is distinct from faster model-based learning that reduces systematic error in adaptation paradigms.
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So, Albert, and WL Chan. "A study of linear PMSM driven ropeless elevators." Building Services Engineering Research and Technology 40, no. 1 (September 3, 2018): 93–108. http://dx.doi.org/10.1177/0143624418797604.
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In recent years, buildings have become taller and wider. The conventional approach of one roped elevator car per hoistway seems increasingly impractical. The idea of ropeless elevators using linear motors was proposed more than 30 years ago, but it was merely treated as wishful thinking by the industry at that time due to lots of safety concerns. And discussion by the industry has mainly been qualitative in nature. In recent years, an international manufacturer announced the development of a prototype and the world's first installation may probably be open to public before the end of 2018. So far, academic studies have mainly focused on the study of linear motors with generic applications, while this paper focuses on the performance of the motor drive from an elevator's point of view. In this paper, we investigate the mechanism of the drive, and the linear permanent magnet synchronous motor and, by discretizing the equations of the full mathematical model, we fine tune the parameters and design suitable controllers. We evaluate its performance by computer simulation, based on the necessary kinematics of a real elevator, so as to arrive at some design guidelines. Finally, the most critical safety concern, i.e. free fall during a total power failure, is quantitatively studied by short circuiting all motor windings. Methods to achieve a reasonably constant and low descending speed, have been studied with parameters estimated analytically, and are verified by simulation. For the sake of illustrating the concept as an initial trial, simplified circuit models, controllers and sensors are all assumed as being ideal. It is hoped that this paper will stimulate the research interest of both the academic world and the industry, while the inclusion of more losses, armature reactions, and imperfections, etc., could be tackled in a further study. Practical application: The application of one roped elevator car in taller and wider buildings seems increasingly impractical. This paper considers the analysis of the application of ropeless elevators using linear motors focusing on the performance of the motor drive from an elevator's point of view. A basic mathematical framework is developed to study and design the controllers and drive of a multi-car elevator system by using linear permanent magnet synchronous motors with emphasis on the elevator performance as a whole system. The paper is aimed at stimulating research interest to drive the appropriate analysis and application of linear permanent magnet synchronous motor driven ropeless elevators.
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Mikolajczyk, Tadeusz, Dariusz Dorsz, and Łukasz Romanowski. "Design and Control System of Parallel Kinematic Manipulator." Applied Mechanics and Materials 436 (October 2013): 390–97. http://dx.doi.org/10.4028/www.scientific.net/amm.436.390.
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This paper presents parallel kinematic manipulator design. A manipulator with three axis and parallelogram mechanism was made using aluminium profile rods. This mechanism was controlled by PC with the use of stepper motors. Kinematics analysis was conducted and its findings were used to make a special software to generate G-code control file. X and y mouse cursor indications with given z value were used as data showing the position of the effector to establish the movement of the arms of the presented manipulator. Step2CNC software was used to control the manipulator. Tests have confirmed the correctness of the study.
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Bennett, Wallace O., Rachel S. Simons, and Elizabeth L. Brainerd. "Twisting and Bending: The Functional Role of Salamander Lateral Hypaxial Musculature During Locomotion." Journal of Experimental Biology 204, no. 11 (June 1, 2001): 1979–89. http://dx.doi.org/10.1242/jeb.204.11.1979.
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SUMMARY The function of the lateral hypaxial muscles during locomotion in tetrapods is controversial. Currently, there are two hypotheses of lateral hypaxial muscle function. The first, supported by electromyographic (EMG) data from a lizard (Iguana iguana) and a salamander (Dicamptodon ensatus), suggests that hypaxial muscles function to bend the body during swimming and to resist long-axis torsion during walking. The second, supported by EMG data from lizards during relatively high-speed locomotion, suggests that these muscles function primarily to bend the body during locomotion, not to resist torsional forces. To determine whether the results from D. ensatus hold for another salamander, we recorded lateral hypaxial muscle EMGs synchronized with body and limb kinematics in the tiger salamander Ambystoma tigrinum. In agreement with results from aquatic locomotion in D. ensatus, all four layers of lateral hypaxial musculature were found to show synchronous EMG activity during swimming in A. tigrinum. Our findings for terrestrial locomotion also agree with previous results from D. ensatus and support the torsion resistance hypothesis for terrestrial locomotion. We observed asynchronous EMG bursts of relatively high intensity in the lateral and medial pairs of hypaxial muscles during walking in tiger salamanders (we call these ‘α-bursts’). We infer from this pattern that the more lateral two layers of oblique hypaxial musculature, Mm. obliquus externus superficialis (OES) and obliquus externus profundus (OEP), are active on the side towards which the trunk is bending, while the more medial two layers, Mm. obliquus internus (OI) and transversus abdominis (TA), are active on the opposite side. This result is consistent with the hypothesis proposed for D. ensatus that the OES and OEP generate torsional moments to counteract ground reaction forces generated by forelimb support, while the OI and TA generate torsional moments to counteract ground reaction forces from hindlimb support. However, unlike the EMG pattern reported for D. ensatus, a second, lower-intensity burst of EMG activity (‘β-burst’) was sometimes recorded from the lateral hypaxial muscles in A. tigrinum. As seen in other muscle systems, these β-bursts of hypaxial muscle coactivation may function to provide fine motor control during locomotion. The presence of asynchronous, relatively high-intensity α-bursts indicates that the lateral hypaxial muscles generate torsional moments during terrestrial locomotion, but it is possible that the balance of forces from both α- and β-bursts may allow the lateral hypaxial muscles to contribute to lateral bending of the body as well.
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Hofmann, Aurélie, Michael Grossbach, Volker Baur, Joachim Hermsdörfer, and Eckart Altenmüller. "Musician’s Dystonia is Highly Task Specific: No Strong Evidence for Everyday Fine Motor Deficits in Patients." Medical Problems of Performing Artists 30, no. 1 (March 1, 2015): 38–46. http://dx.doi.org/10.21091/mppa.2015.1006.
