Microsaccades as a long-term oculomotor correlate in visual perceptual learning

Area of Science:

• Neuroscience
• Cognitive Science
• Ophthalmology

Background:

• Human perceptual learning (VPL) enhances sensory discrimination through experience.
• Feature-based attention (FBA) has been shown to enable long-lasting transfer of VPL benefits to untrained locations.
• The role of fixational eye movements, specifically microsaccades, in VPL remains largely unexplored.

Purpose of the Study:

• To investigate how microsaccades change following training in an orientation discrimination task.
• To determine if these microsaccade changes are associated with VPL and its long-term effects.
• To explore the relationship between microsaccades, feature-based attention, and visual processing dynamics.

Main Methods:

• Human observers trained on an orientation discrimination task, with and without feature-based attention (FBA).
• Continuous recording and analysis of microsaccades (fixational eye movements) during and after training.
• Behavioral data (accuracy, response time) collected alongside oculomotor measures.

Main Results:

• Microsaccade rates significantly decreased during the response window for both trained and untrained locations/orientations after VPL.
• This reduction in microsaccade rate persisted for over a year, correlating with long-term learning benefits.
• Microsaccades showed pre-stimulus bias toward the target and were suppressed more after incorrect responses.

Conclusions:

• Fixational eye movements, particularly microsaccades, are tightly coupled with visual perceptual learning.
• Learning-induced changes in microsaccade dynamics are long-lasting and reflect functional adaptations in the oculomotor system.
• Microsaccades serve as a reliable physiological correlate for tracking long-term changes in VPL.