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PloS One 2022While zebrafish represent an important model for the study of the visual system, visual perception in this species is still less investigated than in other teleost fish....
While zebrafish represent an important model for the study of the visual system, visual perception in this species is still less investigated than in other teleost fish. In this work, we validated for zebrafish two versions of a visual discrimination learning task, which is based on the motivation to reach food and companions. Using this task, we investigated zebrafish ability to discriminate between two different shape pairs (i.e., disk vs. cross and full vs. amputated disk). Once zebrafish were successfully trained to discriminate a full from an amputated disk, we also tested their ability to visually complete partially occluded objects (amodal completion). After training, animals were presented with two amputated disks. In these test stimuli, another shape was either exactly juxtaposed or only placed close to the missing sectors of the disk. Only the former stimulus should elicit amodal completion. In human observers, this stimulus causes the impression that the other shape is occluding the missing sector of the disk, which is thus perceived as a complete, although partially hidden, disk. In line with our predictions, fish reinforced on the full disk chose the stimulus eliciting amodal completion, while fish reinforced on the amputated disk chose the other stimulus. This represents the first demonstration of amodal completion perception in zebrafish. Moreover, our results also indicated that a specific shape pair (disk vs. cross) might be particularly difficult to discriminate for this species, confirming previous reports obtained with different procedures.
Topics: Animals; Discrimination Learning; Discrimination, Psychological; Form Perception; Pattern Recognition, Visual; Visual Perception; Zebrafish
PubMed: 35235595
DOI: 10.1371/journal.pone.0264127 -
Sensors (Basel, Switzerland) Aug 2022Visual prostheses, used to assist in restoring functional vision to the visually impaired, convert captured external images into corresponding electrical stimulation... (Review)
Review
Visual prostheses, used to assist in restoring functional vision to the visually impaired, convert captured external images into corresponding electrical stimulation patterns that are stimulated by implanted microelectrodes to induce phosphenes and eventually visual perception. Detecting and providing useful visual information to the prosthesis wearer under limited artificial vision has been an important concern in the field of visual prosthesis. Along with the development of prosthetic device design and stimulus encoding methods, researchers have explored the possibility of the application of computer vision by simulating visual perception under prosthetic vision. Effective image processing in computer vision is performed to optimize artificial visual information and improve the ability to restore various important visual functions in implant recipients, allowing them to better achieve their daily demands. This paper first reviews the recent clinical implantation of different types of visual prostheses, summarizes the artificial visual perception of implant recipients, and especially focuses on its irregularities, such as dropout and distorted phosphenes. Then, the important aspects of computer vision in the optimization of visual information processing are reviewed, and the possibilities and shortcomings of these solutions are discussed. Ultimately, the development direction and emphasis issues for improving the performance of visual prosthesis devices are summarized.
Topics: Image Processing, Computer-Assisted; Phosphenes; Vision, Ocular; Visual Perception; Visual Prosthesis
PubMed: 36081002
DOI: 10.3390/s22176544 -
Scientific Reports Aug 2022When we see a stimulus, e.g. a star-shaped object, our intuition is that we should perceive a single, coherent percept (even if it is inaccurate). But the neural...
When we see a stimulus, e.g. a star-shaped object, our intuition is that we should perceive a single, coherent percept (even if it is inaccurate). But the neural processes that support perception are complex and probabilistic. Simple lines cause orientation-selective neurons across a population to fire in a probabilistic-like manner. Does probabilistic neural firing lead to non-probabilistic perception, or are the representations behind perception richer and more complex than intuition would suggest? To test this, we briefly presented a complex shape and had participants report the correct shape from a set of options. Rather than reporting a single value, we used a paradigm designed to encourage to directly report a representation over shape space-participants placed a series of Gaussian bets. We found that participants could report more than point-estimates of shape. The spread of responses was correlated with accuracy, suggesting that participants can convey a notion of relative imprecision. Critically, as participants placed more bets, the mean of responses show increased precision. The later bets were systematically biased towards the target rather than haphazardly placed around bet 1. These findings strongly indicate that participants were aware of more than just a point-estimate; Perceptual representations are rich and likely probabilistic.
Topics: Humans; Intuition; Probability; Visual Perception
PubMed: 35915146
DOI: 10.1038/s41598-022-17458-8 -
Scientific Reports Jul 2021Developmental prosopagnosia (DP) is a selective neurodevelopmental condition defined by lifelong impairments in face recognition. Despite much research, the extent to...
