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1.
Nat Commun ; 11(1): 3925, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32764538

RESUMO

Adaptation is a ubiquitous property of sensory systems. It is typically considered that neurons adapt to dominant energy in the ambient environment to function optimally. However, perceptual representation of the stimulus, often modulated by feedback signals, sometimes do not correspond to the input state of the stimulus, which tends to be more linked with feedforward signals. Here we investigated the relative contributions to cortical adaptation from feedforward and feedback signals, taking advantage of a visual illusion, the Flash-Grab Effect, to disassociate the feedforward and feedback representation of an adaptor. Results reveal that orientation adaptation is exclusively dependent on the perceived rather than the retinal orientation of the adaptor. Combined fMRI and EEG measurements demonstrate that the perceived orientation of the Flash-Grab Effect is indeed supported by feedback signals in the cortex. These findings highlight the important contribution of feedback signals for cortical neurons to recalibrate their sensitivity.


Assuntos
Adaptação Fisiológica , Ilusões/fisiologia , Orientação Espacial/fisiologia , Adulto , Eletroencefalografia , Potenciais Evocados Visuais , Retroalimentação Fisiológica , Feminino , Neuroimagem Funcional , Humanos , Imagem por Ressonância Magnética , Masculino , Ilusões Ópticas/fisiologia , Estimulação Luminosa , Psicofísica , Retina/fisiologia , Córtex Visual/fisiologia , Percepção Visual/fisiologia , Adulto Jovem
2.
J Vis ; 20(6): 4, 2020 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-32511665

RESUMO

Vision scientists have attempted to classify visual illusions according to certain aspects, such as brightness or spatial features. For example, Piaget proposed that visual illusion magnitudes either decrease or increase with age. Subsequently, it was suggested that illusions are segregated according to their context: real-world contexts enhance and abstract contexts inhibit illusion magnitudes with age. We tested the effects of context on the Müller-Lyer and Ponzo illusions with a standard condition (no additional context), a line-drawing perspective condition, and a real-world perspective condition. A mixed-effects model analysis, based on data from 76 observers with ages ranging from 6 to 66 years, did not reveal any significant interaction between context and age. Although we found strong intra-illusion correlations for both illusions, we found only weak inter-illusion correlations, suggesting that the structure underlying these two spatial illusions includes several specific factors.


Assuntos
Células Ependimogliais/fisiologia , Ilusões/fisiologia , Individualidade , Adolescente , Adulto , Idoso , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ilusões Ópticas , Adulto Jovem
3.
PLoS One ; 15(5): e0232928, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32433672

RESUMO

The information available through our senses is noisy, incomplete, and ambiguous. Our perceptual systems have to resolve this ambiguity to construct stable and reliable percepts. Previous EEG studies found large amplitude differences in two event-related potential (ERP) components 200 and 400 ms after stimulus onset when comparing ambiguous with disambiguated visual information ("ERP Ambiguity Effects"). These effects so far generalized across classical ambiguous figures from different visual categories at lower (geometry, motion) and intermediate (Gestalt perception) levels. The present study aimed to examine whether these ERP Effects are restricted to ambiguous figures or whether they also occur for different degrees of visibility. Smiley faces with low and high visibility of emotional expressions, as well as abstract figures with low and high visibility of a target curvature were presented. We thus compared ambiguity effects in geometric cube stimuli with visibility in emotional faces, and with visibility in abstract figures. ERP Effects were replicated for the geometric stimuli and very similar ERP Effects were found for stimuli with emotional face expressions but also for abstract figures. Conclusively, the ERP amplitude effects generalize across fundamentally different stimulus categories and show highly similar effects for different degrees of stimulus ambiguity and stimulus visibility. We postulate the existence of a high-level/meta-perceptual evaluation instance, beyond sensory details, that estimates the certainty of a perceptual decision. The ERP Effects may reflect differences in evaluation results.


Assuntos
Potenciais Evocados Visuais/fisiologia , Percepção/fisiologia , Percepção Visual/fisiologia , Adulto , Eletroencefalografia , Emoções , Potenciais Evocados/fisiologia , Feminino , Humanos , Masculino , Ilusões Ópticas , Estimulação Luminosa/métodos , Sorriso
4.
PLoS One ; 15(5): e0233157, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32407367

RESUMO

The horizontal-vertical (HV) illusion is characterized by a tendency to overestimate the length of vertically-arranged objects. Comparative research is primarily confined to primates, a range of species that, although arboreal, often explore their environment moving along the horizontal axis. Such behaviour may have led to the development of asymmetrical perceptual mechanisms to make relative size judgments of objects placed vertically and horizontally. We observed the susceptibility to the HV illusion in fish, whose ability to swim along the horizontal and vertical plane permits them to scan objects' size equally on both axes. Guppies (Poecilia reticulata) were trained to select the longer orange line to receive a food reward. In the test phase, two arrays, containing two same-sized lines were presented, one horizontally and the other vertically. Black lines were also included in each pattern to generate the perception of an inverted T-shape (where a horizontal line is bisected by a vertical one) or an L-shape (no bisection). No bias was observed in the L-shape, which supports the idea of differential perceptual mechanisms for primates and fish. In the inverted T-shape, guppies estimated the bisected line as shorter, providing the first evidence of a length bisection bias in a fish species.


