A Protocol for Cortical Type Analysis of the Human Neocortex Applied on Histological Samples, the Atlas of Von Economo and Koskinas, and Magnetic Resonance Imaging.

Miguel Ángel García-Cabezas,Julia Liao Hacker,Basilis Zikopoulos

doi:10.3389/fnana.2020.576015

Miguel Ángel García-Cabezas, Julia Liao Hacker + Show 1 more

Open Access

https://doi.org/10.3389/fnana.2020.576015

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Abstract

The human cerebral cortex is parcellated in hundreds of areas using neuroanatomy and imaging methods. Alternatively, cortical areas can be classified into few cortical types according to their degree of laminar differentiation. Cortical type analysis is based on the gradual and systematic variation of laminar features observed across the entire cerebral cortex in Nissl stained sections and has profound implications for understanding fundamental aspects of evolution, development, connections, function, and pathology of the cerebral cortex. In this protocol paper, we explain the general principles of cortical type analysis and provide tables with the fundamental features of laminar structure that are studied for this analysis. We apply cortical type analysis to the micrographs of the Atlas of the human cerebral cortex of von Economo and Koskinas and provide tables and maps with the areas of this Atlas and their corresponding cortical type. Finally, we correlate the cortical type maps with the T1w/T2w ratio from widely used reference magnetic resonance imaging scans. The analysis, tables and maps of the human cerebral cortex shown in this protocol paper can be used to predict patterns of connections between areas according to the principles of the Structural Model and determine their level in cortical hierarchies. Cortical types can also predict the spreading of abnormal proteins in neurodegenerative diseases to the level of cortical layers. In summary, cortical type analysis provides a theoretical and practical framework for directed studies of connectivity, synaptic plasticity, and selective vulnerability to neurologic and psychiatric diseases in the human neocortex.

Highlights

The microscopic structure of the cerebral cortex can be studied in Nissl-stained sections following two different epistemological and theoretical approaches
In the previous sections of this Protocol Paper we describe the laminar features observed in Nissl stained sections that vary systematically across the human neocortex and how to assess these variations qualitatively to categorize cortical types
We suggested that factors that favor synaptic plasticity make Agranular and Dysgranular neocortical areas more flexible and more vulnerable to disease: higher synaptic plasticity implies higher metabolic activity and cellular stress (Garcia-Cabezas et al, 2017)

Summary

Introduction

The microscopic structure of the cerebral cortex can be studied in Nissl-stained sections following two different epistemological and theoretical approaches. The most common approach identifies characteristic cytoarchitectonic features (or a combination of features) that are found in a given part of the cortex and absent in others. Modern studies of cortical areas combine classical cytoarchitecture as examined in Nissl-stained sections with quantitative image analysis, myeloarchitecture, immunohistochemistry, receptor binding, and brain imaging (Amunts and Zilles, 2001, 2015; Zilles and Palomero-Gallagher, 2017; Palomero-Gallagher and Zilles, 2019) and provide detailed atlases of the entire human cerebral cortex that can be used by the neuroscience community (Amunts et al, 2013; Ding et al, 2016)

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