Motor Space Research Articles

Human motor learning dynamics in high-dimensional tasks.

Conventional approaches to enhance movement coordination, such as providing instructions and visual feedback, are often inadequate in complex motor tasks with multiple degrees of freedom (DoFs). To effectively address coordination deficits in such complex motor systems, it becomes imperative to develop interventions grounded in a model of human motor learning; however, modeling such learning processes is challenging due to the large DoFs. In this paper, we present a computational motor learning model that leverages the concept of motor synergies to extract low-dimensional learning representations in the high-dimensional motor space and the internal model theory of motor control to capture both fast and slow motor learning processes. We establish the model's convergence properties and validate it using data from a target capture game played by human participants. We study the influence of model parameters on several motor learning trade-offs such as speed-accuracy, exploration-exploitation, satisficing, and flexibility-performance, and show that the human motor learning system tunes these parameters to optimize learning and various output performance metrics.

The impact of visual and motor space size on gaze-based target selection

ABSTRACT Objective Previous studies have demonstrated that making a target larger is sufficient to compensate for the inaccuracy of gaze-based target selection. However, few studies systemically examined the individual contribution of the target’s motor and visual space size in gaze selection. We investigated how the motor and visual space size affect gaze-based target selection. Method Experiment 1 was used to examine the effect of the invisible expanded motor space in a 2D target selection task under hand-based and gaze-based control modes. Experiment 2 was used to examine the impact of the invisible expanded motor space on gaze-based target selection performance with different visual-space sizes. Results As the motor-space size increased, participants selected targets more efficiently and experienced less frustration and temporal demand; these effects were more pronounced in the gaze-based control mode. The selection was faster in the group with a larger visual-space size. Moreover, there were significant interactions between visual-space size and motor-space size on the throughput of gaze-based selection, which refers to the efficiency of input method that containing the accuracy and speed. These interactions also significantly affected endpoint distance variation and effort demand. Conclusions The motor-space size, even invisible, is the determining factor in facilitating the gaze selection performance. Additionally, the size of the visual space has a feedforward effect on selection speed and modulates the effect of motor space. These findings provide insights into the contribution of these two spaces and a new perspective to optimize the gaze-based interface.

Goal-Directed Tactile Exploration for Body Model Learning Through Self-Touch on a Humanoid Robot

An early integration of tactile sensing into motor coordination is the norm in animals, but still a challenge for robots. Tactile exploration through touches on the body gives rise to first body models and bootstraps further development such as reaching competence. Reaching to one’s own body requires connections of the tactile and motor space only. Still, the problems of high dimensionality and motor redundancy persist. Through an embodied computational model for the learning of self-touch on a simulated humanoid robot with artificial sensitive skin, we demonstrate that this task can be achieved (i) effectively and (ii) efficiently at scale by employing the computational frameworks for the learning of internal models for reaching: intrinsic motivation and goal babbling. We relate our results to infant studies on spontaneous body exploration as well as reaching to vibrotactile targets on the body. We analyze the reaching configurations of one infant followed weekly between 4 and 18 months of age and derive further requirements for the computational model: accounting for (iii) continuous rather than sporadic touch and (iv) consistent redundancy resolution. Results show the general success of the learning models in the touch domain, but also point out limitations in achieving fully continuous touch.

Learning and change in a dual lexicon model of speech production.

Speech motor processes and phonological forms influence one another because speech and language are acquired and used together. This hypothesis underpins the Computational Core (CC) model, which provides a framework for understanding the limitations of perceptually-driven changes to production. The model assumes a lexicon of motor and perceptual wordforms linked to concepts and whole-word production based on these forms. Motor wordforms are built up with speech practice. Perceptual wordforms encode ambient language patterns in detail. Speech production is the integration of the two forms. Integration results in an output trajectory through perceptual-motor space that guides articulation. Assuming successful communication of the intended concept, the output trajectory is incorporated into the existing motor wordform for that concept. Novel word production exploits existing motor wordforms to define a perceptually-acceptable path through motor space that is further modified by the perceptual wordform during integration. Simulation results show that, by preserving a distinction between motor and perceptual wordforms in the lexicon, the CC model can account for practice-based changes in the production of known words and for the effect of expressive vocabulary size on production accuracy of novel words.