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OBJECTIVES: 1) To examine the fine motor skills used everyday by patients suffering from musician’s dystonia (MD) in the upper limb in order to verify whether MD is task-specific; and 2) to compare the affected and non-affected hands of MD musicians vs healthy musicians in performance of these tasks in order to clarify whether dystonic symptoms can be found in the non-affected side of MD patients. BACKGROUND: MD is typically considered to be focal and task specific, but patients often report impairment in everyday life activities. Furthermore, in the course of MD, about 15% of patients complain of dystonic symptoms in other parts of the body. METHODS: Twenty-seven musicians affected by MD and 27 healthy musicians were studied using 1) the Motor Performance Test Series, 2) a kinematic analysis of handwriting, and 3) an assessment of the grip force regulation while lifting and moving a manipulandum. RESULTS: Patients performed most fine motor tasks without any evidence of a deficit. Exclusively in the handwriting tasks (2), they exhibited fewer frequencies of the written trace and a prolonged overall writing time. CONCLUSION: MD is highly task specific and does not strongly affect other motor skills. The subtle deficits in handwriting may be explained as a consequence of a general psychological disposition rather than as compensatory mechanisms to avoid the appearance of dystonic symptoms. Furthermore, we did not find signs of multifocal motor deficits in the unaffected hands of MD patients.
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Long, Philip, Wisama Khalil, and Stéphane Caro. "Kinematic and dynamic analysis of lower-mobility cooperative arms." Robotica 33, no. 9 (May 1, 2014): 1813–34. http://dx.doi.org/10.1017/s0263574714001039.
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SUMMARYThis paper studies the modeling and analysis of a system with two cooperative manipulators working together on a common task. The task is defined as the transportation of an object in space. The cooperative system is the dual-arm of the humanoid robot Nao, where the serial architecture of each arm has 5 degrees of freedom. The kinematics representing the closed chain system is studied. The mobility of the closed-loop system is analyzed and the nature of the possible motions explored. The stiffness of some motors can be reduced until they behave as passive joints. Certain joints are then chosen as actuated (independent) and the others as passive (dependent). The serial and parallel singular configurations of the system are considered. From the kinematic analysis, admissible and inadmissible minimum actuation schemes are analyzed. Furthermore the dynamic performance of the schemes is compared to find the optimum minimum actuation scheme.
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Betti, Sonia, Andrea Spoto, Umberto Castiello, and Luisa Sartori. "Testing rTMS-Induced Neuroplasticity: A Single Case Study of Focal Hand Dystonia." Neural Plasticity 2018 (May 30, 2018): 1–12. http://dx.doi.org/10.1155/2018/6464896.
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Focal hand dystonia in musicians is a neurological motor disorder in which aberrant plasticity is caused by excessive repetitive use. This work’s purposes were to induce plasticity changes in a dystonic musician through five daily thirty-minute sessions of 1 Hz repetitive transcranial magnetic stimulation (rTMS) applied to the left M1 by using neuronavigated stimulation and to reliably measure the effect of these changes. To this aim, the relationship between neuroplasticity changes and motor recovery was investigated using fine-grained kinematic analysis. Our results suggest a statistically significant improvement in motor coordination both in a task resembling the dystonic-inducing symptoms and in a reach-to-grasp task. This single case study supports the safe and effective use of noninvasive brain stimulation in neurologic patients and highlights the importance of evaluating outcomes in measurable ways. This issue is a key aspect to focus on to classify the clinical expression of dystonia. These preliminary results promote the adoption of kinematic analysis as a valuable diagnostic tool.
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Ryu, Jihye, and Elizabeth Torres. "The Autonomic Nervous System Differentiates between Levels of Motor Intent and End Effector." Journal of Personalized Medicine 10, no. 3 (July 31, 2020): 76. http://dx.doi.org/10.3390/jpm10030076.
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While attempting to bridge motor control and cognitive science, the nascent field of embodied cognition has primarily addressed intended, goal-oriented actions. Less explored, however, have been unintended motions. Such movements tend to occur largely beneath awareness, while contributing to the spontaneous control of redundant degrees of freedom across the body in motion. We posit that the consequences of such unintended actions implicitly contribute to our autonomous sense of action ownership and agency. We question whether biorhythmic activities from these motions are separable from those which intentionally occur. Here we find that fluctuations in the biorhythmic activities of the nervous systems can unambiguously differentiate across levels of intent. More important yet, this differentiation is remarkable when we examine the fluctuations in biorhythmic activity from the autonomic nervous systems. We find that when the action is intended, the heart signal leads the body kinematics signals; but when the action segment spontaneously occurs without instructions, the heart signal lags the bodily kinematics signals. We conclude that the autonomic nervous system can differentiate levels of intent. Our results are discussed while considering their potential translational value.
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Amir Idzham Iberahim, Mohd, Syadiah Nor Wan Shamsuddin, Mokhairi Makhtar, Mohd Nordin Abdul Rahman, and Nordin Simbak. "Time-based Simplified Denavit-Heartenberg Translation (TS-DH) for Capturing Finger Kinematic Data." International Journal of Engineering & Technology 7, no. 3.28 (August 17, 2018): 20. http://dx.doi.org/10.14419/ijet.v7i3.28.20958.
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Virtual finger model is commonly used in many applications for stroke fine motor rehabilitation especially in Virtual Reality (VR) applications. Capturing movement data for fingers is one of the important phases in any virtual fine motor rehabilitation process. Manual observation provides inconsistent evaluation given by different therapists for different rehabilitation sessions. Although the process of capturing data is performed, without time series of captured data, the data will not have a significant impact in producing consistent and meaningful evaluation. Furthermore, the consistency of the assessment of rehabilitation sessions will deliver more robust rehabilitation progress analysis. This data is very useful when paired with time information which can be analyzed to produce optimal evaluation. This paper proposes Time-based Simplified Denavit-Heartenberg Translation (TS-DH) consisting of forward kinematic with simplified DH parameter for capturing coordinate of end of each bone from virtual finger model paired with timeframe data. The DH model is enhanced by implementing 2 additional rules in assigning joint parameter. The data will be recorded with timeframe of every finger movement. As a conclusion, TS-DH model can be used in any virtual finger environment accurately.
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D'Ausilio, A., L. Maffongelli, E. Bartoli, M. Campanella, E. Ferrari, J. Berry, and L. Fadiga. "Listening to speech recruits specific tongue motor synergies as revealed by transcranial magnetic stimulation and tissue-Doppler ultrasound imaging." Philosophical Transactions of the Royal Society B: Biological Sciences 369, no. 1644 (June 5, 2014): 20130418. http://dx.doi.org/10.1098/rstb.2013.0418.
