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Critical to vision research is the generation of visual displays with precise control over stimulus metrics. Generating stimuli often requires adapting commercial software or developing specialized software for specific research applications. In order to facilitate this process, we give here an overview that allows nonexpert users to generate and customize(More)
Evidence exists that damage to white matter connections may contribute to reduced speed of information processing in traumatic brain injury and stroke. Damage to such axonal projections suggests a particular vulnerability to functions requiring integration across cortical sites. To test this prediction, measurements were made of perceptual grouping, which(More)
The objective of the study was to determine the incidence and type of endometrial abnormalities in long-term users of tamoxifen with breast cancer. All patients with a diagnosis of Oestrogen Receptor positive breast cancer on Tamoxifen therapy who had also undergone endometrial biopsy for abnormal bleeding or other symptoms were included. Among the 37 cases(More)
Mechanisms underlying perceptual grouping serve to bind stimulus components that are contained within grouped patterns. In order to examine the time course of grouping development, grids of spatially isolated dots were followed by pattern masks across a range of SOA. Subjects indicated the predominant perceived grouping of the dot patterns. Masks either(More)
Early visual processing in rats is mediated by several pre-cortical pathways as well as multiple retinal ganglion cell types that vary in response characteristics. Discrete processing is thereby optimized for select ranges of stimulus parameters. In order to explore variation in response characteristics at a perceptual level, visual detection in rats was(More)
For ambiguous stimuli, complex dynamics guide processes of perceptual grouping. Previous studies have suggested two opposing effects on grouping that are produced by the preliminary stimulus state: one that enhances grouping towards the existing structure, and another that opposes this structure. To examine effects of the preliminary state on grouping(More)
Changes in target visibility may be produced by additional stimulus elements at adjacent locations. Such contextual effects may reflect lateral interactions of stimulus representations in early cortical areas. It has been reported that the organization of orientation preference found in primates and cats visual cortex differs from that found in rodents,(More)
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