Two distinct modes of ocular drift observed during figure-ground perception

Area of Science:

• Neuroscience
• Vision Science
• Perceptual Psychology

Background:

• Precise neural coordination is vital for sensory perception.
• Fixational eye movements (FEMs) continuously alter retinal input, potentially challenging perceptual integration.
• Recent evidence indicates FEMs actively contribute to visual processing.

Purpose of the Study:

• To investigate the impact of FEMs on visual perception using a figure-ground segmentation task.
• To analyze interocular coordination of binocular drift and microsaccades during perception.
• To determine if ocular drift patterns differ based on perceptual outcomes.

Main Methods:

• Participants performed a figure-ground segmentation task while maintaining central fixation.
• Binocular drift and microsaccades were simultaneously recorded.
• Interocular coordination was analyzed using 2D cross-correlograms of angular velocities.

Main Results:

• Figure-present trials showed narrow peaks in interocular drift correlation, indicating synchronized patterns.
• Figure-absent trials exhibited broader, less synchronized drift patterns.
• Microsaccades facilitated drift alignment, and changes in drift synchrony occurred even in monocular viewing.

Conclusions:

• Two distinct ocular drift modes are associated with different perceptual outcomes.
• Ocular drift appears to operate under closed-loop control, actively contributing to visual processing.
• FEMs play a significant role in effective visual perception beyond simple randomness.