Microsaccades are different from saccades in scene perception.

Area of Science:

• Cognitive Neuroscience
• Ophthalmology
• Visual Perception

Background:

• Eye-fixation durations are key metrics for cognitive processes in visual tasks like reading and scene perception.
• Fixations contain ongoing motor activity, primarily microsaccades, which share similarities with larger inspection saccades.
• Understanding the nuances of these eye movements is crucial for interpreting cognitive states during visual tasks.

Purpose of the Study:

• To investigate distinct properties of microsaccades and inspection saccades during scene perception.
• To explore the functional characteristics and neurophysiological basis of microsaccades in scene viewing.
• To examine the modulation of fixational eye movements, such as drift, during extended scene perception.

Main Methods:

• Analysis of descriptive measures, including bimodal amplitude distribution, for microsaccades and inspection saccades.
• Evaluation of functional characteristics like inter-saccadic intervals and generating processes.
• Correlation analysis of microsaccade rates between fixation paradigms and scene perception tasks.
• Measurement of slow fixational eye movements (drift) during varying fixation durations in scene viewing.

Main Results:

• Distinct descriptive and functional properties were identified for microsaccades and inspection saccades in scene perception.
• Microsaccade rates showed significant correlation across different tasks, suggesting a common neurophysiological origin.
• Drift eye movements were significantly reduced during longer fixations in scene viewing.

Conclusions:

• Microsaccades and inspection saccades exhibit unique characteristics even within the context of scene perception.
• A shared neurophysiological basis underlies microsaccade generation across different visual tasks.
• The modulation of drift during prolonged fixation provides insights into the control mechanisms of eye movements in scene viewing.