A reaction-diffusion model to capture disparity selectivity in primary visual cortex

Area of Science:

• Neuroscience
• Computational Neuroscience
• Visual System Development

Background:

• Extensive research exists on disparity-selective cells in primate and feline visual cortices.
• Previous studies mapped local disparity for specific orientations but not complete disparity maps in V1.
• Understanding disparity map development in V1 Layer IV is crucial for insights into receptive field organization.

Purpose of the Study:

• To model disparity selectivity and map development in Layer IV of the cat's primary visual cortex (V1).
• To investigate the influence of LGN cell resource availability and target space competition on cortical wiring.
• To explore the relationship between ocular dominance and disparity selectivity at cellular and map levels.

Main Methods:

• A reaction-diffusion two-eye paradigm was employed to model disparity selectivity in V1 Layer IV.
• The model incorporated LGN cell resource limitations and competition for synaptic targets in the cortex.
• Simulations generated 2D disparity-selective simple cell receptive fields, response properties, and disparity maps.

Main Results:

• The model successfully reproduced realistic 2D disparity-selective simple cell receptive fields and disparity maps.
• A lack of correlation was observed between ocular dominance and disparity selectivity at the cell population level.
• Disparity selectivity topography showed weak clustering for similar preferred disparities, mirroring experimental findings in macaques.

Conclusions:

• The developed model provides insights into the organization of disparity-selective complex cell receptive fields from simple cell subunits.
• The weak clustering of disparity maps suggests a non-random organization within V1.
• Findings indicate two potential types of complex cell receptive field organization based on the detailed disparity map structure.