Abstract
Eye-fixation durations are among the best and most widely used measures of ongoing cognition in visual tasks, e.g., reading, visual search or scene perception. However, fixations are characterized by ongoing motor activity (or fixational eye movements) with microsaccades as their most pronounced components. Recent work demonstrated the similarities of microsaccades and inspection saccades. Here, we show that distinct properties of microsaccades and inspection saccades can be found in a scene perception task, based on descriptive measures (e.g., a bimodal amplitude distribution) as well as functional characteristics (e.g., inter saccadic-event intervals and generating processes). Besides these specific differences, microsaccade rates produced by individual participants in a fixation paradigm are correlated with microsaccade rates extracted from fixations in scene perception, indicating a common neurophysiological basis. Finally, we observed that slow fixational eye movements, called drift, are significantly reduced during long fixations in scene viewing, which informs about the control of eye movements in scene viewing.
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Notes
The amplitude was determined as the square root of the sum of the squared maximum values of horizontal and vertical displacements during the saccades.
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Acknowledgments
Supported by Deutsche Forschungsgemeinschaft (grant no. EN 471/3-1) as part of Research Group 868 “Computational Modeling of Behavioral, Cognitive, and Neural Dynamics”. We thank Jorge Otero-Millan and Susana Martinez-Conde for valuable comments.
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Mergenthaler, K., Engbert, R. Microsaccades are different from saccades in scene perception. Exp Brain Res 203, 753–757 (2010). https://doi.org/10.1007/s00221-010-2272-9
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DOI: https://doi.org/10.1007/s00221-010-2272-9