Attention alters spatial resolution by modulating second-order processing

Jigo, Michael; Carrasco, Marisa

doi:10.1167/18.7.2

Cited by 20 publications

(68 citation statements)

References 65 publications

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“…On the other half of trials, a 100% Valid precue was displayed consisting of a white integer (0-3) and a single line to the right or left of the number. Similar to previous studies (Barbot & Carrasco, 2017;Jigo & Carrasco, 2018;Yeshurun, Montagna, et al, 2008), the line indicated which hemifield the target would appear and the number indicated the target's eccentricity: 0 represented the fovea and 1 through 3 indicated eccentric locations 3°, 6°, and 12°respectively. For foveal targets, no lines were presented with the Valid precue.…”

Section: Endogenous Attention Conditionmentioning

confidence: 58%

“…The perceptual consequences of exogenous attention's automaticity have been demonstrated in texture segmentation tasks, which are constrained by spatial resolution (for reviews see, Anton-Erxleben & Carrasco, 2013 ; Carrasco & Barbot, 2014 ; Carrasco & Yeshurun, 2009 ). In these tasks, directing exogenous attention leads to an automatic increase in spatial resolution that improves performance for targets in the periphery where resolution is low but impairs performance near the fovea where resolution is already too high for the target ( Carrasco et al, 2006 ; Jigo & Carrasco, 2018 ; Talgar & Carrasco, 2002 ; Yeshurun, Montagna, et al, 2008 ; Yeshurun & Carrasco, 1998 ; Yeshurun & Carrasco, 2000 ). These impairments caused by valid exogenous cues are unique to texture segmentation tasks, which are characterized by a central performance drop, and have been attributed to an automatic and specific enhancement of contrast sensitivity to high SFs ( Carrasco et al, 2006 ).…”

Section: Discussionmentioning

confidence: 99%

“…Texture segmentation tasks also provide a unique perspective into the flexibility of endogenous attention. When observers direct endogenous attention in these tasks, performance is improved at all eccentricities (Barbot & Carrasco, 2017;Jigo & Carrasco, 2018;Yeshurun, Montagna, et al, 2008). This has been attributed to endogenous attention increasing spatial resolution in the periphery by enhancing contrast sensitivity to high SFs, and decreasing resolution near the fovea by suppressing contrast sensitivity to high SFs (Barbot & Carrasco, 2017).…”

Section: Visual Perception Is Modulated Inflexibly By Exogenous Attenmentioning

confidence: 98%

“…Endogenous attention operates on longer time-scales (≥ 300 ms), is deployed voluntarily, and can be sustained at a location specified by a symbolic cue (for reviews see, Carrasco, 2006 ; Carrasco, 2011 ; Carrasco, 2014 ; Carrasco & Barbot, 2014 ). Both types of attention are associated with partially overlapping cortical networks (e.g., Beck & Kastner, 2009 ; Corbetta & Shulman, 2002 ; Dugué, Merriam, Heeger, & Carrasco, 2018 ) and often have similar effects on visual perception, but can differ ( Barbot et al, 2012 ; Hein, Rolke, & Ulrich, 2006 ; Jigo & Carrasco, 2018 ; Sharp et al, 2018 ; Yeshurun, Montagna, Carrasco, 2008 ; Yeshurun & Levy, 2003 ).…”

Section: Introductionmentioning

confidence: 99%

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Differential impact of exogenous and endogenous attention on the contrast sensitivity function across eccentricity

2020

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Both exogenous and endogenous covert spatial attention enhance contrast sensitivity, a fundamental measure of visual function that depends substantially on the spatial frequency and eccentricity of a stimulus. Whether and how each type of attention systematically improves contrast sensitivity across spatial frequency and eccentricity are fundamental to our understanding of visual perception. Previous studies have assessed the effects of spatial attention at individual spatial frequencies and, separately, at different eccentricities, but this is the first study to do so parametrically with the same task and observers. Using an orientation discrimination task, we investigated the effect of attention on contrast sensitivity over a wide range of spatial frequencies and eccentricities. Targets were presented alone or among distractors to assess signal enhancement and distractor suppression mechanisms of spatial attention. At each eccentricity, we found that exogenous attention preferentially enhanced spatial frequencies higher than the peak frequency in the baseline condition. In contrast, endogenous attention similarly enhanced a broad range of lower and higher spatial frequencies. The presence or absence of distractors did not alter the pattern of enhancement by each type of attention. Our findings reveal how the two types of covert spatial attention differentially shape how we perceive basic visual dimensions across the visual field.