Assuntos
Ilusões Ópticas , Poecilia/fisiologia , Animais , Viés , Estimulação Luminosa
6.
Anim Cogn ; 23(2): 251-264, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31897795

RESUMO

The study of visual illusions has captured the attention of comparative psychologists since the last century, given the unquestionable advantage of investigating complex perceptual mechanisms with relatively simple visual patterns. To date, the observation of animal behavior in the presence of visual illusions has been largely confined to mammal and bird studies. Recently, there has been increasing interest in investigating fish, too. The attention has been particularly focused on guppies, redtail splitfin and bamboo sharks. Overall, the tested species were shown to experience a human-like perception of different illusory phenomena involving size, number, motion, brightness estimation and illusory contours. However, in some cases, no illusory effects, or evidence for a reverse illusion, were also reported. Here, we review the current state of the art in this field. We conclude that a wider investigation of visual illusions in fish is fundamental to form a broader comprehension of perceptual systems of vertebrates. Furthermore, we believe that this type of investigation could help us to address general important issues in perceptual studies, such as the role of ecology in shaping perceptual systems, the existence of interindividual variability in the visual perception of nonhuman species and the role of cortical activity in the emergence of visual illusions.


Assuntos
Percepção de Forma , Poecilia , Percepção Visual , Animais , Aves , Ilusões , Ilusões Ópticas , Visão Ocular , Água
7.
Atten Percept Psychophys ; 82(4): 1912-1927, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31898067

RESUMO

We recently showed that motion dynamics greatly enhance the magnitude of certain size contrast illusions, such as the Ebbinghaus and Delboeuf illusions. Here, we extend our study of the effect of motion dynamics on size illusions through a novel dynamic corridor illusion, in which a single target translates along a corridor background. Across three psychophysical experiments, we quantify the effects of stimulus dynamics on the Ebbinghaus and corridor illusions across different viewing conditions. The results revealed that stimulus dynamics had opposite effects on these different classes of size illusions. Whereas dynamic motion enhanced the magnitude of the Ebbinghaus illusion, it attenuated the magnitude the corridor illusion. Our results highlight precision-driven weighting of visual cues by neural circuits computing perceived object size. This hypothesis is consistent with observations beyond size perception and may represent a more general principle of cue integration in the visual system.


Assuntos
Percepção de Movimento/fisiologia , Ilusões Ópticas/fisiologia , Estimulação Luminosa/métodos , Percepção de Tamanho/fisiologia , Adulto , Sinais (Psicologia) , Feminino , Humanos , Masculino , Psicofísica , Distribuição Aleatória , Adulto Jovem
10.
J Neurosci ; 40(3): 648-660, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31792152

RESUMO

Visual systems have evolved to recognize and extract features from complex scenes using limited sensory information. Contour perception is essential to this process and can occur despite breaks in the continuity of neighboring features. Such robustness of the animal visual system to degraded or occluded shapes may also give rise to an interesting phenomenon of optical illusions. These illusions provide a great opportunity to decipher neural computations underlying contour integration and object detection. Kanizsa illusory contours have been shown to evoke responses in the early visual cortex despite the lack of direct receptive field activation. Recurrent processing between visual areas has been proposed to be involved in this process. However, it is unclear whether higher visual areas directly contribute to the generation of illusory responses in the early visual cortex. Using behavior, in vivo electrophysiology, and optogenetics, we first show that the primary visual cortex (V1) of male mice responds to Kanizsa illusory contours. Responses to Kanizsa illusions emerge later than the responses to the contrast-defined real contours in V1. Second, we demonstrate that illusory responses are orientation-selective. Finally, we show that top-down feedback controls the neural correlates of illusory contour perception in V1. Our results suggest that higher-order visual areas may fill in the missing information in the early visual cortex necessary for illusory contour perception.SIGNIFICANCE STATEMENT Perception of the Kanizsa illusory contours is impaired in neurodevelopmental disorders such as schizophrenia, autism, and Williams syndrome. However, the mechanism of the illusory contour perception is poorly understood. Here we describe the behavioral and neural correlates of Kanizsa illusory contours perception in mice, a genetically tractable model system. We show that top-down feedback controls the neural responses to Kanizsa illusion in V1. To our knowledge, this is the first description of the neural correlates of the Kanizsa illusion in mice and the first causal demonstration of their regulation by top-down feedback.


