Precise Movements Research Articles

A Joint Trajectory Planning and Signal Control Framework for a Network of Connected and Autonomous Vehicles

The advancement of the Intelligent Transport Systems (ITS) and the emerging Connected and Automated Vehicles (CAVs) technology are acknowledged to hold a great potential to mitigate challenging problems in the current transportation networks. Particularly, a proper traffic control strategy with a precise vehicular movement control scheme can alleviate the congestion and improve the safety and efficiency of the traffic. This paper proposes a novel bi-level control framework that combines a design of traffic signal timings at a network level, and a detailed trajectory control policy for individual vehicles at a link-level within a network of CAVs. We develop a group-based longitudinal trajectory planning scheme to coordinate vehicular movements at the lower level of our framework while abiding by the signal operations along with end-to-end vehicle routing decisions from the upper network level optimization. This joint and mutual interaction between the two different control strategies in the urban signalized corridors is complex and can significantly affect the overall network’s performance, nevertheless has not been explored previously in the literature. The proposed framework enables such studies where we derive an efficient algorithm that iteratively solves the mixed-integer linear programming (MILP) and linear programming models in each link at the lower and over the network at the upper levels, respectively. Numerical results show the effectiveness of the proposed joint control framework in network performance regarding the average travel time, queue formation and dissipation across the network.

Neck strength and force in reaction time task of adolescent athletes with and without concussion history: A pilot study

ObjectivesAssess the impact of concussion by comparing reaction time, peak force recruitment, and rate of force development of adolescent athletes returning from concussion against age- and sex-matched controls in visual-elicited neck movement. DesignAthletes sat secured in a custom-built isometric device with their heads secured in a helmet and attached to a 6-axis load cell. They performed neck flexion, extension, and lateral flexion in response to a visual cue. Three trials in each direction were used for statistical analyses; peak force and rate of force development were normalized against athlete mass. SettingLaboratory. Participants26 adolescent/young adult athletes (8F/18M), either recently concussed (and cleared for return to sport) or an age- and sex-matched healthy control. Main outcome measuresReaction time, angle, standard deviation of angle, deviation from target angle, peak force, and RFD over 50, 100, 150,and 200 ms of movement were measured for each trial. ResultsConcussed athletes had decreased normalized peak force (P = 0.008) and rate of force development (P < 0.001–0.007). In neck extension, concussed athletes also had decreased movement precision (P = 0.012). ConclusionsConcussion is associated with alterations of neck biomechanics that decrease overall neck strength.

Magnetic Microsphere Scaffold-Based Soft Microbots for Targeted Mesenchymal Stem Cell Delivery.

A soft microbot assembled from individual magnetic microsphere scaffold (MMS) beads carrying mesenchymal stem cells (MSC) is navigated under magnetic actuation, where an oscillating field induces mechanical flexion to propel the microbot toward the target site. A seven-bead microbot attained a top translational speed of 205.6µms-1 (0.068 body lengths-1 ) under 10mT and 2Hz field oscillation. The shallow flexion angle (10-24.5°) allows precision movements required to navigate narrow spaces. Upon arrival at the target site, the MMS beads unload their MSC cargo following exposure to a phosphate-buffered saline (PBS) solution, mimicking the extracellular fluid's sodium concentration. The released stem cells have excellent viability and vitality, promoting rapid healing (i.e., 83.2% vs 49%) in a scratch-wound assay. When paired with minimally invasive surgical methods, such as laparoscopy and endoscopic surgery, the microbot can provide precise stem cell delivery to hard-to-reach injury sites in the body to promote healing. Moreover, the microbot is designed to be highly versatile, with individual MMS beads customizable for cargoes of live cells, biomolecules, bionanomaterials, and pharmaceutical compounds for various therapeutic requirements.

Effects of short-term motor training on accuracy and precision of simple jaw and finger movements after orthodontic treatment and orthognathic surgery: A case-control study.

