Visual Object Perception Research Articles

Peculiarities of the Activity of the Brain Structures of People with Schizophrenia During the Categorization of Objects of Animate and Inanimate Nature

One of the features of the work of the brain of people suffering from schizophrenia is changes in the activity of their brain during visual categorization of animate and inanimate objects. The purpose of this study was to analyze the brain activity of people with schizophrenia and their visual categorization of objects with different semantic and physical characteristics. It was assumed that the patterns of brain activity in individuals with schizophrenia would differ from the group of healthy individuals both in the early and late stages of visual processing. Using the method of visual evoked potentials, we studied the features of brain activity in 25 people suffering from schizophrenia from 1 to 7 years old, when they categorized images of animate and inanimate nature, low and high spatial frequency. It was found that the amplitudes of P170 (N170) in the left and right posterior and central leads, as well as the amplitudes of P300 in the central lead in people with schizophrenia do not differ during categorization of animate and inanimate objects, which does not correspond to the data obtained earlier from the people without mental health abnormalities. The revealed result is important for a better understanding of the restructuring of the brain during visual perception of objects of different categories, which occurs during the development of schizophrenia.

From pictures to reality: modelling the phenomenology and psychophysics of 3D perception.

The dominant inferential approach to human 3D perception assumes a model of spatial encoding based on a physical description of objects and space. Prevailing models based on this physicalist approach assume that the visual system infers an objective, unitary and mostly veridical representation ofthe external world. However, careful consideration of the phenomenology of 3Dperception challenges these assumptions. I review important aspects of phenomenology, psychophysics and neurophysiology which suggest that human visual perception of 3D objects and space is underwritten by distinct and dissociated spatial encodings that are optimized for specific regions of space. Specifically, I argue that 3D perception is underwritten by at least three distinct encodings for (1) egocentric distance perception at the ambulatory scale, (2) exocentric distance (scaled depth) perception optimized for near space, and (3) perception of object shape and layout (unscaled depth). This tripartite division can more satisfactorily account for the phenomenology, psychophysics and adaptive logic of human 3D perception. This article is part of a discussion meeting issue 'New approaches to 3D vision'.

Multimodal visual system analysis as a biomarker of visual hallucinations in Parkinson's disease.

Visual hallucinations (VH) are present in up to 75% of Parkinson's disease (PD) patients. However, their neural bases and participation of the visual system in VH are not well-understood in PD. Seventy-four participants, 12 PD with VH (PDVH), 35 PD without VH (PDnoVH) and 27 controls underwent a battery of primary visual function and visual cognition tests, retinal optical coherence tomography and structural and resting-state functional brain MRI. We quantified cortical thickness with Freesurfer and functional connectivity (FC) of Visual (VIS), Fronto-Parietal (FP), Ventral Attention (VAN) and Dorsal Attention (DAN) networks with CONN toolbox. Group comparisons were performed with MANCOVA. Area Under the Curve (AUC) was computed to assess the ability of visual variables to differentiate PDVH and PDnoVH. There were no significant PDVH vs PDnoVH differences in disease duration, motor manifestations, general cognition or dopamine agonist therapy (DA) use. Compared to PDnoVH and HC, and regardless of DA use, PDVH showed significantly reduced contrast sensitivity, visuoperceptive and visuospatial abilities, increased retina photoreceptor layer thickness, reduced cortical thickness mostly in right visual associative areas, decreased between-network VIS-VAN and VAN-DAN connectivity and increased within-network DAN connectivity. The combination of clinical and imaging variables that best discriminated PDVH and PDnoVH (highest AUC), where within-network DAN FC, photoreceptor layer thickness and cube analysis test from Visual Object and Space Perception Battery (accuracy of 81.8%). Compared to PDnoVH, PDVH have specific functional and structural abnormalities within the visual system, which can be quantified non-invasively and could potentially constitute biomarkers for VH in PD.

