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Effects of spatial and feature attention on disparity-rendered structure-from-motion stimuli in the human visual cortex.

Ip IB, Bridge H, Parker AJ - PLoS ONE (2014)

Bottom Line: Here we test whether this non-spatial component can co-select individual features that are perceptually bound into a coherent object.Our study used binocular disparity and visual motion to define disparity structure-from-motion (dSFM) stimuli.Our results demonstrate that feature and global feature attention effects are variable across participants, suggesting that the feature attention system may be limited in its ability to automatically select features within the attended object.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, United Kingdom; Nuffield Department of Clinical Neurosciences, The Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford, Oxford, United Kingdom.

ABSTRACT
An important advance in the study of visual attention has been the identification of a non-spatial component of attention that enhances the response to similar features or objects across the visual field. Here we test whether this non-spatial component can co-select individual features that are perceptually bound into a coherent object. We combined human psychophysics and functional magnetic resonance imaging (fMRI) to demonstrate the ability to co-select individual features from perceptually coherent objects. Our study used binocular disparity and visual motion to define disparity structure-from-motion (dSFM) stimuli. Although the spatial attention system induced strong modulations of the fMRI response in visual regions, the non-spatial system's ability to co-select features of the dSFM stimulus was less pronounced and variable across subjects. Our results demonstrate that feature and global feature attention effects are variable across participants, suggesting that the feature attention system may be limited in its ability to automatically select features within the attended object. Careful comparison of the task design suggests that even minor differences in the perceptual task may be critical in revealing the presence of global feature attention.

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Related in: MedlinePlus

Cortical responses to cylinders.A: Cortical responses to cylinders disambiguated by disparity under attended (open) and unattended (filled) conditions compared to a baseline of static dots with zero-disparity. B: Average BOLD response to attended cylinders disambiguated by disparity under clockwise (light gray) and counter-clockwise (dark gray) conditions compared to a baseline of static dots with zero-disparity. C: Average BOLD response to unattended cylinder when rotating in the same (light gray) or different (dark gray) directions to the attended cylinder compared to the baseline. All errors are ± s.e.m. averaged across left and right hemispheres and two scans within participant sessions.
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pone-0100074-g003: Cortical responses to cylinders.A: Cortical responses to cylinders disambiguated by disparity under attended (open) and unattended (filled) conditions compared to a baseline of static dots with zero-disparity. B: Average BOLD response to attended cylinders disambiguated by disparity under clockwise (light gray) and counter-clockwise (dark gray) conditions compared to a baseline of static dots with zero-disparity. C: Average BOLD response to unattended cylinder when rotating in the same (light gray) or different (dark gray) directions to the attended cylinder compared to the baseline. All errors are ± s.e.m. averaged across left and right hemispheres and two scans within participant sessions.

Mentions: The 7 visual areas defined using retinotopy procedures (V1–V3, hV4, V3a/b, V7 and hMT+) were restricted to that part of the cortical area that was activated by a localizer scan which contrasted the response to two ambiguous SFM-cylinders compared to a blank gray screen. The responses to an attended or unattended cylinder compared to a baseline composed of a field of static zero-disparity dots are shown for each of these ROIs in Fig. 3A. A Wilcoxon signed rank test was used to assess areas that had activation greater than baseline. Attended cylinders generated significantly greater activity than baseline in all regions-of-interest. The response to unattended cylinders in V3 and V3a/b was significantly less than the uniform gray screen, whereas in hMT+ the response was significantly greater than baseline (p<0.05, corrected). Comparing attended to unattended activation, using a Wilcoxon matched pairs test, revealed significantly greater responses to the attended stimulus in V2, V3, hV4, V3a/b and V7 (p<0.001, corrected). There was no difference in cortical response between an attended cylinder rotating clockwise or counter-clockwise i.e. in the same or in the opposite direction from the unattended cylinder (Fig. 3B).


