Distribution of cytochrome oxidase‐rich patches in human primary visual cortex. Issue 3 (16th April 2018)

• Record Type: Journal Article
• Authors: Marcondes, Marco; Rosa, Marcello G.P.; Fiorani, Mario; Lima, Bruss; Gattass, Ricardo
• Is Part Of: Journal of comparative neurology. Volume 527:Issue 3(2019)
• Page Start: 614
• Page End: 624
• Publication Date: 2018-04-16
• Subjects: blob -- cytochrome oxidase -- modular organization -- patches -- striate cortex -- V1; Comparative neurobiology -- Periodicals; Neurology -- Periodicals; 616
• DOI: 10.1002/cne.24435
• Languages: English
• ISSNs: 0021-9967

Abstract

Abstract: We studied the tangential distribution of cytochrome oxidase (CytOx)‐rich patches (blobs) in the striate cortex (V1) of normally sighted Homo sapiens . We analyzed the spatial density and cross‐sectional area of patches in CytOx‐reacted tangential sections of flat‐mounted preparations of V1 and surrounding areas. CytOx‐rich patches were most clearly defined in the supragranular cortical layers of V1, particularly at middle levels of layer III. Variations in patch spatial density were subtle across different visual eccentricity representations. Within the binocular representation of V1, the average patch spatial density decreased slightly with increasing cortical eccentricity, from around 1.0 patch/mm 2 in the foveal representation to 0.6 patch/mm 2 at the representation of ∼60° eccentricity, but seemed to increase again at the representation of the monocular crescent. Across the entire sample, the cross‐sectional area of patches (i.e., patch size) varied from approximately 0.2–0.8 mm 2, with a mean value of 0.32 mm 2 . Notably, there was no significant variation in the mean patch size across eccentricity representations. Human patches are on average larger than those reported for nonhuman primate brains, and analysis of species with different brain sizes suggests an approximately linear relationship between V1 area and patch size. The relative constancy of patch metrics across eccentricities is in stark contrast with the exponential variation in V1 cortical magnification, suggesting a nearly invariant modular organization throughout human V1. Abstract : Human patch profile across V1 cortical layers. Photomicrograph of a coronal section through the calcarine fissure stained for CytOx. Patches (shown by arrow heads) are most evident in layers II and III of V1, especially in the middle of layer III. The overlain diagram at the bottom indicates the location and thickness of the cortical layers. The asterisk labels layer IVa.