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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 Article
TL;DR: In this article, the authors investigated the consequences of functional segregation for the control of fixation durations during scene viewing using gaze-contingent displays, using high-pass or low-pass filters to either the central or the peripheral visual field and compared eye-movement patterns with an unfiltered control condition.
Abstract: Processing in our visual system is functionally segregated, with the fovea specialized in processing fine detail (high spatial frequencies) for object identification, and the periphery in processing coarse information (low frequencies) for spatial orienting and saccade target selection. Here we investigate the consequences of this functional segregation for the control of fixation durations during scene viewing. Using gaze-contingent displays, we applied high-pass or low-pass filters to either the central or the peripheral visual field and compared eye-movement patterns with an unfiltered control condition. In contrast with predictions from functional segregation, fixation durations were unaffected when the critical information for vision was strongly attenuated (foveal low-pass and peripheral high-pass filtering); fixation durations increased, however, when useful information was left mostly intact by the filter (foveal high-pass and peripheral low-pass filtering). These patterns of results are difficult to explain under the assumption that fixation durations are controlled by foveal processing difficulty. As an alternative explanation, we developed the hypothesis that the interaction of foveal and peripheral processing controls fixation duration. To investigate the viability of this explanation, we implemented a computational model with two compartments, approximating spatial aspects of processing by foveal and peripheral activations that change according to a small set of dynamical rules. The model reproduced distributions of fixation durations from all experimental conditions by variation of few parameters that were affected by specific filtering conditions.

36 citations

01 Jan 1994
TL;DR: In this paper, the scaling property of receptive field sizes with eccentricity is considered and the notion of a fovea can be incorporated into conventional scale-space theory leading to foveal log-polar scale space.
Abstract: This paper addresses the formulation of a foveal scale-space and its relation to the scaling property of receptive field sizes with eccentricity. It is shown how the notion of a fovea can be incorporated into conventional scale-space theory leading to a foveal log-polar scale-space. Natural assumptions about uniform treatment of structures over scales and finite processing capacity imply a linear increase of minimum receptive field size as a function of eccentricity. These assumptions are similar to the ones used for deriving linear scale-space theory and the Gaussian receptive field model for an idealized visual front-end.

36 citations

Journal ArticleDOI
TL;DR: Processing times did not differ between the two ERP conditions indicating that “cognitive readiness” during self-paced processing can be ruled out as an alternative explanation for differences in processing times between the ERP and the FRP conditions.
Abstract: The boundary paradigm, in combination with parafoveal masks, is the main technique for studying parafoveal preprocessing during reading. The rationale is that the masks (e.g., strings of X’s) prevent parafoveal preprocessing, but do not interfere with foveal processing. A recent study, however, raised doubts about the neutrality of parafoveal masks. In the present study, we explored this issue by means of fixation-related brain potentials (FRPs). Two FRP conditions presented rows of 5 words. The task of the participant was to judge whether the final word of a list was a “new” word, or whether it was a repeated (i.e., “old”) word. The critical manipulation was that the final word was X-masked during parafoveal preview in one condition, whereas another condition presented a valid preview of the word. In two additional event-related brain potential (ERP) conditions, the words were presented serially with no parafoveal preview available; in one of the conditions with a fixed timing, in the other word presentation was self-paced by the participants. Expectedly, the valid-preview FRP condition elicited the shortest processing times. Processing times did not differ between the two ERP conditions indicating that “cognitive readiness” during self-paced processing can be ruled out as an alternative explanation for differences in processing times between the ERP and the FRP conditions. The longest processing times were found in the X-mask FRP condition indicating that parafoveal X-masks interfere with foveal word recognition.

36 citations

Journal ArticleDOI
TL;DR: How neural representations on the visual salience map are processed in parallel are demonstrated in parallel, thus facilitating visual search, as shown in monkeys trained to perform a multiple-fixation visual conjunction search task.
Abstract: Searching for a visual object naturally involves sequences of gaze fixations, during which the current foveal image is analyzed and the next object to inspect is selected as a saccade target. Fixation durations during such sequences are short, suggesting that saccades may be concurrently processed. Therefore, the selection of the next saccade target may occur before the current saccade target is acquired. To test this hypothesis, we trained four female rhesus monkeys (Macaca mulatta) to perform a multiple-fixation visual conjunction search task. We simultaneously recorded the activity of sensorimotor neurons in the midbrain superior colliculus (SC) in two monkeys. In this task, monkeys made multiple fixations before foveating the target. Fixation durations were significantly shorter than the latency of the initial responses to the search display, with approximately one-quarter being shorter than the shortest response latencies. The time at which SC sensorimotor activity discriminated the target from distracters occurred significantly earlier for the selection of subsequent fixations than for the selection of the first fixation. Target selection during subsequent fixations occurred even before the visual afferent delay in more than half of the neuronal sample, suggesting that the process of selection can encompass at least two future saccade targets. This predictive selection was present even when differences in saccade latencies were taken into account. Altogether, these findings demonstrate how neural representations on the visual salience map are processed in parallel, thus facilitating visual search.

36 citations

Journal ArticleDOI
TL;DR: Binocular performance in the central and peripheral visual fields was compared for normal and anisometropic amblyopes and results are discussed in terms of tolerance to interocular sensitivity differences in the periphery and selective losses in cortical cells.
Abstract: Purpose. Binocular performance in the central and peripheral visual fields was compared for normal and anisometropic amblyopes. Methods. Binocular and monocular thresholds to a light detection task were measured along the four principal meridia in 10 young normal subjects and 10 anisometropic amblyopes using the Humphrey's Visual Field Analyser. Thresholds were obtained at the fovea and at retinal eccentricities of 5o, 10o, 15o, 25o, 40o and 55o on the horizontal, vertical and oblique meridia of 45o and 135o. Results. Binocular summation ratios (binocular sensitivity/ 'best' monocular sensitivity) were calculated for all the eccentricities. In the normal group, the mean binocular summation ratio for the fovea and the peripheral field was not significantly different. In the amblyopic group, subjects showed no or minimal binocular summation in the foveal region but reached normal ratios in the periphery. Discussion. Results are discussed in terms of tolerance to interocular sensitivity differences in the pe...

36 citations


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