Journal of Vision最新文献

Binocular rivalry occurs when two eyes are presented with two conflicting stimuli. Although the physical stimulation stays the same, the conscious percept changes over time. This property makes it a unique paradigm in both vision science and consciousness research. Two key parameters, contrast and attention, were repeatedly shown to affect binocular rivalry dynamics in a similar manner. This was taken as evidence that attention acts by enhancing effective stimulus contrast. Brief transition periods between the two clear percepts have so far been much less investigated. In a previous study we demonstrated that transition periods can appear in different forms depending on the stimulus type and the observer. In the current study, we investigated how attention and contrast affect transition appearance. Observers viewed binocular rivalry and reported their perception of the four most common transition types by a button press while either the stimulus contrast or the locus of exogenous attention was manipulated. We show that contrast and attention similarly affect the overall binocular rivalry dynamics, but their effects on the appearance of transitions differ. These results suggest that the effect of attention is different from a simple enhancement of stimulus strength, which becomes evident only when different transition types are considered.

This study investigates how optical information and dynamical constraints influence movement production and perception. In Experiment 1, 16 volunteers walked or performed a Y-balance movement with and without sight on sturdy or foam-padded floors. The optical information and force environment affected the participants' kinematics, such as stride duration, stride length, stride width, gait speed, joint ranges of motion for walking, total movement duration, and joint ranges of motion for Y-balance. Naïve observers then watched these movements on a point-light display and distinguished movements executed under different optical information (Experiment 2) and force environment (Experiment 3) conditions. They were able to pick out movements performed without sight, especially for those performed on a padded floor; they were also able to discriminate movements performed on different supporting surfaces, especially when the actors were blindfolded. Thus, discriminating movement conditions from point-light displays was possible, and better with higher kinematic variability. Logistic regressions showed discriminating movements relied on the movement kinematics that varied the most between conditions. This information was valid and useful regardless of viewing perspective; that is, whether the walking and Y-balance were displayed in the frontal or side view, the perceptual performance was equivalent. Thus, both optical information and dynamical constraints shape movement patterns in ways that are perceptible through the kinematic variations.

Studies of the early visual system often require characterizing the visual preferences of large populations of neurons. This task typically requires multiple stimuli such as sparse noise and drifting gratings, each of which probes only a limited set of visual features. Here, we introduce a new dynamic stimulus with sharp-edged stripes that we term Zebra noise and a new analysis model based on wavelets, and we show that in combination they are highly efficient for mapping multiple aspects of the visual preferences of thousands of neurons. We used two-photon calcium imaging to record the activity of neurons in the mouse visual cortex. Zebra noise elicited strong responses that were more repeatable than those evoked by traditional stimuli. The wavelet-based model captured the repeatable aspects of the resulting responses, providing measures of neuronal tuning for multiple stimulus features: position, orientation, size, spatial frequency, drift rate, and direction. The method proved efficient, requiring only 5 minutes of stimulus (repeated three times) to characterize the tuning of thousands of neurons across visual areas. In combination, the Zebra noise stimulus and the wavelet-based model provide a broadly applicable toolkit for the rapid characterization of visual representations, promising to accelerate future studies of visual function.

To correctly parse the visual scene, one must detect edges and determine their underlying cause. Previous work has demonstrated that neural networks trained to differentiate shadow and occlusion edges exhibit sensitivity to boundary sharpness and texture differences. Here, we investigate whether human observers are also sensitive to these cues using synthetic edge stimuli formed by quilting together two natural textures, allowing us to parametrically manipulate boundary sharpness, texture modulation, and luminance modulation. Observers classified five sets of synthetic boundary images as shadows, occlusions, or textures generated by varying these three cues in all possible combinations. These three cues exhibited strong interactions to determine categorization. For sharp edges, increasing luminance modulation made it less likely the patch would be classified as a texture and more likely it would be classified as an occlusion, whereas for blurred edges, increasing luminance modulation made it more likely the patch would be classified as a shadow. Boundary sharpness had a profound effect, so that in the presence of luminance modulation, increasing sharpness decreased the likelihood of classification as a shadow and increased the likelihood of classification as an occlusion. Texture modulation had little effect, except for a sharp boundary with zero luminance modulation. Results were consistent across all five stimulus sets, and human performance was well explained by a multinomial logistic regression model. Our results demonstrate that human observers make use of the same cues as previous machine learning models when detecting and determining the cause of an edge.

For goal-directed movements like throwing darts or shooting a soccer penalty, the optimal location to aim depends on the endpoint variability of an individual. Currently, there is no consensus on whether people can optimize their movement planning based on information about their motor variability. Here, we tested the role of different types of feedback for movement planning under risk. We measured saccades toward a bar that consisted of a reward and a penalty region. Participants either received error-based feedback about their endpoint or reinforcement feedback about the resulting reward. We additionally manipulated the feedback schedule to assess the role of feedback frequency and whether feedback focusses on individual trials or a group of trials. Participants with trial-by-trial reinforcement feedback performed best. They were less loss-aversive, had the least endpoint deviation from optimality, and showed more consistent performance at the group level. This combination of reduced between-participant variability and the improved alignment with optimality suggests that reinforcement feedback about a single movement is particularly effective to optimize movement planning under risk.