Exploring the Effects of Tasks with Different Decision-Making Levels on Ball Control, Passing Performance, and External Load in Youth Football.

This study aimed to understand how the design of decision-making tasks affects youth football players' ball control, passing performance, and external load. A total of 16 male youth football players (age: 12.94 ± 0.25 years) competed in various tasks based on the following levels of decision-making: (i) low decision-making (Low DM), which consisted of a predefined ball control and passing sequence; (ii) moderate decision-making (Mod DM), which consisted of maintaining possession in a square with four players and two balls while maintaining the same position; and (iii) high decision-making (High DM), which consisted of a 3 vs. 3 + 2 neutral players ball possession game. The study design consisted of a pre-post design (a 6 min pre-test game, a 6 min intervention, and a 6 min post-test game). The players' ball control and passing performance were measured using the game performance evaluation tool and notational analysis, while GPS data were used to determine their physical performance. The pre-post test analysis revealed decrements in players' ability to identify more offensive players after the Mod DM task (W = 9.50, p = 0.016), while there was an increase in their ability to receive the ball towards the space following the High DM task (t = -2.40, p = 0.016). Analysis between groups showed lower values in most ball control variables for the Low DM task compared to the Mod DM task (ball control execution, p = 0.030; appropriateness, p = 0.031; motor space, p = 0.025), while there were also lower values in the distance covered while sprinting (p = 0.042). Overall, prescriptive tasks (Low DM) that are repetitive in nature may affect players' perceptual attunement, whereas static tasks (e.g., Mod DM) may limit their ability to locate players in more offensive positions. Moreover, game-based situations (High DM) seem to acutely enhance players' performance, possibly due to contextual dependency. Overall, coaches should carefully consider the type of practice structure when designing tasks that aim to improve players' technical skills in youth football.

IMPACTO DAS CARACTERÍSTICAS MORFOLÓGICAS E DAS HABILIDADES MOTORAS AO REALIZAR GYAKU TSUKI

ABSTRACT Objective The aim of this study was to determine the influence of morphology on karate characteristics and basic motor skills for the criterion variable counter-punch (gyako zuki) in boys, after a two-year training program. Methods A system of 25 variables (12 morphological, 12 motor, and one situational (gyako zuki)) was applied in a sample of 82 karatists, aged 10 to 14 years. Data were processed using regression analysis. Results Body weight had a statistically significant influence on the criterion variable in the initial measurement, as well as on the triceps and back skinfolds in the final measurement. In the motor space, semi-squat endurance had a significant impact on both initial and final measurements. In the reduced system, triple jump, half-squat endurance, and long jump impacted the initial measurement, while the 30-second torso lift, hyperextension on the bench, and semi-squat endurance impacted the final measurement. Conclusion From the data obtained, it can be concluded that the counter-punch (gyako zuki) performance results were better in participants with higher body weight, longer arms, less subcutaneous upper arm and back fat, greater static and explosive power in the lower limbs, and greater hamstring and spine flexibility. Evidence Level II; Therapeutic Studies – Investigating the results.

Relacije između motoričkih sposobnosti i morfoloških karakteristika kao predispozicije učenika za bavljenje sportom

The aim of this paper is to look at the relationship between morphological characteristics and motor abilities as a predisposition of students to play sports. On a sample of 58 students aged 9 (±0.5), a set of two variables was applied to define the morphological space (body height and body mass), and a set of three variables to assess the motor space of explosive power and motor speed (standing long jump, shuttle running 10 x 5 m, and hand tapping). The explanation of individual differences (variability) on the criterion variable based on a linear combination of a set of predictor variables was performed using a multiple linear regression. It has been established that better results on the long jump motor test are achieved by those students who achieved better results on the 10 x 5 m shuttle running test and who have a lower body mass. In addition, it can be concluded that better results in the motor test of shuttle running 10 x 5 m are achieved by those students who have a lower body mass and better results on the standing long jump and hand tapping tests. When it comes to the results in the hand tapping motor test, it can be stated that students who have a lower body height and a better/ faster result in the shuttle running 10 x 5 m will achieve better results. Accordingly, in physical and health education classes, special attention should be paid to the development of explosive strength and motor speed as particularly important motor abilities in the identification and selection of children and young people for sports.

Design and Performance Analysis of a Bioelectronic Controlled Hybrid Serial-Parallel Wrist Exoskeleton.