Reorganization of the functional connectome from rest to a visual perception task in schizophrenia and bipolar disorder

Functional connectome organization is altered in schizophrenia (SZ) and bipolar disorder (BD). However, it remains unclear whether network reorganization during a task relative to rest is also altered in these disorders.This study examined connectome organization in patients with SZ (N = 43) and BD (N = 42) versus healthy controls (HC; N = 39) using fMRI data during a visual object-perception task and at rest. Graph analyses were conducted for the whole-brain network using indices selected a priori: three reflecting network segregation (clustering coefficient, local efficiency, modularity), two reflecting integration (characteristic path length, global efficiency).Group differences were limited to network segregation and were more evident in SZ (clustering coefficient, modularity) than in BD (clustering coefficient) compared to HC. State differences were found across groups for segregation (local efficiency) and integration (characteristic path length). There was no group-by-state interaction for any graph index.In summary, aberrant network organization compared to HC was confirmed, and was more evident in SZ than in BD. Yet, reorganization was largely intact in both disorders. These findings help to constrain models of dysconnection in SZ and BD, suggesting that the extent of functional dysconnectivity in these disorders tends to persist across changes in mental state.

A topological solution to object segmentation and tracking

The world is composed of objects, the ground, and the sky. Visual perception of objects requires solving two fundamental challenges: 1) segmenting visual input into discrete units and 2) tracking identities of these units despite appearance changes due to object deformation, changing perspective, and dynamic occlusion. Current computer vision approaches to segmentation and tracking that approach human performance all require learning, raising the question, Can objects be segmented and tracked without learning? Here, we show that the mathematical structure of light rays reflected from environment surfaces yields a natural representation of persistent surfaces, and this surface representation provides a solution to both the segmentation and tracking problems. We describe how to generate this surface representation from continuous visual input and demonstrate that our approach can segment and invariantly track objects in cluttered synthetic video despite severe appearance changes, without requiring learning.

Mediating effect of sequential memory on the relationship between visual-motor integration and self-care performance in young children with autism spectrum disorder.

ObjectiveVisual perception is a skill that contributes to the performance of self-care and important development tasks in early childhood. The relationship between self-care and visual perception is especially significant for young children with autism spectrum disorder (ASD), who have been described as visual learners. However, this relationship is not clearly understood among young children with ASD. We investigated the role of motor-free visual perception on the relationship between self-care and visual-motor integration in young children with ASD.MethodsA sample of 66 children with ASD aged 48 to 83 months were recruited. Measurements included the Assessment of Motor and Process Skills, the Developmental Test of Visual Perception—Third Edition, and Test of Visual-Perceptual Skills—Third Edition.ResultsThe results indicated that self-care performance had significant positive correlations with visual-motor integration, visual discrimination, visual memory, visual spatial relationships, and visual sequential memory. Of these, visual sequential memory and visual spatial relationships were the main factors related to self-care performance. Sequential memory was a mediator of the relationship between visual-motor integration and self-care performance.ConclusionThis study establishes a deeper understanding of self-care and motor-free visual perception among young children with ASD. Understanding the relationship between visual perception and self-care in young children with ASD may aid professionals in providing self-care interventions for this population.

What You See Is What You Hear: Sounds Alter the Contents of Visual Perception

Visual object recognition is not performed in isolation but depends on prior knowledge and context. Here, we found that auditory context plays a critical role in visual object perception. Using a psychophysical task in which naturalistic sounds were paired with noisy visual inputs, we demonstrated across two experiments (young adults; ns = 18–40 in Experiments 1 and 2, respectively) that the representations of ambiguous visual objects were shifted toward the visual features of an object that were related to the incidental sound. In a series of control experiments, we found that these effects were not driven by decision or response biases (ns = 40–85) nor were they due to top-down expectations (n = 40). Instead, these effects were driven by the continuous integration of audiovisual inputs during perception itself. Together, our results demonstrate that the perceptual experience of visual objects is directly shaped by naturalistic auditory context, which provides independent and diagnostic information about the visual world.