Assuntos
Retroalimentação Sensorial/fisiologia , Percepção de Forma/fisiologia , Ilusões Ópticas/fisiologia , Córtex Visual/fisiologia , Animais , Mapeamento Encefálico , Condicionamento Operante , Fenômenos Eletrofisiológicos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Optogenética , Orientação/fisiologia , Estimulação Luminosa , Transferência de Experiência
11.
Atten Percept Psychophys ; 82(2): 585-592, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31820280

RESUMO

Some types of object features, such as color, shape, or location, can be processed separately within the visual system, requiring that they be correctly "bound" to a single object via attentional selection of a subset of visual information. Forcing selection to spread too widely can cause an illusion where these features misbind to objects, creating illusory objects that were never present. Here, we present a novel display that produces a robust color-location misbinding illusion that we call foveal gravity (viewable at https://osf.io/2bndg/). When observers selected only a set of colored objects, colors were largely perceived in their correct locations. When observers additionally selected objects in the far periphery, colors in the near periphery migrated closer to the fovea on over 35% of trials. We speculate that foveal gravity occurs because locations closer to the fovea are more likely to defeat more peripheral locations in competitive interactions to "win" the task-relevant color.


Assuntos
Percepção de Cores/fisiologia , Fóvea Central/fisiologia , Ilusões Ópticas/fisiologia , Estimulação Luminosa/métodos , Adolescente , Adulto , Atenção/fisiologia , Feminino , Humanos , Masculino , Adulto Jovem
12.
Atten Percept Psychophys ; 82(2): 550-563, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31646439

RESUMO

The world around us is filled with complex objects, full of color, motion, shape, and texture, and these features seem to be represented separately in the early visual system. Anne Treisman pointed out that binding these separate features together into coherent conscious percepts is a serious challenge, and she argued that selective attention plays a critical role in this process. Treisman also showed that, consistent with this view, outside the focus of attention we suffer from illusory conjunctions: misperceived pairings of features into objects. Here we used Treisman's logic to study the structure of pre-attentive representations of multipart, multicolor objects, by exploring the patterns of illusory conjunctions that arise outside the focus of attention. We found consistent evidence of some pre-attentive binding of colors to their parts, and weaker evidence of binding multiple colors of the same object. The extent to which such hierarchical binding occurs seems to depend on the geometric structure of multipart objects: Objects whose parts are easier to separate seem to exhibit greater pre-attentive binding. Together, these results suggest that representations outside the focus of attention are not entirely a "shapeless bundles of features," but preserve some meaningful object structure.


Assuntos
Atenção/fisiologia , Percepção de Cores/fisiologia , Ilusões Ópticas/fisiologia , Estimulação Luminosa/métodos , Cor , Feminino , Humanos , Masculino , Distribuição Aleatória , Adulto Jovem
13.
Atten Percept Psychophys ; 82(2): 478-499, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31875311

RESUMO

It is often assumed that results from standard visual search tasks will be replicated in related tasks but his idea is rarely tested. In a conceptual replication of Li, Cave, and Wolfe (2008), we investigated the attentional demands of Kanizsa-style illusory contours using orientation-based search, comparing performance for items defined by real- as compared to illusory contours. After confirming the initial findings in standard search, we tested the same manipulation in multiple-target search, Thornton and Gilden's (2007) hybrid standard/multiple-target search, and simple- and selective enumeration. The RT slope differences between real- and illusory contours did not replicate in Thornton and Gilden's task, though they did in multiple-target search and selective enumeration. In fact, absolute differences between real- and illusory contours in RT costs per distractor were 2 - 6 times larger than in standard search. To determine whether performance differences between real and illusory contours originated from shape-definition (necessary for distinguishing target shapes from distractors) or unit formation (grouping disconnected parts to define an item/unit), simple and selective enumeration were compared. The differences between real- and illusory-contours only emerged in selective enumeration (enumerating targets among distractors), which suggests the discrepancies between conditions originate from shape definition rather than unit formation processes. There was no evidence of subitizing in selective enumeration for illusory contour figures, but contrary to attention-based theories of enumeration, there was no subitizing for the real-contour controls either. This study contributes to research on illusory contours but it is especially important to the study of search and enumeration.