Effects of spatial and feature attention on disparity-rendered structure-from-motion stimuli in the human visual cortex.

Ip IB, Bridge H, Parker AJ - PLoS ONE (2014)

Cortical responses to cylinders.A: Cortical responses to cylinders disambiguated by disparity under attended (open) and unattended (filled) conditions compared to a baseline of static dots with zero-disparity. B: Average BOLD response to attended cylinders disambiguated by disparity under clockwise (light gray) and counter-clockwise (dark gray) conditions compared to a baseline of static dots with zero-disparity. C: Average BOLD response to unattended cylinder when rotating in the same (light gray) or different (dark gray) directions to the attended cylinder compared to the baseline. All errors are ± s.e.m. averaged across left and right hemispheres and two scans within participant sessions.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4061053&req=5

pone-0100074-g003: Cortical responses to cylinders.A: Cortical responses to cylinders disambiguated by disparity under attended (open) and unattended (filled) conditions compared to a baseline of static dots with zero-disparity. B: Average BOLD response to attended cylinders disambiguated by disparity under clockwise (light gray) and counter-clockwise (dark gray) conditions compared to a baseline of static dots with zero-disparity. C: Average BOLD response to unattended cylinder when rotating in the same (light gray) or different (dark gray) directions to the attended cylinder compared to the baseline. All errors are ± s.e.m. averaged across left and right hemispheres and two scans within participant sessions.
Mentions: The 7 visual areas defined using retinotopy procedures (V1–V3, hV4, V3a/b, V7 and hMT+) were restricted to that part of the cortical area that was activated by a localizer scan which contrasted the response to two ambiguous SFM-cylinders compared to a blank gray screen. The responses to an attended or unattended cylinder compared to a baseline composed of a field of static zero-disparity dots are shown for each of these ROIs in Fig. 3A. A Wilcoxon signed rank test was used to assess areas that had activation greater than baseline. Attended cylinders generated significantly greater activity than baseline in all regions-of-interest. The response to unattended cylinders in V3 and V3a/b was significantly less than the uniform gray screen, whereas in hMT+ the response was significantly greater than baseline (p<0.05, corrected). Comparing attended to unattended activation, using a Wilcoxon matched pairs test, revealed significantly greater responses to the attended stimulus in V2, V3, hV4, V3a/b and V7 (p<0.001, corrected). There was no difference in cortical response between an attended cylinder rotating clockwise or counter-clockwise i.e. in the same or in the opposite direction from the unattended cylinder (Fig. 3B).

Bottom Line: Here we test whether this non-spatial component can co-select individual features that are perceptually bound into a coherent object.Our study used binocular disparity and visual motion to define disparity structure-from-motion (dSFM) stimuli.Our results demonstrate that feature and global feature attention effects are variable across participants, suggesting that the feature attention system may be limited in its ability to automatically select features within the attended object.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, United Kingdom; Nuffield Department of Clinical Neurosciences, The Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford, Oxford, United Kingdom.

ABSTRACT
An important advance in the study of visual attention has been the identification of a non-spatial component of attention that enhances the response to similar features or objects across the visual field. Here we test whether this non-spatial component can co-select individual features that are perceptually bound into a coherent object. We combined human psychophysics and functional magnetic resonance imaging (fMRI) to demonstrate the ability to co-select individual features from perceptually coherent objects. Our study used binocular disparity and visual motion to define disparity structure-from-motion (dSFM) stimuli. Although the spatial attention system induced strong modulations of the fMRI response in visual regions, the non-spatial system's ability to co-select features of the dSFM stimulus was less pronounced and variable across subjects. Our results demonstrate that feature and global feature attention effects are variable across participants, suggesting that the feature attention system may be limited in its ability to automatically select features within the attended object. Careful comparison of the task design suggests that even minor differences in the perceptual task may be critical in revealing the presence of global feature attention.

Show MeSH
Related in: MedlinePlus