scholarly journals Cortical Magnification in Human Visual Cortex Parallels Task Performance around the Visual Field

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Noah C Benson ◽  
Eline R Kupers ◽  
Antoine Babot ◽  
Marisa Carrasco ◽  
Jonathan Winawer
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Polar Angle ◽  
Monozygotic Twin ◽  
Human Vision ◽  
Retinal Cell ◽  
Vertical Meridian ◽  
Cortical Magnification ◽  
Cell Densities ◽  
And Behavior

Human vision has striking radial asymmetries, with performance on many tasks varying sharply with stimulus polar angle. Performance is generally better on the horizontal than vertical meridian, and on the lower than upper vertical meridian, and these asymmetries decrease gradually with deviation from the vertical meridian. Here we report cortical magnification at a fine angular resolution around the visual field. This precision enables comparisons between cortical magnification and behavior, between cortical magnification and retinal cell densities, and between cortical magnification in twin pairs. We show that cortical magnification in human primary visual cortex, measured in 163 subjects, varies substantially around the visual field, with a pattern similar to behavior. These radial asymmetries in cortex are larger than those found in the retina, and they are correlated between monozygotic twin pairs. These findings indicate a tight link between cortical topography and behavior, and suggest that visual field asymmetries are partly heritable.

scholarly journals Cortical Magnification in Human Visual Cortex Parallels Task Performance around the Visual Field

2020 ◽  
Author(s):  
Noah C. Benson ◽  
Eline R. Kupers ◽  
Antoine Barbot ◽  
Marisa Carrasco ◽  
Jonathan Winawer
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Polar Angle ◽  
Monozygotic Twin ◽  
Human Vision ◽  
Retinal Cell ◽  
Vertical Meridian ◽  
Cortical Magnification ◽  
Cell Densities ◽  
And Behavior

AbstractHuman vision has striking radial asymmetries, with performance on many tasks varying sharply with stimulus polar angle. Performance is better on the horizontal than vertical meridian, and on the lower than upper vertical meridian, and these asymmetries decrease gradually with deviation from the vertical meridian. Here we report cortical magnification at a fine angular resolution around the visual field. This precision enables comparisons between cortical magnification and behavior, between cortical magnification and retinal cell densities, and between cortical magnification in twin pairs. We show that cortical magnification in human primary visual cortex, measured in 181 subjects, varies around the visual field, with a pattern similar to behavior. We find that these cortical asymmetries are larger than those found in the retina, and that they are correlated between monozygotic twin pairs. These novel findings indicate a tight link between cortical topography and behavior, and suggest that visual field asymmetries are, at least in part, heritable.

scholarly journals Asymmetries in visual acuity around the visual field

2020 ◽  
Author(s):  
Antoine Barbot ◽  
Shutian Xue ◽  
Marisa Carrasco
Keyword(s):  
Visual Acuity ◽  
Visual Field ◽  
Psychometric Function ◽  
Spatial Resolution ◽  
Visual Processing ◽  
Polar Angle ◽  
Angular Distance ◽  
Human Vision ◽  
Gradual Change ◽  
Vertical Meridian

Human vision is heterogeneous around the visual field. At a fixed eccentricity, performance is better along the horizontal than the vertical meridian, and 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 meridians or whether, and how far, they extend into the upper and lower hemifields. Here, we measured visual acuity at isoeccentric peripheral locations (10 deg eccentricity), every 15º of polar angle. On each trial, observers judged the orientation (±45º) of one out of four equidistant, suprathreshold grating stimuli varying in spatial frequency (SF). On each block, we measured performance as a function of stimulus SF at 4 out of 24 isoeccentric locations. We estimated the 75%-correct SF threshold, SF cutoff point (i.e., chance-level) and slope of the psychometric function for each location. We found higher SF estimates –i.e., better acuity– for the horizontal than the vertical meridian, and for the lower than the upper vertical meridian. These asymmetries were most pronounced at the cardinal meridians and decreased gradually as the angular distance from the vertical meridian increased. This gradual change in acuity with polar angle reflected a shift of the psychometric function without changes in slope. The same pattern was found under binocular and monocular viewing conditions. These findings advance our understanding of visual processing around the visual field and help constrain models of visual perception.

scholarly journals Linking individual differences in human V1 to perception around the visual field

2021 ◽  
Author(s):  
Marc Himmelberg ◽  
Jonathan Winawer ◽  
Marisa Carrasco
Keyword(s):  
Individual Differences ◽  
Visual Field ◽  
Contrast Sensitivity ◽  
Polar Angle ◽  
Strongly Correlated ◽  
Ideal Model ◽  
Vertical Meridian ◽  
Perceptual Contrast ◽  
Cortical Magnification ◽  
Ideal Model System

