Abstract: PURPOSE: The functional role and information processing at the intermediate level of the primate visual system remain elusive.
METHODS: Using 7T BOLD fMRI at 1-mm isotropic resolution, we investigated laminar and columnar organizations for color, disparity and naturalistic texture in human second visual area (V2), along with its informational connectivity to lower and higher order visual cortices.
RESULTS: Although color-selective thin and disparity-selective thick stripe-columns can be clearly identified in area V2, BOLD activity to naturalistic textures exhibited neither columnar organization nor response preference among thin, thick and pale stripes. Cortical depth-dependent analyses revealed strongest color-selectivity in the superficial layers of V2, and its feedforward and feedback connectivity with V1 and hV4. Disparity-selectivity was similar across different cortical depth in V2, demonstrating significant feedforward and feedback connectivity with V1 and V3ab. Interestingly, the selectivity for naturalistic texture was strongest in the deep layers of V2, with significant feedback connectivity from hV4.
CONCLUSIONS: Therefore, compared to color and disparity, the selectivity to naturalistic textures in area V2 is more related to feedback processing and may develop after the critical period for forming cortical columns.

Key words: V2, naturalistic texture, color, disparity, 7T fMRI