Wrist exoskeletons are increasingly being used in the rehabilitation of stroke and hand dysfunction because of its ability to assist patients in high intensity, repetitive, targeted and interactive rehabilitation training. However, the existing wrist exoskeletons cannot effectively replace the work of therapist and improve hand function, mainly because the existing exoskeletons cannot assist patients to perform natural hand movement covering the entire physiological motor space (PMS). Here, we present a bioelectronic controlled hybrid serial-parallel wrist exoskeleton HrWr-ExoSkeleton (HrWE) which is based on the PMS design guidance, the gear set can carry out forearm pronation/supination (P/S) and the 2-DoF parallel configuration fixed on the gear set can carry out wrist flexion/extension (F/E) and radial/ulnar deviation (R/U). This special configuration not only provides enough range of motion (RoM) for rehabilitation training (85F/85E, 55R/55U, and 90P/90S), but also makes it easier to provide the interface for finger exoskeletons and be adapted to upper limb exoskeletons. In addition, to further improve the rehabilitation effect, we propose a HrWE-assisted active rehabilitation training platform based on surface electromyography signals.

The Curved Openspace Algorithm and a Spike-Latency Model for Sonar-Based Obstacle Avoidance.

The rapid control of a sonar-guided vehicle to pursue a goal while avoiding obstacles has been a persistent research topic for decades. Taking into account the limited field-of-view of practical sonar systems and vehicle kinematics, we propose a neural model for obstacle avoidance that maps the 2-D sensory space into a 1-D motor space and evaluates motor actions while combining obstacles and goal information. A two-stage winner-take-all (WTA) mechanism is used to select the final steering action. To avoid excessive scanning of the environment, an attentional system is proposed to control the directions of sonar pings for efficient, task-driven, sensory data collection. A mobile robot was used to test the proposed model navigating through a cluttered environment using a narrow field-of-view sonar system. We further propose a spiking neural model using spike-timing representations, a spike-latency memory, and a “race-to-first-spike” WTA circuit.

STRUCTURE OF SITUATIONAL MOTOR ABILITIES IN HANDBALL

Goal work is to determine the structure of situational motor skills in handball, code students of the Faculty of Sports and Physical Education in Leposavić, aged 19 to 21. By applying the method of component factor analysis inthree latent dimensions are isolated in the situational motor space: the first is responsible for the speed of movement without the ball and with the ball and handling the ball; the second for the power of throwing the ball and situational accuracy of shooting from 7 m; The results of the research confirmed the connection between isolated latent situational motor dimensions and that the speed of ballless movement with the ball, ball handling, ball throwing power and situational accuracy depend on the same regulatory mechanisms. The conclusion is that in determining the optimal anthropological model in domain kinesiological education, planning, programming and selection in handball, special attention should be paid to situational motor skills.

Effect of cumulative distance in motor space on segment-sized slips in 3-word phrases

Slips, or speech errors (e.g., “teep a cape” for “keep a tape”), have been described as the disordered arrangement of discrete elements, giving rise to the hypothesis that these arise from misordering during phonological encoding. An alternative hypothesis is that slips are articulatory timing errors, conditioned by the same motor factors that underlie coarticulation. This hypothesis motivates the present study, which used a modified slip procedure to elicit errors from 40 native English-speaking adults. Participants spoke 3-word phrases that were constructed as mini tongue twisters, with alternating word onsets and repeating rhymes. These phrases were designed to condition slips to a greater or less extent according to coarticulatory-adjacent processes (e.g., palatalization). A metric of cumulative distance-traveled in motor space during phrase production was also calculated: the degree of change in vocal tract shapes across the phrase, estimated using data generated within the tubesounds model in ArtiSynth. Phrases designed to more strongly condition slips were expected to cover less cumulative distance in motor space than phrases designed to less strongly condition slips. The distance-traveled metric did not always align with this expectation, but was nonetheless a better predictor of presence/absence of slips than phrase condition in analyses on preliminary data.