건축의 표면의 특성이 날카로운 조형의 위협성 인지에 미치는 영향에 관한 연구

Designers express diverse opinions on how to apply sharp shapes in buildings. Sharply-changed contour of sharp shapes is one visual primitive that can be quickly extracted by people1). As a critical part of architectural design, architectural surface boasts of some characteristics that affect brain to recognize threat of sharp contours. In this day with diversified aesthetics, aesthetics rests with audience’s visual perception and cognition of objective objects, as well as their professional knowledge, life experience, thoughts and culture. In the course of evolution, general aesthetic awareness acquired by the brain is minimally impacted by subjective factors. Under the background, this study, on neuroscience view, adopts interdisciplinary approach to explain brain’s perception mechanism to threats and selective attention mechanism by applying interdisciplinary approach. Starting with analyzing five stages of aesthetic cognition, it exposes brain’s preference for characteristics in line with survival instinct, such as “transparency” and “reflection”, in accordance with viewpoint of evolutionary aesthetics. Aesthetic preference can be triggered by both materials, and permeability of architectural shape structures. In summary, this study aims to reveal reasons of threat perception and attraction of sharp shapes, so as to determine influence of surface characteristics on cognition and aesthetic effects of sharp shapes. It is hoped to provide scientific references and proposals for applying surface characteristics in buildings with sharp shapes.

Nature-inspired saccadic-like electrical stimulation paradigm promotes sustained retinal ganglion cell responses by spatiotemporally alternating activation of contiguous multi-electrode patterns

Objective. Retinal electrical stimulation using multi-electrode arrays (MEAs) aims to restore visual object perception in blind patients. However, the rate and duration of the artificial visual sensations are limited due to the rapid response decay of the stimulated neurons. Hence, we investigated a novel nature-inspired saccadic-like stimulation paradigm (biomimetic) to evoke sustained retinal responses. For implementation, the macroelectrode was replaced by several contiguous microelectrodes and activated non-simultaneously but alternating topologically. Approach. MEAs with hexagonally arranged electrodes were utilized to simulate and record mouse retinal ganglion cells (RGCs). Two shapes were presented electrically using MEAs: a 6e-hexagon (six hexagonally arranged 10 µm electrodes; 6e-hexagon diameter: 80 µm) and a double-bar (180 µm spaced, 320 µm in length). Electrodes of each shape were activated in three different modes (simultaneous, circular, and biomimetic (‘zig-zag’)), stimulating at different frequencies (1–20 Hz). Main results. The biomimetic stimulation generated enhanced RGC responses increasing the activity rate by 87.78%. In the spatiotemporal context, the electrical representation of the 6e-hexagon produced sustained and local RGC responses (∼130 µm corresponding to ∼2.5° of the human visual angle) for up to 90 s at 10 Hz stimulation and resolved the electrically presented double-bar. In contrast, during conventional simultaneous stimulation, the responses were poor and declined within seconds. Similarly, the applicability of the biomimetic mode for retinal implants (7 × 8 pixels) was successfully demonstrated. An object shape impersonating a smile was presented electrically, and the recorded data were used to emulate the implant’s performance. The spatiotemporal pixel mapping of the activity produced a complete retinal image of the smile. Significance. The application of electrical stimulation in the biomimetic mode produced locally enhanced RGC responses with significantly reduced fading effects and yielded advanced spatiotemporal performance reflecting the presented electrode shapes in the mapped activity imprint. Therefore, it is likely that the RGC responses persist long enough to evoke visual perception and generate a seamless image, taking advantage of the flicker fusion. Hence, replacing the implant’s macroelectrodes with microelectrodes and their activation in a topologically alternating biomimetic fashion may overcome the patient’s perceptual image fading, thereby enhancing the spatiotemporal characteristics of artificial vision.