Orthognathic surgery has been performed with increasing frequency for the treatment of severe malocclusion, yet the postsurgical neuromuscular recovery of patients has been inadequately studied. To investigate the effect of short-term and simple jaw motor training on accuracy and precision of jaw motor control in patients following orthodontic treatment and orthognathic surgery. Twenty patients who had completed preoperative orthodontics, 20 patients who had undergone bimaxillary orthognathic surgery and 20 age-and-gender-matched healthy controls participated in the study. Participants were asked to perform 10 continuous jaw opening and finger lifting movements before and after a 30-min motor training session. The variability in the amplitude of these simple movements was expressed as percentage in relation to the target position (accuracy - Daccu ) and as coefficient of variation (precision - CVprec ) to describe the motor performance. Furthermore, the changes in amplitude before and after training were measured in percentage. Daccu and CVprec of simple jaw and finger movements significantly decreased after motor training (p ≤ .018) in all groups. The relative changes in finger movements were higher than jaw movements (p < .001) but with no differences among the groups (p ≥ .247). Both accuracy and precision of simple jaw and finger movements improved after short-term motor training in all three groups, demonstrating the inherent potential for optimization of novel motor tasks. Finger movements improved more than jaw movements but with no differences between groups, suggesting that changes in occlusion and craniofacial morphology are not associated with impaired neuroplasticity or physiological adaptability of jaw motor function.

Is Balance Training Using Biofeedback Effective in the Prophylaxis of Falls in Women over the Age of 65?

The paper aims to investigate the usefulness of training in improving mobility and reducing the risk of falls of patients with osteoarthritis by using a force plate and virtual reality as rehabilitation tools. The study involved 72 women randomly divided into two equal groups: the force plate training group, which underwent virtual balance training with visual motor feedback, and the gym training group, which received conventional balance training only. The functional balance assessment was performed before and after the rehabilitation by computerized posturography in a relaxed upright position with open and closed eyes, with visual motor feedback. In the FPT group in the feedback measurement, the mean radius of sways was 30% smaller after rehabilitation (p < 0.00002); the feedback coordination coefficient was more than 10% bigger after rehabilitation (p < 0.001) and reached 92%, which is excellent for elderly people. Total stagnation and stumbling reported by patients decreased after rehabilitation compared to the first examination. Both tested forms of training can contribute to reducing the risk of falls. However, a more significant improvement was obtained in the force plate training group perhaps because the physical effort on a force plate trains the precise movements needed to reposition the centre of gravity without generating excessive inertia forces responsible for loss of balance and falls. Perhaps the most desirable method of intervention is to train a person's ability to perform slow but definite body movements.

Effective motor learning and coordination abilities of girls and boys aged 9-10

Introduction&#x0D; Learning is a complex and multi-dimensional process that depends on cognitive and emotional processes and the development of functional systems of the human body. One type of learning is motor learning. Its course and effects depend on many factors. One of the factors may be coordination abilities.&#x0D; Purpose&#x0D; The cognitive aim of the study is to assessment of the effectiveness (speed, efficiency) of learning complex motor activity in relation to the selected aspect of physical development (coordination abilities) of a selected group of girls and boys.&#x0D; Materials and methods&#x0D; The study was conducted among 73 children (44 boys and 29 girls) aged 9 - 10 years. Authors used the pedagogical experiment method and the research tool was the program for learning how to juggle three tennis balls. To assess the selected aspects of physical development we chose the direct categorized observation method. As research tools Authors used the Vienna Test System (VTS) and 2hand test.&#x0D; Results&#x0D; Boys achieved a higher average level of eye-hand coordination (2-hand test), but the differences between them and girls were not statistically significant. Girls achieved, on average, higher results than boys in terms of precise hand movements (MLS test). Statistically significant differences in their favor occurred in most of the tests performed.&#x0D; Conclusion&#x0D; There are functions between the speed and efficiency of learning a complex motor activity and coordination abilities. They are more pronounced than boys. It is important to develop coordination abilities in the didactic process to support motor learning.&#x0D; &#x0D;

An Octagonal Acoustofluidic Device for Multimode Cell and Particle Patterning and Dynamical Manipulation

