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Schizophrenia Research Feb 2023Visual illusions have long been used as tools to investigate sensory-perceptual deficits in schizophrenia. Recent conflicting accounts have called into question the... (Review)
Review
Visual illusions have long been used as tools to investigate sensory-perceptual deficits in schizophrenia. Recent conflicting accounts have called into question the assumption of abnormal illusion perception in patients and, therefore, the validity of this approach. Here, we present a systematic review of the current evidence regarding visual illusion perception abnormalities in patients with schizophrenia. Relevant publications were identified by a systematic search of PubMed, Literatura LILACS, PsycINFO, Embase, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), IBECS, BIOSIS, and Web of Science. Forty-five studies were selected which included illusions classified as 'Motion illusions', 'Geometric-optical illusions', 'Illusory contours', 'Depth inversion illusion', and 'Non-specific'. There is concordant evidence of abnormal processing of illusions in patients for most categories, especially in facial Depth Inversion and Müller-Lyer illusions. There were significant methodological disparities and shortcomings, but risk of bias was overall low for individual studies. The usefulness of visual illusions as tools in clinical settings as well as in basic research may be contingent on significant methodological refinements.
Topics: Humans; Illusions; Schizophrenia; Optical Illusions; Form Perception; Visual Perception
PubMed: 36610221
DOI: 10.1016/j.schres.2022.12.030 -
Attention, Perception & Psychophysics Feb 2023Kanizsa-type illusory contours demonstrate an important function of the visual system-object inference from incomplete boundaries, which can be due to low luminance...
Kanizsa-type illusory contours demonstrate an important function of the visual system-object inference from incomplete boundaries, which can be due to low luminance environments, camouflage, or occlusion. At a perceptual level, Kanizsa figures have been shown to have various degrees of clarity, depending on the features of the inducers. The aim of the present study is to evaluate whether contour clarity influences search efficiency of Kanizsa-type illusory contours. Experiment 1 will examine search for a Kanizsa-type illusory target among Kanizsa-type illusory distractors, by manipulating contour clarity using inducer size in three conditions, compared with search for a nonillusory perceptually grouped target among nonillusory perceptually grouped distractors with manipulated inducer size. Experiment 2 will address the effects of contour clarity on visual search by manipulating the number of arcs (i.e., line ends) comprising the inducers, in a visual search task of Kanizsa-type stimuli, compared with visual search for nonillusory grouped targets and distractors when the number of arcs are manipulated. To examine whether surface alterations had an impact on search in Experiment 1 due to changes in inducer size, Experiment 3 will examine search for Kanizsa stimuli formed from "smoothed" inducers, in comparison to search for Kanizsa stimuli used in Experiment 1. Together, these experiments will demonstrate whether contour clarity impacts visual search of illusory contours.
Topics: Humans; Optical Illusions; Photic Stimulation; Form Perception
PubMed: 36600153
DOI: 10.3758/s13414-022-02644-7 -
Frontiers in Psychology 2022Lightness Illusions (Contrast, Assimilation, and Natural Scenes with Edges and Gradients) show that appearances do not correlate with the light sent from the scene to...
Lightness Illusions (Contrast, Assimilation, and Natural Scenes with Edges and Gradients) show that appearances do not correlate with the light sent from the scene to the eye. Lightness Illusions begin with a control experiment that includes two identical Gray Regions-Of-Interest(GrayROI) that have equal appearances in uniform surrounds. The Illusion experiment modifies "the-rest-of-the-scene" to make these GrayROIs appear different from each other. Our visual system performs complex-spatial transformations of scene-luminance patterns using two independent spatial mechanisms: optical and neural. First, optical veiling glare transforms scene luminances into a different light pattern on receptors, called retinal contrasts. This article provides a new Python program that calculates retinal contrast. Equal scene luminances become unequal retinal contrasts. Uniform scene segments become nonuniform retinal gradients; darker regions acquire substantial scattered light; and the retinal range-of-light changes. The glare on each receptor is the sum of the individual contributions from every other scene segment. Glare responds to the content of the entire scene. Glare is a optical transformation. Lightness Illusions are intended to demonstrate how our "brain sees" using simple-uniform patterns. However, the after-glare pattern of light on receptors is a morass of high-and low-slope gradients. Quantitative measurements, and pseudocolor renderings are needed to appreciate the magnitude, and spatial patterns of glare. Glare's gradients are invisible when you inspect them. Illusions are generated by neural responses from "the-rest-of-the-scene." The neural network input is the simultaneous array of all receptors' responses. Neural processing performs vision's second spatial transformation. Neural processing generates appearances in Illusions and Natural Scenes. "Glare's Paradox" is that glare adds more re-distributed light to GrayROIs that appear darker, and less light to those that appear lighter. This article describes nine experiments in which neural-spatial-image processing overcompensates the effects of glare. This article studies the first-step in imaging: s glare. Despite near invisibility, glare modifies all quantitative measurements of images. This article reveals glare's modification of input data used in quantitative image analysis and models of vision, as well as visual image-quality metrics. Glare redefines the challenges in modeling Lightness Illusions. Neural spatial processing is more powerful than we realized.