Abstract A central question in neuroscience is how the organization of cortical maps relates to perception, for which human primary visual cortex (V1) is an ideal model system. V1 nonuniformly samples the retinal image, with greater cortical magnification (surface area per degree of visual field) at the fovea than periphery, and at the horizontal than vertical meridian. Moreover, the size and organization of V1 differs greatly across individuals. Here, we used fMRI and psychophysics in the same individuals to quantify individual differences in V1 cortical magnification and perceptual contrast sensitivity at the four polar angle meridians. Across individuals, the overall size of V1 and localized cortical magnification both positively correlated with contrast sensitivity. Moreover, increases in cortical magnification and contrast sensitivity at the horizontal compared to the vertical meridian were strongly correlated. These data reveal a tight link between cortical anatomy and visual perception at the level of individual observer and stimulus location.

scholarly journals Identification of the ventral occipital visual field maps in the human brain

2016 ◽  
Author(s):  
Jonathan Winawer ◽  
Nathan Witthoft
Keyword(s):  
Visual Field ◽  
Human Brain ◽  
Human Subjects ◽  
Polar Angle ◽  
Vertical Meridian ◽  
Retinotopic Mapping ◽  
Collateral Sulcus ◽  
Anatomical Images ◽  
Visual Field Maps ◽  
Magnetic Resonance Imaging Mri

The location and topography of the first three visual field maps in the human brain, V1-V3, are well agreed upon and routinely measured across most laboratories. The position of 4th visual field map, "hV4", is identified with less consistency in the neuroimaging literature. Using magnetic resonance imaging (MRI) data, we describe landmarks to help identify the position and borders of hV4. The data consist of anatomical images, visualized as cortical meshes to highlight the sulcal and gyral patterns, and functional data obtained from retinotopic mapping experiments, visualized as eccentricity and angle maps on the cortical surface. Several features of the functional and anatomical data can be found across nearly all subjects and are helpful for identifying the location and extent of the hV4 map. The medial border of hV4 is shared with the posterior, ventral portion of V3, and is marked by a retinotopic representation of the upper vertical meridian. The anterior border of hV4 is shared with the VO-1 map, and falls on a retinotopic representation of the peripheral visual field, usually coincident with the posterior transverse collateral sulcus. The ventro-lateral edge of the map typically falls on the inferior occipital gyrus, where functional MRI artifacts often obscure the retinotopic data. Finally, we demonstrate the continuity of retinotopic parameters between hV4 and its neighbors; hV4 and V3v contain iso-eccentricity lines in register, whereas hV4 and VO-1 contain iso-polar angle lines in register. Together, the multiple constraints allow for a consistent identification of the hV4 map across most human subjects.

scholarly journals Cross-dataset reproducibility of population receptive field (pRF) estimates and cortical magnification asymmetries

2021 ◽  
Author(s):  
Marc M. Himmelberg ◽  
Jan W. Kurzawski ◽  
Noah C. Benson ◽  
Denis G. Pelli ◽  
Marisa Carrasco ◽  
...  
Keyword(s):  
Visual Field ◽  
Receptive Field ◽  
Large Scale ◽  
Receptive Fields ◽  
Polar Angle ◽  
New York University ◽  
Retinotopic Maps ◽  
Human Connectome Project ◽  
Cortical Magnification ◽  
Size Estimates

AbstractPopulation receptive field (pRF) models fit to fMRI data are used to non-invasively measure retinotopic maps in human visual cortex, and these maps are a fundamental component of visual neuroscience experiments. We examined the reproducibility of retinotopic maps across two datasets: a newly acquired retinotopy dataset from New York University (NYU) (n=44) and a public dataset from the Human Connectome Project (HCP) (n=181). Our goal was to assess the degree to which pRF properties are similar across datasets, despite substantial differences in their experimental protocols. The two datasets differ in stimulus design, participant pool, fMRI protocol, MRI field strength, and preprocessing pipelines. We assessed the cross-dataset reproducibility of the two datasets in terms of the similarity of vertex-wise pRF estimates and in terms of large-scale cortical magnification properties. Within V1, V2, V3, and hV4, the group-median NYU and HCP vertex-wise polar angle estimates were nearly identical. Both eccentricity and pRF size estimates were also strongly correlated between the two datasets, but with a slope different from 1; the eccentricity and pRF size estimates were systematically greater in the NYU data. Next, to compare large-scale map properties, we quantified two polar angle asymmetries in V1 cortical magnification previously identified in the HCP data. The prior work reported more cortical surface area representing the horizontal than vertical visual field meridian, and the lower than upper vertical visual field meridian. We confirm both of these results in the NYU dataset. Together, our findings show that the retinotopic properties of V1-hV4 can be reliably measured between two datasets, despite numerous differences in their experimental design. fMRI-derived retinotopic maps are reproducible because they rely on an explicit computational model that is grounded in physiological evidence of how visual receptive fields are organized, allowing one to quantitatively characterize the BOLD signal in terms of stimulus properties (i.e., location and size). The new NYU Retinotopy Dataset will serve as a useful benchmark for testing hypotheses about the organization of visual areas and for comparison to the HCP Retinotopy Dataset.

