A neural basis for the spatial suppression of visual motion perception

Area of Science:

• Neuroscience
• Computational Neuroscience
• Psychophysics

Background:

• Sensory perception accuracy theoretically increases with neuronal population size.
• However, larger stimuli sometimes lead to reduced perceptual performance, a paradoxical finding.
• The underlying neural mechanisms remain unclear.

Purpose of the Study:

• Investigate the neural basis of paradoxical perceptual performance with larger stimuli.
• Determine how neuronal population activity relates to stimulus size and perception.
• Explain the interaction of neural mechanisms contributing to perceptual accuracy.

Main Methods:

• Trained monkeys to discriminate visual motion direction with stimuli of varying sizes.
• Simultaneously recorded neuronal activity from populations of motion-sensitive neurons in cortical area MT.
• Developed a computational model constrained by neural and behavioral data.

Main Results:

• Noise correlations limited the increase in stimulus information with larger stimulus sizes.
• Neural surround suppression reduced neuronal sensitivity for larger stimuli.
• A neural read-out strategy prioritized neurons with receptive fields near the stimulus center.

Conclusions:

• Paradoxical percepts arise from a complex interplay of neural mechanisms.
• Tradeoffs between neural sensitivity and noise influence perceptual accuracy.
• Understanding these mechanisms is crucial for explaining sensory perception limits.