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Updated: Jul 13, 2026
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Investigating the Deployment of Visual Attention Before Accurate and Averaging Saccades via Eye Tracking and Assessment of Visual Sensitivity
Published on: March 18, 2019
The sources of variability in saccadic eye movements
1Department of Neuroscience, Erasmus MC, Rotterdam, The Netherlands. r.j.vanbeers@phys.uu.nl
Summary
Human eye movements (saccades) show variability. Target location uncertainty is the main cause, followed by motor command noise, affecting planning and execution.
Area of Science:
- Neuroscience
- Motor Control
- Ophthalmology
Background:
- Human movements, particularly saccadic eye movements, exhibit variability.
- The precise origins of this variability remain incompletely understood.
Purpose of the Study:
- To investigate the sources of spatiotemporal variability in human saccadic eye movements.
- To differentiate between sensory and motor contributions to saccade trajectory variability.
Main Methods:
- Two experiments measured saccade trajectories, analyzing spatiotemporal variability.
- A noise model was developed to estimate motor command noise and target localization uncertainty.
Main Results:
- Saccade direction variability was lower for horizontal/vertical movements than oblique.
- Saccade amplitude, duration, and peak velocity were correlated.
- Target localization uncertainty was the primary source of endpoint variability.
- Motor command noise contributed significantly, but less than sensory uncertainty.
- Temporal variability showed an inverse relationship between saccade duration and peak velocity.
Conclusions:
- Uncertainty in target localization is the dominant factor in saccade endpoint variability.
- Noise in motor command execution also contributes to saccade variability.
- Temporal variability suggests noise in both movement planning and execution.
- These factors collectively explain the observed variability in saccade trajectories, crucial for understanding brain-based movement control.
