| The goal of visual science is a complete functional description of vision in the biological system. Historically, this was not possible. Vision scientists could investigate the properties of visual perception, but the visual system was terra incognita. In the past 30 years, our knowledge of the visual system has grown substantially. Neuroscientists have provided detailed descriptions of the receptive field properties of neurons in the visual hierarchy. The visual cortex has been mapped in great detail in the macaque, and to lesser extent in humans. In addition, new technologies such as functional neuroimaging have greatly enhanced our ability to investigate the functional properties of the visual areas. With the present day knowledge of the visual system and new technologies, vision scientists are beginning to realize the goal of a complete functional description of vision in the biological system.; In this thesis, four independent projects investigate the neural mechanisms of ambiguity resolution in binocular vision and object perception to reveal important strategies employed by the visual system. Chapter 1 introduces the experimental questions to be addressed in the thesis chapters. Chapter 2 provides an introduction to the methodologies. Chapter 3 investigates how the visual system resolves interocular conflicts in the magnocellular and parvocellular pathways of vision. The results of the experiments indicate incompatible information in parvocellular pathway generates competition (i.e. binocular rivalry), while incompatible information in magnocellular pathway tends to be integrated (i.e. fusion). Chapter 4 studies the contribution high-level representations of the two eyes' stimuli to binocular rivalry. The experiments show that competing high-level representations do not contribute to the induction of rivalry, and thus provide support to the notion that rivalry is based on competing low-level image features. In chapter 5, a novel analysis was performed on functional imaging data to investigate the organization of cortical regions that support object perception. In our analysis, we found the representations of object categories are relatively independent of one another in the brain, supporting the view of modularity for object processes. Finally in Chapter 6, we studied a novel illusion based on the relative motion of objects. Our findings indicated the illusion is the result of differences in the perceived velocity of first and second order patterns in the context of moving objects. |
