Distribution of cytochrome oxidase-rich patches in human primary visual cortex

Marco Marcondes, Marcello G.P. Rosa, Mario Fiorani, Bruss Lima, Ricardo Gattass

Research output: Contribution to journalArticleResearchpeer-review

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/mm2 in the foveal representation to 0.6 patch/mm2 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 mm2, with a mean value of 0.32 mm2. 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.

Original languageEnglish
Pages (from-to)614-624
Number of pages11
JournalThe Journal of Comparative Neurology
Volume527
Issue number3
DOIs
Publication statusPublished - 15 Feb 2019

Keywords

  • Blob
  • Cytochrome oxidase
  • Modular organization
  • Patches
  • Striate cortex
  • V1

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