Signal-dependent noise determines motor planning

  title={Signal-dependent noise determines motor planning},
  author={Christopher M. Harris and Daniel M. Wolpert},
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 target,. However, humans show highly stereotyped trajectories in which velocity profiles of both the eye and hand are smooth and symmetric for brief movements,. 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… 

Saccadic Eye Movements Minimize the Consequences of Motor Noise

The stereotyped durations and trajectories of saccadic eye movements are optimal for minimizing the variability in saccade endpoints that is caused by motor noise, and the simple and sensible principle of minimizing the consequences of motor noise explains the full stereotypy.

The Main Sequence of Saccades Optimizes Speed-accuracy Trade-off

It is proposed that a fundamental constraint on the deployment of foveal vision lies in the motor system that is perturbed by signal-dependent noise (proportional noise) on the motor command, which imposes a compromise between the speed and accuracy of an eye movement.

Gain control of saccadic eye movements is probabilistic

The findings indicate that the oculomotor system possesses a probabilistic representation of its own sensorimotor uncertainty and uses that representation to adjust the parameters of each saccade, and reveals that the saccadic system uses a Probabilistic-Bayesian control strategy to compensate for uncertainty in a statistically principled way.

Stochastic optimal feedforward-feedback control determines timing and variability of arm movements with or without vision

A stochastic optimal feedforward-feedback control model is introduced that can predict the nominal timing and trial-by-trial variability of self-paced arm reaching movements carried out with or without online visual feedback of the hand.

Optimal Control of Natural Eye-Head Movements Minimizes the Impact of Noise

This work shows that minimizing the impact of uncertainty, i.e., noise affecting motor performance, can account for the choice of combined eye–head movements and correctly predicts changes in eye and head movement imposed by an experimental increase in the head moment of inertia.

A velocity plan with internal feedback control best explains modulation of saccade kinematics during eye-hand coordination

Modulation of peak saccades velocity due to modulation of the velocity of the accompanying hand movement was better captured using a velocity tracking stochastic optimal control model compared to an endpoint model of saccade control, the first evidence of trajectory planning and control for the saccadic system based on optimal control theory.

Time Course of Precision in Smooth-Pursuit Eye Movements of Monkeys

Noise in sensory processing of visual motion provides the major source of variation in the initiation of pursuit, and changes in the form of the sensory input while keeping the motor response fixed had significant effects on the signal-to-noise ratio in pursuit.

A sensory source for motor variation

The magnitudes of the inferred sensory errors agree with the observed thresholds for sensory discrimination by perceptual systems, suggesting that the very different neural processes of perception and action are limited by the same sources of noise.

Noisy optimal control strategies for modelling saccades

This work proposes a framework for computing the optimal control law for arbitrary dynamical systems, subject to noise, and where the cost function depends on a statistical distribution of the eye’s position, and describes a modified form of gradient descent for computing this law.



Temporal and amplitude generalization in motor learning.

This work used a three-dimensional robotic interface to investigate how adaptation to altered dynamics experienced only for movements at one temporal rate and amplitude generalizes to movements made at a different rate or amplitude.

Time-Optimal Control of Saccadic Eye Movements

A new theory describing the time-optimal control of saccadic eye movements is proposed based on Pontryagin's minimum principle and physiological considerations and the predictions of the model under a time- optimal controller are in good agreement with the data.

Fourier analysis of saccades in monkeys and humans.

The Fourier spectra of human and monkey saccades are described, finding a regular pattern of local minima in the power plot, which cannot be attributed to noise and adding to the evidence that the human saccade also is driven by a pulse-step signal.

Optimality in human motor performance: ideal control of rapid aimed movements.

The present conceptual framework provides insights into principles of motor performance, and it links the study of physical action to research on sensation, perception, and cognition, where psychologists have been concerned for some time about the degree to which mental processes incorporate rational and normative rules.

Adaptive representation of dynamics during learning of a motor task

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.

The coordination of arm movements: an experimentally confirmed mathematical model

  • T. FlashN. Hogan
  • Engineering
    The Journal of neuroscience : the official journal of the Society for Neuroscience
  • 1985
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.

Binocular co‐ordination of human horizontal saccadic eye movements.

The binocular co‐ordination of human horizontal saccades was analysed for the first time systematically over the full oculomotor range with a precise and accurate scleral sensor coil technique and showed an abduction‐adduction asymmetry and were not well yoked dynamically.

The information capacity of the human motor system in controlling the amplitude of movement.

  • P. Fitts
  • Psychology
    Journal of experimental psychology
  • 1954
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.