Developmental prosopagnosia (DP) is a selective neurodevelopmental condition defined by lifelong impairments in face recognition. Despite much research, the extent to which DP is associated with broader visual deficits beyond face processing is unclear. Here we investigate whether DP is accompanied by deficits in colour perception. We tested a large sample of 92 DP individuals and 92 sex/age-matched controls using the well-validated Ishihara and Farnsworth-Munsell 100-Hue tests to assess red-green colour deficiencies and hue discrimination abilities. Group-level analyses show comparable performance between DP and control individuals across both tests, and single-case analyses indicate that the prevalence of colour deficits is low and comparable to that in the general population. Our study clarifies that DP is not linked to colour perception deficits and constrains theories of DP that seek to account for a larger range of visual deficits beyond face recognition.
Topics: Adult; Color Perception; Discrimination, Psychological; Electroencephalography; Facial Recognition; Female; Humans; Male; Middle Aged; Pattern Recognition, Visual; Photic Stimulation; Prosopagnosia; Visual Perception; Young Adult
PubMed: 34215772
DOI: 10.1038/s41598-021-92840-6 -
Neuroscience Bulletin Jan 2023Accurate self-motion perception, which is critical for organisms to survive, is a process involving multiple sensory cues. The two most powerful cues are visual (optic... (Review)
Review
Accurate self-motion perception, which is critical for organisms to survive, is a process involving multiple sensory cues. The two most powerful cues are visual (optic flow) and vestibular (inertial motion). Psychophysical studies have indicated that humans and nonhuman primates integrate the two cues to improve the estimation of self-motion direction, often in a statistically Bayesian-optimal way. In the last decade, single-unit recordings in awake, behaving animals have provided valuable neurophysiological data with a high spatial and temporal resolution, giving insight into possible neural mechanisms underlying multisensory self-motion perception. Here, we review these findings, along with new evidence from the most recent studies focusing on the temporal dynamics of signals in different modalities. We show that, in light of new data, conventional thoughts about the cortical mechanisms underlying visuo-vestibular integration for linear self-motion are challenged. We propose that different temporal component signals may mediate different functions, a possibility that requires future studies.
Topics: Animals; Humans; Motion Perception; Bayes Theorem; Optic Flow; Cues; Vestibule, Labyrinth; Photic Stimulation; Visual Perception
PubMed: 35821337
DOI: 10.1007/s12264-022-00916-8 -
Investigative Ophthalmology & Visual... Apr 2021The purpose of this study was to compare binocular visual attention, visual processing speeds, and visuo-cognitive search ability in children with and without amblyopia...
PURPOSE
The purpose of this study was to compare binocular visual attention, visual processing speeds, and visuo-cognitive search ability in children with and without amblyopia and investigate the association of visual acuity and binocular function with these measures.
METHODS
Participants included 20 children with amblyopia (mean age = 9.0 ± 1.2 years; 15 anisometropic and 5 strabismic) and 20 children with normal vision development (9.5 ± 1.7 years). Vision assessment included visual acuity (monocular and binocular) and binocular function (Worth 4 Dot and Randot Preschool Stereotest). Visual attention and processing speeds were assessed using the three subtests of the Useful Field of View (UFOV; central processing, divided attention, and selective attention). Visuo-cognitive search was measured using static and dynamic presentations of the Trail Making Tests (TMTs), parts A and B, with increasing levels of executive function demand. All children performed these tasks binocularly.
RESULTS
Children with amblyopia demonstrated slower visual processing times on the UFOV (P = 0.04), and slower completion times on the TMT search tests (P = 0.014), compared to controls. TMT performance for children with amblyopia was also more negatively impacted with increasing executive function demands on the TMT part B, compared to controls (P = 0.005). Binocular visual acuity was associated with TMT (P = 0.006) and UFOV (P = 0.07) performance, but none of the other visual function measures were related to performance on these tasks.
CONCLUSIONS
Children with amblyopia exhibit deficits in higher-order visual processing skills, including visual attention and visual search, particularly with increasing executive function demands. These findings have implications for understanding the impact of amblyopia on everyday function in children.