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The activation of listener's motor system during speech processing was first demonstrated by the enhancement of electromyographic tongue potentials as evoked by single-pulse transcranial magnetic stimulation (TMS) over tongue motor cortex. This technique is, however, technically challenging and enables only a rather coarse measurement of this motor mirroring. Here, we applied TMS to listeners’ tongue motor area in association with ultrasound tissue Doppler imaging to describe fine-grained tongue kinematic synergies evoked by passive listening to speech. Subjects listened to syllables requiring different patterns of dorso-ventral and antero-posterior movements (/ki/, /ko/, /ti/, /to/). Results show that passive listening to speech sounds evokes a pattern of motor synergies mirroring those occurring during speech production. Moreover, mirror motor synergies were more evident in those subjects showing good performances in discriminating speech in noise demonstrating a role of the speech-related mirror system in feed-forward processing the speaker's ongoing motor plan.
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Butt, Abdul Haleem, Erika Rovini, Hamido Fujita, Carlo Maremmani, and Filippo Cavallo. "Data-Driven Models for Objective Grading Improvement of Parkinson’s Disease." Annals of Biomedical Engineering 48, no. 12 (October 1, 2020): 2976–87. http://dx.doi.org/10.1007/s10439-020-02628-4.
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AbstractParkinson’s disease (PD) is a progressive disorder of the central nervous system that causes motor dysfunctions in affected patients. Objective assessment of symptoms can support neurologists in fine evaluations, improving patients’ quality of care. Herein, this study aimed to develop data-driven models based on regression algorithms to investigate the potential of kinematic features to predict PD severity levels. Sixty-four patients with PD (PwPD) and 50 healthy subjects of control (HC) were asked to perform 13 motor tasks from the MDS-UPDRS III while wearing wearable inertial sensors. Simultaneously, the clinician provided the evaluation of the tasks based on the MDS-UPDRS scores. One hundred-ninety kinematic features were extracted from the inertial motor data. Data processing and statistical analysis identified a set of parameters able to distinguish between HC and PwPD. Then, multiple feature selection methods allowed selecting the best subset of parameters for obtaining the greatest accuracy when used as input for several predicting regression algorithms. The maximum correlation coefficient, equal to 0.814, was obtained with the adaptive neuro-fuzzy inference system (ANFIS). Therefore, this predictive model could be useful as a decision support system for a reliable objective assessment of PD severity levels based on motion performance, improving patients monitoring over time.
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Sorokoumov, P. S. "Formalization of Tasks for Robotic Manipulators: Review and Prospects." Mekhatronika, Avtomatizatsiya, Upravlenie 22, no. 4 (April 5, 2021): 200–207. http://dx.doi.org/10.17587/mau.22.200-207.
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This overview of the problems formulations for robotic manipulators at different abstraction levels can be used to find the causes of troubles with some types of control systems. For many variants of manipulators, for example, biomorphic ones, it is not yet possible to achieve the required quality and universality. Nevertheless these tasks are solvable, which is proved by the natural movement control systems of biological organisms. One of the reasons of the difficulties is the complexity of the formalization of motion control, which prevents the development of universal approaches. The existing formalizations were separated by functional level to facilitate analysis. The high-level problems (the division of complex motor tasks into stages) are successfully solved by general planners or logical inference procedures. The middle-level problems (the trajectory tracing according to an abstract motor task) are so far solved less efficiently. Some existing tools, as linguistic methods, can greatly facilitate solution, but require significant and very laborious formalization of conditions. Inverse problems of kinematics and dynamics, conjugation of trajectory sections and direct control of the manipulator motors with error handling are further stages of processing; the quality of known solutions is usually acceptable. Based on the data collected, it can be argued that the development of methods for solving medium-level problems, i.e. constructing the trajectory of the robot according to the description of the action, is the most important domain for the successful creation of new types of manipulator control systems.
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Ackermann, Hermann, Ingo Hertrich, and Gabriele Scharf. "Kinematic Analysis of Lower Lip Movements in Ataxic Dysarthria." Journal of Speech, Language, and Hearing Research 38, no. 6 (December 1995): 1252–59. http://dx.doi.org/10.1044/jshr.3806.1252.
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The present study investigates the influence of cerebellar disorders on articulatory performance. A linear trend between peak velocity and movement amplitude seems to represent a basic organizational principle both of upper limb and speech motor control. This relationship is preserved in arm movements of patients with cerebellar dysfunction. However, these subjects show a decreased slope of the respective regression lines under the instruction to perform movements as fast as possible. In order to find out whether these findings also hold for speech motor control, peak velocity, range, and duration both of the opening and closing gestures during production of /pap/- as well as /pa:p/-sequences—embedded into a carrier phrase each—were measured using an optoelectric system. In addition, vowel length (/a/, /a:/) was determined at the acoustic speech signal: (a) The cerebellar patients showed a prolongation of both vowel targets. Most of them, nevertheless, presented with discernible durational contrasts; (b) The articulatory gestures were characterized by a highly linear relationship between peak velocity and movement range in the cerebellar as well as in the control group; (c) As a rule, the cerebellar subjects had decreased velocity-displacement ratios as compared to the normals; (d) The discrepancy in slope of the computed regression lines between the controls and the patients varied according to the type of movement (opening vs. closing gesture) and—to a lesser degree—linguistic demands (short vs. long vowel). These data indicate an impaired ability of cerebellar patients to increase muscular forces in order to produce adequately scaled articulatory gestures of short duration.
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Lee, I.-Ching, Yung-Jung Chen, and Chin-Liang Tsai. "Kinematic performance of fine motor control in attention-deficit/hyperactivity disorder: The effects of comorbid developmental coordination disorder and core symptoms." Pediatrics International 55, no. 1 (February 2013): 24–29. http://dx.doi.org/10.1111/ped.12010.
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Casartelli, Luca, Alessandra Federici, Ambra Cesareo, Emilia Biffi, Giulia Valtorta, Massimo Molteni, Luca Ronconi, and Renato Borgatti. "Role of the cerebellum in high stages of motor planning hierarchy." Journal of Neurophysiology 117, no. 4 (April 1, 2017): 1474–82. http://dx.doi.org/10.1152/jn.00771.2016.
