Rudiger von der Heydt, PhD
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| Mechanisms of Visual Perception |
| We see the world three-dimensional, although our eyes register only two-dimensional images. It is known that the visual cortex transforms the image information into a representation of elementary features, such as pieces of contour and patches of color. It is less clear how the brain further organizes visual information. Studies of perception suggest a stage where elementary features are grouped according to surfaces and objects, and the layout of objects in space is represented. Research in our laboratory is concerned with the transformation from the image to an object representation. How does the visual system determine which features are related, how does it set apart foreground objects from the background, and how does it represent relationships? We discovered that edge selective cells of areas V2 and V4 represent figure-ground direction. Thus, neurons that were thought to represent only local features carry information about global shape and where the features belong. The data suggest fast parallel processes that precede object recognition. An early stage of visual organization could play an important role in visual tasks that require selective processing of information from a specific object. But how can features be assigned to objects before objects are recognized? How do mechanisms for selection interact with this early stage of organization? Research in the laboratory involves neurophysiological, psychophysical, and modeling work. |
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