Neural basis of visuospatial tests in behavioral variant frontotemporal dementia

BackgroundRecent models of visuospatial functioning suggest the existence of three main circuits emerging from the dorsal (“where”) route: parieto-prefrontal pathway, parieto-premotor, and parieto-medial temporal. Neural underpinnings of visuospatial task performance and the sparing of visuospatial functioning in bvFTD are unclear. We hypothesized different neural and cognitive mechanisms in visuospatial tasks performance in bvFTD and AD.MethodsTwo hundred and sixteen participants were enrolled for this study: 72 patients with bvFTD dementia and 144 patients with AD. Visual Object and Space Perception Battery Position Discrimination and Number Location (VOSP-PD and VOSP-NL) and Rey-Osterrieth Complex Figure (ROCF) were administered to examine visuospatial functioning, together with a comprehensive neuropsychological battery. FDG-PET was acquired to evaluate brain metabolism. Voxel-based brain mapping analyses were conducted to evaluate the brain regions associated with visuospatial function in bvFTD and AD.ResultsPatients with AD performed worst in visuospatial tasks in mild dementia, but not at prodromal stage. Attention and executive functioning tests showed higher correlations in bvFTD than AD with ROCF, but not VOSP subtests. Visuospatial performance in patients with bvFTD was associated with bilateral frontal regions, including the superior and medial frontal gyri, supplementary motor area, insula and middle cingulate gyrus.ConclusionThese findings support the role of prefrontal and premotor regions in visuospatial processing through the connection with the posterior parietal cortex and other posterior cortical regions. Visuospatial deficits should be interpreted with caution in patients with bvFTD, and should not be regarded as hallmarks of posterior cortical dysfunction.

Impact of Visual Impairment on Vision-Related Quality of Life in Parkinson's Disease.

Visual impairment is frequent and highly disabling in Parkinson's disease (PD); however, few studies have comprehensively evaluated its impact on vision-related quality of life. To evaluate the relationship between visual function tests and the visual impairment perceived by PD patients in daily living activities. We cross-sectionally evaluated 62 PD patients and 33 healthy controls (HC). Visual disability was measured with a comprehensive battery of primary visual function and visual cognition tests (visual outcomes), and vision-related quality of life was evaluated with the National Eye Institute 25-Item Visual Function Questionnaire (NEI VFQ-25). The relationship between visual outcomes and NEI VFQ-25 sub-scores was analyzed with Pearson's correlations and stepwise linear regression. In PD patients, and not in HC, most NEI VFQ-25 sub-scores were significantly correlated with Cube Analysis and Dot Counting from Visual Object and Space Perception (VOSP) battery (visual perception), Clock Drawing Test (visuoconstructive capacity) and Trail Making Test part-A (visual attention and processing speed) and to a lesser extent with high- and low-contrast visual acuity. Dot Counting (VOSP) was the test primarily associated with most NEI VFQ-25 sub-scores (5 out of 12). Roth-28 color test was the one that best explained the variance of Peripheral Vision (R2: 0.21) and Role Difficulties (R2: 0.36) sub-scores of NEI VFQ-25, while photopic contrast sensitivity explained 41% of Driving sub-score variance. Vision-related quality of life in PD is mainly influenced by alterations in visual perception, visuoconstructive capacity and visual attention and processing speed. Future studies are warranted to confirm and further extend our findings.

Using High-Density Electroencephalography to Explore Spatiotemporal Representations of Object Categories in Visual Cortex.

Visual object perception involves neural processes that unfold over time and recruit multiple regions of the brain. Here, we use high-density EEG to investigate the spatiotemporal representations of object categories across the dorsal and ventral pathways. In , human participants were presented with images from two animate object categories (birds and insects) and two inanimate categories (tools and graspable objects). In , participants viewed images of tools and graspable objects from a different stimulus set, one in which a shape confound that often exists between these categories (elongation) was controlled for. To explore the temporal dynamics of object representations, we employed time-resolved multivariate pattern analysis on the EEG time series data. This was performed at the electrode level as well as in source space of two regions of interest: one encompassing the ventral pathway and another encompassing the dorsal pathway. Our results demonstrate shape, exemplar, and category information can be decoded from the EEG signal. Multivariate pattern analysis within source space revealed that both dorsal and ventral pathways contain information pertaining to shape, inanimate object categories, and animate object categories. Of particular interest, we note striking similarities obtained in both ventral stream and dorsal stream regions of interest. These findings provide insight into the spatio-temporal dynamics of object representation and contribute to a growing literature that has begun to redefine the traditional role of the dorsal pathway.