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Motor planning is not a monolithic process, and distinct stages of motor planning are responsible for encoding different levels of abstractness. However, how these distinct components are mapped into different neural substrates remains an open question. We studied one of these high-level motor planning components, defined as second-order motor planning, in a patient (R.G.) with an extremely rare case of cerebellar agenesis but without any other cortical malformations. Second-order motor planning dictates that when two acts must be performed sequentially, planning of the second act can influence execution of the first. We used an optoelectronic system for kinematic analysis to compare R.G.’s performance with age-matched controls in a second-order motor planning task. The first act was to reach for an object, and the second was to place it into a small or large container. Our results showed that despite the expected difficulties in fine-motor skills, second-order motor planning (i.e., the ability to modulate the first act as a function of the nature of the second act) was preserved even in the patient with congenital absence of the cerebellum. These results open new intriguing speculations about the role of the cerebellum in motor planning abilities. Although prudence is imperative when suggesting conclusions made on the basis of single-case findings, this evidence suggests fascinating hypotheses about the neural circuits that support distinct stages of the motor planning hierarchy, and regarding the functional role of second-order motor planning in motor cognition and its potential dysfunction in autism. NEW & NOTEWORTHY Traditionally, the cerebellum was considered essential for motor planning. By studying an extremely rare patient with cerebellar agenesis and a group of neurotypical controls, we found that high stages of the motor planning hierarchy can be preserved even in this patient with congenital absence of the cerebellum. Our results provide interesting insights that shed light on the neural circuits supporting distinct levels of motor planning. Furthermore, the results are intriguing because of their potential clinical implications in autism.
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Li, Xin, Xilun Ding, and Gregory S. Chirikjian. "Analysis of a mechanism with redundant drive for antenna pointing." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 231, no. 2 (November 13, 2016): 229–39. http://dx.doi.org/10.1177/0954410016636157.
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Orientation accuracy is a key factor in the design of mechanisms for antenna pointing. Our design uses a redundantly actuated parallel mechanism which may provide an effective way to solve this problem, and even can increase its payload capability and reliability. The presented mechanism can be driven by rotary motors fixed on the base to reduce the inertia of the moving parts and to lower the power consumption. The mechanism is redundantly actuated by three arms, and is used as a two-dimensional antenna tracking and pointing device. Both the forward and inverse kinematics are investigated to find all the possible solutions. Detailed characters of the platform are analyzed to demonstrate the advantages in eliminating singularities and improving pointing accuracy. A method of calculating the overconstrained orientational error is also proposed based on the differential kinematics. All the methods are verified by numerical examples.
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Heikkinen, Taneli, Timo Bragge, Niina Bhattarai, Teija Parkkari, Jukka Puoliväli, Outi Kontkanen, Patrick Sweeney, Larry C. Park, and Ignacio Munoz-Sanjuan. "Rapid and robust patterns of spontaneous locomotor deficits in mouse models of Huntington’s disease." PLOS ONE 15, no. 12 (December 28, 2020): e0243052. http://dx.doi.org/10.1371/journal.pone.0243052.
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Huntington's disease (HD) is an inherited neurodegenerative disorder characterized by severe disruption of cognitive and motor functions, including changes in posture and gait. A number of HD mouse models have been engineered that display behavioral and neuropathological features of the disease, but gait alterations in these models are poorly characterized. Sensitive high-throughput tests of fine motor function and gait in mice might be informative in evaluating disease-modifying interventions. Here, we describe a hypothesis-free workflow that determines progressively changing locomotor patterns across 79 parameters in the R6/2 and Q175 mouse models of HD. R6/2 mice (120 CAG repeats) showed motor disturbances as early as at 4 weeks of age. Similar disturbances were observed in homozygous and heterozygous Q175 KI mice at 3 and 6 months of age, respectively. Interestingly, only the R6/2 mice developed forelimb ataxia. The principal components of the behavioral phenotypes produced two phenotypic scores of progressive postural instability based on kinematic parameters and trajectory waveform data, which were shared by both HD models. This approach adds to the available HD mouse model research toolbox and has a potential to facilitate the development of therapeutics for HD and other debilitating movement disorders with high unmet medical need.
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Finisguerra, Alessandra, Laura Maffongelli, Michela Bassolino, Marco Jacono, Thierry Pozzo, and Alessandro D'Ausilio. "Generalization of motor resonance during the observation of hand, mouth, and eye movements." Journal of Neurophysiology 114, no. 4 (October 2015): 2295–304. http://dx.doi.org/10.1152/jn.00433.2015.
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Transcranial magnetic stimulation (TMS) of the motor cortex shows that hand action observation (AO) modulates corticospinal excitability (CSE). CSE modulation alternatively maps low-level kinematic characteristics or higher-level features, like object-directed action goals. However, action execution is achieved through the control of muscle synergies, consisting of coordinated patterns of muscular activity during natural movements, rather than single muscles or object-directed goals. This synergistic organization of action execution also underlies the ability to produce the same functional output (i.e., grasping an object) using different effectors. We hypothesize that motor system activation during AO may rely on similar principles. To investigate this issue, we recorded both hand CSE and TMS-evoked finger movements which provide a much more complete description of coordinated patterns of muscular activity. Subjects passively watched hand, mouth and eyelid opening or closing, which are performing non-object-directed (intransitive) actions. Hand and mouth share the same potential to grasp objects, whereas eyelid does not allow object-directed (transitive) actions. Hand CSE modulation generalized to all effectors, while TMS evoked finger movements only to mouth AO. Such dissociation suggests that the two techniques may have different sensitivities to fine motor modulations induced by AO. Differently from evoked movements, which are sensitive to the possibility to achieve object-directed action, CSE is generically modulated by “opening” vs. “closing” movements, independently of which effector was observed. We propose that motor activities during AO might exploit the same synergistic mechanisms shown for the neural control of movement and organized around a limited set of motor primitives.
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Rivera, Angela R. V., and Richard W. Blob. "Forelimb muscle function in pig-nosed turtles, Carettochelys insculpta : testing neuromotor conservation between rowing and flapping in swimming turtles." Biology Letters 9, no. 5 (October 23, 2013): 20130471. http://dx.doi.org/10.1098/rsbl.2013.0471.
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Changes in muscle activation patterns can lead to new locomotor modes; however, neuromotor conservation—the evolution of new forms of locomotion through changes in structure without concurrent changes to underlying motor patterns—has been documented across diverse styles of locomotion. Animals that swim using appendages do so via rowing (anteroposterior oscilations) or flapping (dorsoventral oscilations). Yet few studies have compared motor patterns between these swimming modes. In swimming turtles, propulsion is generated exclusively by limbs. Kinematically, turtles swim using multiple styles of rowing (freshwater species), flapping (sea turtles) and a unique hybrid style with superficial similarity to flapping by sea turtles and characterized by increased dorsoventral motions of synchronously oscillated forelimbs that have been modified into flippers ( Carettochelys insculpta ). We compared forelimb motor patterns in four species of turtle (two rowers, Apalone ferox and Trachemys scripta ; one flapper, Caretta caretta ; and Carettochelys ) and found that, despite kinematic differences, motor patterns were generally similar among species with a few notable exceptions: specifically, presence of variable bursts for pectoralis and triceps in Trachemys (though timing of the non-variable pectoralis burst was similar), and the timing of deltoideus activity in Carettochelys and Caretta compared with other taxa. The similarities in motor patterns we find for several muscles provide partial support for neuromotor conservation among turtles using diverse locomotor styles, but the differences implicate deltoideus as a prime contributor to flapping limb motions.
