A quantitative framework for motion visibility in human cortex.

Area of Science:

• Neuroscience
• Visual Perception
• Computational Neuroscience

Background:

• Motion visibility manipulations are key to studying perception, decision-making, and inference.
• Existing research lacks a unified quantitative framework for how visibility parameters modulate cortical responses.
• Different visibility manipulations (contrast, coherence, duration) may affect cortical regions uniquely.

Purpose of the Study:

• To develop and apply a quantitative framework modeling human cortical responses to varying motion visibility parameters.
• To systematically investigate the effects of contrast, coherence, and duration on visual cortex activity.
• To provide a reference for interpreting perceptual studies that use these visibility manipulations.

Main Methods:

• Human participants viewed random-dot motion stimuli with varied contrast, coherence, and duration.
• Blood-oxygen-level dependent (BOLD) responses were measured using functional magnetic resonance imaging (fMRI).
• A novel computational framework was developed to model and quantify cortical responses across visual areas.

Main Results:

• All visual areas showed sensitivity to contrast, coherence, and duration.
• Early visual areas (V1-V4) were most sensitive to contrast changes.
• V3A and the human middle temporal area (hMT+) showed higher sensitivity to coherence.
• Motion visibility parameters share cortical representation but are encoded with distinct functional forms and sensitivities.

Conclusions:

• The developed quantitative framework effectively models human cortical responses to motion visibility manipulations.
• Different parameters of motion visibility (contrast, coherence, duration) have distinct effects across the human visual cortex.
• This framework serves as a crucial reference for interpreting a wide range of perceptual and neuroscientific studies.