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Author

Brian A. Wandell

Other affiliations: PARC, Hewlett-Packard, University of California, Irvine  ...read more
Bio: Brian A. Wandell is an academic researcher from Stanford University. The author has contributed to research in topics: Visual cortex & Visual system. The author has an hindex of 83, co-authored 341 publications receiving 28529 citations. Previous affiliations of Brian A. Wandell include PARC & Hewlett-Packard.


Papers
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Journal ArticleDOI
TL;DR: This work identified the borders between several retinotopically organized visual areas in the posterior occipital lobe and estimated the spatial resolution of the fMRI signal and found that signal amplitude falls to 60% at a spatial frequency of 1 cycle per 9 mm of visual cortex.
Abstract: A method of using functional magnetic resonance imaging (fMRI) to measure retinotopic organization within human cortex is described. The method is based on a visual stimulus that creates a traveling wave of neural activity within retinotopically organized visual areas. We measured the fMRI signal caused by this stimulus in visual cortex and represented the results on images of the flattened cortical sheet. We used the method to locate visual areas and to evaluate the spatial precision of fMRI. Specifically, we: (i) identified the borders between several retinotopically organized visual areas in the posterior occipital lobe; (ii) measured the function relating cortical position to visual field eccentricity within area V1; (iii) localized activity to within 1.1 mm of visual cortex; and (iv) estimated the spatial resolution of the fMRI signal and found that signal amplitude falls to 60% at a spatial frequency of 1 cycle per 9 mm of visual cortex. This spatial resolution is consistent with a linespread whose full width at half maximum spreads across 3.5 mm of visual cortex. In a series of experiments, we measured the retinotopic organization of human cortical area V1 and identified the locations of other nearby retinotopically organized visual areas. We also used the retinotopic organization of human primary visual cortex to measure the spatial localization and spatial resolution that can be obtained from functional magnetic resonance imaging (fMRI) of human visual cortex. Human primary visual cortex (area V1) is located in the

1,585 citations

Journal ArticleDOI
TL;DR: The current understanding of the causal relationships between neural activity and the blood-oxygen-level-dependent (BOLD) signal is described, and how these analyses have challenged some basic assumptions that have guided neuroscience are reviewed.
Abstract: The development of functional magnetic resonance imaging (fMRI) has brought together a broad community of scientists interested in measuring the neural basis of the human mind. Because fMRI signals are an indirect measure of neural activity, interpreting these signals to make deductions about the nervous system requires some understanding of the signaling mechanisms. We describe our current understanding of the causal relationships between neural activity and the blood-oxygen-level-dependent (BOLD) signal, and we review how these analyses have challenged some basic assumptions that have guided neuroscience. We conclude with a discussion of how to use the BOLD signal to make inferences about the neural signal.

1,513 citations

Book
01 Jan 1995
TL;DR: In Foundations of Vision as mentioned in this paper, Wandell divides the study of vision into three parts: encoding, representation, and interpretation, and each part is designed to inform students on vision.
Abstract: Originally published in Contemporary Psychology: APA Review of Books, 1997, Vol 42(7), 649-649. In Foundations of Vision (see record 1995-98050-000), Brian Wandell divides the study of vision into three parts: encoding, representation, and interpretation. Each part is designed to inform students on

1,312 citations

Journal ArticleDOI
25 Oct 2007-Neuron
TL;DR: Recent measurements of human visual field maps are surveyed, hypotheses about the function and relationships between maps are described, and methods to improve map measurements and characterize the response properties of neurons comprising these maps are considered.

1,104 citations

Journal ArticleDOI
TL;DR: The pRF method is non-invasive and can be applied to a wide range of conditions when it is useful to link fMRI signals in the visual pathways to neuronal receptive fields, and the visual field maps obtained are more accurate than those obtained using conventional visual field mapping.

1,076 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, a structural similarity index is proposed for image quality assessment based on the degradation of structural information, which can be applied to both subjective ratings and objective methods on a database of images compressed with JPEG and JPEG2000.
Abstract: Objective methods for assessing perceptual image quality traditionally attempted to quantify the visibility of errors (differences) between a distorted image and a reference image using a variety of known properties of the human visual system. Under the assumption that human visual perception is highly adapted for extracting structural information from a scene, we introduce an alternative complementary framework for quality assessment based on the degradation of structural information. As a specific example of this concept, we develop a structural similarity index and demonstrate its promise through a set of intuitive examples, as well as comparison to both subjective ratings and state-of-the-art objective methods on a database of images compressed with JPEG and JPEG2000. A MATLAB implementation of the proposed algorithm is available online at http://www.cns.nyu.edu//spl sim/lcv/ssim/.

40,609 citations

Journal ArticleDOI
TL;DR: In this article, a visual attention system inspired by the behavior and the neuronal architecture of the early primate visual system is presented, where multiscale image features are combined into a single topographical saliency map.
Abstract: A visual attention system, inspired by the behavior and the neuronal architecture of the early primate visual system, is presented. Multiscale image features are combined into a single topographical saliency map. A dynamical neural network then selects attended locations in order of decreasing saliency. The system breaks down the complex problem of scene understanding by rapidly selecting, in a computationally efficient manner, conspicuous locations to be analyzed in detail.

10,525 citations

Journal ArticleDOI
TL;DR: A set of automated procedures for obtaining accurate reconstructions of the cortical surface are described, which have been applied to data from more than 100 subjects, requiring little or no manual intervention.

9,599 citations

01 Jan 1998
TL;DR: A visual attention system, inspired by the behavior and the neuronal architecture of the early primate visual system, is presented, which breaks down the complex problem of scene understanding by rapidly selecting conspicuous locations to be analyzed in detail.

8,566 citations