Reflexive tracking eye movements and motion perception: one or two neural populations?

Area of Science:

• Neuroscience
• Computational Neuroscience
• Vision Science

Background:

• Neurons in the middle temporal (MT) and medial superior temporal (MST) areas are crucial for motion perception and smooth eye movements.
• High variability exists in both perceptual and oculomotor systems, even with identical stimuli.
• Previous research on single-trial correlations between motion perception and smooth pursuit eye movements yielded conflicting results.

Purpose of the Study:

• To investigate the relationship between motion perception and reflexive eye movements (ocular following).
• To determine if direction-dependent biases and trial-by-trial variability are correlated between perception and oculomotor action.
• To explore the neural underpinnings of motion processing for both perception and action.

Main Methods:

• Simultaneous measurement of eye movement direction and perceived direction during ocular following of a moving random dot field.
• Analysis of oculomotor and perceptual errors, focusing on direction-dependent biases and trial-by-trial variability.
• Investigating reflexive tracking eye movements (ocular following) rather than volitional smooth pursuit.

Main Results:

• Oculomotor errors were largest for near-cardinal directions, demonstrating cardinal repulsion in reflexive eye movements.
• Biases in perceptual and oculomotor errors correlated across different test directions.
• No significant trial-by-trial correlations were found between perception and action for the same direction.

Conclusions:

• Partially overlapping neuronal populations likely underlie both motion perception and oculomotor control.
• Independent downstream noise sources obscure trial-by-trial correlations between perception and action.
• Direction-dependent anisotropies suggest shared sensory processing but distinct noise characteristics.