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Foveal

About: Foveal is a research topic. Over the lifetime, 2652 publications have been published within this topic receiving 94120 citations.


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Journal ArticleDOI
TL;DR: Observations show that pursuit velocity altered the effect of stimulation, which suggest that the stimulation acted on visual motion processing before information about the pursuit movement itself is incorporated, and hypothesize that the directional bias for pursuit originates in the visual signal conveyed to the pursuit system.
Abstract: 1 Many cells in the superior temporal sulcus (STS) of the monkey that represent the foveal region of the visual field discharge during pursuit eye movements Damage to these areas produces a defic

234 citations

Journal ArticleDOI
TL;DR: The functional visual field defined in terms of a discrimination task of a target presented peripherally among ambiguous background patterns was investigated for various foveal loads which were to be recognized at the central retina.
Abstract: The functional visual field defined in terms of a discrimination task of a target presented peripherally among ambiguous background patterns was investigated for various foveal loads which were to be recognized at the central retina. Foveal loads were numbers, letters, place names, traffic signs, and other figures to simulate commonplace situations for foveal information processing, and grouped into three in order of recognition difficulty based on daily experience. Boundaries of the functional visual field were obtained for simple fixation and for certain foveal loads. Comparison of these boundaries clearly showed shrinkage of the functional visual field size with the foveal loads of greater recognition difficulty.

233 citations

Journal ArticleDOI
TL;DR: Functional magnetic resonance imaging (fMRI) is used to demonstrate that the type of task that a human subject engages in determines the way in which ignored visual background stimuli are processed in parahippocampal cortex.
Abstract: Observers commonly experience functional blindness to unattended visual events, and this problem has fuelled an intense debate concerning the fate of unattended visual information in neural processing. Here we used functional magnetic resonance imaging (fMRI) to demonstrate that the type of task that a human subject engages in determines the way in which ignored visual background stimuli are processed in parahippocampal cortex. Increasing the perceptual difficulty of a foveal target task attenuated processing of task-irrelevant background scenes, whereas increasing the number of objects held in working memory did not have this effect. These dissociable effects of perceptual and working memory load clarify how task-irrelevant, unattended stimuli are processed in category-selective areas in human ventral visual cortex.

228 citations

Journal ArticleDOI
TL;DR: Three experiments are reported that examined the relationship between covert visual attention and a viewer’s ability to use extrafoveal visual information during object identification, and evidence is found for a model in which extraFoveal information acquired during a fixation derives primarily from the location toward which the eyes will move next.
Abstract: Three experiments are reported that examined the relationship between covert visual atten­ tion and a viewer's ability to use extrafoveal visual information during object identification. Sub­ jects looked at arrays of four objects while their eye movements were recorded. Their task was to identify the objects in the array for an immediate probe memory test. During viewing, the number and location of objects visible during given fixations were manipulated. In Experiments 1 and 2, we found that multiple extrafoveal previews of an object did not afford any more benefit than a single extrafoveal preview, as assessed by means of time of fixation on the objects. In Ex­ periment 3, we found evidence for a model in which extrafoveal information acquired during a fixation derives primarily from the location toward which the eyes will move next. The results are discussed in terms of their implications for the relationship between covert visual attention and extrafoveal information use, and a sequential attention model is proposed. 196 During normal perception, the eyes tend to move in short hops or saccades, punctuated by fixations during which the eyes remain relatively stationary and visual in­ formation acquisition takes place. This article is concerned with the acquisition and use of information from stimuli beyond the fovea (i.e., extrafoveal stimuli) during an eye fixation, given that the fixation occurs during a sequence of fixations and saccades (in contrast to tachistoscopic procedures). The acquisition of information from an extra­ foveal stimulus can be seen as serving at least two dis­ tinct functions. First, extrafoveal processing is necessary for determining where to position future eye movements (see, e.g., Loftus, 1983; Morris, 1987; Rayner & Pol­ latsek, 1987). Second, and more important for the pur­ poses of this study, while an extrafoveal stimulus may not be fully analyzed before it is fixated, partial analysis of an extrafoveal stimulus often provides information that subsequently speeds the analysis of that stimulus once it

224 citations

Journal Article
TL;DR: The results show that oxygenation of the parafoveal monkey retina is similar to that previously observed in the cat area centralis, and differs as expected considering the thinner retina and the absence of inner retinal neurons and retinal circulation.
Abstract: Purpose Oxygen distribution was characterized in the macaque retina, which is more like the human retina than others studied previously. Methods Profiles of oxygen tension (PO2) as a function of distance were recorded in a parafoveal region about halfway between the fovea and optic disk, and from the fovea in one animal. A one-dimensional diffusion model was used to determine photoreceptor oxygen consumption (QO2). Results In the parafovea, the PO2 decreased as the electrode was withdrawn from the choroid toward the inner retina, reaching a minimum value during dark adaptation of about 9 mmHg at about 70% retinal depth, and then increasing more proximally. Approximately 90% of the oxygen requirement of the photoreceptors was supplied by the choroidal circulation and 10% by the retinal circulation. In light adaptation, there was a monotonic PO2 gradient from the choroid to the inner retina, indicating that all of the oxygen used by photoreceptors was supplied by the choroid. In the fovea, the choroid supplied almost all the oxygen in both dark and light adaptation, with a minor supply from the vitreous humor. Dark-adapted foveal oxygen consumption was lower than parafoveal oxygen consumption. Light reduced the oxygen consumption of the photoreceptors, in both regions studied, by 16-36%. Conclusions The results show that oxygenation of the parafoveal monkey retina is similar to that previously observed in the cat area centralis. In the fovea, the oxygen distribution differs as expected considering the thinner retina and the absence of inner retinal neurons and retinal circulation.

223 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023144
2022385
202195
2020119
2019108
201883