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Extraretinal control of saccadic suppression
M R Diamond1, J Ross, M C Morrone
1Department of Psychology, The University of WA, Nedlands Western Australia 6907, Australia.
Summary
Saccadic suppression, a visual phenomenon during eye movements, has both retinal and extraretinal components. This study reveals that extraretinal signals significantly contribute to visual processing during saccades.
Area of Science:
- Neuroscience
- Visual Perception
- Ophthalmology
Background:
- Saccadic suppression is a brief period of reduced visual sensitivity during rapid eye movements (saccades).
- The precise mechanisms underlying saccadic suppression, particularly the contribution of retinal versus extraretinal factors, remain debated.
Purpose of the Study:
- To investigate the time course and underlying sources of saccadic suppression.
- To differentiate between suppression caused by retinal image motion and extraretinal signals.
Main Methods:
- Contrast thresholds for luminance- and color-modulated gratings were measured during voluntary and simulated saccades.
- Experiments varied grating luminance and introduced visual noise to assess its impact on suppression.
Main Results:
- A significant decrease in contrast sensitivity (saccadic suppression) was observed for luminance-modulated gratings during real saccades, but not simulated ones.
- Suppression anticipated saccades, peaked at onset, and extended afterward, with reduced magnitude at lower luminance.
- Visual noise amplified suppression during simulated saccades but had minimal effect on real saccades.
Conclusions:
- Saccadic suppression possesses a significant extraretinal component, distinct from retinal image motion.
- The findings support a model where extraretinal signals saturate visual processing during saccades.
- Chromatic stimuli did not elicit measurable saccadic suppression.