Stimulus-dependent contrast sensitivity asymmetries around the visual field

Himmelberg, Marc M.; Winawer, Jonathan; Carrasco, Marisa

doi:10.1101/2020.06.30.181156

Cited by 7 publications

(34 citation statements)

References 76 publications

(102 reference statements)

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“…The Gabor was oriented 15° clockwise or counter-clockwise from vertical with a spatial frequency of 4 cycles per degree. These stimulus parameters were chosen to match a recent psychophysical experiment [28] to later compare model and human performance.…”

Section: Resultsmentioning

confidence: 99%

“…These contrast thresholds are much lower (i.e. better performance) than those of human observers, who have thresholds of about 2–4% contrast for stimuli presented at the same eccentricity [28]. Given a fixed set of outputs from the cone mosaic, the ideal observer performance depends on the mRGC:cone ratio.…”

Section: Resultsmentioning

confidence: 99%

“…The mRGC:cone ratios are up sampled by a factor of 8 and cone density is resampled to have equal log10 spaced values. Individual dots represent the predicted model performance for nasal (red star), superior (blue star), temporal (green star) and inferior (black star) retinal locations at 4.5° eccentricity (matched to stimulus eccentricity in [28]).…”

Section: Resultsmentioning

confidence: 99%

“…At iso-eccentric locations, performance is better along the horizontal than vertical meridian (horizontal-vertical anisotropy or “HVA” e.g., [9–12]) and better along the lower than upper vertical meridian (vertical-meridian asymmetry or “VMA” [10–14]). These radial asymmetries are observed in many different visual tasks, such as those mediated by contrast sensitivity [10–12, 15–28] and spatial resolution [9, 13, 15, 16, 29–32], contrast appearance [33], visual search [34–42], crowding [14, 42–45], and tasks that are thought to recruit higher visual areas such as visual working memory [31].…”

Section: Introductionmentioning

confidence: 99%

“…These polar angle effects can be large. For instance, for a Gabor patch at 4.5° eccentricity with a spatial frequency of 4 cycles per degree, contrast thresholds are close to double for the upper vertical meridian compared to the horizontal meridian [10, 11, 28]. This is an effect size similar to doubling stimulus’ eccentricity from 4.5° to 9° on the horizontal axis [16, 28].…”

Section: Introductionmentioning

confidence: 99%

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Asymmetries around the visual field: From retina to cortex to behavior

Kupers

Benson

Carrasco

et al. 2020

Preprint

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Visual performance varies around the visual field. It is best near the fovea compared to the periphery, and at iso-eccentric locations it is best on the horizontal, intermediate on the lower, and poorest on the upper meridian. The fovea-to-periphery performance decline is linked to the decreases in cone density, retinal ganglion cell (RGC) density, and V1 cortical magnification factor (CMF) as eccentricity increases. The origins of radial asymmetries are not well understood. Optical quality and cone density vary across the retina, but recent computational modeling has shown that these factors can only account for a small percentage of behavior. Here, we investigate how visual processing beyond the cones contributes to radial asymmetries in performance. First, we quantify the extent of asymmetries in cone density, midget RGC density, and V1-V2 CMF. We find that both radial asymmetries and eccentricity gradients are amplified from cones to mRGCs, and from mRGCs to cortex. Second, we extend our previously published computational observer model to quantify the contribution of spatial filtering by mRGCs to behavioral asymmetries. Starting with photons emitted by a visual display, the model simulates the effect of human optics, fixational eye movements, cone isomerizations and mRGC spatial filtering. The model performs a forced choice orientation discrimination task on mRGC responses using a linear support vector machine classifier. The model shows radial asymmetries in performance that are larger than those from a model operating on the cone outputs, but considerably smaller than those observed from human performance. We conclude that spatial filtering properties of mRGCs contribute to radial performance differences, but that a full account of these differences will entail a large contribution from cortical representations.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Asymmetries around the visual field: From retina to cortex to behavior

Kupers

Benson

Carrasco

et al. 2020

Preprint

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Cortical Magnification in Human Visual Cortex Parallels Task Performance around the Visual Field

Benson

Kupers

Barbot

et al. 2020

Preprint

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Human vision has striking radial asymmetries, with performance on many tasks varying sharply as a function of stimulus polar angle. Performance is better on the horizontal than vertical meridian, and on the lower than upper vertical meridian. Here we show that the surface area in human primary visual cortex, measured in 181 subjects, is asymmetrically distributed with a similar pattern, thus indicating a tight link between cortical topography and behavior.

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An image-computable model on how endogenous and exogenous attention differentially alter visual perception

Jigo

Heeger

Carrasco

2021

Preprint

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Attention can facilitate or impair texture segmentation, altering whether objects are isolated from their surroundings in visual scenes. We simultaneously explain several empirical phenomena of texture segmentation and its attentional modulation with a single image-computable model. At the model’s core, segmentation relies on the interaction between sensory processing and attention, with different operating regimes for involuntary and voluntary attention systems. Model comparisons were used to identify computations critical for texture segmentation and attentional modulation. The model reproduced (i) the central performance drop, which is the parafoveal advantage for segmentation over the fovea, (ii) the peripheral improvements and central impairments induced by involuntary attention and (iii) the uniform improvements across eccentricity by voluntary attention. The proposed model reveals distinct functional roles for involuntary and voluntary attention and provides a generalizable quantitative framework for predicting the perceptual impact of attention across the visual field.

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Stimulus-dependent contrast sensitivity asymmetries around the visual field

Cited by 7 publications

References 76 publications

Asymmetries around the visual field: From retina to cortex to behavior

Asymmetries around the visual field: From retina to cortex to behavior

Cortical Magnification in Human Visual Cortex Parallels Task Performance around the Visual Field

An image-computable model on how endogenous and exogenous attention differentially alter visual perception

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