PubMed: 36591105
DOI: 10.3389/fpsyg.2022.958787 -
Cerebral Cortex (New York, N.Y. : 1991) May 2023Converging evidence has found that the perceived visual size illusions are heritable, raising the possibility that visual size illusions might be predicted by intrinsic...
Converging evidence has found that the perceived visual size illusions are heritable, raising the possibility that visual size illusions might be predicted by intrinsic brain activity without external stimuli. Here we measured resting-state brain activity and 2 classic visual size illusions (i.e. the Ebbinghaus and the Ponzo illusions) in succession, and conducted spectral dynamic causal modeling analysis among relevant cortical regions. Results revealed that forward connection from right V1 to superior parietal lobule (SPL) was predictive of the Ebbinghaus illusion, and self-connection in the right SPL predicted the Ponzo illusion. Moreover, disruption of intrinsic activity in the right SPL by repetitive transcranial magnetic stimulation (TMS) temporally increased the Ebbinghaus rather than the Ponzo illusion. These findings provide a better mechanistic understanding of visual size illusions by showing the causal and distinct contributions of right parietal cortex to them, and suggest that spontaneous fluctuations in intrinsic brain activity are relevant to individual difference in behavior.
Topics: Humans; Illusions; Optical Illusions; Transcranial Magnetic Stimulation; Parietal Lobe; Human Rights; Visual Perception
PubMed: 36562991
DOI: 10.1093/cercor/bhac508 -
Science Bulletin Feb 2022We present a novel method for designing transformation optical devices based on electrostatics. An arbitrary transformation of electrostatic field can lead to a new...
We present a novel method for designing transformation optical devices based on electrostatics. An arbitrary transformation of electrostatic field can lead to a new refractive index distribution, where wavefronts and energy flux lines correspond to equipotential surfaces and electrostatic flux lines, respectively. Owing to scalar wave propagating exactly following an eikonal equation, wave optics and geometric optics share the same solutions in the devices. The method is utilized to design multipole lenses derived from multipoles in electrostatics. The source and drain in optics are considered as corresponding to positive charge and negative charge in the static field. By defining winding numbers in virtual and physical spaces, we explain the reason for some multipole lenses with illusion effects. Besides, we introduce an equipotential absorber to replace the drain to correspond to a negative charge with a grounded conductor. Therefore, it is a very general platform to design intriguing devices based on the combination of electrostatics and transformation optics.
PubMed: 36546073
DOI: 10.1016/j.scib.2021.09.017 -
Scientific Reports Dec 2022Lightness of a surface depends not only on its physical characteristics, but also on the properties of the surrounding context. As a result, varying the context can...
Lightness of a surface depends not only on its physical characteristics, but also on the properties of the surrounding context. As a result, varying the context can significantly alter surface lightness, an effect exploited in many lightness illusions. Computational models can produce outcomes similar to human illusory percepts, allowing for demonstrable assessment of the applied mechanisms and principles. We tested 8 computational models on 13 typical displays used in lightness research (11 Illusions and 2 Mondrians), and compared them with results from human participants (N = 85). Results show that HighPass and MIR models predict empirical results for simultaneous lightness contrast (SLC) and its close variations. ODOG and its newer variants (ODOG-2 and L-ODOG) in addition to SLC displays were able to predict effect of White's illusion. RETINEX was able to predict effects of both SLC displays and Dungeon illusion. Dynamic decorrelation model was able to predict obtained effects for all tested stimuli except two SLC variations. Finally, FL-ODOG model was best at simulating human data, as it was able to predict empirical results for all displays, bar the Reversed contrast illusion. Finally, most models underperform on the Mondrian displays that represent most natural stimuli for the human visual system.
Topics: Humans; Optical Illusions; Contrast Sensitivity; Computer Simulation; Visual Perception
PubMed: 36543784
DOI: 10.1038/s41598-022-22395-7 -
Optics Express Dec 2022The realization of an optical cloak that can hide a target object is no longer fiction, yet distinguishing the optically cloaked surface from our illusion remains an...
The realization of an optical cloak that can hide a target object is no longer fiction, yet distinguishing the optically cloaked surface from our illusion remains an open problem. Here, the detection of a one-dimensional optically cloaked surface is presented by leveraging the spin Hall effect of light, the microscopic and transverse splitting of linearly polarized light at an optical interface into two circular polarizations. We first derive an analytical formula for the spin Hall shift at a planar surface with a linear phase gradient and demonstrate that the spin Hall effect of light at the cloaked surface differs from that at its perceived image. The theoretical description and numerical computation are generalized for a curved surface with a nonlinear phase gradient. Two approaches for examining optically cloaked surfaces are presented, in which the unknown incident angle and phase gradient are successfully reproduced. This work suggests the potential of the spin Hall effect of light in various applications, including anti-counterfeiting and security.