Assuntos
Atenção/fisiologia , Percepção de Forma/fisiologia , Ilusões Ópticas/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Estimulação Luminosa/métodos , Desempenho Psicomotor/fisiologia , Adolescente , Feminino , Previsões , Humanos , Masculino , Orientação/fisiologia , Adulto Jovem
14.
Atten Percept Psychophys ; 82(4): 1896-1911, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31875317

RESUMO

Explanations of the Ponzo size illusion, the simultaneous contrast illusion, and the Craik-O'Brien-Cornsweet brightness illusions involve either stimulus-driven processes (assimilation, enhanced contrast, and anchoring) or prior experiences. Real-world up-down asymmetries for typical direction of illumination and ground planes in our physical environment should influence these illusions if they are experience based, but not if they are stimulus driven. Results presented here demonstrate differences in illusion strengths between upright and inverted versions of all three illusions. A left-right asymmetry of the Cornsweet illusion was produced by manipulating the direction of illumination, providing further support for the involvement of an experience-based explanation. When the inducers were incompatible with the targets being located at the different distances, the Ponzo illusion persisted and so did the influence from orientation, providing evidence for involvement of processes other than size constancy. As defined here, upright for the brightness illusions is consistent with an interpretation of a shaded bulging surface and a 3D object resulting from a light-from-above assumption triggering compensation for varying illumination. Upright for the Ponzo illusion is consistent with the inducers in the form of converging lines being interpreted as railway tracks receding on the ground triggering size constancy effects. The implications of these results, and other results providing evidence against experience-based accounts of the illusions, are discussed.


Assuntos
Sensibilidades de Contraste/fisiologia , Percepção de Forma/fisiologia , Ilusões Ópticas/fisiologia , Orientação Espacial/fisiologia , Estimulação Luminosa/métodos , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
15.
Atten Percept Psychophys ; 82(2): 500-517, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31875319

RESUMO

In time-based visual selection, task-irrelevant, old stimuli can be inhibited in order to allow the selective processing of new stimuli that appear at a later point in time (the preview benefit; Watson & Humphreys, 1997). The current study investigated if illusory and non-illusory perceptual groups influence the ability to inhibit old and prioritize new stimuli in time-based visual selection. Experiment 1 showed that with Kanizsa-type illusory stimuli, a preview benefit occurred only when displays contained a small number of items. Experiment 2 demonstrated that a set of Kanizsa-type illusory stimuli could be selectively searched amongst a set of non-illusory distractors with no additional preview benefit obtained by separating the two sets of stimuli in time. Experiment 3 showed that, similarly to Experiment 1, non-illusory perceptual groups also produced a preview benefit only for a small number of number of distractors. Experiment 4 demonstrated that local changes to perceptually grouped old items eliminated the preview benefit. The results indicate that the preview benefit is reduced in capacity when applied to complex stimuli that require perceptual grouping, regardless of whether the grouped elements elicit illusory contours. Further, inhibition is applied at the level of grouped objects, rather than to the individual elements making up those groups. The findings are discussed in terms of capacity limits in the inhibition of old distractor stimuli when they consist of perceptual groups, the attentional requirements of forming perceptual groups and the mechanisms and efficiency of time-based visual selection.


Assuntos
Atenção/fisiologia , Ilusões Ópticas/fisiologia , Estimulação Luminosa/métodos , Tempo de Reação/fisiologia , Percepção Visual/fisiologia , Adolescente , Feminino , Humanos , Inibição Psicológica , Masculino , Adulto Jovem
16.
J Vis ; 19(14): 12, 2019 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-31830241

RESUMO

Common factors are ubiquitous. For example, there is a common factor, g, for intelligence. In vision, there is much weaker evidence for such common factors. For example, visual illusion magnitudes correlate only weakly with each other. Here, we investigated whether illusions are hyper-specific as in perceptual learning. First, we tested 19 variants of the Ebbinghaus illusion that differed in color, shape, or texture. Correlations between the illusion magnitudes of the different variants were mostly significant. Second, we reanalyzed a dataset from a previous experiment where 10 illusions were tested under four conditions of luminance and found significant correlations between the different luminance conditions of each illusion. However, there were only very weak correlations between the 10 different illusions. Third, five visual illusions were tested with four orientations. Again, there were significant correlations between the four orientations of each illusion, but not across different illusions. The weak inter-illusion correlations suggest that there is no unique common mechanism for the tested illusions. We suggest that most illusions make up their own factor.


