scholarly journals Visuomotor control of intermittent circular tracking movements with visually guided orbits in 3D VR environment

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251371
Author(s):  
Woong Choi ◽  
Naoki Yanagihara ◽  
Liang Li ◽  
Jaehyo Kim ◽  
Jongho Lee
Keyword(s):  
Control System ◽  
Visuomotor Control ◽  
Target Velocity ◽  
Visually Guided ◽  
Velocity Control ◽  
Position Information ◽  
Velocity Information ◽  
Tracking Movements ◽  
Study Participants ◽  
Intermittent Motion

The analysis of visually guided tracking movements is important to the understanding of imitation exercises and movements carried out using the human visuomotor control system. In this study, we analyzed the characteristics of visuomotor control in the intermittent performance of circular tracking movements by applying a system that can differentiate between the conditions of invisible and visible orbits and visible and invisible target phases implemented in a 3D VR space. By applying visuomotor control based on velocity control, our study participants were able to track objects with visible orbits with a precision of approximately 1.25 times greater than they could track objects with invisible orbits. We confirmed that position information is an important parameter related to intermittent motion at low speeds (below 0.5 Hz) and that tracked target velocity information could be obtained more precisely than position information at speeds above 0.5 Hz. Our results revealed that the feedforward (FF) control corresponding to velocity was delayed under the visible-orbit condition at speeds over 0.5 Hz, suggesting that, in carrying out imitation exercises and movements, the use of visually presented 3D guides can interfere with exercise learning and, therefore, that the effects of their use should be carefully considered.

scholarly journals The effect of a temporary absence of target velocity information on visual tracking

2010 ◽  
Vol 3 (4) ◽  
Author(s):  
Patricia M. Cisarik ◽  
Sanjeev Kasthurirangan ◽  
Frank E. Visco Jr. ◽  
Harold E. Bedell ◽  
Scott B. Stevenson ◽  
...  
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Target Velocity ◽  
Laser Target ◽  
Position Information ◽  
Saccade Programming ◽  
Velocity Information ◽  
Behavioral Evidence ◽  
Pursuit Velocity ◽  
Made In

Experiments with the Rashbass ‘step-ramp’ paradigm have revealed that the initial catchup saccade that occurs near pursuit onset uses target velocity as well as position information in its programming. Information about both position and motion also influences smooth pursuit. To investigate the timing of velocity sampling near the initiation of saccades and smooth pursuit, we analyzed the eye movements made in nine ‘step-ramp’ conditions, produced by combining –2, 0 and +2 deg steps with –8, 0 and +8 deg/s ramps. Each trial had either no temporal gap or a 50-ms gap during which the laser target was extinguished, beginning 25, 50, 75 or 100 ms after the step. Six subjects repeated each of the resulting 45 conditions 25 times. With no temporal gap, saccades were larger in the step-ramp-away’ than the ‘step-only’ condition, confirming that saccade programming incorporates ramp velocity information. A temporal gap had no effect on the accuracy of saccades on ‘step-only’ trials, but often caused undershoots in ‘step-ramp’ trials. A 50-ms gap within the first 100 ms also increased the latency of the initial saccade. Although initial pursuit velocity was unaffected by a temporal gap, a gap that started at 25 ms reliably delayed pursuit onset for ramp motion of the target toward the fovea. Later gaps had a minimal effect on initial pursuit latency. The similar timing of the temporal gaps in target motion information that affect the initiation of saccades and pursuit provides further behavioral evidence that the two types of eye movements share pre-motor neural mechanisms.

How Position, Velocity, and Temporal Information Combine in the Prospective Control of Catching: Data and Model

2005 ◽  
Vol 17 (4) ◽  
pp. 668-686 ◽  
Author(s):  
Joost C. Dessing ◽  
C. (Lieke) E. Peper ◽  
Daniel Bullock ◽  
Peter J. Beek
Keyword(s):  
Neural Control ◽  
Neural Model ◽  
Temporal Information ◽  
Behavioral Experiment ◽  
Position Information ◽  
Prospective Control ◽  
Ball Velocity ◽  
Velocity Information ◽  
Centered Ball ◽  
Information Streams

The cerebral cortex contains circuitry for continuously computing properties of the environment and one's body, as well as relations among those properties. The success of complex perceptuomotor performances requires integrated, simultaneous use of such relational information. Ball catching is a good example as it involves reaching and grasping of visually pursued objects that move relative to the catcher. Although integrated neural control of catching has received sparse attention in the neuroscience literature, behavioral observations have led to the identification of control principles that may be embodied in the involved neural circuits. Here, we report a catching experiment that refines those principles via a novel manipulation. Visual field motion was used to perturb velocity information about balls traveling on various trajectories relative to a seated catcher, with various initial hand positions. The experiment produced evidence for a continuous, prospective catching strategy, in which hand movements are planned based on gaze-centered ball velocity and ball position information. Such a strategy was implemented in a new neural model, which suggests how position, velocity, and temporal information streams combine to shape catching movements. The model accurately reproduces the main and interaction effects found in the behavioral experiment and provides an interpretation of recently observed target motion-related activity in the motor cortex during interceptive reaching by monkeys. It functionally interprets a broad range of neurobiological and behavioral data, and thus contributes to a unified theory of the neural control of reaching to stationary and moving targets.

