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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

Spatial attention increased BOLD response to cylinders.Icons on the top show a schematic view of the stimulus screen from the perspective of the participant. Left half of figure shows responses to two cylinders compared to a baseline composed of two fields of static zero-disparity dots, with attention directed to the left cylinder. The right half of the figure shows the same conditions with attention directed to the right cylinder. Borders of visual areas (white lines) were defined using standard retinotopic mapping. All data were fully cluster-corrected at p<0.05. The color bar indicates significance levels of activation maps with a z-statistic ranging from 2.3–12. The key gives the orientation of the flat patch in relation to the dorsal, ventral and medial axis. Light gray areas mark gyri, dark gray areas sulci.
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pone-0100074-g002: Spatial attention increased BOLD response to cylinders.Icons on the top show a schematic view of the stimulus screen from the perspective of the participant. Left half of figure shows responses to two cylinders compared to a baseline composed of two fields of static zero-disparity dots, with attention directed to the left cylinder. The right half of the figure shows the same conditions with attention directed to the right cylinder. Borders of visual areas (white lines) were defined using standard retinotopic mapping. All data were fully cluster-corrected at p<0.05. The color bar indicates significance levels of activation maps with a z-statistic ranging from 2.3–12. The key gives the orientation of the flat patch in relation to the dorsal, ventral and medial axis. Light gray areas mark gyri, dark gray areas sulci.

Mentions: Significantly higher BOLD activity in the retinotopic visual cortex was generated by presenting two structure-from-motion cylinders disambiguated by binocular disparity (dSFM) compared to a baseline composed of two fields of static, zero-disparity dots. The focus of spatial attention was directed either to the left or to the right cylinder. Attention selectively increased BOLD responses in cortical regions associated with the attended cylinder. Fig. 2 left column, shows the cortical activation (compared to the baseline) when the left cylinder was attended and the right cylinder was ignored; Fig. 2 right column, shows the activation when the left cylinder was ignored and the right cylinder attended. Data are displayed on the flattened occipital lobes of single subjects with the statistical significance represented by color scale from red to yellow (high significance).


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)

Spatial attention increased BOLD response to cylinders.Icons on the top show a schematic view of the stimulus screen from the perspective of the participant. Left half of figure shows responses to two cylinders compared to a baseline composed of two fields of static zero-disparity dots, with attention directed to the left cylinder. The right half of the figure shows the same conditions with attention directed to the right cylinder. Borders of visual areas (white lines) were defined using standard retinotopic mapping. All data were fully cluster-corrected at p<0.05. The color bar indicates significance levels of activation maps with a z-statistic ranging from 2.3–12. The key gives the orientation of the flat patch in relation to the dorsal, ventral and medial axis. Light gray areas mark gyri, dark gray areas sulci.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0100074-g002: Spatial attention increased BOLD response to cylinders.Icons on the top show a schematic view of the stimulus screen from the perspective of the participant. Left half of figure shows responses to two cylinders compared to a baseline composed of two fields of static zero-disparity dots, with attention directed to the left cylinder. The right half of the figure shows the same conditions with attention directed to the right cylinder. Borders of visual areas (white lines) were defined using standard retinotopic mapping. All data were fully cluster-corrected at p<0.05. The color bar indicates significance levels of activation maps with a z-statistic ranging from 2.3–12. The key gives the orientation of the flat patch in relation to the dorsal, ventral and medial axis. Light gray areas mark gyri, dark gray areas sulci.
Mentions: Significantly higher BOLD activity in the retinotopic visual cortex was generated by presenting two structure-from-motion cylinders disambiguated by binocular disparity (dSFM) compared to a baseline composed of two fields of static, zero-disparity dots. The focus of spatial attention was directed either to the left or to the right cylinder. Attention selectively increased BOLD responses in cortical regions associated with the attended cylinder. Fig. 2 left column, shows the cortical activation (compared to the baseline) when the left cylinder was attended and the right cylinder was ignored; Fig. 2 right column, shows the activation when the left cylinder was ignored and the right cylinder attended. Data are displayed on the flattened occipital lobes of single subjects with the statistical significance represented by color scale from red to yellow (high significance).

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