Features and Objects in the Visual System

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The visual system is divided into a ventral stream specialized for object recognition and a dorsal stream specialized for motion processing and visuomotor guidance such as grasping objects. Because of this functional separation, there are many models of object representation in the ventral stream and many models of motion processing in the dorsal stream, but research has been mostly devoid of investigations as to the nature or existence of object representations in the dorsal stream. Based on the difference in functionality, the two streams would use these objects differently and therefore represent them differently too. That is, the ventral stream would be processing features relevant for object recognition, including shape, color, texture, etc. While the dorsal stream processes features relevant for action, such as spatial location, motion, 3d shape for grasping, etc. Thus, it becomes very important to correctly integrate or ‘bind' the relevant features into each stream. Both streams process features, and these feature-selective neurons need to be connected or integrated into a distributed network to form a representation of the object. Feature integration, aka the Binding Problem, is a long outstanding problem in neuroscience.******The projects in this proposal investigate the nature of feature integration and object representations in the dorsal stream. They will determine which features are integrated into the dorsal stream, how those features are integrated into a dorsal stream object representation, the stages of processing in the dorsal stream that are dependent on features versus those that work on object representations, and how object representations are selected and attended to within the dorsal stream. The studies in the proposal are important in that their results will produce new testable models for dorsal stream processing as well as test and constrain current models of feature integration and object representation. This research is important to vision scientists, cognitive and systems neuroscientists, computational modeling and computer vision researchers, which are all areas of strength in Canada.