Design of a Velocity Control System Using an Inlet Metered Pump

2017 ◽  
Author(s):  
Hasan H. Ali ◽  
Roger C. Fales ◽  
Noah D. Manring
Keyword(s):  
Fluid Flow ◽  
Control System ◽  
High Efficiency ◽  
Flow Direction ◽  
Low Cost ◽  
Hydraulic Cylinder ◽  
Fast Response ◽  
Open Loop ◽  
Velocity Control ◽  
Pump System

This work introduces a new way to control hydraulic cylinder velocity using an inlet metering pump system to control the hydraulic flow entering the cylinder. The inlet metering system consists of a fixed displacement pump and an inlet metering valve that adjusts the hydraulic fluid flow entering the pump as required. The energy losses associated with flow metering in the system are reduced because the pressure drop across the inlet metering valve can be arbitrarily small. The fluid is supplied to the inlet metering valve at a fixed pressure using a charge pump. A velocity control system is designed using the inlet metering system as means to control the fluid flow to a hydraulic cylinder. In addition to the inlet metering system, the velocity control system designed in this work includes a four-way directional valve to set the fluid flow direction according to the desired direction of the hydraulic cylinder velocity. Open-loop and closed-loop proportional and proportional derivative (P and PD) controllers are designed. Designs with the goals of stability and performance of the system are studied so that a precise and smooth velocity control system for the hydraulic cylinder is achieved. In addition to potentially high efficiency of this system, there is potential for other benefits including low cost, fast response, and less complicated dynamics compared to other systems. The results presented in this work show that the inlet metering velocity control system can be designed so that the system is stable, there is zero overshoot and no oscillation.

Egocentric Action in Early Infancy: Spatial Frames of Reference for Saccades

1997 ◽  
Vol 8 (3) ◽  
pp. 224-230 ◽  
Author(s):  
Rick O. Gilmore ◽  
Mark H. Johnson
Keyword(s):  
Spatial Information ◽  
Visual Space ◽  
Frames Of Reference ◽  
Saccade Target ◽  
Visually Guided ◽  
Retinal Position ◽  
Position Information ◽  
Visual Spatial ◽  
Visually Guided Action ◽  
Spatial Frames Of Reference

The extent to which infants combine visual (i e, retinal position) and nonvisual (eye or head position) spatial information in planning saccades relates to the issue of what spatial frame or frames of reference influence early visually guided action We explored this question by testing infants from 4 to 6 months of age on the double-step saccade paradigm, which has shown that adults combine visual and eye position information into an egocentric (head- or trunk-centered) representation of saccade target locations In contrast, our results imply that infants depend on a simple retinocentric representation at age 4 months, but by 6 months use egocentric representations more often to control saccade planning Shifts in the representation of visual space for this simple sensorimotor behavior may index maturation in cortical circuitry devoted to visual spatial processing in general

scholarly journals Neuronal Responses to Moving Targets in Monkey Frontal Eye Fields

2008 ◽  
Vol 100 (3) ◽  
pp. 1544-1556 ◽  
Author(s):  
Carlos R. Cassanello ◽  
Abhay T. Nihalani ◽  
Vincent P. Ferrera
Keyword(s):  
Eye Movements ◽  
Neuronal Response ◽  
Target Position ◽  
Saccadic Eye Movements ◽  
Quantitative Model ◽  
Initial Position ◽  
Target Velocity ◽  
Frontal Eye Fields ◽  
Moving Targets ◽  
Velocity Information

Due to delays in visuomotor processing, eye movements directed toward moving targets must integrate both target position and velocity to be accurate. It is unknown where and how target velocity information is incorporated into the planning of rapid (saccadic) eye movements. We recorded the activity of neurons in frontal eye fields (FEFs) while monkeys made saccades to stationary and moving targets. A substantial fraction of FEF neurons was found to encode not only the initial position of a moving target, but the metrics (amplitude and direction) of the saccade needed to intercept the target. Many neurons also encoded target velocity in a nearly linear manner. The quasi-linear dependence of firing rate on target velocity means that the neuronal response can be directly read out to compute the future position of a target moving with constant velocity. This is demonstrated using a quantitative model in which saccade amplitude is encoded in the population response of neurons tuned to retinal target position and modulated by target velocity.

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