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Kumbár, Vojtěch, Adam Polcar, and Jiří Čupera. "Rheological profiles of blends of the new and used motor oils." Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 61, no. 1 (2013): 115–21. http://dx.doi.org/10.11118/actaun201361010115.
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The objective of this paper is to find changes of a rheological profile of the new engine oil if the used engine oil will be add. And also find changes of a rheological profile of the used engine oil if the new engine oil will be add. For these experiments has been created the blends of the new and the used engine oil. The temperature dependence of the density [kg.m−3] has been measured in the range of −10 °C and +60 °C. The instrument Densito 30PX with the scale for measuring engine oils has been used. The dynamic viscosity [mPa.s] has been measured in the range of −10 °C and +100 °C. The Anton Paar digital viscometer with the concentric cylinders geometry has been used. In the accordance with the expected behaviour, the density and the kinematic viscosity of all oils was decreasing with the increasing temperature. To the physical properties has been the mathematical models created. For the temperature dependence of the density has been used the linearly mathematical model and the exponentially mathematical model. For the temperature dependence of the dynamic viscosity has been used the polynomial 6th degree. The knowledge of density and viscosity behaviour of an engine oil as a function of its temperature is of great importance, especially when considering running efficiency and performance of combustion engines. Proposed models can be used for description and prediction of rheological behaviour of engine oils.
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O’Brien, Kevin, Michele Basso, and James Schmiedeler. "2299." Journal of Clinical and Translational Science 1, S1 (September 2017): 61. http://dx.doi.org/10.1017/cts.2017.220.
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OBJECTIVES/SPECIFIC AIMS: Incomplete spinal cord injury (iSCI) is a life-long disability that typically results in a profound loss of locomotion capability. Current rehabilitation methods rarely restore full community ambulation, which in turn limits quality of life. Most individuals with iSCI exhibit persistent deficits in eccentric muscle control and reach recovery plateaus below the levels necessary for independent community ambulation. Eccentric motor control is essential during the weight acceptance phase of gait, which is emphasized during downhill walking. METHODS/STUDY POPULATION: The overground locomotion of subjects with chronic iSCI was analyzed both prior to and following a 12-week downhill body-weight-supported treadmill training regimen and compared to that of matched healthy controls in terms of kinematics, kinetics, and EMG activation. RESULTS/ANTICIPATED RESULTS: We expect to find significant differences between the controls and subjects with iSCI, with deficits in eccentric motor control accounting for some of these differences. In addition, we expect the downhill training to yield significant improvement in eccentric muscle control that translates into improvements in functional, overground walking for the subjects with iSCI. DISCUSSION/SIGNIFICANCE OF IMPACT: The goal is to determine if downhill training can improve eccentric motor control and extend recovery beyond established plateaus. OpenSim modeling of the experimental data will help quantify changes in eccentric control of individual muscles to clarify where specific gains are made.
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Ben-Shaul, Yoram, Rotem Drori, Itay Asher, Eran Stark, Zoltan Nadasdy, and Moshe Abeles. "Neuronal Activity in Motor Cortical Areas Reflects the Sequential Context of Movement." Journal of Neurophysiology 91, no. 4 (April 2004): 1748–62. http://dx.doi.org/10.1152/jn.00957.2003.
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Natural actions can be described as chains of simple elements, whereas individual motion elements are readily concatenated to generate countless movement sequences. Sequence-specific neurons have been described extensively, suggesting that the motor system may implement temporally complex motions by using such neurons to recruit lower-level movement neurons modularly. Here, we set out to investigate whether activity of movement-related neurons is independent of the sequential context of the motion. Two monkeys were trained to perform linear arm movements either individually or as components of double-segment motions. However, comparison of neuronal activity between these conditions is delicate because subtle kinematic variations generally occur within different contexts. We therefore used extensive procedures to identify the contribution of variations in motor execution to differences in neuronal activity. Yet, even after application of these procedures we find that neuronal activity in the motor cortex (PMd and M1) associated with a given motion segment differs between the two contexts. These differences appear during preparation and become even more prominent during motion execution. Interestingly, despite context-related differences on the single-neuron level, the population as a whole still allows a reliable readout of movement direction regardless of the sequential context. Thus the direction of a movement and the sequential context in which it is embedded may be simultaneously and reliably encoded by neurons in the motor cortex.
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Foster, Nathan C., Simon J. Bennett, Joe Causer, Digby Elliott, Geoffrey Bird, and Spencer J. Hayes. "Facilitating sensorimotor integration via blocked practice underpins imitation learning of atypical biological kinematics in autism spectrum disorder." Autism 24, no. 6 (March 13, 2020): 1494–505. http://dx.doi.org/10.1177/1362361320908104.
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The reduced efficacy of voluntary imitation in autism is suggested to be underpinned by differences in sensorimotor processing. We examined whether the imitation of novel atypical biological kinematics by autistic adults is enhanced by imitating a model in a predictable blocked practice trial order. This practice structure is expected to facilitate trial-to-trial sensorimotor processing, integration and encoding of biological kinematics. The results showed that neurotypical participants were generally more effective at imitating the biological kinematics across all experimental phases. Importantly, and compared to a pre-test where imitation was performed in a randomised (unpredictable) trial order, the autistic participants learned to imitate the atypical kinematics more effectively following an acquisition phase of repeatedly imitating the same model during blocked practice. Data from the post-test showed that autistic participants remained effective at imitating the atypical biological kinematics when the models were subsequently presented in a randomised trial order. These findings show that the reduced efficacy of voluntary imitation in autism can be enhanced during learning by facilitating trial-to-trial processing and integration of sensorimotor information using blocked practice. Lay Abstract Autistic people sometimes find it difficult to copy another person’s movement accurately, especially if the movement is unfamiliar or novel (e.g. to use chop sticks). In this study, we found that autistic people were generally less accurate at copying a novel movement than non-autistic people. However, by making a small adjustment and asking people to copy this movement for a set number of attempts in a predictable manner, we showed that autistic people did successfully learn to copy a new movement. This is a very important finding for autistic people because rather than thinking they cannot copy new movements, all that needs to be considered is for parents/guardians, teachers and/or support workers to make a small adjustment so that learning occurs in a predictable manner for new skills to be successfully acquired through copying. The implications from this study are wide-ranging as copying (imitation) and motor learning are important developmental processes for autistic infants and children to acquire in order to interact within the world. Therefore, practising these behaviours in the most effective way can certainly help the developmental pathway.
