Visual processing in biological systems is classically described as a hierarchy of increasingly sophisticated representations, originating in primary visual cortex (V1), progressing through intermediate area V4, and ascending to inferotemporal cortex. The computational mechanisms that produce representations in intermediate area V4 have remained a mystery. In this thesis I show that the standar...

The reaction mechanisms for diesel soot oxidation over V4/ZrO2 or V4/TiO2 oxide catalysts were studied by the means of in-situ UV-Raman spectroscopy. The results indicate that the formation of surface oxygen complexes (SOC) is a key step and the SOC species mainly exist as carboxyl groups. The presence of NO in the reaction gas stream can promote the formation of SOC species. For soot oxidation...

The role of area V4 in the primate extrastriate cortex has received much attention in recent years. However, the deficit specificity following area V4 ablations has been difficult to determine due to the ablations including area V4 and additional adjacent areas, deficit attenuation and the numerous variations in the results of different research teams. In order to address these issues, we exami...

In the primate visual system, area V4 is located in the ventral pathway and is traditionally thought to be involved in processing color and form information. However, little is known about its functional role in processing motion information. Using intrinsic signal optical imaging over large fields of view in V1, V2, and V4, we mapped the direction of motion responses in anesthetized macaques. ...

In this paper, we present an efficient multilayer general area router, named V4, for MCM and dense PCB designs. The unique feature of the V4 router is that it uses no more than four vias to route every net and yet produces high quality routing solutions. A number of combinatorial optimization techniques are used in the V4 router to produce high quality routing solutions in polynomial time. As a...

Object recognition in primates is mediated by the ventral visual pathway and is classically described as a feedforward hierarchy of increasingly sophisticated representations. Neurons in macaque monkey area V4, an intermediate stage along the ventral pathway, have been shown to exhibit selectivity to complex boundary conformation and invariance to spatial translation. How could such a represent...

Cortical visual area V4 in macaque monkeys has a large proportion of neurons that are sensitive to the wavelength or to the color of light. We tested its role in hue discrimination by removing it in macaque monkeys trained to discriminate small differences in hue. Hue discrimination thresholds were permanently elevated in 4 macaque monkeys in which V4 was removed bilaterally. In contrast, there...

The primate visual system has an exquisite ability to discriminate partially occluded shapes. Recent electrophysiological recordings suggest that response dynamics in intermediate visual cortical area V4, shaped by feedback from prefrontal cortex (PFC), may play a key role. To probe the algorithms that may underlie these findings, we build and test a model of V4 and PFC interactions based on a ...

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