-
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 -
Current Biology : CB Jun 2022Visual perception in human adults varies throughout the visual field, both across eccentricity - decreasing with distance from the center of gaze - and around...
Visual perception in human adults varies throughout the visual field, both across eccentricity - decreasing with distance from the center of gaze - and around isoeccentric locations - that is, with polar angle at a constant distance from the center of gaze. At isoeccentric locations, the same visual information yields better performance along the horizontal than vertical meridian (horizontal-vertical anisotropy, HVA) and along the lower than upper vertical meridian (vertical-meridian asymmetry, VMA). These perceptual polar angle asymmetries in adults have been well characterized. Poor perception at upper visual field locations would be particularly detrimental to children: in their perceptual world, given their height, many important events occur above eye level. Developmental aspects of visual perception have been well characterized, and some basic dimensions, such as contrast sensitivity, continue to develop through childhood, but there is no research on polar angle asymmetries before adulthood. Here, we investigated whether these asymmetries are present in children, and if so, whether they differ from those of adults. We found clear differences between children and adults in performance around the visual field: the HVA is less pronounced and the VMA is not present for children.
Topics: Adult; Anisotropy; Child; Contrast Sensitivity; Humans; Vision, Ocular; Visual Fields
PubMed: 35671720
DOI: 10.1016/j.cub.2022.04.052 -
Annual Review of Neuroscience Jul 2023Despite increasing evidence of its involvement in several key functions of the cerebral cortex, the vestibular sense rarely enters our consciousness. Indeed, the extent... (Review)
Review
Despite increasing evidence of its involvement in several key functions of the cerebral cortex, the vestibular sense rarely enters our consciousness. Indeed, the extent to which these internal signals are incorporated within cortical sensory representation and how they might be relied upon for sensory-driven decision-making, during, for example, spatial navigation, is yet to be understood. Recent novel experimental approaches in rodents have probed both the physiological and behavioral significance of vestibular signals and indicate that their widespread integration with vision improves both the cortical representation and perceptual accuracy of self-motion and orientation. Here, we summarize these recent findings with a focus on cortical circuits involved in visual perception and spatial navigation and highlight the major remaining knowledge gaps. We suggest that vestibulo-visual integration reflects a process of constant updating regarding the status of self-motion, and access to such information by the cortex is used for sensory perception and predictions that may be implemented for rapid, navigation-related decision-making.
Topics: Motion Perception; Cues; Visual Perception; Vestibule, Labyrinth; Cerebral Cortex
PubMed: 37428601
DOI: 10.1146/annurev-neuro-120722-100503 -
Investigative Ophthalmology & Visual... May 2023Center-surround contrast suppression-typically induced when a center pattern is surrounded by another pattern with similar spatial features-is considered a perceptual...
PURPOSE
Center-surround contrast suppression-typically induced when a center pattern is surrounded by another pattern with similar spatial features-is considered a perceptual analogue of center-surround neurophysiology in the visual system. Surround suppression strength is altered in a range of brain conditions affecting young people (e.g., schizophrenia, depression, migraine) and is modulated by various neurotransmitters. The early teen years are associated with neurotransmitter changes in the human visual cortex, which could impact on excitation-inhibition balance and center-surround antagonistic effects. Hence, we predict that early adolescence is associated with perceptual changes in center-surround suppression.
METHODS
In this cross-sectional study, we tested 196 students at every age from 10 to 17 years and 30 adults (aged 21-34 years) to capture the preteen, adolescent, and adult periods. Contrast discrimination thresholds were measured for a central, circular, vertical sinusoidal grating pattern (0.67° radius, 2 cyc/deg spatial frequency, 2 deg/s drift rate) with and without the surround (4° radius, otherwise same spatial properties as the center). Individual suppression strength was determined by comparing the perceived contrast of the target with and without the surround.
RESULTS
After excluding unreliable data (7% of total), we found an effect of age on perceptual center-surround contrast suppression strength, F(8,201) = 2.30, P = 0.02, with weaker suppression in the youngest adolescents relative to adults (Bonferroni pairwise comparisons between adults vs 12-year-olds P = 0.01; adults vs 13-year-olds P = 0.002).