Differential mapping spiking neural network for sensor-based robot control

In this work, a spiking neural network (SNN) is proposed for approximating differential sensorimotor maps of robotic systems. The computed model is used as a local Jacobian-like projection that relates changes in sensor space to changes in motor space. The SNN consists of an input (sensory) layer and an output (motor) layer connected through plastic synapses, with inter-inhibitory connections at the output layer. Spiking neurons are modeled as Izhikevich neurons with a synaptic learning rule based on spike timing-dependent plasticity. Feedback data from proprioceptive and exteroceptive sensors are encoded and fed into the input layer through a motor babbling process. A guideline for tuning the network parameters is proposed and applied along with the particle swarm optimization technique. Our proposed control architecture takes advantage of biologically plausible tools of an SNN to achieve the target reaching task while minimizing deviations from the desired path, and consequently minimizing the execution time. Thanks to the chosen architecture and optimization of the parameters, the number of neurons and the amount of data required for training are considerably low. The SNN is capable of handling noisy sensor readings to guide the robot movements in real-time. Experimental results are presented to validate the control methodology with a vision-guided robot.

The Motor Representation of Sensory Experience

How do we estimate the position of an object in the world around us? Naturally, we would direct our gaze to that object. Accordingly, neural motor coordinates entail the distance of external objects and thus might be used to derive perceptual estimates. Several general frameworks in the history of perceptual science have offered such a view.1-4 However, a mechanism showing how motor and visual processes communicate remains elusive. Here, we report that every post-saccadic error biases visual localization in a serially dependent manner. In order to simulate a realignment of visual space through motor coordinates, we induced an artificial de-alignment between visual and motor space. We found that when performing saccades under this distortion, post-saccadic error information clearly realigned visual and motor space, again in a serially dependent manner. These results demonstrate that the consequences of every saccade directly influence where we see objects in the world. On a neural basis, this requires that motor signals, which generate close to the saccade production machinery, are reported to cortical areas and arrange visual space. This view is consistent with recent electrophysiological findings of post-saccadic error processing in posterior parietal cortex.5.

Sensorimotor control and linear visuomotor gains.

In everyday life, we often use graphical interfaces where the visual space is mapped to the motor space with a visuomotor gain called the control display gain. One of the key objectives in the field of Human Computer Interaction is to design this control display gain so as to enhance users' performance. Although the control display gain involved in operating systems has been found to improve users' pointing performance, the reasons for this improvement have not yet been fully elucidated, especially because the control display gains on operating systems are both non-constant and non-linear. Here, we tested non-constant but linear velocity-based control display gains to determine which parameters were responsible for pointing performance changes based on analyses of the movement kinematics. Using a Fitts' paradigm, constant gains of 1 and 3 were compared with a linearly increasing gain (i.e., the control display gain increases with the motor velocity) and a decreasing gain (i.e., the control display gain decreases with the motor velocity). Three movements with various indexes of difficulty (ID) were tested (3, 5 and 7 bits). The increasing gain was expected to increase the velocity of the initial impulse phase and decrease that of the correction phase, thus decreasing the movement time (MT), and the contrary in the case of the decreasing gain. Although the decreasing gain increased MT at ID3, the increasing gain was found to be less efficient than the constant gain of 3, probably because a non-constant gain between the motion and its visual consequences disrupted the sensorimotor control. In addition, the kinematic analyses of the movements suggested that the motion profile was planned by the central nervous system based on the visuomotor gain at maximum motor velocity, as common features were observed between the constant gain of 1 and the decreasing gain, and between the constant gain of 3 and the increasing gain. By contrast, the amplitude of the velocity profile seemed to be specific to each particular visuomotor mapping process.

The patterning of local variability during the acquisition of a novel whole-body continuous motor skill in young adults.

There is increasing evidence that movement variability during motor skill acquisition plays a functional role. Specifically, initial variability might represent exploration of the possible motor space for solutions and error identification. Following practice, individuals might exploit a reduced amount of motor solutions to execute the task. While this variability pattern has been supported during discrete upper limb and multi-finger force tasks, there is a paucity of evidence for continuous whole-body motor tasks. Therefore, the purpose of this study was to characterize the role of variability during the acquisition of a whole-body continuous motor task across practice sessions in young adults. Twelve young adults aged 18-35-years participated in this study. Subjects practiced a novel, sagittal plane task, the kettlebell swing, using an online training video. We conducted an uncontrolled manifold analysis to partition local variability of the configuration of the kettlebell and body segments based on their impact on the position of the center-of-mass (COM) in the sagittal plane. Our results demonstrated that following initial practice, variability that did not affect the COM position remained elevated, suggesting sustained exploration of motor solutions. Following multiple practice sessions, variability related to motor solutions decreased, potentially indicating exploitation. The results from this study support the proposal that young adults initially utilize a range of motor solutions when acquiring a whole-body motor skill, followed by exploitation of stereotypic movement.

