Master's Thesis
Technical Report AI-97-259
Department of Computer Sciences
The University of Texas at Austin
January 1997
The psychological phenomenon known as the tilt aftereffect was used to demonstrate the functional properties of RF-LISSOM, a self-organizing model of laterally connected orientation maps in the primary visual cortex. The same self-organizing processes that are responsible for the development of the map and its lateral connections are shown to result in tilt aftereffects as well. The model allows analysis of data that are difficult to measure in humans, thus providing a view of the cortex that is otherwise not available. The results give computational support for the idea that tilt aftereffects arise from lateral interactions between adapting feature detectors, as has long been surmised. They also suggest that indirect tilt aftereffects could result from the conservation of synaptic resources. The model thus provides a unified computational explanation of self-organization and both direct and indirect tilt aftereffects in the primary visual cortex.