The combination of cell patterning and manipulation has become a popular field of research in the current clinical background and experimental environment, and the significance of patterning is helpful to study the relationship between cells. Acoustic-based manipulation methods have become the current mainstream method due to their excellent noncontact and biocompatibility, and high controllability. This work proposed an octagonal chamber enclosed by multiple piezoelectric (PZT) transducers to generate multiple modes of ultrasonic acoustic fields by configuring different excitation signals. Cells and particles can be manipulated at the fixed pressure nodes in the formed acoustic field, and diversified patterns, such as stripes, lattices, and hexagons, can be formed. Furthermore, based on the advantages of the multi-PZT configuration of the device, the pattern conversion and precise quantitative movement of cells and particles can be achieved by adjusting the phase parameters of the excitation signals. This work investigated the relationship between the combination of different PZT, the phase parameters of the excitation signal, and the pattern formation through numerical simulation and experiments. Also, the overall quantitative movements of the patterns were achieved by adjusting the phase shift of excitation signals of PZT transducers. The mathematical relationship between the relative movement offset and the wavelength was studied and verified. Finally, the device realized complex trajectory motion control of cells and particles by automatically and rapidly switching the working modes and phase parameters of the PZT transducers. As an open and low-cost device, this research can provide a new idea for cell patterning and position manipulation.

Wireless Piezoelectric Motor Drive

Nanopositioners with embedded piezoelectric motors are used in a variety of industries, from microscopy to laser processing or measurement systems. A concrete example would be fine-tuning of multiple mirror or lens units in a system. After fine adjustment of a mirror or lens, its position is expected to be maintained when the system is not energized. Features such as small size, direct drive, and maintaining position with high rigidity at power off make inertia-type piezoelectric motors suitable for such “set and go”-type applications. However, wiring with dedicated control electronics for each positioner can increase system complexity. In this study, a wireless driving method for piezoelectric inertia-type motors is introduced for the first time, to the best of our knowledge. In our approach, sawtooth signals for driving a two-phase piezoelectric inertia motor are converted into two complementary pulse-width-modulated (PWM) signals at 1.0 MHz and amplified by class-D amplifier topology, in which GaN transistors are implemented. The amplified complementary PWM signals are applied to a transmitter coil. A receiver coil, which forms an LC network with the capacitances of the piezoelectric multilayer actuators, picks up the driving signals. The filtered voltage waveform by the receiver coil is converted into a modified sawtooth signal, which can operate the piezoelectric inertia-type motor wirelessly. Initial measurements revealed that even a single driving pulse can be transmitted to the receiver coil and precise movements of the slider can be obtained. Mean step sizes for single pulse drive are 140 nm in one direction and 125 nm in the reverse direction.

Differential Effects of Astrocyte Manipulations on Learned Motor Behavior and Neuronal Ensembles in the Motor Cortex.

Although motor cortex is crucial for learning precise and reliable movements, whether and how astrocytes contribute to its plasticity and function during motor learning is unknown. Here, we report that astrocyte-specific manipulations in primary motor cortex (M1) during a lever push task alter motor learning and execution, as well as the underlying neuronal population coding. Mice that express decreased levels of the astrocyte glutamate transporter 1 (GLT1) show impaired and variable movement trajectories, whereas mice with increased astrocyte Gq signaling show decreased performance rates, delayed response times, and impaired trajectories. In both groups, which include male and female mice, M1 neurons have altered interneuronal correlations and impaired population representations of task parameters, including response time and movement trajectories. RNA sequencing further supports a role for M1 astrocytes in motor learning and shows changes in astrocytic expression of glutamate transporter genes, GABA transporter genes, and extracellular matrix protein genes in mice that have acquired this learned behavior. Thus, astrocytes coordinate M1 neuronal activity during motor learning, and our results suggest that this contributes to learned movement execution and dexterity through mechanisms that include regulation of neurotransmitter transport and calcium signaling.SIGNIFICANCE STATEMENT We demonstrate for the first time that in the M1 of mice, astrocyte function is critical for coordinating neuronal population activity during motor learning. We demonstrate that knockdown of astrocyte glutamate transporter GLT1 affects specific components of learning, such as smooth trajectory formation. Altering astrocyte calcium signaling by activation of Gq-DREADD upregulates GLT1 and affects other components of learning, such as response rates and reaction times as well as trajectory smoothness. In both manipulations, neuronal activity in motor cortex is dysregulated, but in different ways. Thus, astrocytes have a crucial role in motor learning via their influence on motor cortex neurons, and they do so by mechanisms that include regulation of glutamate transport and calcium signals.

