scholarly journals Detecting changes in spatial frequency: Exploring the interaction of object- and space-based visual processing

2010 ◽  
Vol 3 (9) ◽  
pp. 861-861
Author(s):  
J. M. Brown ◽  
J. L. Solberg
Keyword(s):  
Spatial Frequency ◽  
Visual Processing

Spatial frequency analsis in early visual processing

1980 ◽  
Vol 290 (1038) ◽  
pp. 11-22 ◽  
Keyword(s):  
Spatial Frequency ◽  
Visual Processing ◽  
Spatial Information ◽  
Multiple Channels ◽  
Low Contrast ◽  
Local Sign ◽  
Early Visual Processing ◽  
Low Luminance ◽  
Lowered Sensitivity ◽  
Prior Adaptation

The existence of multiple channels, or multiple receptive field sizes, in the visual system does not commit us to any particular theory of spatial encoding in vision. However, distortions of apparent spatial frequency and width in a wide variety of conditions favour the idea that each channel carries a width- or frequency-related code or ‘label’ rather than a ‘local sign’ or positional label. When distortions of spatial frequency occur without prior adaptation (e.g. at low contrast or low luminance) they are associated with lowered sensitivity, and may be due to a mismatch between the perceptual labels and the actual tuning of the channels. A low-level representation of retinal space could be constructed from the spatial information encoded by the channels, rather than being projected intact from the retina.

scholarly journals Long-term adaptation to ocular aberrations alters visual processing of spatial frequency information

2016 ◽  
Vol 16 (12) ◽  
pp. 554
Author(s):  
Antoine Barbot ◽  
Krystel Huxlin ◽  
Duje Tadin ◽  
Geunyoung Yoon
Keyword(s):  
Spatial Frequency ◽  
Visual Processing ◽  
Frequency Information ◽  
Ocular Aberrations

Sounds prevent selective monitoring of high spatial frequency channels in vision

2012 ◽  
Vol 25 (0) ◽  
pp. 40
Author(s):  
Alexis Pérez-Bellido ◽  
Joan López-Moliner ◽  
Salvador Soto-Faraco
Keyword(s):  
Standard Deviation ◽  
Spatial Frequency ◽  
Visual Processing ◽  
Reaction Times ◽  
High Spatial Frequency ◽  
Visual Signals ◽  
Sensory Interactions ◽  
Multisensory Interactions ◽  
Visual Targets ◽  
Selective Monitoring

Prior knowledge about the spatial frequency (SF) of upcoming visual targets (Gabor patches) speeds up average reaction times and decreases standard deviation. This has often been regarded as evidence for a multichannel processing of SF in vision. Multisensory research, on the other hand, has often reported the existence of sensory interactions between auditory and visual signals. These interactions result in enhancements in visual processing, leading to lower sensory thresholds and/or more precise visual estimates. However, little is known about how multisensory interactions may affect the uncertainty regarding visual SF. We conducted a reaction time study in which we manipulated the uncertanty about SF (SF was blocked or interleaved across trials) of visual targets, and compared visual only versus audio–visual presentations. Surprisingly, the analysis of the reaction times and their standard deviation revealed an impairment of the selective monitoring of the SF channel by the presence of a concurrent sound. Moreover, this impairment was especially pronounced when the relevant channels were high SFs at high visual contrasts. We propose that an accessory sound automatically favours visual processing of low SFs through the magnocellular channels, thereby detracting from the potential benefits from tuning into high SF psychophysical-channels.

scholarly journals Anorexia nervosa and body dysmorphic disorder are associated with abnormalities in processing visual information

2015 ◽  
Vol 45 (10) ◽  
pp. 2111-2122 ◽  
Author(s):  
W. Li ◽  
T. M. Lai ◽  
C. Bohon ◽  
S. K. Loo ◽  
D. McCurdy ◽  
...  
Keyword(s):  
Anorexia Nervosa ◽  
Spatial Frequency ◽  
Visual Processing ◽  
Visual Information ◽  
Body Dysmorphic Disorder ◽  
High Spatial Frequency ◽  
Event Related Potentials ◽  
Visual Stream ◽  
N170 Component ◽  
Related Potentials

BackgroundAnorexia nervosa (AN) and body dysmorphic disorder (BDD) are characterized by distorted body image and are frequently co-morbid with each other, although their relationship remains little studied. While there is evidence of abnormalities in visual and visuospatial processing in both disorders, no study has directly compared the two. We used two complementary modalities – event-related potentials (ERPs) and functional magnetic resonance imaging (fMRI) – to test for abnormal activity associated with early visual signaling.MethodWe acquired fMRI and ERP data in separate sessions from 15 unmedicated individuals in each of three groups (weight-restored AN, BDD, and healthy controls) while they viewed images of faces and houses of different spatial frequencies. We used joint independent component analyses to compare activity in visual systems.ResultsAN and BDD groups demonstrated similar hypoactivity in early secondary visual processing regions and the dorsal visual stream when viewing low spatial frequency faces, linked to the N170 component, as well as in early secondary visual processing regions when viewing low spatial frequency houses, linked to the P100 component. Additionally, the BDD group exhibited hyperactivity in fusiform cortex when viewing high spatial frequency houses, linked to the N170 component. Greater activity in this component was associated with lower attractiveness ratings of faces.ConclusionsResults provide preliminary evidence of similar abnormal spatiotemporal activation in AN and BDD for configural/holistic information for appearance- and non-appearance-related stimuli. This suggests a common phenotype of abnormal early visual system functioning, which may contribute to perceptual distortions.

scholarly journals Interocular Differences in Spatial Frequency Influence the Pulfrich Effect

