Neural dynamics of form perception: Boundary completion, illusory figures, and neon color spreading.

Abstract

A real-time visual processing theory is used to analyze real and illusory contour formation, contour and brightness interactions, neon color spreading, complementary color induction, and filling-in of discounted illuminants and scotomas. The theory also physically interprets and generalizes Land's retinex theory. These phenomena are traced to adaptive processes that overcome limitations of visual uptake to synthesize informative visual representations of the external world. Two parallel contour sensitive processes interact to generate the theory's brightness, color, and form estimates. A boundary contour process is sensitive to orientation and amount of contrast but not to direction of contrast in scenic edges. It synthesizes boundaries sensitive to the global configuration of scenic elements. A feature contour process is insensitive to orientation but sensitive to both amount of contrast and to direction of contrast in scenic edges. It triggers a diffusive filling-in of featural quality within perceptual domains whose boundaries are determined by completed boundary contours. The boundary contour process is hypothesized to include cortical interactions initiated by hypercolumns in Area 17 of the visual cortex. The feature contour process is hypothesized to include cortical interactions initiated by the cytochrome oxydase staining blobs in Area 17. Relevant data from striate and prestriate visual cortex, including data that support two predictions, are reviewed. Implications for other perceptual theories and axioms of geometry are discussed.

Predictive coding explains binocular rivalry: An epistemological review

“…A number of formal models have been developed which are able to reproduce aspects of binocular rivalry (Dayan, 1998;Grossberg & Mingolla, 1985;Kalarickal, 2000;Kawamoto & Anderson, 1985;Koene, 2006;Laing & Chow, 2002;Lehky, 1988;Lumer, 1998;Matsuoka, 1984;Noest et al, 2007;Wilson, 2003;Wilson, 2007;Zhou, Gao, White, Merk, & Yao, 2004). The majority of these models analyse binocular rivalry a priori as a phenomenon driven by adaptation of the winning neural population, and lateral and/or top down inhibition of the competing population.…”

Preemption effects in visual search: Evidence for low-level grouping.

“…Although these contours do not correspond directly to any structure in the image, they are equivalent in many respects to the "physical" contours derived from luminance differences (see, e.g., Petry & Meyer, 1987). It is generally believed that subjective contours result from boundary-completion processes carried out via nonlinear interactions among receptive fields at early stages of visual processing (e.g., Grossberg & Mingolla, 1985a;von der Heydt & Peterhans, 1989;Zucker, 1987a). Cells in cortical area V2 have been found that are responsive to such contours (von der Heydt & Peterhans, 1989;Peterhans & von der Heydt, 1989, 1991, and psychophysical evidence has also been found for their existence at early levels (Gurnsey et al, 1992).…”

Occipital network for figure/ground organization

“…What neural architecture allows local and global information to be combined rapidly, to provide for Wgure/ground categorization? In terms of neural architecture, does the mechanism employ lateral interactions (e.g., Gerrits and Vendrik 1970;Grossberg and Mingolla 1985;Grossberg 1994;Baek and Sajda 2005;Pao et al 1999;Zhaoping 2005), top-down feedback (e.g., Lamme and Roelfsema 2000;Lamme et al 2002;Roelfsema et al 2002;Craft et al 2007) or more sophisticated combinations? In terms of its coding mechanism, do the Wgure/ground conWgurations use border-based coding (e.g., von der Heydt et al 2003Heydt et al , 2005Craft et al 2007) or region-based coding (e.g., Lamme 1995;Zipser et al 1996;Lamme et al 1998;Super et al 2001;Roelfsema et al 2002)?…”