Bioacoustics and beyond: Investigating animal sensory systems and cognitive processes

Whit Au served on my dissertation committee at the University of Hawaii and mentored me while I was in the Marine Mammal Research Program at the Hawaii Institute of Marine Biology (1997–2003). He guided me through the process of recording echoes from objects ensonified by dolphins and oversaw my first human listening study. When I became a professor, I continued to study dolphin bioacoustics. I also broadened the scope of my research program to accommodate the interests of my students, just like Whit did. In this talk, I will summarize several animal perception and cognition projects I have pursued with my graduate students. First, we explored how humans discriminate acoustically among bottlenose dolphin signature whistles with and without masking by boat noise. In another study, we investigated auditory rhythm perception in African penguins. Next, we researched long-term memory in river otters using multimodal stimuli. One of our current projects focuses on visual object perception and learning in olive baboons. I will always be grateful for Whit’s support when I was in graduate school and I will continue to follow his model for graduate student mentoring in the future.

Neuroanatomical correlations of visuospatial processing in primary progressive aphasia.

Clinical phenotyping of primary progressive aphasia has largely focused on speech and language presentations, leaving other cognitive domains under-examined. This study investigated the diagnostic utility of visuospatial profiles and examined their neural basis among the three main primary progressive aphasia variants. We studied the neuropsychological performances of 118 primary progressive aphasia participants and 30 cognitively normal controls, across 11 measures of visuospatial cognition, and investigated their neural correlates via voxel-based morphometry analysis using visuospatial composite scores derived from principal component analysis. The principal component analysis identified three main factors: visuospatial-executive, visuospatial-memory and visuomotor components. Logopenic variant primary progressive aphasia performed significantly worst across all components; nonfluent/agrammatic variant primary progressive aphasia showed deficits in the visuospatial-executive and visuomotor components compared with controls; and the semantic variant primary progressive aphasia scored significantly lower than nonfluent/agrammatic variant primary progressive aphasia and control in the visuospatial-memory component. Grey matter volumes over the right parieto-occipital cortices correlated with visuospatial-executive performance; volumetric changes in the right anterior parahippocampal gyrus and amygdala were associated with visuospatial-memory function, and visuomotor composite scores correlated significantly with the grey matter volume at the right precentral gyrus. Discriminant function analysis identified three visuospatial measures: Visual Object and Space Perception and Benson figure copy and recall test, which classified 79.7% (94/118) of primary progressive aphasia into their specific variant. This study shows that each primary progressive aphasia variant also carries a distinctive visuospatial cognitive profile that corresponds with grey matter volumetric changes and in turn can be largely represented by their performance on the visuomotor, visuospatial-memory and executive functions.

Art et modernisation dans la presse carioca des années 1960: la mode dans les pages du Correio da Manhã et du Jornal do Brasil

In the early 1960s, one can register, internationally, a growth in the population of modern artists and an expansion of the limits of the art world, whose works were marked by the visual perception of everyday life and art objects aligned to universes little explored until then. In Brazil, a country in the process of modernization and expansion of the consumer society, some precariousness in the industry and in the market were responsible for an unprecedented role of artists in the implementation and modernization of new sectors, such as fashion and the press. Thisarticle examines the contribution of artists and intellectuals in the construction of these sectors in Rio de Janeiro. The carioca press played a prominent role in the dissemination and legitimation of the products and effects of these actions.

The contribution of low contrast-preferring neurons to information representation in the primary visual cortex after learning.

Animals exhibit improved perception of lower-contrast visual objects after training. We explored this neuronal mechanism using multiple single-unit recordings from deep layers of the primary visual cortex (V1) of trained rats during orientation discrimination. We found that the firing rates of a subset of neurons increased by reducing luminance contrast, being at least above basal activities at low contrast. These low contrast–preferring neurons were rare during passive viewing without training or anesthesia after training. They fired more frequently in correct-choice than incorrect-choice trials. At single-neuron and population levels, they efficiently represented low-contrast orientations. Following training, in addition to generally enhanced excitation, the phase synchronization of spikes to beta oscillations at high contrast was stronger in putative inhibitory than excitatory neurons. The change in excitation-inhibition balance might contribute to low-contrast preference. Thus, low-contrast preference in V1 activity is strengthened in an experience-dependent manner, which may contribute to low-contrast visual discrimination.