Effects of Failure on California Sea Lion (Zalophus californianus) Gameplay Strategies and Interest in a Cognitive Task: Implications for Cognitive Enrichment in Pinnipeds

Cognitive enrichment for professionally managed species has become more prevalent in recent years in both zoological and research settings and has been encouraged as a means of welfare enhancement. However, the task’s difficulty must be specifically tailored as it can impact the successful nature of the sessions, as tasks that are too simple or difficult may not be perceived as enriching by the animals. While pinnipeds are common in zoos, aquariums, and research facilities, few studies have explored the use of cognitively challenging enrichment in this species, and the level of difficulty and presence of failure on animal success and engagement in this type of session has not been assessed. In this study, gameplay strategies during computerized enrichment sessions were evaluated before and after a game that introduced failure, or the loss of opportunity to complete a level for a reward after an incorrect movement. Interest in participation during the session, measured as the latency without contact, was also tested as a proxy for this enrichment’s effect on welfare. When incorrect movements resulted in a short pause and removed the opportunity to finish individual levels for a reward, all three sea lions tested significantly reduced the amount of time spent on each of several strategies they employed, but significantly increased the number of button presses per strategy, suggesting the animals focused on more precise movements as their proficiency improved. Two sea lions also showed a significant decline in latency without contact following the introduction of failure in the form of a single opportunity to complete a task for a reward after previously having unlimited opportunities, while one maintained a low latency without contact across both test conditions. The results suggest that more cognitively challenging tasks incorporating failure did not cause a reduction in gameplay performance and session interest in sea lions. Individual variation was also noted in strategy use, emphasizing the importance of evaluating the individual in terms of enrichment provision.

Aesthetic Genioplasty Based on Strategic Categorization.

Genioplasty is a popular procedure used for lower facial contour correction. Various osteotomy techniques enable us to perform advancement, setback, reduction, or narrowing procedures. Computed tomographic images facilitate preoperative planning in detail. The authors used a novel planning method based on strategic categorization. The analytic results are described. This retrospective study reviewed 208 patients who underwent genioplasty procedures for facial contouring from October of 2015 to April of 2020. During preoperative evaluation of the mandible, the operative procedure selected was one of three types: (1) horizontal segment osteotomy, (2) vertical and horizontal segment osteotomy, and (3) bone graft after repositioning. Adequate osteotomies were followed by rigid fixation using a titanium plate and screws. The follow-up period ranged from 8 to 24 months (average, 17 months). The results were assessed based on medical records, photographs, and facial bone computed tomographic images. Overall, the patients were satisfied with the outcomes and had responder-based improvement in lower facial contour and balance. Chin point deviations were noted in 176 cases; left-side deviation ( n = 135) was more frequent than right-side deviation ( n = 41). Strategic osteotomies based on precise measurements led to correction of asymmetries. Temporary partial sensory losses reported in 12 cases resolved within an average of 6 months after surgery. Each patient's chief complaint and bony structures should be carefully evaluated before genioplasty procedures are performed. During the operation, meticulous osteotomy, precise movement, and rigid fixation are necessary. The strategic process used for genioplasty resulted in aesthetic balance and predictable outcomes. Therapeutic, IV.

First-in-Human Integrated Use of a Dedicated Microsurgical Robot with a 4K 3D Exoscope: The Future of Microsurgery

Innovative techniques can help overcome the limitations of the human body. Operating on very small structures requires adequate vision of the surgical field and precise movements of sophisticated instruments. Both the human eye and hand are limited when performing microsurgery. Conventional microsurgery uses operation microscopes to enhance the visualization of very small structures. Evolving technology of high-definition 3D cameras provides the opportunity to replace conventional operation microscopes, thereby improving ergonomics for surgeons. This leaves the human hand as a limiting factor in microsurgery. A dedicated robot for microsurgery has been developed to overcome this limitation and enhance the precision and stability of the surgeons' hands. We present the first-in-human case in reconstructive microsurgery where both technologies are integrated using a dedicated microsurgical robot in combination with a 4K 3D exoscope.

