The Cytoarchitectonic Map of Constantin von Economo and Georg N. Koskinas

Abstract

In 1925 Constantin von Economo (1876–1931) and Georg N. Koskinas (1885–1975), working in the Psychiatric Clinic of Julius Wagner-Jauregg (1857–1940) at the University of Vienna, published their monumental Atlas and Textbook of Cytoarchitectonics of the Adult Human Cerebral Cortex, following in the footsteps of Theodor Meynert (1833–1892) and Korbinian Brodmann (1868–1918). Von Economo and Koskinas provided a much more detailed verbal and pictorial description of the variations in cellular structure (cytoarchitecture) of cerebral cortical layers, compared to Brodmann. By dissecting each gyrus and sulcus perpendicularly to its axis, von Economo and Koskinas successfully addressed the core problem of flattening out the convoluted polyhedral surface of the human cerebral mantle. They defined five structural cortical types (agranular, frontal, parietal, polar, and granulous) and 107 cytoarchitectonic area modifications (35 frontal, 13 limbic, 6 insular, 18 parietal, 7 occipital, 14 temporal, and 14 hippocampal). Their numerous discoveries include the koniocortex, i.e. the dusty appearance of sensory areas, and the identification, at the boundaries of koniocortex with ordinary isocortex in parietal, temporal and occipital areas, of thin bands with giant pyramidal cells, the so-called parasensory zones. Von Economo and Koskinas also provided the first comprehensive description of the distinct rod and corkscrew cells in cingulate and frontoinsular areas known today as “von Economo neurons” that are putatively involved in social behavior and the pathophysiology of neurodevelopmental and mental diseases. The cortical cytoarchitectonics system of von Economo and Koskinas may be especially meaningful in conjunction with modern studies on functional imaging in the human brain.