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Fregly, Benjamin J., Felix E. Zajac, and Christine A. Dairaghi. "Bicycle Drive System Dynamics: Theory and Experimental Validation." Journal of Biomechanical Engineering 122, no. 4 (March 22, 2000): 446–52. http://dx.doi.org/10.1115/1.1286678.
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Bicycle pedaling has been studied from both a motor control and an equipment setup and design perspective. In both cases, although the dynamics of the bicycle drive system may have an influence on the results, a thorough understanding of the dynamics has not been developed. This study pursued three objectives related to developing such an understanding. The first was to identify the limitations of the inertial/frictional drive system model commonly used in the literature. The second was to investigate the advantages of an inertial/frictional/compliant model. The final objective was to use these models to develop a methodology for configuring a laboratory ergometer to emulate the drive system dynamics of road riding. Experimental data collected from the resulting road-riding emulator and from a standard ergometer confirmed that the inertial/frictional model is adequate for most studies of road-riding mechanics or pedaling coordination. However, the compliant model was needed to reproduce the phase shift in crank angle variations observed experimentally when emulating the high inertia of road riding. This finding may be significant for equipment setup and design studies where crank kinematic variations are important or for motor control studies where fine control issues are of interest. [S0148-0731(00)02004-5]
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Kiørboe, Thomas, Anders Andersen, Vincent J. Langlois, and Hans H. Jakobsen. "Unsteady motion: escape jumps in planktonic copepods, their kinematics and energetics." Journal of The Royal Society Interface 7, no. 52 (May 12, 2010): 1591–602. http://dx.doi.org/10.1098/rsif.2010.0176.
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We describe the kinematics of escape jumps in three species of 0.3–3.0 mm-sized planktonic copepods. We find similar kinematics between species with periodically alternating power strokes and passive coasting and a resulting highly fluctuating escape velocity. By direct numerical simulations, we estimate the force and power output needed to accelerate and overcome drag. Both are very high compared with those of other organisms, as are the escape velocities in comparison to startle velocities of other aquatic animals. Thus, the maximum weight-specific force, which for muscle motors of other animals has been found to be near constant at 57 N (kg muscle) −1 , is more than an order of magnitude higher for the escaping copepods. We argue that this is feasible because most copepods have different systems for steady propulsion (feeding appendages) and intensive escapes (swimming legs), with the muscular arrangement of the latter probably adapted for high force production during short-lasting bursts. The resulting escape velocities scale with body length to power 0.65, different from the size-scaling of both similar sized and larger animals moving at constant velocity, but similar to that found for startle velocities in other aquatic organisms. The relative duration of the pauses between power strokes was observed to increase with organism size. We demonstrate that this is an inherent property of swimming by alternating power strokes and pauses. We finally show that the Strouhal number is in the range of peak propulsion efficiency, again suggesting that copepods are optimally designed for rapid escape jumps.
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Valle, Giacomo, Albulena Saliji, Ezra Fogle, Andrea Cimolato, Francesco M. Petrini, and Stanisa Raspopovic. "Mechanisms of neuro-robotic prosthesis operation in leg amputees." Science Advances 7, no. 17 (April 2021): eabd8354. http://dx.doi.org/10.1126/sciadv.abd8354.
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Above-knee amputees suffer the lack of sensory information, even while using most advanced prostheses. Restoring intraneural sensory feedback results in functional and cognitive benefits. It is unknown how this artificial feedback, restored through a neuro-robotic leg, influences users’ sensorimotor strategies and its implications for future wearable robotics. To unveil these mechanisms, we measured gait markers of a sensorized neuroprosthesis in two leg amputees during motor tasks of different difficulty. Novel sensorimotor strategies were intuitively promoted, allowing for a higher walking speed in both tasks. We objectively quantified the augmented prosthesis’ confidence and observed the reshaping of the legs’ kinematics toward a more physiological gait. In a possible scenario of a leg amputee driving a conventional car, we showed a finer pressure estimation from the prosthesis. Users exploited different features of the neural stimulation during tasks, suggesting that a simple prosthesis sensorization could be effective for future neuro-robotic prostheses.
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Drucker, E., and J. Jensen. "Kinematic and electromyographic analysis of steady pectoral fin swimming in the surfperches." Journal of Experimental Biology 200, no. 12 (January 1, 1997): 1709–23. http://dx.doi.org/10.1242/jeb.200.12.1709.
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The musculoskeletal mechanism of pectoral fin propulsion was investigated in representatives of the two subfamilies of the Embiotocidae (surfperches). Kinematic and electromyographic records of steady swimming by the open-water cruiser Amphistichus rhodoterus and the benthic maneuverer Embiotoca lateralis were compared at 80 % of the species' respective pectoral­caudal gait transition speeds. Synchronized records of fin movement and the intensity of pectoral muscle activity allowed previous hypotheses of muscle function, based on anatomical lines of action, to be tested. Divisions of the pectoral musculature inserting on the central and trailing- edge fin rays serve simple functions of abduction and adduction. Muscles controlling the fin's leading edge, by contrast, play more complex roles during the fin stroke, including deceleration of the fin at the downstroke­upstroke transition and rotation of the adducted fin during the non-propulsive period between fin beats. In spite of their phylogenetic and ecological divergence, the surfperches exhibit a number of mechanistic similarities which probably characterize the family. The timings of kinematic events and the maximal excursions of the fin tip, as well as the temporal order of muscle activation and the time to peak activity, are largely conserved. The predominant dorsoventral component of fin movement during the stride is consistent with a lift-based mechanism of propulsion. E. lateralis exhibits a greater anteroposterior range of motion and a more continuous period of fine motor control of the fin than A. rhodoterus, differences which may correspond to the species' respective capacities for maneuvering. Mechanistic variation in the family is associated with rather minor structural differences (in fin shape and fin base orientation). Owing to the similar functional demands placed on the pectoral fins of many fishes, it is probable that the mechanistic details of embiotociform swimming are widely distributed within the Perciformes.
