Cytoarchitectonic Observations of Volodymyr Betz Contextual to Modern Concept of the Brain Modular Organization

Modern neurobiology is based on a neuron doctrine, recognizing a network of nerve cells organized into numerous spatial and/or functional clusters (modules) as the main substrate of brain function. A concept of columnar organization of the cortex, the emergence of which is associated with the idea of a vertical cortical cylinder and a number of complementary cytoarchitectonic, electrophysiological, and neuroontogenetic data, is the best-known illustration of such a structural principle. The proposed article provides the results of cytoarchitectonic observations of Volodymyr Betz that, from the point of view of modernity, illustrate a modular principle of brain organization. Particularly, it is emphasized that Betz provided the first description of “bundling” of apical dendrites of cortical pyramidal neurons (one of the key morphological traits of modular structure of the brain). It is also noted that Betz first described entorhinal islands (another example of a widespread modular organization of the cortex). Finally, the authors mention a pioneering statement of Betz regarding the cluster arrangement of giant pyramidal neurons in the primary motor cortex. Thus, the list of the above-mentioned scientific achievements of Betz, consistent with the idea of modular organization of the brain, includes the description of three cytoarchitectonic phenomena of the human cerebral cortex and the macroscopic counterpart of one of them (entorhinal tuberosity).