Visual rivalry paradigms provide a powerful tool for probing the mechanisms of visual awareness and perceptual suppression. Although the dynamics and determinants of perceptual switches in visual rivalry have been extensively studied and modeled, recent advances in experimental design-particularly those that quantify the depth and variability of perceptual suppression-have outpaced the development of computational models. Here we extend an existing dynamical model of binocular rivalry to encompass two novel experimental paradigms: a threshold detection variant of binocular rivalry, and tracking continuous flash suppression. Together, these tasks provide complementary measures of the dynamics and magnitude of perceptual suppression. Through numerical simulation, we demonstrate that a single mechanism, competitive (hysteretic) inhibition between slowly adapting monocular populations, is sufficient to account for the suppression depth findings across both paradigms. This unified model offers a foundation for the development of a quantitative theory of perceptual suppression in visual rivalry.

Individuals with cerebral visual impairment (CVI) often struggle with visuospatial processing, particularly in highly cluttered or complex environments. These challenges are commonly assessed through visual search tasks, using global measures such as reaction time (RT), accuracy, and search area. Accordingly, impaired search performance in CVI manifests as longer RTs, lower accuracy, and broader search areas. However, rather than elucidating the underlying mechanism of the impaired search process, these measures decode its outcome. In the present study, we utilized eye-tracking data to compute detailed measures of fixation count and duration, aiming to characterize gaze pattern sequences and determine whether prolonged RTs in CVI stem from slower visual scanning or increased fixation counts. Our reanalysis of two previously published datasets reveals that longer RTs in CVI arise from elevated fixation counts, specifically on distractors, rather than from slower visual scanning. Our findings indicate recurrent disruptions in maintaining gaze on the target, likely reflecting difficulties in sustaining attention on the target, suppressing distractors, and preventing inhibition of return. Together, these findings highlight an inefficient search pattern that is more biased toward distractors than focused on targets. By revealing these underlying mechanisms, gaze-based measures offer a deeper understanding of visuospatial processing deficits in CVI.

In macular degeneration (MD), depth perception from binocular disparity is impacted in regions with vision loss in either eye, but monocular cues like motion parallax remain available. This study investigates whether combining motion parallax with disparity improves depth perception and compensates for the loss of depth due to central field loss (CFL). Eleven MD participants and 19 controls viewed a horizontal sine-wave corrugation in depth, defined by disparity and/or motion parallax, judging which half-cycle appeared farther away in depth. We measured thresholds for each cue alone and for the two cues combined. In MD participants, cue integration benefits depended on scotoma characteristics. Disparity performance correlated strongly with the size of the stereoblind zone, while motion parallax thresholds showed no significant relation, suggesting preservation despite CFL. MD participants with extensive stereoblind zones showed elevated thresholds for both single cues compared to controls but demonstrated optimal integration when disparity was added to motion parallax. Those with small stereoblind zones achieved control-like thresholds and exhibited optimal or better than predicted integration. However, asymmetric patterns emerged with suboptimal performance when motion parallax was added to threshold disparity. Controls with simulated scotomas maintained stable integration, contrasting with variable patterns in MD. Our results show that individuals with CFL retain significant capacity for depth cue integration, contingent upon residual binocular disparity. Thus, motion parallax emerges as a valuable compensatory cue to improve depth perception in individuals with MD.

How stimulus properties are processed in the human brain over time is critical to how we engage in dynamic everyday environments. To understand how changes in basic stimulus properties relate to changes in human electrical brain activity over time, previous work has estimated the brain's temporal response function (TRF) by cross-correlating random luminance sequences with electroencephalogram (EEG) signals at various lags to approximate the brain's response to temporal changes in luminance. Using this technique, it was found that luminance changes produce long-lasting "echoes" in the alpha frequency range. However, the neural origin of these echoes and the precise stimulus features that induce them have not been extensively studied. We measured TRFs in response to luminance and contrast changes. Additionally, the fact that EEG responses generated in the primary visual cortex (V1) have a unique pattern of polarity reversal depending on the visual field location (with upper stimuli projecting negatively and lower projecting positively) allowed us to test whether the TRFs generated from upper or lower visual field stimulation were counter-phased, as would be expected if the echoes were generated within V1. We found a luminance echo lasting ∼1 s in the alpha frequency and contrast echoes lasting only around 300 ms. For both stimuli, the TRF was initially counter-phased between upper and lower visual fields but quickly became in phase after ∼100 ms. Our findings demonstrate the existence of contrast (in addition to luminance) echoes in the alpha band, which appear to emerge from V1, perhaps as a traveling wave.

Perception and decision-making in the present are not solely driven by the current inputs reaching sensory organs, but are also influenced by previous stimuli and decisions (i.e., task responses). This "serial dependence" effect is not limited to the immediately preceding stimulus or response, but it has been shown to extend several trials back in the past. However, owing to potential correlations across past responses, effects from more remote trials may be inflated, even when assessing the effect of past stimuli. In this work, we assess the potential role of response autocorrelation as a potential source of spurious results. We first show that, in serial dependence models, the effect of responses decays slowly across trials, and that such a slow decay increases the probability of observing spurious effects, even when considering past stimuli. We then provide an analytical tool to contain such spurious results. Finally, we apply our approach to a real dataset from a previous study, showing that the effect from two trials back may indeed be inflated. Our results suggest that serial dependence may be more limited in time than previously thought, and that caution is in order when assessing effects from multiple trials back in the past.