scholarly journals Aberrant Visual Population Receptive Fields in Human Albinism

2019 ◽  
Author(s):  
Ethan J. Duwell ◽  
Erica N. Woertz ◽  
Jedidiah Mathis ◽  
Joseph Carroll ◽  
Edgar A. DeYoe
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Spatial Information ◽  
Receptive Fields ◽  
Visual Space ◽  
Mirror Image ◽  
Visual Responses ◽  
Central Visual Field ◽  
Vertical Meridian ◽  
The Right

ABSTRACTRetinotopic organization is a fundamental feature of visual cortex thought to play a vital role in encoding spatial information. One important aspect of normal retinotopy is the representation of the right and left hemifields in contralateral visual cortex. However, in human albinism, many temporal retinal afferents decussate pathologically at the optic chiasm resulting in partially superimposed representations of opposite hemifields in each hemisphere of visual cortex. Previous fMRI studies in human albinism suggest that the right and left hemifield representations are superimposed in a mirror-symmetric manner. This should produce imaging voxels which respond to two separate regions in visual space mirrored across the vertical meridian. However, it is not yet clear how retino-cortical miswiring in albinism manifests at the level of single voxel population receptive fields. Here we used fMRI retinotopic mapping in conjunction with population receptive field (pRF) modeling to fit both single and dual pRF models to the visual responses of voxels in visual areas V1-V3 of five subjects with albinism. We found that subjects with albinism (but not controls) have sizable clusters of voxels with dual pRFs consistently corresponding to, but not fully coextensive with regions of hemifield overlap. These dual pRFs were typically positioned at roughly mirror image locations across the vertical meridian but were uniquely clustered within the visual field for each subject. We also found that single pRFs are larger in albinism than controls, and that single pRF sizes in the central visual field were anti-correlated with subjects’ foveal cone densities. Finally, dual pRF and aberrant hemifield representation characteristics varied significantly across subjects with albinism suggesting more central heterogeneity than previously appreciated.

A Formal Mapping Model for Striate Cortex

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 29-29
Author(s):  
J von Berg
Keyword(s):  
Visual Field ◽  
Striate Cortex ◽  
Ocular Dominance ◽  
Mapping Function ◽  
Brain Structures ◽  
Imaging Results ◽  
Cortical Magnification ◽  
Cell Densities ◽  
Point To Point ◽  
Neural Maps

Cortical magnification has been measured with different techniques in many primates, including humans. The most popular models assume a value reciprocal to eccentricity, and are therefore rotation symmetric. To simulate the location of a projected stimulus, a real mapping function is needed. We use the complex logarithm log( z+ a)—introduced for this purpose by Schwartz (1977 Biological Cybernetics25 181 – 194), which is close to recent brain imaging results in humans and macaque monkeys. The model contradicts the idea of symmetric magnification and the linear model implicitly used by most anatomists. Our model gives a quantitative correspondence from visual field to striate cortex and vice versa, which we use to relate topology and geometry of cortical structures such as ocular dominance stripes, orientation fields, and cytochrome oxidase blobs in V1 to the visual field. This model may serve to relate empirical knowledge about spatial properties of these brain structures to psychophysical stimulus arrangements. Together with the description of cell densities, the point-to-point (and thus simplified) model may be used as a basis for formalising convergence and divergence properties of connections in neural maps.