Assuntos
Ilusões Ópticas , Visão Ocular , Percepção Visual , Adolescente , Adulto , Idoso , Cor , Análise Fatorial , Feminino , Humanos , Ilusões , Aprendizagem , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Adulto Jovem
17.
Acta Neurobiol Exp (Wars) ; 79(4): 399-412, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31885396

RESUMO

Perceptual estimates of spatial dimensions of visual objects depend on their shape and surface attributes. The present psychophysical study emphasizes two main contributors to the Oppel­Kundt illusion: the outline of the filled space and the mode of filling. In past experiments, both factors have been considered significant. Our experiments were performed by using combined stimuli of the Oppel­Kundt figures and supplementary objects situated within the empty intervals of the figures. Line segments, empty and filled rectangles, blurred contours, and grey and color images were used for the supplementary stimuli role. The experimental data demonstrated an innate property of the objects to balance the illusion of distance if they were placed within the Oppel­Kundt figure and to create an illusion of extent when compared with an empty space interval. Both the balance magnitude and the induced illusion strength varied depending on the objects' spatial structure. The supplementary objects showed a tendency to differ from each other by their functional capacity and were ranked from lowest to highest: a line segment, a solid bar with a blurred outline, a contour of a rectangle, a solid fill rectangle, greyscale patterns, and color pictures. The experimental findings provided support for an explanation of the Oppel­Kundt illusion in terms of the spatial­temporal summation of excitations representing the object outline and surface attributes at the lower cortical levels of the visual system. Along with the facts already established in current literature, the experimental data gave rise to the assumption that any visual object could appear larger than its occupied area, and that the Oppel­Kundt illusion could become a separate case in the common sensory phenomenon of object size illusion.


Assuntos
Percepção de Forma/fisiologia , Ilusões Ópticas/fisiologia , Percepção de Tamanho/fisiologia , Percepção Espacial/fisiologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estimulação Luminosa , Adulto Jovem
18.
Sci Rep ; 9(1): 15657, 2019 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-31666630

RESUMO

Social animals, including humans, structure social groups where social hierarchy exists. Recognizing social rank of other group members is a crucial ability to subsist in such environments. Here we show preliminary evidence with a relatively small number of samples that children with autism spectrum disorder, a neurodevelopmental disorder involving social dysfunction, exhibit atypical, and more robust recognition of social rank than normal children, which may be developed to compensate deficits of the neural systems processing social information.


Assuntos
Transtorno do Espectro Autista/psicologia , Comportamento Social , Adolescente , Criança , Feminino , Humanos , Masculino , Ilusões Ópticas
19.
PLoS One ; 14(10): e0223583, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31600294

RESUMO

We examined the influence of linear perspective cues and texture gradients in the perceptual rescaling of stimuli over a highly-salient Ponzo illusion of a corridor. We performed two experiments using the Method of Constant Stimuli where participants judged the size of one of two rings. In experiment 1, one ring was presented in the upper visual-field at the end of the corridor and the other in the lower visual-field at the front of the corridor. The perceived size of the top and bottom rings changed as a function of the availability of linear perspective and textures. In experiment 2, only one ring was presented either at the top or the bottom of the image. The perceived size of the top but not the bottom ring changed as a function of the availability of linear perspective and textures. In both experiments, the effects of the cues were additive. Perceptual rescaling was also stronger for the top compared to the bottom ring. Additional eye-tracking revealed that participants tended to gaze more in the upper than the lower visual-field. These findings indicate that top-down mechanisms provide an important contribution to the Ponzo illusion. Nonetheless, additional maximum likelihood estimation analyses revealed that linear perspective fulfilled a greater contribution in experiment 2, which is suggestive of a bottom-up mechanism. We conclude that both top-down and bottom-up mechanisms play important roles. However, the former seems to fulfil a more prominent role when both stimuli are presented in the image.


Assuntos
Sinais (Psicologia) , Ilusões Ópticas , Estimulação Luminosa , Percepção de Tamanho , Movimentos Oculares/fisiologia , Feminino , Fixação Ocular/fisiologia , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Adulto Jovem
20.
J Comp Psychol ; 133(4): 417-418, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31647270

RESUMO

Researchers and artists have long been interested in visual illusions because they illustrate the interesting, complicated, and constrained ways in which we perceive the world. Although we may not be familiar with the names of the many different visual illusions that exist (e.g., the Necker cube, the Müller-Lyer illusion, and the Hermann grid illusion, to name a few), people with typically functioning will certainly have seen many of these. We have known for centuries that humans perceive these illusions. We have known for the past few decades that nonhuman mammals can perceive these illusions, and very recent work has revealed that birds and fish perceive some of these illusions, though sometimes in a way opposite to how our own species does. (PsycINFO Database Record (c) 2019 APA, all rights reserved).


Assuntos
Ilusões Ópticas/fisiologia , Animais , Humanos
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