Correspondences between retinotopic areas and myelin maps in human visual cortex

Abstract

We generated probabilistic area maps and maximum probability maps (MPMs) for a set of 18 retinotopic areas previously mapped in individual subjects (Georgieva et al., 2009 and Kolster et al., 2010) using four different inter-subject registration methods. The best results were obtained using a recently developed multimodal surface matching method. The best set of MPMs had relatively smooth borders between visual areas and group average area sizes that matched the typical size in individual subjects. Comparisons between retinotopic areas and maps of estimated cortical myelin content revealed the following correspondences: (i) areas V1, V2, and V3 are heavily myelinated; (ii) the MT cluster is heavily myelinated, with a peak near the MT/pMSTv border; (iii) a dorsal myelin density peak corresponds to area V3D; (iv) the phPIT cluster is lightly myelinated; and (v) myelin density differs across the four areas of the V3A complex. Comparison of the retinotopic MPM with cytoarchitectonic areas, including those previously mapped to the fs_LR cortical surface atlas, revealed a correspondence between areas V1–3 and hOc1–3, respectively, but little correspondence beyond V3. These results indicate that architectonic and retinotopic areal boundaries are in agreement in some regions, and that retinotopy provides a finer-grained parcellation in other regions. The atlas datasets from this analysis are freely available as a resource for other studies that will benefit from retinotopic and myelin density map landmarks in human visual cortex.

Cytoarchitecture of the human lateral occipital cortex: mapping of two extrastriate areas hOc4la and hOc4lp

“…This is in accordance with the present cytoarchitectonic findings, where hOc4la has comparable relationships with areas hOc5 and hOc4v Rottschy et al 2007). This is also found in various functional maps (e.g., Abdollahi et al 2014). Area LO-1 is located anterior to the functionally defined area V3 and ventral to V3A.…”

“…LO-2 but not LO-1 contains objectselective representations (Sayres and Grill-Spector 2008), and LO-2 but not LO-1 overlaps with body part-selective regions (Weiner and Grill-Spector 2011). Comparisons between functional maps and myelin-based contrast detected by MRI indicated a close relation between functional and structural partitioning in many regions of the visual cortex, but also some interesting differences, which require further evaluations of both approaches (Abdollahi et al 2014;Glasser and Van Essen 2011;Glasser et al 2014).…”

“…hOc3d occupies posterior locations to hOc4d. Ventrally, LO-1 abuts cytoarchitectonic areas hOc3v and hOc4v, which overlap with functional areas V3 and hV4, VO1 or phPITv, respectively (Abdollahi et al 2014).…”

Four-dimensional maps of the human somatosensory system

“…Computation was restricted to regions whose overall responsiveness was higher than 10%. These maps were plotted using CARET software (77) (www.nitrc.org/projects/ caret) and directly compared with retinotopic regions in the occipital cortex (72) to confidence ellipses of rostral intraparietal sulcus (78), the most rostral of which corresponds to phAIP, and to cytoarchitectonic sensorimotor regions (79), opercular areas (17), and area 44 (80). The subdivision between dorsal and ventral premotor areas was made according to Tomassini et al (81).…”

The HCP 7T Retinotopy Dataset: Description and pRF Analysis

“…In the 3 field of vision, researchers have successfully exploited functional magnetic resonance imaging (fMRI) to 4 noninvasively measure visual field representations ('retinotopy') in the living human brain (Engel et al, 5 1994;Sereno et al, 1995; DeYoe et al, 1996; Engel et al, 1997). These efforts enable parcellation of 6 visual cortex into distinct maps of the visual field, thereby laying the foundation for detailed investigations 7 of the properties of visual cortex (parcellation references: Abdollahi et al, 2014;Benson et al, 2014; 8 Wang et al, 2015; review references: Tootell et al, 1996;Wandell et al, 2007;Silver and Kastner, 2009; 9 Wandell and Winawer, 2011). One of the datasets acquired by the Human Connectome Project (HCP) 10…”