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Geng, Rui, Jian She Li, and Yao Dong Gu. "Biomechanical Evaluation of Two Rowing Training Methods." Applied Mechanics and Materials 105-107 (September 2011): 283–85. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.283.
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This study is trying to find kinematics differences between on-water rowing and its simulation on Concept2 ergometer, and explain biomechanical differences between on-water rowing and its simulation on Concept2 ergometer, which can affect the rowers motor control pattern and their on-water rowing technique. Positions of the handle, seat and trunk, shell acceleration were measured in single scull on both machines and on-water in four female rowers. It was found there is about 60-80% similarity between on-ergo and on-water rowing, the drive length on Concept2 ergometer is 10%-12% shorter than on-water, the stroke rate on-water is 10-15% higher than on Concept2 ergometer, legs drive was 4-6% longer on Concept2 ergometer than on-water. Significant differences were found in the handle velocity and shell acceleration profiles. Machines should be considered as a cross-training for rowers and can’t replace on-water rowing.
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Churchland, Mark M., and Krishna V. Shenoy. "Temporal Complexity and Heterogeneity of Single-Neuron Activity in Premotor and Motor Cortex." Journal of Neurophysiology 97, no. 6 (June 2007): 4235–57. http://dx.doi.org/10.1152/jn.00095.2007.
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The relationship between neural activity in motor cortex and movement is highly debated. Although many studies have examined the spatial tuning (e.g., for direction) of cortical responses, less attention has been paid to the temporal properties of individual neuron responses. We developed a novel task, employing two instructed speeds, that allows meaningful averaging of neural responses across reaches with nearly identical velocity profiles. Doing so preserves fine temporal structure and reveals considerable complexity and heterogeneity of response patterns in primary motor and premotor cortex. Tuning for direction was prominent, but the preferred direction was frequently inconstant with respect to time, instructed-speed, and/or reach distance. Response patterns were often temporally complex and multiphasic, and varied with direction and instructed speed in idiosyncratic ways. A wide variety of patterns was observed, and it was not uncommon for a neuron to exhibit a pattern shared by no other neuron in our dataset. Response patterns of individual neurons rarely, if ever, matched those of individual muscles. Indeed, the set of recorded responses spanned a much higher dimensional space than would be expected for a model in which neural responses relate to a moderate number of factors—dynamic, kinematic, or otherwise. Complex responses may provide a basis-set representing many parameters. Alternately, it may be necessary to discard the notion that responses exist to “represent” movement parameters. It has been argued that complex and heterogeneous responses are expected of a recurrent network that produces temporally patterned outputs, and the present results would seem to support this view.
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Nadel, Bernard A., and Jiang Lin. "Automobile transmission design as a constraint satisfaction problem: modelling the kinematic level." Artificial Intelligence for Engineering Design, Analysis and Manufacturing 5, no. 3 (August 1991): 137–71. http://dx.doi.org/10.1017/s0890060400002651.
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This paper describes our preliminary results in applying constraint satisfaction techniques in a system we call TRANS-FORM for designing automatic automobile power transmissions. The work is being conducted in collaboration with the Ford Motor Company Advanced Transmission Design Department in Livonia, Michigan. Our current focus is on the design of the mechanical subsystem, but we anticipate extending this later to the electrical and hydraulic subsystems also. For simplicity, in the initial work reported here we restrict ourselves to the relatively well-explored class of transmissions having four forward speeds and one reverse speed, built from two planetary gearsets, cross-connected by two permanent links. Moreover, we pursue design of such transmissions only at the ‘kinematic level’. These two restrictions correspond to limiting respectively the breadth (generality) and the depth (detail or granularity) of the search space employed. We find that, at least for the restricted version of the problem pursued here, transmission design is an application very naturally formulated as a constraint satisfaction problem. Our present problem requires only 10 variables, with an average of about seven values each, and 43 constraints—making it similar in difficulty to about the 10-queens problem. So far, two of the classic transmissions, known as Axod and HydraMatic, have been rediscovered (at the kinematic level) by our program. Preliminary results also indicate that the constraint satisfaction framework will continue to remain adequate and natural even when the search space is allowed to be much broader and deeper. We expect that searches of such expanded spaces will soon lead to the discovery of totally new transmissions.
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Iezzi, Ennio, Antonella Conte, Antonio Suppa, Rocco Agostino, Loredana Dinapoli, Alessandra Scontrini, and Alfredo Berardelli. "Phasic Voluntary Movements Reverse the Aftereffects of Subsequent Theta-Burst Stimulation in Humans." Journal of Neurophysiology 100, no. 4 (October 2008): 2070–76. http://dx.doi.org/10.1152/jn.90521.2008.
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Theta-burst stimulation (TBS) is a technique that elicits long-lasting changes in the excitability of human primary motor cortex (M1). Tonic contraction of the target muscle modifies the aftereffects of TBS, whereas interactions between phasic muscle contraction and the aftereffects of TBS are unknown. In this paper, we investigated whether phasic voluntary movements influence TBS-induced changes in M1 excitability. We examined whether a brief sequence of phasic finger movements performed by healthy humans before both intermittent TBS (iTBS) and continuous TBS (cTBS) influences TBS-induced aftereffects. Ten healthy subjects underwent iTBS and cTBS. To evaluate the TBS-induced aftereffects on M1 excitability, single TMS pulses were given over the FDI motor area before (T0) and 5 (T1), 15 (T2), and 30 min (T3) after TBS. To find out whether finger movements influenced the TBS-induced aftereffects, we tested motor-evoked potentials (MEPs) size by single TMS pulses at T0, immediately after movements, and at T1–T3. We also measured the kinematic variables mean amplitude and mean peak velocity of the movements. When no phasic voluntary movements preceded TBS, iTBS elicited facilitatory and cTBS elicited inhibitory aftereffects on MEP size. Conversely, movements performed before TBS elicited significant changes in the direction of the TBS-induced aftereffects. iTBS produced inhibitory instead of facilitatory aftereffects and cTBS produced facilitatory instead of inhibitory aftereffects. Finger movements alone had no effects on MEPs size tested with single-pulse TMS. Peripheral electrical stimulation had no effect on iTBS-induced aftereffects. Repeated phasic finger movements interfere with TBS-induced aftereffects probably by modulating mechanisms of brain metaplasticity.
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Chen, Jing, Matteo Valsecchi, and Karl R. Gegenfurtner. "LRP predicts smooth pursuit eye movement onset during the ocular tracking of self-generated movements." Journal of Neurophysiology 116, no. 1 (July 1, 2016): 18–29. http://dx.doi.org/10.1152/jn.00184.2016.
