scholarly journals The perceptual continuity field is retinotopic

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Thérèse Collins
Keyword(s):  
Visual Perception ◽  
Visual Processing ◽  
Serial Dependence ◽  
Recent Past ◽  
Retinal Position ◽  
External Space ◽  
Brain Level ◽  
Spatial Window ◽  
Late Stages ◽  
The Brain

AbstractVisual perception is systematically biased towards input from the recent past: perceived orientation, numerosity, and face identity are pulled towards previously seen stimuli. To better understand the brain level at which serial dependence occurs, the present study examined its spatial tuning. In three experiments, serial dependence occurred between stimuli occupying the same retinal position. Serial dependence between stimuli at distant retinal locations was smaller, even when the stimuli occupied the same location in external space. The spatial window over which serial dependence occurs is thus retinotopic, but wide, suggesting that serial dependence occurs at late stages of visual processing.

scholarly journals Serial dependence tracks objects and scenes independently

2021 ◽  
Author(s):  
Thérèse Collins
Keyword(s):  
Visual Processing ◽  
Scene Perception ◽  
Temporal Integration ◽  
Object Perception ◽  
Serial Dependence ◽  
Recent Past ◽  
Individual Object ◽  
Ensemble Perception ◽  
Visual Attribute ◽  
Feature Values

The visual world is made up of objects and scenes. Object perception requires both discriminating an individual object from others and binding together different perceptual samples of that object across time. Such binding manifests by serial dependence, the attraction of the current perception of a visual attribute towards values of that attribute seen in the recent past. Scene perception is subserved by global mechanisms like ensemble perception, the rapid extraction of the average feature value of a group of objects. The current study examined to what extent the perception of single objects in multi-object scenes depended on previous feature values of that object, or on the average previous attribute of all objects in the scene. Results show that serial dependence occurs independently on two simultaneously present objects, that ensemble perception depends on previous ensembles, and that serial dependence of an individual object occurs only on the features of that particular object. These results suggest that the temporal integration of successive perceptual samples operates simultaneously at independent levels of visual processing.

Primary Visual Perception from the Bottom Up

2017 ◽  
Author(s):  
Martin V. Butz ◽  
Esther F. Kutter
Keyword(s):  
Visual Perception ◽  
Visual Processing ◽  
Visual Information ◽  
Information Needs ◽  
Depth Information ◽  
Top Down ◽  
Edge Detectors ◽  
Brain Extracts ◽  
Visual Properties ◽  
The Brain

This chapter addresses primary visual perception, detailing how visual information comes about and, as a consequence, which visual properties provide particularly useful information about the environment. The brain extracts this information systematically, and also separates redundant and complementary visual information aspects to improve the effectiveness of visual processing. Computationally, image smoothing, edge detectors, and motion detectors must be at work. These need to be applied in a convolutional manner over the fixated area, which are computations that are predestined to be solved by means of cortical columnar structures in the brain. On the next level, the extracted information needs to be integrated to be able to segment and detect object structures. The brain solves this highly challenging problem by incorporating top-down expectations and by integrating complementary visual information aspects, such as light reflections, texture information, line convergence information, shadows, and depth information. In conclusion, the need for integrating top-down visual expectations to form complete and stable perceptions is made explicit.

scholarly journals Aberrant intrinsic functional connectivity within and between corticostriatal and temporal–parietal networks in adults and youth with bipolar disorder

2016 ◽  
Vol 46 (7) ◽  
pp. 1509-1522 ◽  
Author(s):  
J. Stoddard ◽  
S. J. Gotts ◽  
M. A. Brotman ◽  
S. Lever ◽  
D. Hsu ◽  
...  
Keyword(s):  
Bipolar Disorder ◽  
Functional Connectivity ◽  
Visual Processing ◽  
Age Groups ◽  
Neural Circuitry ◽  
Brain Regions ◽  
Functional Magnetic Resonance ◽  
Intrinsic Functional Connectivity ◽  
Late Stages ◽  
The Brain