Motoričke sposobnosti dece osnovnoškolskog uzrasta - razlike u odnosu na uzrast

Physical education, from the earliest age in preschool institutions, and then through primary and secondary schools, is the only place where children can, in the right way, acquire the knowledge on sports, skills, behaviour, necessary in order to get the continuity of physical activities in the adulthood. Primary school is a period when the students experience great changes in the overall developing status. Therefore, Physical Education has a fundamental role in the development of psychosomatic characteristics of children. While planning lessons of Physical Education, there is a special emphasis on the development of motor skills. The goal of this research refers to the establishing of the existing differences in the motor space of primary school children in relation to age. The sample consisted of 231 examinees who attended 3rd, 4th, 5th and 6th grade (age 11 ± 1.6 years), out of which there were (N = 109; TV = 147.6 ± 7; TM = 39.6 ± 7.1) boys, and (N = 122; TV = 148.3 ± 5.9; TM = 40 ± 5.3) girls. All examinees were the students from the territory of Zlatibor region and with the signed permission for performing testing by both parents. Motor skills have been estimated within school Physical Education, all with the purpose of getting more realistic picture on the motor skills of children. The presented results point to the existing differences between the groups of examinees of both genders on a general level, as well as the individual differences within the motor space. These differences are more noticeable with boys (F = 5.92; P = .00) than with girls (F = 4.79; P = .00). Statistically greater differences with boys have been noted in the following variables: "Hand tapping", "Hand clapping", "Throwing basketball ball", "the 30 m running flying start", "Pull-ups", and "Torso lift-ups". With girls, statistically significant difference have been notes in the following variables: "Throwing basketball ball", "the 30 m running flying start" and "Torso lift-ups". The value of this work is reflected in the fact that, during testing, a great number of tests were used for estimation of the examinees' motor space, all with the purpose of getting more complete picture on the existence of differences among the groups, categorised by gender and age. The importance of testing and perception of differences in motor skills and their monitoring presents one of the important activities during PE classes, all with the purpose of the adequate lesson programming, but also monitoring the motor development.

СТАН РОЗВИТКУ ДІТЕЙ У ГРУПАХ РАННЬОГО ВІКУ В ЗАКЛАДАХ ДОШКІЛЬНОЇ ОСВІТИ: РЕЗУЛЬТАТИ КОНСТАТУВАЛЬНОГО ЕКСПЕРИМЕНТУ

Preliminary results of the problem of personal development of a child in the early stages of ontogenesis, which is the topic of research "Education of young children in preschool educational institutions of different types", carried out in the Laboratory of Preschool Education and Upbringing of the Institute of Problems on Education of the NAES of Ukraine (2019-2021). Based on the theoretical analysis of the researched problem, practice of organization of educational process in groups of early age of preschool educational institutions of Ukraine, the necessity of application of a polycriteria approach to clarification of a state of development of children of early age groups in preschool educational institutions is proved. The criterion-diagnostic apparatus and methodological tools were developed, which allowed to study the organization of the educational environment and educational process in groups of early age in preschool educational institutions, the readiness of educators of early age groups to implement a personality-oriented approach to organizing children's activities, development of 3-years old children in the following aspects: motor, communicative, social, artistic and aesthetic.Preliminary analysis of the data of the ascertaining stage of the pedagogical experiment, quantitative and qualitative results are presented. Thus, the study of the educational environment in early age groups made it possible to establish: the motor space of preschool educational institutions of different types has no fundamental differences; there is a dominance of the educator's position, which minimizes the communicative and personal activity of children; uniformity of methods and forms of interaction of teachers with children, the majority of group forms of the organization of children, actions of children according to the sample and instructions. The study of educators' readiness for innovative pedagogical activity showed the predominance of medium and low levels over sufficient and high ones. According to the criteria and indicators of upbringing / development of young children: cognitive (initial ideas about the means and methods of a particular activity; mastering passive and active vocabulary sufficient for the activity), emotional (interest in a particular activity, desire to act alone or together with an adult, identifying a positive attitude to a particular activity and interaction with others), activity (acting on a sample, adequate use of objects and performing 2-3 actions with them), there were clarified the signs that made it possible to determine the levels of motor, communicative, social, artistic and aesthetic development in young children (primary, secondary, sufficient, high).