Nonuniform structural properties of wings confer sensing advantages.

Sensory feedback is essential to both animals and robotic systems for achieving coordinated, precise movements. Mechanosensory feedback, which provides information about body deformation, depends not only on the properties of sensors but also on the structure in which they are embedded. In insects, wing structure plays a particularly important role in flapping flight: in addition to generating aerodynamic forces, wings provide mechanosensory feedback necessary for guiding flight while undergoing dramatic deformations during each wingbeat. However, the role that wing structure plays in determining mechanosensory information is relatively unexplored. Insect wings exhibit characteristic stiffness gradients and are subject to both aerodynamic and structural damping. Here we examine how both of these properties impact sensory performance, using finite element analysis combined with sensor placement optimization approaches. We show that wings with nonuniform stiffness exhibit several advantages over uniform stiffness wings, resulting in higher accuracy of rotation detection and lower sensitivity to the placement of sensors on the wing. Moreover, we show that higher damping generally improves the accuracy with which body rotations can be detected. These results contribute to our understanding of the evolution of the nonuniform stiffness patterns in insect wings, as well as suggest design principles for robotic systems.

Bioinspired smooth neuromorphic control for robotic arms

Beyond providing accurate movements, achieving smooth motion trajectories is a long-standing goal of robotics control theory for arms aiming to replicate natural human movements. Drawing inspiration from biological agents, whose reaching control networks effortlessly give rise to smooth and precise movements, can simplify these control objectives for robot arms. Neuromorphic processors, which mimic the brain’s computational principles, are an ideal platform to approximate the accuracy and smoothness of biological controllers while maximizing their energy efficiency and robustness. However, the incompatibility of conventional control methods with neuromorphic hardware limits the computational efficiency and explainability of their existing adaptations. In contrast, the neuronal subnetworks underlying smooth and accurate reaching movements are effective, minimal, and inherently compatible with neuromorphic hardware. In this work, we emulate these networks with a biologically realistic spiking neural network for motor control on neuromorphic hardware. The proposed controller incorporates experimentally-identified short-term synaptic plasticity and specialized neurons that regulate sensory feedback gain to provide smooth and accurate joint control across a wide motion range. Concurrently, it preserves the minimal complexity of its biological counterpart and is directly deployable on Intel’s neuromorphic processor. Using the joint controller as a building block and inspired by joint coordination in human arms, we scaled up this approach to control real-world robot arms. The trajectories and smooth, bell-shaped velocity profiles of the resulting motions resembled those of humans, verifying the biological relevance of the controller. Notably, the method achieved state-of-the-art control performance while decreasing the motion jerk by 19% to improve motion smoothness. Overall, this work suggests that control solutions inspired by experimentally identified neuronal architectures can provide effective, neuromorphic-controlled robots.

Inter-axonal molecular crosstalk via Lumican proteoglycan sculpts murine cervical corticospinal innervation by distinct subpopulations

How CNS circuits sculpt their axonal arbors into spatially and functionally organized domains is not well understood. Segmental specificity of corticospinal connectivity is an exemplar for such regional specificity of many axon projections. Corticospinal neurons (CSN) innervate spinal and brainstem targets with segmental precision, controlling voluntary movement. Multiple molecularly distinct CSN subpopulations innervate the cervical cord for evolutionarily enhanced precision of forelimb movement. Evolutionarily newer CSNBC-lat exclusively innervate bulbar-cervical targets, while CSNmedial are heterogeneous; distinct subpopulations extend axons to either bulbar-cervical or thoraco-lumbar segments. We identify that Lumican controls balance of cervical innervation between CSNBC-lat and CSNmedial axons during development, which is maintained into maturity. Lumican, an extracellular proteoglycan expressed by CSNBC-lat, non-cell-autonomously suppresses cervical collateralization by multiple CSNmedial subpopulations. This inter-axonal molecular crosstalk between CSN subpopulations controls murine corticospinal circuitry refinement and forelimb dexterity. Such crosstalk is generalizable beyond the corticospinal system for evolutionary incorporation of new neuron populations into preexisting circuitry.