BackgroundMajor questions remain regarding the dysfunctional neural circuitry underlying the pathophysiology of bipolar disorder (BD) in both youths and adults. In both age groups, studies implicate abnormal intrinsic functional connectivity among prefrontal, limbic and striatal areas.MethodWe collected resting-state functional magnetic resonance imaging (fMRI) data from youths and adults (ages 10–50 years) with BD (n = 39) and healthy volunteers (HV; n = 78). We identified brain regions with aberrant intrinsic functional connectivity in BD by first comparing voxel-wise mean global connectivity and then conducting correlation analyses. We used k-means clustering and multidimensional scaling to organize all detected regions into networks.ResultsAcross the brain, we detected areas of dysconnectivity in both youths and adults with BD relative to HV. There were no significant age-group × diagnosis interactions. When organized by interregional connectivity, the areas of dysconnectivity in patients with BD comprised two networks: one of temporal and parietal areas involved in late stages of visual processing, and one of corticostriatal areas involved in attention, cognitive control and response generation.ConclusionsThese data suggest that two networks show abnormal intrinsic functional connectivity in BD. Regions in these networks have been implicated previously in BD. We observed similar dysconnectivity in youths and adults with BD. These findings provide guidance for refining models of network-based dysfunction in BD.

Behavioural and EEG atypicalities during rest, visual perception, and cognitive control in autistic adults

2020 ◽  
Author(s):  
Amandine Lassalle ◽  
Michael X Cohen ◽  
Laura Dekkers ◽  
Elizabeth Milne ◽  
Rasa Gulbinaite ◽  
...  
Keyword(s):  
Visual Perception ◽  
Cognitive Control ◽  
Visual Processing ◽  
Autism Spectrum ◽  
Neural Dynamics ◽  
Simple Explanation ◽  
Control Task ◽  
Neural Structure ◽  
Eeg Power ◽  
Autistic Adults

Background: People with an Autism Spectrum Condition diagnosis (ASD) are hypothesized to show atypical neural dynamics, reflecting differences in neural structure and function. However, previous results regarding neural dynamics in autistic individuals have not converged on a single pattern of differences. It is possible that the differences are cognitive-set-specific, and we therefore measured EEG in autistic individuals and matched controls during three different cognitive states: resting, visual perception, and cognitive control.Methods: Young adults with and without an ASD (N=17 in each group) matched on age (range 20 to 30 years), sex, and estimated Intelligence Quotient (IQ) were recruited. We measured their behavior and their EEG during rest, a task requiring low-level visual perception of gratings of varying spatial frequency, and the “Simon task” to elicit activity in the executive control network. We computed EEG power and Inter-Site Phase Clustering (ISPC; a measure of connectivity) in various frequency bands.Results: During rest, there were no ASD vs. controls differences in EEG power, suggesting typical oscillation power at baseline. During visual processing, without pre-baseline normalization, we found decreased broadband EEG power in ASD vs. controls, but this was not the case during the cognitive control task. Furthermore, the behavioral results of the cognitive control task suggest that autistic adults were better able to ignore irrelevant stimuli.Conclusions: Together, our results defy a simple explanation of overall differences between ASD and controls, and instead suggest a more nuanced pattern of altered neural dynamics that depend on which neural networks are engaged.

scholarly journals Neuronal adaptation: Delay compensation at the level of single neurons?

2008 ◽  
Vol 31 (2) ◽  
pp. 210-212 ◽  
Author(s):  
J. Patrick Mayo ◽  
Marc A. Sommer
Keyword(s):  
Visual Processing ◽  
Visual Input ◽  
Single Neurons ◽  
Delay Compensation ◽  
Time Intervals ◽  
Neuronal Adaptation ◽  
First Response ◽  
Late Stages

AbstractSaccades divide visual input into rapid, discontinuous periods of stimulation on the retina. The response of single neurons to such sequential stimuli is neuronal adaptation; a robust first response followed by an interval-dependent diminished second response. Adaptation is pervasive in both early and late stages of visual processing. Given its inherent coding of brief time intervals, neuronal adaptation may play a fundamental role in compensating for visual delays.

scholarly journals Camouflage, communication and thermoregulation: lessons from colour changing organisms

2008 ◽  
Vol 364 (1516) ◽  
pp. 463-470 ◽  
Author(s):  
Devi Stuart-Fox ◽  
Adnan Moussalli
Keyword(s):  
Visual Perception ◽  
Visual Processing ◽  
Comparative Studies ◽  
Visual Cues ◽  
Colour Change ◽  
Visual Environment ◽  
Multiple Predators ◽  
Physiological Colour Change ◽  
Colour Patterns ◽  
Insight Into