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Section: Endogenous Attention Conditionmentioning

confidence: 58%

Section: Discussionmentioning

confidence: 99%

Section: Visual Perception Is Modulated Inflexibly By Exogenous Attenmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Differential impact of exogenous and endogenous attention on the contrast sensitivity function across eccentricity

2020

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“…Our findings also relate to texture segmentation tasks, in which performance is constrained by the spatial resolution of the visual system and the scale of the texture target: Performance peaks at mid-eccentricity, where resolution is optimal for the scale of the texture target, and drops at more peripheral locations where resolution is too low and at more foveal locations where resolution is too high (Barbot & Carrasco, 2017;Carrasco & Barbot, 2014;Carrasco, Loula & Ho, 2006;Gurnsey, Pearson & Day, 1996;Jigo & Carrasco, 2018;Morikawa, 2000;Talgar & Carrasco, 2002;Yeshurun & Carrasco, 1998, 2000Yeshurun, Montagna & Carrasco, 2008). Modulating the contribution of either high SFs or low SFs affects texture-segmentation performance in a manner consistent with resolution changes: selectively removing high SFs from the stimulus display eliminates the CPD (Morikawa, 2000).…”

Section: Discussionmentioning

confidence: 71%

Asymmetries in visual acuity around the visual field

Barbot¹,

Xue²,

Carrasco³

2020

Preprint

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Human vision is heterogeneous across the visual field. At a fixed eccentricity, performance is better along the horizontal than the vertical meridian, and better along the lower than the upper vertical meridian. These asymmetric patterns, termed performance fields, have been found in numerous visual tasks, including those mediated by contrast sensitivity and spatial resolution. However, it is unknown whether spatial resolution asymmetries are confined to the cardinal meridia or whether, and how far, they extend into the upper and lower hemifields. Here, we measured the extent of the vertical meridian asymmetry by assessing spatial frequency (SF) sensitivity at isoeccentric peripheral locations (10 degree eccentricity), every 15º of polar angle. On each trial, observers judged the orientation (±45º) of a suprathreshold grating stimulus varying in spatial frequency. We estimated 75%-correct SF thresholds, SF cutoff points (i.e., chance-level) and slopes of the psychometric function for each of the 24 isoeccentric locations. We found higher SF sensitivity in the lower than the upper hemifield, with this asymmetry being most pronounced at the vertical meridian and decreasing gradually as the angular distance from the vertical meridian increased. This gradual change in SF sensitivity with polar angle reflected a shift of the psychometric function without reliable changes in slope. The same pattern was found under binocular and monocular conditions. These findings advance our understanding of visual processing around the visual field and help constrain models of visual perception.

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Spatial attention alters visual appearance

Carrasco

Barbot

2019

Current Opinion in Psychology

108

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Does attention alter appearance? This critical issue, debated for over a century, remains unsettled. From psychophysical evidence that covert attention affects early vision-it enhances contrast sensitivity and spatial resolution-and from neurophysiological evidence that attention increases the neuronal contrast sensitivity (contrast gain), one could infer that attention changes stimulus appearance. Surprisingly, few studies have directly investigated this issue. Here we developed a psychophysical method to directly assess the phenomenological correlates of attention in humans. We show that attention alters appearance; it boosts the apparent stimulus contrast. These behavioral results are consistent with neurophysiological findings suggesting that attention changes the strength of a stimulus by increasing its 'effective contrast' or salience. At any given moment, our visual system is confronted with far more information than it can process effectively. The high energy cost of neuronal activity involved in cortical computation severely limits our capacity to process this information 1. Visual attention serves as a mediating mechanism, enabling us to selectively grant priority of processing to certain aspects of the visual scene. One means of granting priority is to direct one's gaze towards the relevant location. However, many situations call for one to attend to an area in the periphery without actually directing gaze toward it. For example, when driving it is generally best to keep your eyes on the road ahead while covertly monitoring the periphery for cars, pedestrians and potential road hazards. The impact of covert attention 2 on visual performance is well-documented across a range of perceptual tasks, such as visual search 3-6 , letter identification 7,8 , contrast sensitivity 9-12 and spatial resolution 13-16. Several studies that used single-cell recording 17-22 , event-related potentials 23,24 and functional magnetic resonance imaging (fMRI) 25-27 indicate that attentional modulation occurs as early as striate and extrastriate visual cortex. Transient attention, a type of covert attention, is the stimulus-driven, reflexive capture of attention by an abrupt, salient peripheral cue 3-6,8-10,13-16,28-30. For example, a ball rolling out into the street instantly grabs one's transient attention, improving discriminability 8-16 and speeding information processing 3,4 , enabling one to make a better and faster judgment of whether to swerve away. Explanations of how attention improves performance range from claims that the deployment of attention affects processing at the decisional level 9-11,31,32 , to claims that attention actually enhances perceptual sensitivity 2-6,8-16. At the perceptual level, two prominent models have been proposed: signal enhancement

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Attention alters spatial resolution by modulating second-order processing

Cited by 20 publications

References 65 publications

Differential impact of exogenous and endogenous attention on the contrast sensitivity function across eccentricity

Differential impact of exogenous and endogenous attention on the contrast sensitivity function across eccentricity

Asymmetries in visual acuity around the visual field

Spatial attention alters visual appearance

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