The discovery of the pyramidal neurons: Vladimir Betz and a new era of neuroscience

Abstract

As a consequence of nascent technology, the 19th century witnessed a profound change in orientation to the nervous system. For example, improved microscopy in the first half of the 19th century allowed high magnification without blurring. The subsequent observation of nucleated cells led to the identification of individual brain cells. Philosophical changes in approach to the natural sciences took their lead from those applied to physical observations. The Ukrainian anatomist and histologist, Vladimir Alekseyevich Betz (1834-94) played a pivotal role in reshaping scientific and philosophical approaches to the brain, connecting cerebral localization, function and brain microstructure. Betz revolutionized methods of cell fixation and staining. Sometimes his efforts yielded enormously complicated technological improvements. Betz's greatest contribution, however, was connecting his discovery of the function of giant pyramidal neurons of the primary motor cortex ('cells of Betz') with the cortical organization. Considering cortical cytoarchitectonics in relation with physiological function, Betz recognized this organization in two areas: motor and sensory. He defined a functional area on histological grounds and thereby opened the way to study precise cortical areas. Betz participated in the scientific transformation of cytoarchitectonics based on macro- and microscopic studies of the cortical surface, enabling him to view the paths of nerve cells in the brain. Betz's influence allowed systemization of scattered scientific findings. The discovery of pyramidal cells was a turning point in the prevailing philosophical and scientific approach to the brain, linking cytoarchitecture, neurophysiology and cerebral localization.