CONCLUSIONS
Our data demonstrate different center-surround interactions in the visual system-a key building block for visual perception-in early adolescence relative to adulthood.
Topics: Adult; Humans; Adolescent; Child; Contrast Sensitivity; Cross-Sectional Studies; Photic Stimulation; Visual Perception; Visual Cortex; Neurotransmitter Agents
PubMed: 37200040
DOI: 10.1167/iovs.64.5.14 -
ELife Jul 2019The human visual system is tasked with recovering the different physical sources of optical structure that generate our retinal images. Separate research has focused on...
The human visual system is tasked with recovering the different physical sources of optical structure that generate our retinal images. Separate research has focused on understanding how the visual system estimates (a) environmental sources of image structure and (b) blur induced by the eye's limited focal range, but little is known about how the visual system distinguishes environmental sources from optical defocus. Here, we present evidence that this is a fundamental perceptual problem and provide insights into how and when the visual system succeeds and fails in solving it. We show that fully focused surface shading can be misperceived as defocused and that optical blur can be misattributed to the material properties and shape of surfaces. We further reveal how these misperceptions depend on the relationship between shading gradients and sharp contours, and conclude that computations of blur are inherently linked to computations of surface shape, material, and illumination.
Topics: Form Perception; Humans; Optical Phenomena; Photic Stimulation; Visual Perception
PubMed: 31298655
DOI: 10.7554/eLife.48214 -
Progress in Neurobiology Dec 2021One of the central questions in visual neuroscience is how the sparse retinal signals leaving our eyes are transformed into a rich subjective visual experience of the... (Review)
Review
One of the central questions in visual neuroscience is how the sparse retinal signals leaving our eyes are transformed into a rich subjective visual experience of the world. Invasive physiology studies, which offers the highest spatial resolution, have revealed many facts about the processing of simple visual features like contrast, color, and orientation, focusing on the early visual areas. At the same time, standard human fMRI studies with comparably coarser spatial resolution have revealed more complex, functionally specialized, and category-selective responses in higher visual areas. Although the visual system is the best understood among the sensory modalities, these two areas of research remain largely segregated. High-resolution fMRI opens up a possibility for linking them. On the one hand, it allows studying how the higher-level visual functions affect the fine-scale activity in early visual areas. On the other hand, it allows discovering the fine-scale functional organization of higher visual areas and exploring their functional connectivity with visual areas lower in the hierarchy. In this review, I will discuss examples of successful work undertaken in these directions using high-resolution fMRI and discuss where this method could be applied in the future to advance our understanding of the complexity of higher-level visual processing.
Topics: Brain Mapping; Cognition; Humans; Magnetic Resonance Imaging; Visual Perception
PubMed: 33497652
DOI: 10.1016/j.pneurobio.2021.101998 -
Journal of Vision Oct 2021Retinal motion of the visual scene is not consciously perceived during ocular saccades in normal everyday conditions. It has been suggested that extra-retinal signals...
Retinal motion of the visual scene is not consciously perceived during ocular saccades in normal everyday conditions. It has been suggested that extra-retinal signals actively suppress intra-saccadic motion perception to preserve stable perception of the visual world. However, using stimuli optimized to preferentially activate the M-pathway, Castet and Masson (2000) demonstrated that motion can be perceived during a saccade. Based on this psychophysical paradigm, we used electroencephalography and eye-tracking recordings to investigate the neural correlates related to the conscious perception of intra-saccadic motion. We demonstrated the effective involvement during saccades of the cortical areas V1-V2 and MT-V5, which convey motion information along the M-pathway. We also showed that individual motion perception was related to retinal temporal frequency.
