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The geometry of the topographic map in striate cortex
1Department of Psychology, University College of London, U.K.
Vision Research
|January 1, 1989
Summary
The conic surface model accurately describes primate striate cortical maps, accommodating variations in foveal emphasis across species like macaques and owl monkeys. This geometric model also explains changes in receptive field size and magnification with visual eccentricity.
Area of Science:
- Neuroscience
- Computational Neuroscience
- Primate Visual System
Background:
- Johnston (1986) proposed a conic surface model for primate striate cortical map geometry.
- This model orients a conic surface with its base at the eye and axis along the line of sight.
Purpose of the Study:
- To test Johnston's conic surface model using cortical magnification and topographic map data.
- To extend the model to explain receptive field size and magnification changes with eccentricity.
Main Methods:
- Analysis of cortical magnification data from macaque, squirrel, and cebus monkeys.
- Examination of distance data from topographic maps of macaque and owl monkey cortex.
- Modeling changes in mean cortical receptive field size and inverse magnification.
Main Results:
- The conic model successfully accommodates topographic maps from both macaque and owl monkey cortex, despite differences in foveal emphasis, by adjusting parameters.
- The model was extended to explain differential changes in receptive field size and inverse magnification with eccentricity.
Conclusions:
- Johnston's conic surface model provides a robust framework for understanding primate striate cortical map geometry.
- The model accurately predicts receptive field properties, suggesting a constant mean receptive field size on tangent planes to a cone with a specific apical angle.