Two-Dimensional Mapping of the Central and Parafoveal Visual Field to Human Visual Cortex

2007 ◽  
Vol 97 (6) ◽  
pp. 4284-4295 ◽  
Author(s):  
Mark M. Schira ◽  
Alex R. Wade ◽  
Christopher W. Tyler
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Visual Processing ◽  
Visual Space ◽  
Two Dimensional ◽  
Local Anisotropy ◽  
Fitting Procedures ◽  
Early Visual Cortex ◽  
Cortical Magnification ◽  
Dimensional Mapping

Primate visual cortex contains a set of maps of visual space. These maps are fundamental to early visual processing, yet their form is not fully understood in humans. This is especially true for the central and most important part of the visual field—the fovea. We used functional magnetic resonance imaging (fMRI) to measure the mapping geometry of human V1 and V2 down to 0.5° of eccentricity. By applying automated atlas fitting procedures to parametrize and average retinotopic measurements of eight brains, we provide a reference standard for the two-dimensional geometry of human early visual cortex of unprecedented precision and analyze this high-quality mean dataset with respect to the 2-dimensional cortical magnification morphometry. The analysis indicates that 1) area V1 has meridional isotropy in areal projection: equal areas of visual space are mapped to equal areas of cortex at any given eccentricity. 2) V1 has a systematic pattern of local anisotropies: cortical magnification varies between isopolar and isoeccentricity lines, and 3) the shape of V1 deviates systematically from the complex-log model, the fit of which is particularly poor close to the fovea. We therefore propose that human V1 be fitted by models based on an equal-area principle of its two-dimensional magnification. 4) V2 is elongated by a factor of 2 in eccentricity direction relative to V1 and has significantly more local anisotropy. We propose that V2 has systematic intrinsic curvature, but V1 is intrinsically flat.

scholarly journals Geometry and Geodesy on the Primary Visual Cortex as a Surface of Revolution

2020 ◽  
Vol 25 (4) ◽  
pp. 64
Author(s):  
Lorenzo G. Resca ◽  
Nicholas A. Mecholsky
Keyword(s):  
Differential Geometry ◽  
Visual Cortex ◽  
Visual Field ◽  
Eye Movement ◽  
Primary Visual Cortex ◽  
Three Dimensional ◽  
Dimensional Euclidean Space ◽  
Surface Of Revolution ◽  
Magnification Factors ◽  
Cortical Magnification

Biological mapping of the visual field from the eye retina to the primary visual cortex, also known as occipital area V1, is central to vision and eye movement phenomena and research. That mapping is critically dependent on the existence of cortical magnification factors. Once unfolded, V1 has a convex three-dimensional shape, which can be mathematically modeled as a surface of revolution embedded in three-dimensional Euclidean space. Thus, we solve the problem of differential geometry and geodesy for the mapping of the visual field to V1, involving both isotropic and non-isotropic cortical magnification factors of a most general form. We provide illustrations of our technique and results that apply to V1 surfaces with curve profiles relevant to vision research in general and to visual phenomena such as ‘crowding’ effects and eye movement guidance in particular. From a mathematical perspective, we also find intriguing and unexpected differential geometry properties of V1 surfaces, discovering that geodesic orbits have alternative prograde and retrograde characteristics, depending on the interplay between local curvature and global topology.

scholarly journals Identification of the ventral occipital visual field maps in the human brain

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 1526 ◽  
Author(s):  
Jonathan Winawer ◽  
Nathan Witthoft
Keyword(s):  
Visual Field ◽  
Human Brain ◽  
Human Subjects ◽  
Polar Angle ◽  
Imaging Data ◽  
Vertical Meridian ◽  
Retinotopic Mapping ◽  
Collateral Sulcus ◽  
Anatomical Images ◽  
Visual Field Maps

The location and topography of the first three visual field maps in the human brain, V1-V3, are well agreed upon and routinely measured across most laboratories. The position of 4th visual field map, ‘hV4’, is identified with less consistency in the neuroimaging literature.  Using magnetic resonance imaging data, we describe landmarks to help identify the position and borders of ‘hV4’. The data consist of anatomical images, visualized as cortical meshes to highlight the sulcal and gyral patterns, and functional data obtained from retinotopic mapping experiments, visualized as eccentricity and angle maps on the cortical surface. Several features of the functional and anatomical data can be found across nearly all subjects and are helpful for identifying the location and extent of the hV4 map. The medial border of hV4 is shared with the posterior, ventral portion of V3, and is marked by a retinotopic representation of the upper vertical meridian. The anterior border of hV4 is shared with the VO-1 map, and falls on a retinotopic representation of the peripheral visual field, usually coincident with the posterior transverse collateral sulcus. The ventro-lateral edge of the map typically falls on the inferior occipital gyrus, where functional MRI artifacts often obscure the retinotopic data. Finally, we demonstrate the continuity of retinotopic parameters between hV4 and its neighbors; hV4 and V3v contain iso-eccentricity lines in register, whereas hV4 and VO-1 contain iso-polar angle lines in register. Together, the multiple constraints allow for a consistent identification of the hV4 map across most human subjects.

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