Topics: Humans; Motion; Motion Perception; Photic Stimulation; Retina; Saccades; Visual Cortex; Visual Perception
PubMed: 34698810
DOI: 10.1167/jov.21.11.19 -
Current Opinion in Psychology Oct 2019How do we explain the seemingly rich nature of visual phenomenology while accounting for impoverished perception in the periphery? This apparent mismatch has led some to... (Review)
Review
How do we explain the seemingly rich nature of visual phenomenology while accounting for impoverished perception in the periphery? This apparent mismatch has led some to posit that rich phenomenological content overflows cognitive access, whereas others hold that phenomenology is in fact sparse and constrained by cognitive access. Here, we review the Rich versus Sparse debate as it relates to a phenomenon called subjective inflation, wherein minimally attended or peripheral visual perception tends to be subjectively evaluated as more reliable than attended or foveal perception when objective performance is matched. We argue that subjective inflation can account for rich phenomenology without invoking phenomenological overflow. On this view, visual phenomenology is constrained by cognitive access, but seemingly inflated above what would be predicted based on sparse sensory content.
Topics: Cognition; Consciousness; Humans; Vision, Ocular; Visual Perception
PubMed: 30503986
DOI: 10.1016/j.copsyc.2018.11.006 -
Journal of Cognitive Neuroscience Jun 2023Visual perception and mental imagery have been shown to share a hierarchical topological visual structure of neural representation, despite the existence of dissociation...
Visual perception and mental imagery have been shown to share a hierarchical topological visual structure of neural representation, despite the existence of dissociation of neural substrate between them in function and structure. However, we have limited knowledge about how the visual hierarchical cortex is involved in visual perception and visual imagery in a unique and shared fashion. In this study, a data set including a visual perception and an imagery experiment with human participants was used to train 2 types of voxel-wise encoding models. These models were based on Gabor features and voxel activity patterns of high-level visual cortex (i.e., fusiform face area, parahippocampal place area, and lateral occipital complex) to predict activity in the early visual cortex (EVC, i.e., V1, V2, V3) during perception, and then tested with respect to the generalization of these models to mental imagery. Our results showed that during perception and imagery, activities in the EVC could be independently predicted by the Gabor features and activity of high-level visual cortex via voxel-wise encoding models, which suggested that perception and imagery might share neural representation in the EVC. We further found Gabor-specific and non-Gabor-specific patterns of neural response to stimuli in the EVC, which were shared by perception and imagery. These findings provide insight into the mechanisms of how visual perception and imagery share representation in the EVC.
Topics: Humans; Imagination; Visual Perception; Visual Cortex; Magnetic Resonance Imaging
PubMed: 37043235
DOI: 10.1162/jocn_a_01992 -
Brain Stimulation 2022Visual phenomena like brightness illusions impressively demonstrate the highly constructive nature of perception. In addition to physical illumination, the subjective...
BACKGROUND
Visual phenomena like brightness illusions impressively demonstrate the highly constructive nature of perception. In addition to physical illumination, the subjective experience of brightness is related to temporal neural dynamics in visual cortex.
OBJECTIVE
Here, we asked whether biasing the temporal pattern of neural excitability in visual cortex by transcranial alternating current stimulation (tACS) modulates brightness perception of concurrent rhythmic visual stimuli.
METHODS
Participants performed a brightness discrimination task of two flickering lights, one of which was targeted by same-frequency electrical stimulation at varying phase shifts. tACS was applied with an occipital and a periorbital active control montage, based on simulations of electrical currents using finite element head models.
RESULTS
Experimental results reveal that flicker brightness perception is modulated dependent on the phase shift between sensory and electrical stimulation, solely under occipital tACS. Phase-specific modulatory effects by tACS were dependent on flicker-evoked neural phase stability at the tACS-targeted frequency, recorded prior to electrical stimulation. Further, the optimal timing of tACS application leading to enhanced brightness perception was correlated with the neural phase delay of the cortical flicker response.
CONCLUSIONS
Our results corroborate the role of temporally coordinated neural activity in visual cortex for brightness perception of rhythmic visual input in humans. Phase-specific behavioral modulations by tACS emphasize its efficacy to transfer perceptually relevant temporal information to the cortex. These findings provide an important step towards understanding the basis of visual perception and further confirm electrical stimulation as a tool for advancing controlled modulations of neural activity and related behavior.
Topics: Bias; Humans; Photic Stimulation; Transcranial Direct Current Stimulation; Visual Cortex; Visual Perception
PubMed: 34990876
DOI: 10.1016/j.brs.2022.01.001