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Two separate neural mechanisms of brightness induction
S K Shevell1, I Holliday, P Whittle
1Department of Psychology, University of Chicago, IL 60637.
Vision Research
|December 1, 1992
Summary
Perceived brightness is not absolute but relative, influenced by surrounding light. Two neural pathways, one local and one global, process visual scene contrast for brightness perception.
Area of Science:
- Neuroscience
- Vision Science
- Perception
Background:
- Perceived brightness is influenced by surrounding light levels, a phenomenon known as simultaneous contrast.
- The neural mechanisms underlying this contextual modulation of brightness perception are not fully understood.
Purpose of the Study:
- To investigate the distinct neural mechanisms mediating brightness perception based on local and global visual scene information.
Main Methods:
- Analyzing neural processing at different levels of the visual system.
- Examining the role of retinal image contrast between adjacent regions.
- Investigating the influence of binocularly fused "cyclopian" representation on perception.
Main Results:
- Brightness perception is modulated by two separate neural mechanisms operating at distinct visual system levels.
- One mechanism relies on local retinal image contrast.
- A second mechanism utilizes a global, "cyclopian" representation influenced by remote visual field areas.
Conclusions:
- Brightness perception is a complex process involving both local and global visual scene analysis.
- These findings elucidate the dual neural pathways contributing to contextual brightness perception.