Journal ArticleDOI
Signal-dependent noise determines motor planning
Chris Harris,Daniel M. Wolpert +1 more
TLDR
This theory provides a simple and powerful unifying perspective for both eye and arm movement control and accurately predicts the trajectories of both saccades and arm movements and the speed–accuracy trade-off described by Fitt's law.Abstract:
When we make saccadic eye movements or goal-directed arm movements, there is an infinite number of possible trajectories that the eye or arm could take to reach the target1,2. However, humans show highly stereotyped trajectories in which velocity profiles of both the eye and hand are smooth and symmetric for brief movements3,4. Here we present a unifying theory of eye and arm movements based on the single physiological assumption that the neural control signals are corrupted by noise whose variance increases with the size of the control signal. We propose that in the presence of such signal-dependent noise, the shape of a trajectory is selected to minimize the variance of the final eye or arm position. This minimum-variance theory accurately predicts the trajectories of both saccades and arm movements and the speed–accuracy trade-off described by Fitt's law5. These profiles are robust to changes in the dynamics of the eye or arm, as found empirically6,7. Moreover, the relation between path curvature and hand velocity during drawing movements reproduces the empirical ‘two-thirds power law’8,9. This theory provides a simple and powerful unifying perspective for both eye and arm movement control.read more
Citations
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Journal ArticleDOI
The effect of work pace on workload, motor variability and fatigue during simulated light assembly work
TL;DR: Increasing the work pace did not show adverse effects in terms of biomechanical exposures and muscle fatigue, but it did lead to more errors, which suggests that an increase in work pace might diminish production quality, even without any noticeable fatigue being experienced by the operators.
Journal ArticleDOI
Kalman Filtering Naturally Accounts for Visually Guided and Predictive Smooth Pursuit Dynamics
TL;DR: This model provides a general framework of how the brain can combine continuous sensory information with a dynamic internal memory and transform it into motor commands and suggests that the brain circuitry generating a pursuit command might be simpler than previously believed.
Journal ArticleDOI
Controlling the statistics of action: obstacle avoidance.
TL;DR: This work found the optimal trajectory for obstacle avoidance by minimizing the mean-squared error at the end of the movement while keeping the probability of collision with the obstacle below a fixed limit.
Journal ArticleDOI
Stages in learning motor synergies: a view based on the equilibrium-point hypothesis.
TL;DR: A novel view on stages in motor learning based on recent developments of the notion of synergies, the uncontrolled manifold hypothesis, and the equilibrium-point hypothesis (referent configuration) that allow to merge these notions into a single scheme of motor control is described.
Journal ArticleDOI
Experimentally Confirmed Mathematical Model for Human Control of a Non-Rigid Object
TL;DR: It is demonstrated that the well-known "minimum-jerk" model for smooth reaching movements cannot accomplish the transport of a mass-on-a-spring to a target in an optimally smooth way, and the model extends the concept of smoothness to allow for the control of non-rigid objects.
References
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Journal ArticleDOI
The information capacity of the human motor system in controlling the amplitude of movement.
TL;DR: The motor system in the present case is defined as including the visual and proprioceptive feedback loops that permit S to monitor his own activity, and the information capacity of the motor system is specified by its ability to produce consistently one class of movement from among several alternative movement classes.
Journal ArticleDOI
The coordination of arm movements: an experimentally confirmed mathematical model.
Tamar Flash,Neville Hogan +1 more
TL;DR: A mathematical model is formulated which is shown to predict both the qualitative features and the quantitative details observed experimentally in planar, multijoint arm movements, and is successful only when formulated in terms of the motion of the hand in extracorporal space.
Journal ArticleDOI
An Internal Model for Sensorimotor Integration
TL;DR: A sensorimotor integration task was investigated in which participants estimated the location of one of their hands at the end of movements made in the dark and under externally imposed forces, providing direct support for the existence of an internal model.
Journal ArticleDOI
Adaptive representation of dynamics during learning of a motor task
TL;DR: The investigation of how the CNS learns to control movements in different dynamical conditions, and how this learned behavior is represented, suggests that the elements of the adaptive process represent dynamics of a motor task in terms of the intrinsic coordinate system of the sensors and actuators.
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The coordination of arm movements: an experimentally confirmed mathematical model.
Tamar Flash,Neville Hogan +1 more