Extraretinal and retinal amplitude and phase errors during Filehne illusion and path perception

Area of Science:

• Neuroscience
• Visual Perception
• Human Motion Estimation

Background:

• Pursuit eye movements create retinal motion, requiring visual system compensation.
• Accurate motion perception relies on integrating retinal and extraretinal (eye-velocity) signals.
• Illusions like the Filehne illusion arise from mismatches in these speed estimates.

Purpose of the Study:

• Investigate speed and timing errors in visual motion perception during sinusoidal pursuit eye movements.
• Characterize a new visual illusion, the slalom illusion, related to self-motion perception.
• Develop a linear model to quantify signal mismatches in visual illusions.

Main Methods:

• Used sinusoidal pursuit eye movements to induce retinal motion.
• Employed a motion-nulling procedure to measure speed and timing differences.
• Analyzed the Filehne and slalom illusions using a linear model to determine gain ratios and phase differences.

Main Results:

• Identified the slalom illusion, where perceived self-motion oscillates during sinusoidal pursuit.
• Found consistently low ratios of extraretinal to retinal gain (<1) for both illusions.
• Demonstrated that timing errors were minimal, implicating speed mismatches as the primary cause.

Conclusions:

• Both the Filehne and slalom illusions result from a speed mismatch between retinal and extraretinal signals.
• The visual system's underestimation of extraretinal speed contributes to these perceptual errors.
• Findings are relevant for understanding self-motion perception during active eye movements.