An analysis of daylighting performance of learning spaces in local government sector schools in Kandy

Natural lighting creates a pleasant environment, promotes healthier conditions and saves energy, and is an important factor in the design of education institutions. Many research indicates the positive impacts of better daylighting integration in educational spaces for student’s health and wellbeing. For this research, an in-depth lighting integration analysis was carried out in three typical classrooms in Berrewaerts college Kandy, Sri Lanka. A field study comprised of a questionnaire-based survey and measurement of illuminance was combined with daylight simulation using Autodesk Ecotect 2011 & Autodesk Revit. The study reveals that lack of awareness in integration of natural light with the design can either result in increasing the negative effects of excessive daylight exposure or lack of adequate daylighting. In upper levels and east facing classrooms the main problems were associated with high levels of daylight such as excessive shadow and light patches, uneven light distribution and color distribution and impede perception of objects and text. At ground floor level and south facing classrooms, when natural light is not properly integrated with the design resulted in uneven light distribution, non-uniformity of light resulted in difficulty in reading at work plane and impede the visual perception of objects and text.

How blurry are echoes? Quantifying the spatial resolution of echoic vs. visual object perception

How blurry are echoes? Quantifying the spatial resolution of echoic vs. visual object perception

Visuospatial dysfunction is associated with posterior distribution of white matter damage in non-demented cerebral amyloid angiopathy.

Cerebral amyloid angiopathy (CAA) is a well-recognized contributor to cognitive decline in the elderly. The posterior cortical predilection of CAA pathology would cause visuospatial dysfunction, which is still underexplored. We aimed to investigate whether the visuospatial dysfunction in CAA is associated with the posterior distribution of small vessel disease (SVD) imaging markers. We recruited 60 non-demented CAA cases from a Chinese prospective cohort and 30 cases with non-CAA SVD as controls. We used the Visual Object and Space Perception (VOSP) battery to evaluate visuospatial abilities, and multivariable regression models to assess their associations with SVD imaging markers. There was visuospatial dysfunction, especially visual object perception impairment, in CAA compared to controls (Z-score of VOSP: -0.11±0.66 vs. 0.22±0.54, p=0.023). The VOSP score in CAA was independently related to the fronto-occipital gradient of white matter hyperintensity volumes (coefficient = 0.03, 95% confidence interval [CI] = 0.003-0.05, p=0.030) and mean fractional anisotropy values on diffusion tensor imaging (coefficient = 4.72, 95% CI = 0.97-8.48, p=0.015), but not the severity of global SVD imaging markers or the gradient of lobar cerebral microbleeds with adjustments for age and global cognition score. This finding suggests that the damage of posterior white matter rather than global disease severity may be a major contributor to visuospatial dysfunction in CAA.

Diplopia in Parkinson's disease: Indication of a cortical phenotype with cognitive dysfunction?

Visual disturbances are increasingly recognized as common non-motor symptoms in Parkinson's disease (PD). In PD patients, intermittent diplopia has been found to be associated with the presence of visual hallucinations and the Parkinson's psychosis spectrum. Here, we investigated whether diplopia in PD is associated with other non-motor traits and cognitive impairment. We investigated 50 non-demented PD patients with and without intermittent diplopia and 24 healthy controls for visual disturbances, as well as motor and non-motor symptoms. All participants underwent a neuropsychological test battery; visuospatial abilities were further evaluated with subtests of the Visual Object and Space Perception Battery (VOSP). The two PD patient groups did not differ significantly in age, symptom duration, motor symptom severity, frequency of visual hallucinations, or visual sensory efficiency. PD patients with diplopia reported more frequent non-motor symptoms including more subjective cognitive problems and apathy without changes in global cognition measures compared to those without diplopia. PD patients with diplopia had greater impairment in several tests of visuospatial function (pentagon copying p=.002; number location p=.001; cube analysis p<.02) and object perception (p<.001) compared to PD patients without diplopia and healthy controls. By contrast, no consistent group differences were observed in executive function, memory, or language. PD patients with diplopia have a greater non-motor symptom burden and deficits in visuospatial function compared to PD patients without diplopia. PD patients with diplopia might be prone to a cortical phenotype with cognitive decline and apathy associated with worse prognosis.