Vision ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 20
Author(s):  
Seung Hyun Min ◽  
Alexandre Reynaud ◽  
Robert F. Hess
Keyword(s):  
Spatial Frequency ◽  
Visual Processing ◽  
Image Features ◽  
Motion In Depth ◽  
Spatial Properties ◽  
Parallel Motion ◽  
Stereo Motion ◽  
Pulfrich Effect ◽  
Micro Elements ◽  
Gabor Elements

The Pulfrich effect is a stereo-motion phenomenon. When the two eyes are presented with visual targets moving in fronto-parallel motion at different luminances or contrasts, the perception is of a target moving-in-depth. It is thought that this percept of motion-in-depth occurs because lower luminance or contrast delays the speed of visual processing. Spatial properties of an image such as spatial frequency and size have also been shown to influence the speed of visual processing. In this study, we use a paradigm to measure interocular delay based on the Pulfrich effect where a structure-from-motion defined cylinder, composed of Gabor elements displayed at different interocular phases, rotates in depth. This allows us to measure any relative interocular processing delay while independently manipulating the spatial frequency and size of the micro elements (i.e., Gabor patches). We show that interocular spatial frequency differences, but not interocular size differences of image features, produce interocular processing delays.

The Effect of Spatial-Frequency Filtering on the Visual Processing of Global Structure

Perception ◽  
10.1068/p5364 ◽  
2006 ◽  
Vol 35 (12) ◽  
pp. 1583-1609 ◽  
Author(s):  
Vicente Sierra-Vázquez ◽  
Ignacio Serrano-Pedraza ◽  
Dolores Luna
Keyword(s):  
Spatial Frequency ◽  
Visual Processing ◽  
Global Structure ◽  
Frequency Filtering ◽  
Spatial Frequency Filtering

scholarly journals Selective modulation of visual sensitivity during fixation

2018 ◽  
Vol 119 (6) ◽  
pp. 2059-2067 ◽  
Author(s):  
Chris Scholes ◽  
Paul V. McGraw ◽  
Neil W. Roach
Keyword(s):  
Eye Movements ◽  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Eye Movement ◽  
Visual Processing ◽  
Spatial Scales ◽  
Gain Control ◽  
Visual Sensitivity ◽  
Ocular Movements ◽  
Spatial Frequencies

During periods of steady fixation, we make small-amplitude ocular movements, termed microsaccades, at a rate of 1–2 every second. Early studies provided evidence that visual sensitivity is reduced during microsaccades—akin to the well-established suppression associated with larger saccades. However, the results of more recent work suggest that microsaccades may alter retinal input in a manner that enhances visual sensitivity to some stimuli. Here we parametrically varied the spatial frequency of a stimulus during a detection task and tracked contrast sensitivity as a function of time relative to microsaccades. Our data reveal two distinct modulations of sensitivity: suppression during the eye movement itself and facilitation after the eye has stopped moving. The magnitude of suppression and facilitation of visual sensitivity is related to the spatial content of the stimulus: suppression is greatest for low spatial frequencies, while sensitivity is enhanced most for stimuli of 1–2 cycles/°, spatial frequencies at which we are already most sensitive in the absence of eye movements. We present a model in which the tuning of suppression and facilitation is explained by delayed lateral inhibition between spatial frequency channels. Our data show that eye movements actively modulate visual sensitivity even during fixation: the detectability of images at different spatial scales can be increased or decreased depending on when the image occurs relative to a microsaccade. NEW & NOTEWORTHY Given the frequency with which we make microsaccades during periods of fixation, it is vital that we understand how they affect visual processing. We demonstrate two selective modulations of contrast sensitivity that are time-locked to the occurrence of a microsaccade: suppression of low spatial frequencies during each eye movement and enhancement of higher spatial frequencies after the eye has stopped moving. These complementary changes may arise naturally because of sluggish gain control between spatial channels.

scholarly journals The Effect of Spatial Frequency on the Visual Category Representation in the Macaque Inferior Temporal Cortex

2021 ◽  
Author(s):  
Esmaeil Farhang ◽  
Ramin Toosi ◽  
Behnam Karami ◽  
Roxana Koushki ◽  
Ehsan Rezayat ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Visual Processing ◽  
Visual Information ◽  
Temporal Cortex ◽  
Inferior Temporal Cortex ◽  
Category Representation ◽  
Neural Basis ◽  
Shape Information ◽  
Category Information ◽  
The Impact

ABSTRACTTo expand our knowledge about the object recognition, it is critical to understand the role of spatial frequency (SF) in an object representation that occurs in the inferior temporal (IT) cortex at the final stage of processing the visual information across the ventral visual pathway. Object categories are being recognized hierarchically in at least three levels of abstraction: superordinate (e.g., animal), mid-level (e.g., human face), and subordinate (e.g., face identity). Psychophysical studies have shown rapid access to mid-level category information and low SF (LSF) contents. Although the hierarchical representation of categories has been shown to exist inside the IT cortex, the impact of SF on the multi-level category processing is poorly understood. To gain a deeper understanding of the neural basis of the interaction between SF and category representations at multiple levels, we examined the neural responses within the IT cortex of macaque monkeys viewing several SF-filtered objects. Each stimulus could be either intact or bandpass filtered into either the LSF (coarse shape information) or high SF (HSF) (fine shape information) bands. We found that in both High- and Low-SF contents, the advantage of mid-level representation has not been violated. This evidence suggests that mid-level category boundary maps are strongly represented in the IT cortex and remain unaffected with respect to any changes in the frequency content of stimuli. Our observations indicate the necessity of the HSF content for the superordinate category representation inside the IT cortex. In addition, our findings reveal that the representation of global category information is more dependent on the HSF than the LSF content. Furthermore, the lack of subordinate representation in both LSF and HSF filtered stimuli compared to the intact stimuli provide strong evidence that all SF contents are necessary for fine category visual processing.

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