Multivariate Analysis of BOLD Activation Patterns Recovers Graded Depth Representations in Human Visual and Parietal Cortex
Navigating through natural environments requires localizing objects along three distinct spatial axes. Information about position along the horizontal and vertical axes is available from an object’s position on the retina, while position along the depth axis must be inferred based on second-order cu...
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Published in | eNeuro Vol. 6; no. 4; p. ENEURO.0362-18.2019 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Society for Neuroscience
01.07.2019
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Subjects | |
Online Access | Get full text |
ISSN | 2373-2822 2373-2822 |
DOI | 10.1523/ENEURO.0362-18.2019 |
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Summary: | Navigating through natural environments requires localizing objects along three distinct spatial axes. Information about position along the horizontal and vertical axes is available from an object’s position on the retina, while position along the depth axis must be inferred based on second-order cues such as the disparity between the images cast on the two retinae. Past work has revealed that object position in two-dimensional (2D) retinotopic space is robustly represented in visual cortex and can be robustly predicted using a multivariate encoding model, in which an explicit axis is modeled for each spatial dimension. However, no study to date has used an encoding model to estimate a representation of stimulus position in depth. Here, we recorded BOLD fMRI while human subjects viewed a stereoscopic random-dot sphere at various positions along the depth (
z
) and the horizontal (
x
) axes, and the stimuli were presented across a wider range of disparities (out to ∼40 arcmin) compared to previous neuroimaging studies. In addition to performing decoding analyses for comparison to previous work, we built encoding models for depth position and for horizontal position, allowing us to directly compare encoding between these dimensions. Our results validate this method of recovering depth representations from retinotopic cortex. Furthermore, we find convergent evidence that depth is encoded most strongly in dorsal area V3A. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 The authors declare no competing financial interests. This work was supported by National Eye Institute Grants R01-EY025872 (to J.S.) and F32-EY028438 (to T.S.), Thai Red Cross Society funding (C.C.), and the National Science Foundation Graduate Research Fellowships Program (V.V.). M.H. and V.V. authors contributed equally to this work. Author contributions: M.H., V.V., C.C., T.S., and J.S. designed research; M.H., V.V., C.C., and T.S. performed research; M.H. and V.V. analyzed data; M.H. and V.V. wrote the paper. |
ISSN: | 2373-2822 2373-2822 |
DOI: | 10.1523/ENEURO.0362-18.2019 |