Date on Master's Thesis/Doctoral Dissertation

12-2014

Document Type

Doctoral Dissertation

Degree Name

Ph. D.

Department

Psychological and Brain Sciences

Committee Chair

He, Zijiang

Committee Co-Chair (if applicable)

Pani, John

Committee Member

DeMarco, Paul J.

Committee Member

Sephton, Sandra

Committee Member

Zahorik, Pavel

Subject

Visual discrimination; Visual pathways; Visual perception

Abstract

We receive most information about our surrounding space and objects through the eyes. To reconstruct the 3D space and objects in the visual system from the 2D retinal images, surface representation must be a critical intermediate stage in the visual processing stream. It is hypothesized in the dissertation that the visual system represents textured surface by a border-to-interior strategy: boundary contours would be encoded first and then border-ownership assignments would be resolved. This process would solve the related problems such as figure-ground segregation, surface depth relationship, occlusion, transparency, etc. As a result, the boundary contours of the surfaces would be well defined and then the visual system could register the local features in different domains with the boundary contours, gradually from the adjacent areas of the boundary contours to the interior of the surfaces. To testify this hypothesis in the current proposal, a monocular boundary contour (MBC) paradigm is adapted from earlier studies by Ooi and He (2005, 2006). In Chapter 1, the boundary-contour-based hypothesis, with the MBC paradigm, is used to re-address a decade-long debate about binocular vision: whether (and how) binocular integration and inhibition coexist. In Chapter 2–5, the MBC-induced binocular suppression is systematically investigated, especially in Chapter 3 where the cortical speed of the hypothesized border-to-interior spreading is quantitatively estimated. In the end, the rules how the surface fragments are integrated to a global representation is further studied in Chapter 6 and 7, especially focusing on the role of luminance and color contrast polarities.

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