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Several studies have indicated that human observers are very efficient at tracking self-generated hand movements with their gaze, yet it is not clear whether this is simply a by-product of the predictability of self-generated actions or if it results from a deeper coupling of the somatomotor and oculomotor systems. In a first behavioral experiment we compared pursuit performance as observers either followed their own finger or tracked a dot whose motion was externally generated but mimicked their finger motion. We found that even when the dot motion was completely predictable in terms of both onset time and kinematics, pursuit was not identical to that produced as the observers tracked their finger, as evidenced by increased rate of catch-up saccades and by the fact that in the initial phase of the movement gaze was lagging behind the dot, whereas it was ahead of the finger. In a second experiment we recorded EEG in the attempt to find a direct link between the finger motor preparation, indexed by the lateralized readiness potential (LRP) and the latency of smooth pursuit. After taking into account finger movement onset variability, we observed larger LRP amplitudes associated with earlier smooth pursuit onset across trials. The same held across subjects, where average LRP onset correlated with average eye latency. The evidence from both experiments concurs to indicate that a strong coupling exists between the motor systems leading to eye and finger movements and that simple top-down predictive signals are unlikely to support optimal coordination.
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Reynaga, Crystal M., Caitrin E. Eaton, Galatea A. Strong, and Emanuel Azizi. "Compliant Substrates Disrupt Elastic Energy Storage in Jumping Tree Frogs." Integrative and Comparative Biology 59, no. 6 (May 29, 2019): 1535–45. http://dx.doi.org/10.1093/icb/icz069.
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Abstract Arboreal frogs navigate complex environments and face diverse mechanical properties within their physical environment. Such frogs may encounter substrates that are damped and absorb energy or are elastic and can store and release energy as the animal pushes off during take-off. When dealing with a compliant substrate, a well-coordinated jump would allow for the recovery of elastic energy stored in the substrate to amplify mechanical power, effectively adding an in-series spring to the hindlimbs. We tested the hypothesis that effective use of compliant substrates requires active changes to muscle activation and limb kinematics to recover energy from the substrate. We designed an actuated force platform, modulated with a real-time feedback controller to vary the stiffness of the substrate. We quantified the kinetics and kinematics of Cuban tree frogs (Osteopilus septentrionalis) jumping off platforms at four different stiffness conditions. In addition, we used electromyography to examine the relationship between muscle activation patterns and substrate compliance during take-off in a knee extensor (m. cruralis) and an ankle extensor (m. plantaris). We find O. septentrionalis do not modulate motor patterns in response to substrate compliance. Although not actively modulated, changes in the rate of limb extension suggest a trade-off between power amplification and energy recovery from the substrate. Our results suggest that compliant substrates disrupt the inertial catch mechanism that allows tree frogs to store elastic energy in the tendon, thereby slowing the rate of limb extension and increasing the duration of take-off. However, the slower rate of limb extension does provide additional time to recover more energy from the substrate. This work serves to broaden our understanding of how the intrinsic mechanical properties of a system may broaden an organism’s capacity to maintain performance when facing environmental perturbations.
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Javaherchi, Hossein, Kambiz Ghaemi Osgouie, and Amir Ali Akbar Khayyat. "Optimal Balancing of a 3-RPS Robot Manipulator Using Genetic Algorithm." Applied Mechanics and Materials 390 (August 2013): 377–82. http://dx.doi.org/10.4028/www.scientific.net/amm.390.377.
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Optimal balancing is a very important issue in mechanism design and has only recently been introduced to the designing step of robotic mechanisms. In creating the best robot design, the optimal balancing plays a vital role because it reduces the required motor power. To have a more-effective control system, it is very important to eliminate or significantly reduce the gravity load especially at the actuated joints. Tackling of a balancing problem with these objectives, leads to an optimization problem. This paper aims to describe the use of conventional and evolutionary optimization techniques for a 3-RPS parallel manipulator, using Genetic Algorithm (GA). To this end, it is required to find the desired weight for the links, to minimize the force at the actuators. At first the direct and inverse kinematic and dynamic analyses are performed, and then the optimum weight of the robot will be obtained. Afterwards, the optimization model is improved by adding two new elements. Also, a comprehensive user-friendly general-purpose software package is introduced. The methods used in this article can be applied to obtain solutions for a wide range of similar problems without further simplifications.
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Titarenko, Svitlana. "MULTIMEDIA TECHNOLOGIES USAGE TO OPTIMIZE MOTOR ACTIVITY OF KINDERGARTEN CHILDREN." OPEN EDUCATIONAL E-ENVIRONMENT OF MODERN UNIVERSITY, no. 8 (2020): 147–53. http://dx.doi.org/10.28925/2414-0325.2020.8.13.
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The article analyzes psychological and pedagogical literature on the problem of optimization of the preschool children’s motor activity. It is noted that movements are just as necessary for the normal growth and development of a child as good nutrition. Physical exercise does not only develop and strengthen a child’s body, prevents various diseases, but also is one of the effective means of treating and restoring a child's strength after illness. Based on the analysis of modern scientific and methodological literature, it is found that a considerable part of the studies in the field of physical education is devoted to the creation of recommendations for physical exercises of schoolchildren and other segments of the population on the basis of computer technologies, control systems, assessment and accumulation of information on the physical fitness level and health status. It is established that the use of multimedia technology in the process of carrying out physical and health measures in the institution of preschool education helps to optimize the motor activity of preschool children. The specifics of the multimedia presentations usage in work with preschool children are characterized. It is noted that multimedia technologies allow solving the problem of finding and storing information, planning, controlling and managing physical education, diagnostics of health status and of children’s physical fitness level. The author notes that the presentation can also be used to explain to children the rules of sports games, tactical actions of players, vividly present historical events, biographies of athletes. It is noted that the creation of flash presentations and videos with complexes of developmental exercises is appropriate to use during the morning gymnastics. The use of multimedia educational tools allows to visualize clearly the spatial characteristics of movements, to calculate with high accuracy the kinematic parameters of the motor actions performing technique in the playing activities, which is of particular importance in the development of children’s spatial orientation. It is noted that the priority area in the work of each pre-school educational establishment is to improve the quality of education through the use of innovative technologies in physical education classes, in particular optimization of physical activity. The prospects for further research in this area, the need to use multimedia technologies in the process of preparing future caregivers for the implementation of the tasks in physical education of preschool children in the context of distance education which include the need to find and develop of science-based information and communication technologies in the preschoolers’ physical education are specified.