Organisms capable of rapid physiological colour change have become model taxa in the study of camouflage because they are able to respond dynamically to the changes in their visual environment. Here, we briefly review the ways in which studies of colour changing organisms have contributed to our understanding of camouflage and highlight some unique opportunities they present. First, from a proximate perspective, comparison of visual cues triggering camouflage responses and the visual perception mechanisms involved can provide insight into general visual processing rules. Second, colour changing animals can potentially tailor their camouflage response not only to different backgrounds but also to multiple predators with different visual capabilities. We present new data showing that such facultative crypsis may be widespread in at least one group, the dwarf chameleons. From an ultimate perspective, we argue that colour changing organisms are ideally suited to experimental and comparative studies of evolutionary interactions between the three primary functions of animal colour patterns: camouflage; communication; and thermoregulation.

scholarly journals Perceptual decisions are biased toward relevant prior choices

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Helen Feigin ◽  
Shira Baror ◽  
Moshe Bar ◽  
Adam Zaidel
Keyword(s):  
Sensory Information ◽  
Irrelevant Stimulus ◽  
Stimulus Feature ◽  
Serial Dependence ◽  
Low Level ◽  
Subsequent Test ◽  
Key Factor ◽  
High Level ◽  
Motor Actions ◽  
The Brain

AbstractPerceptual decisions are biased by recent perceptual history—a phenomenon termed 'serial dependence.' Here, we investigated what aspects of perceptual decisions lead to serial dependence, and disambiguated the influences of low-level sensory information, prior choices and motor actions. Participants discriminated whether a brief visual stimulus lay to left/right of the screen center. Following a series of biased ‘prior’ location discriminations, subsequent ‘test’ location discriminations were biased toward the prior choices, even when these were reported via different motor actions (using different keys), and when the prior and test stimuli differed in color. By contrast, prior discriminations about an irrelevant stimulus feature (color) did not substantially influence subsequent location discriminations, even though these were reported via the same motor actions. Additionally, when color (not location) was discriminated, a bias in prior stimulus locations no longer influenced subsequent location discriminations. Although low-level stimuli and motor actions did not trigger serial-dependence on their own, similarity of these features across discriminations boosted the effect. These findings suggest that relevance across perceptual decisions is a key factor for serial dependence. Accordingly, serial dependence likely reflects a high-level mechanism by which the brain predicts and interprets new incoming sensory information in accordance with relevant prior choices.

Context-Dependent Modulation of Early Visual Cortical Responses to Numerical and Nonnumerical Magnitudes

2021 ◽  
pp. 1-12
Author(s):  
Joonkoo Park ◽  
Sonia Godbole ◽  
Marty G. Woldorff ◽  
Elizabeth M. Brannon
Keyword(s):  
Visual Processing ◽  
Context Dependency ◽  
Numerical Magnitude ◽  
Continuous Variables ◽  
Processing Stream ◽  
Cortical Responses ◽  
Early Visual Cortex ◽  
Context Dependent ◽  
Visual Cortical ◽  
The Brain

Abstract Whether and how the brain encodes discrete numerical magnitude differently from continuous nonnumerical magnitude is hotly debated. In a previous set of studies, we orthogonally varied numerical (numerosity) and nonnumerical (size and spacing) dimensions of dot arrays and demonstrated a strong modulation of early visual evoked potentials (VEPs) by numerosity and not by nonnumerical dimensions. Although very little is known about the brain's response to systematic changes in continuous dimensions of a dot array, some authors intuit that the visual processing stream must be more sensitive to continuous magnitude information than to numerosity. To address this possibility, we measured VEPs of participants viewing dot arrays that changed exclusively in one nonnumerical magnitude dimension at a time (size or spacing) while holding numerosity constant and compared this to a condition where numerosity was changed while holding size and spacing constant. We found reliable but small neural sensitivity to exclusive changes in size and spacing; however, changing numerosity elicited a much more robust modulation of the VEPs. Together with previous work, these findings suggest that sensitivity to magnitude dimensions in early visual cortex is context dependent: The brain is moderately sensitive to changes in size and spacing when numerosity is held constant, but sensitivity to these continuous variables diminishes to a negligible level when numerosity is allowed to vary at the same time. Neurophysiological explanations for the encoding and context dependency of numerical and nonnumerical magnitudes are proposed within the framework of neuronal normalization.

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