When incompatible images are presented to corresponding regions of each eye, perception alternates between the two monocular views (binocular rivalry). In this study, we have investigated how involuntary (exogenous) and voluntary (endogenous) attention can influence the perceptual dominance of one rival image or the other during contour rivalry. Subjects viewed two orthogonal grating stimuli that were presented to both eyes. Involuntary attention was directed to one of the grating stimuli with a brief change in orientation. After a short period, the cued grating was removed from the image in one eye and the uncued grating was removed from the image in the other eye, generating binocular rivalry. Subjects usually reported dominance of the cued grating during the rivalry period. We found that the influence of the cue declined with the interval between its onset and the onset of binocular rivalry in a manner consistent with the effect of involuntary attention. Finally, we demonstrated that voluntary attention to a grating stimulus could also influence the ongoing changes in perceptual dominance that accompany longer periods of binocular rivalry Voluntary attention did not increase the mean dominance period of the attended grating, but rather decreased the mean dominance period of the non-attended grating. This pattern is analogous to increasing the perceived contrast of the attended grating. These results suggest that the competition during binocular rivalry might be an example of a more general attentional mechanism within the visual system.
consumption of processed sugar-and starchcontaining foods, and dental caries: a systematic review.
Interindividual variation has been shown in the rates at which subjects alternate in perception during viewing of binocular rivalry and other ambiguous figures. A similar pattern of interindividual variation is evident in the rate of eye movements. The aim of this study was to determine whether individual differences in the rate of binocular rivalry predict individual differences in the rate of eye movements. First, participants reported changes in perception during contour rivalry. We found that the alternation rate during rivalry varied from 0.15 to 0.59/s between individuals. Next, participants viewed different visual displays while their eye movements were tracked. We found that the rate of saccadic eye movements varied by 1.9–4.4/s between individuals. Although the temporal characteristics of eye movements and binocular rivalry differed in their absolute rate, we found a significant positive correlation between these measures; that is, the frequency of saccadic eye movements can predict an individual's rate of perceptual alternation during rivalry. These findings suggest a potential link between the mechanisms involved in binocular rivalry and those processes involved in controlling eye movements.
Neurons in the early stages of visual processing are often thought of as edge detectors for different orientations. Here we investigate the existence of detectors for specific combinations of edges-detectors for specific curvatures. Previous attempts to demonstrate such detectors through aftereffects have ultimately been explained by adaptation to local orientation rather than curvature per se. To control for local aftereffects, we adapted one patch of visual field to two adjacent gratings presented as an obtuse contour (compound patch), and another patch to the same component gratings presented alternately (component patch). In this way both patches are adapted equally to the local orientation components of the stimuli, but only the compound patch is adapted to the global contour. Thus any difference in adaptation between the patches must result from the presence of the contour as a global figure. We found that perceived contrast of probe stimuli was not differentially altered in the two patches. However, apparent curvature of the probes was consistently greater in the compound patch than in the component patch. This effect was considerably reduced by increasing the spatial separation of the component gratings. The results are consistent with curvature detectors involved in the perceptual grouping of edges.
Although different features of an object are processed in anatomically distinct regions of the cerebral cortex, they often appear bound together in perception. Here, using binocular rivalry, we reveal that the awareness of form can occur independently from the awareness of colour. First, we report that, if both eyes briefly view a grating stimulus prior to the presentation of the same grating in one eye and an orthogonal grating in the other, subjects tend to report perceptual dominance of the non-primed grating. The primer was most effective when it was similar in orientation, spatial frequency and spatial phase to one of the rival images. Next, we showed that the process underlying the binocular integration of chromatic information was selectively influenced by the colour of a previously presented stimulus. We then combined these paradigms by using a primer that had the same colour as one rival stimulus, but the same form as the other stimulus. In this situation, we found that rival stimuli differing in form and colour can sometimes achieve states of dominance in which the chromatic information from one eye's image combines with the form of the other eye's image temporarily creating a binocular impression that corresponds with neither monocular component. Finally, we demonstrated that during continuous viewing of rival stimuli differing in form and colour, chromatic integration could occur independently of form rivalry. Paradoxically, however, we found that changes to the form of the stimulus had more of an influence on chromatic integration than on form rivalry. Together these phenomena show that the neural processes involved in integrating information from the two eyes can operate selectively on different stimulus features.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.