PubMed: 36522922
DOI: 10.1364/OE.477099 -
Analytical Chemistry Dec 2022Although light-sheet-based super-resolution microscopy is an excellent detection technique for biological samples because of minimal photodamage, uneven light paths due...
Although light-sheet-based super-resolution microscopy is an excellent detection technique for biological samples because of minimal photodamage, uneven light paths due to solid-angle illumination limits it, resulting in an optical illusion. Furthermore, the optical illusion limits the observations of individual molecules in diffraction. In this study, a four-dimensional cuboid multiangle illumination-based light-sheet super-resolution (4D CMLS) imaging system was developed to minimize optical illusions in cells. The lab-built 4D CMLS imaging system was integrated with total internal reflection fluorescence and a differential interference contrast microscope. A specially designed rotatable cuboid prism simply overcame the optical illusion by rotating a specimen on the prism to change the direction of light coming from an illumination lens. 4D CMLS reconstructed images of nanoparticles of different sizes were acquired in multi-illumination angles of 0°, 90°, 180°, and 270°. Additionally, a 4D multiangle illumination-based algorithm was created to select the optimal illumination angle by combining three-dimensional super-resolution imaging with multiangle observation, even in the presence of obstacles. The 4D CMLS imaging method demonstrates the in-depth 4D observation of samples at an optimum angle that can be used in various applications, such as single-molecule and subcellular organelle observations in single cells at subdiffraction limit resolutions that describe the scenario of nature.
Topics: Optical Illusions; Lighting; Microscopy; Imaging, Three-Dimensional; Nanoparticles
PubMed: 36509731
DOI: 10.1021/acs.analchem.2c03729 -
Neuroreport Dec 2022The Sander illusion and the horizontal-vertical (H-V) illusion are both size and orientation geometric-optical illusions. The Sander geometric figures can be simply...
OBJECTIVE
The Sander illusion and the horizontal-vertical (H-V) illusion are both size and orientation geometric-optical illusions. The Sander geometric figures can be simply regarded as being made up of surrounding frames and inner targeted line segments. Similarly, H-V illusory geometric figures are made up of the targeted line segments. The role of surrounding frames and inner targeted line segments in the perception and cognition of geometric-optical illusions is not well understood.
METHODS
The time course of event-related potentials (ERP) and the ERP-based standardized low-resolution electromagnetic tomography (sLORETA) source localization were investigated in the Sander illusion and the H-V illusion, which had the same length as the targeted line segments, respectively. The P1, N1, P2, N2 and P3 components of the ERP were focused and measured.
RESULTS
The ERP results demonstrated that the existence of surrounding frames in the Sander illusions-induced significant alterations in the P1, N1, P2, N2 and P3 components, compared with the H-V illusion without surrounding frames. In the Sander illusion, different tilted line segments and surrounding frames resulted in significant differences in the P2, N2 and P3 components. The sLORETA results also demonstrated brain activities of source localization as a function of the surrounding frames and the tilted inner line segments.
CONCLUSIONS
These findings implicate that the perceptual and cognitive processes of the geometric-optical illusions are correlated to the surrounding frames/background, as well as the orientation/direction of inner targeted line segments in geometric figures.
Topics: Humans; Optical Illusions; Illusions; Evoked Potentials
PubMed: 36367794
DOI: 10.1097/WNR.0000000000001843 -
Vision Research Jan 2023One of the original Ponzo illusion figures, which consists of two converging lines between which two parallel lines of similar length have been inserted orthogonal to...
One of the original Ponzo illusion figures, which consists of two converging lines between which two parallel lines of similar length have been inserted orthogonal to the figure's axis of mirror symmetry, was itself mirror-reflected so that the overall shape of the figure became "< >" or "> <", and one line at a time was inserted into each half. The usual illusion - the overestimation of the length of a line that is nearer to a vertex than a farther-away comparison line - occurred. Experiments 1 and 2 used different distances of target and comparison lines to the vertices, but identical distances of these lines from the converging lines, and so, as a tandem, deconfounded the two variables. Experiments 3 and 4 changed the symmetries of the modified Ponzo figure by reducing opposing half-angles of the converging lines or by tilting target and comparison lines concordantly or discordantly. The first measure, which created unequal distances of the endpoints of the target and comparison lines from the converging lines, hardly affected the amount of illusion. The second measure often attenuated the illusion - equally so for concordant and discordant tilts - suggesting that global and local symmetries of the stimuli, and their accordance, were less important than the vertical versus oblique orientation of target and comparison lines. Descriptively, the main cause of the Ponzo illusion seems to be the size of the gap between target and converging lines. The neural substrate of the effect may be interactions between orientation-sensitive and end-inhibited neurons.
Topics: Humans; Illusions; Optical Illusions; Neurons
PubMed: 36347085
DOI: 10.1016/j.visres.2022.108143