Design and Analysis of a Permanent Magnet Synchronous Motor Considering Axial Asymmetric Position of Rotor to Stator

This paper presents the design and analysis of a permanent magnet synchronous motor (PMSM) considering the axial asymmetric PM overhang for a smart actuator (SA) application such as an isokinetic exercise machine. This structure helps take advantage of the motor space effectively and makes the system small in size and light in weight. However, two drawbacks related to the performance of motor occur when the axial asymmetric PM overhang is used: (1) an axial attractive force (AAF) is created, which can produce motor noise and vibration; (2) the torque of motor is reduced compared with the symmetric PM overhang model. We used five steps to solve these problems. Firstly, the AAF according to the variation in axial position of the rotor to the stator was calculated and analyzed. Secondly, the torque was calculated under the same conditions to confirm that the system requirements were satisfied. The three-dimensional finite element analysis was used to determine the AAF and torque. Thirdly, the appropriate axial position of the rotor to the stator was suggested considering the analysis results and space inside the housing. Next, the commercial bearing type was chosen so that the total force acting on the bearing was below the bearing load limit to ensure motor stability. Finally, a prototype model was made and tested to confirm the accuracy of the analytical results. Through this study, by using the axial asymmetric PM overhang, the total length of SA was reduced by 5mm and the performance of motor was guaranteed.

The Emergence of Discrete Perceptual-Motor Units in a Production Model That Assumes Holistic Phonological Representations.

Intelligible speakers achieve specific vocal tract constrictions in rapid sequence. These constrictions are associated in theory with speech motor goals. Adult-focused models of speech production assume that discrete phonological representations, sequenced into word-length plans for output, define these goals. This assumption introduces a serial order problem for speech. It is also at odds with children's speech. In particular, child phonology and timing control suggest holistic speech plans, and so the hypothesis of whole word production. This hypothesis solves the serial order problem by avoiding it. When the same solution is applied to adult speech the problem becomes how to explain the development of highly intelligible speech. This is the problem addressed here. A modeling approach is used to demonstrate how perceptual-motor units of production emerge over developmental time with the perceptual-motor integration of holistic speech plans that are also phonological representations; the specific argument is that perceptual-motor units are a product of trajectories (nearly) crossing in motor space. The model, which focuses on the integration process, defines the perceptual-motor map as a set of linked pairs of experienced perceptual and motor trajectories. The trajectories are time-based excursions through speaker-defined perceptual and motor spaces. By hypothesis, junctures appear where motor trajectories near or overlap one another in motor space when the shared (or extremely similar) articulatory configurations in these regions are exploited to combine perceptually-linked motor paths along different trajectories. Junctures form in clusters in motor space. These clusters, along with their corresponding (linked) perceptual points, represent perceptual-motor units of production, albeit at the level of speech motor control only. The units serve as pivots in motor space during speaking; they are points of transition from one motor trajectory to another along perceptually-linked paths that are selected to produce best approximations of whole word targets.

Investigating Gesture Typing for Indirect Touch

With the development of ubiquitous computing, entering text on HMDs and smart TVs using handheld touchscreen devices (e.g., smartphone and controller) is becoming more and more attractive. In these indirect touch scenarios, the touch input surface is decoupled from the visual display. Compared with direct touch input, entering text using a keyboard in indirect touch is more challenging because before the finger touch, no visual feedback is available for locating the touch finger. Aiming at this problem, in this paper, we investigate the feasibility of gesture typing for indirect touch since keeping the finger in touch with the screen during typing makes it possible to provide continuous visual feedback, which is beneficial for increasing the input performance. We first examine users' gesture typing ability in terms of the appropriate keyboard size and location in motor space and then compare the typing performance in direct and indirect touch mode. We then propose an improved design to address the uncertainty and inaccuracy of the first touch. Our evaluation result shows that users can quickly acquire indirect gesture typing, and type 22.3 words per minute after 30 phases, which significantly outperforms previous numbers in literature. Our work provides the empirical support for leveraging gesture typing for indirect touch.