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Suggested robotic-assisted thoracic surgery training curriculum.

Robotic-assisted surgery, a technological advancement in the field of surgery, has become increasingly popular among surgeons of many specialties over time. Robotic-assisted thoracic surgery (RATS) is comparable to video-assisted thoracic surgery (VATS) in terms of patient care outcomes; however, the perception of increased operative time and a lack of cost-effectiveness have led to controversy regarding its alleged benefits. Nevertheless, robotic surgery is one of the preferred options for minimally invasive surgery by some thoracic surgeon over VATS, due to its ability to provide 3-D vision, precise wrist movements, enhanced magnification, and instrument stability and articulation. Notably, trainees in the field of thoracic surgery experience difficulty gaining knowledge and learning skills associated with RATS due to its complexity, limited access to robotic instruments, the lack of a standardized curriculum for trainees, and lack of mentorship or proctorship, thus leading to a steeper learning curve compared to laparoscopic or VATS procedures that are cost-friendly, easy to learn, and feasible to practice. Nevertheless, focusing on RATS training for thoracic surgeons will keep them familiar with robotic techniques, including the pre-operative setup and intra-operative process, which will ultimately decrease operative times. In this paper, we will review the literature, express and discuss the most viable training curriculum from authors' point of view to help achieve this goal.

Emergent Low-Frequency Activity in Cortico-Cerebellar Networks with Motor Skill Learning.

The motor cortex controls skilled arm movement by recruiting a variety of targets in the nervous system, and it is important to understand the emergent activity in these regions as refinement of a motor skill occurs. One fundamental projection of the motor cortex (M1) is to the cerebellum. However, the emergent activity in the motor cortex and the cerebellum that appears as a dexterous motor skill is consolidated is incompletely understood. Here, we report on low-frequency oscillatory (LFO) activity that emerges in cortico-cerebellar networks with learning the reach-to-grasp motor skill. We chronically recorded the motor and the cerebellar cortices in rats, which revealed the emergence of coordinated movement-related activity in the local-field potentials as the reaching skill consolidated. Interestingly, we found this emergent activity only in the rats that gained expertise in the task. We found that the local and cross-area spiking activity was coordinated with LFOs in proficient rats. Finally, we also found that these neural dynamics were more prominently expressed during accurate behavior in the M1. This work furthers our understanding on emergent dynamics in the cortico-cerebellar loop that underlie learning and execution of precise skilled movement.

Upper limb prostheses: bridging the sensory gap.

Replacing human hand function with prostheses goes far beyond only recreating muscle movement with feedforward motor control. Natural sensory feedback is pivotal for fine dexterous control and finding both engineering and surgical solutions to replace this complex biological function is imperative to achieve prosthetic hand function that matches the human hand. This review outlines the nature of the problems underlying sensory restitution, the engineering methods that attempt to address this deficit and the surgical techniques that have been developed to integrate advanced neural interfaces with biological systems. Currently, there is no single solution to restore sensory feedback. Rather, encouraging animal models and early human studies have demonstrated that some elements of sensation can be restored to improve prosthetic control. However, these techniques are limited to highly specialized institutions and much further work is required to reproduce the results achieved, with the goal of increasing availability of advanced closed loop prostheses that allow sensory feedback to inform more precise feedforward control movements and increase functionality.

The “Little Person” in the Brain Who Helps to Direct Our Movements

Imagine an expert piano player’s hands as they fly across the piano keys. Have you ever wondered how it is possible to control such complicated and precise movements? The brain controls our movements and processes all the information we receive from the entire body as we interact with the world. We perform many complex movement-related tasks, and our brains manage them all the time without us even noticing! To manage the whole body efficiently, the brain is organized so that specific brain areas control or gather information from specific body parts. The parts of the body that perform the most complex tasks are assigned more space in the brain. Can you think of a body part that is responsible for very complex movements? What would happen in your brain if you could no longer move that body part?