Topics: Adolescent; Amblyopia; Attention; Child; Female; Humans; Male; Video Games; Vision, Binocular; Visual Acuity; Visual Perception
PubMed: 33848323
DOI: 10.1167/iovs.62.4.15 -
NeuroImage Aug 2020How the brain fluidly orchestrates visual behavior is a central question in cognitive neuroscience. Researchers studying neural responses in humans and nonhuman primates... (Review)
Review
How the brain fluidly orchestrates visual behavior is a central question in cognitive neuroscience. Researchers studying neural responses in humans and nonhuman primates have mapped out visual response profiles and cognitive modulation in a large number of brain areas, most often using pared down stimuli and highly controlled behavioral paradigms. The historical emphasis on reductionism has placed most studies at one pole of an inherent trade-off between strictly controlled experimental variables and open designs that monitor the brain during its natural modes of operation. This bias toward simplified experiments has strongly shaped the field of visual neuroscience, with little guarantee that the principles and concepts established within that framework will apply more generally. In recent years, a growing number of studies have begun to relax strict experimental control with the aim of understanding how the brain responds under more naturalistic conditions. In this article, we survey research that has explicitly embraced the complexity and rhythm of natural vision. We focus on those studies most pertinent to understanding high-level visual specializations in brains of humans and nonhuman primates. We conclude that representationalist concepts borne from conventional visual experiments fall short in their ability to capture the real-life visual operations undertaken by the brain. More naturalistic approaches, though fraught with experimental and analytic challenges, provide fertile ground for neuroscientists seeking new inroads to investigate how the brain supports core aspects of our daily visual experience.
Topics: Animals; Brain; Brain Mapping; Facial Recognition; Humans; Primates; Social Perception; Visual Perception
PubMed: 32278093
DOI: 10.1016/j.neuroimage.2020.116790 -
Proceedings of the National Academy of... Jun 2021A large and highly valuable category of forensic evidence consists of patterned impressions created during the perpetration of a crime. These crime scene artifacts, such... (Review)
Review
A large and highly valuable category of forensic evidence consists of patterned impressions created during the perpetration of a crime. These crime scene artifacts, such as fingerprints or tire tracks, offer visual sensory information that is assessed by trained human observers and compared to sensory experiences elicited by model patterns that would have been produced under a hypothesized set of conditions. By means of this "forensic feature comparison," the observer makes a judgment about whether the evidence and the model are sufficiently similar to support common origin. In light of documented failures of this approach, significant concerns have been raised about its scientific validity. In response to these concerns, the US Department of Justice has made assertions about how forensic examiners perform feature comparison tasks that are not consistent with modern scientific understanding of the processes of sensation and perception. Clarification of these processes highlights new ways of thinking about and improving the accuracy of forensic feature comparison and underscores the vital role of science in achieving justice.
Topics: Decision Making; Forensic Sciences; Humans; Pattern Recognition, Automated; Photic Stimulation; Social Justice; United States; Visual Perception
PubMed: 34031260
DOI: 10.1073/pnas.2102702118 -
Current Opinion in Psychology Oct 2019It is well established that attention improves performance on many visual tasks. However, for more than 100 years, psychologists, philosophers, and neurophysiologists... (Review)
Review
It is well established that attention improves performance on many visual tasks. However, for more than 100 years, psychologists, philosophers, and neurophysiologists have debated its phenomenology-whether attention actually changes one's subjective experience. Here, we show that it is possible to objectively and quantitatively investigate the effects of attention on subjective experience. First, we review evidence showing that attention alters the appearance of many static and dynamic basic visual dimensions, which mediate changes in appearance of higher-level perceptual aspects. Then, we summarize current views on how attention alters appearance. These findings have implications for our understanding of perception and attention, illustrating that attention affects not only how we perform in visual tasks, but actually alters our experience of the visual world.
Topics: Attention; Brain; Contrast Sensitivity; Humans; Photic Stimulation; Visual Perception
PubMed: 30572280
DOI: 10.1016/j.copsyc.2018.10.010 -
Current Opinion in Psychology Oct 2019The concept of a preattentive feature has been central to vision and attention research for about half a century. A preattentive feature is a feature that guides... (Review)
Review
The concept of a preattentive feature has been central to vision and attention research for about half a century. A preattentive feature is a feature that guides attention in visual search and that cannot be decomposed into simpler features. While that definition seems straightforward, there is no simple diagnostic test that infallibly identifies a preattentive feature. This paper briefly reviews the criteria that have been proposed and illustrates some of the difficulties of definition.
Topics: Attention; Humans; Reaction Time; Visual Perception
PubMed: 30472539
DOI: 10.1016/j.copsyc.2018.11.005