Abstract <p>The olfactory analyzer is a relatively simple, but important part of the nervous system for realization of many mental functions, the studies of which can significantly deepen knowledge about molecular mechanisms of chemical reception, regulation of gene expression, formation of new neurons, and development of neural networks in the mature brain, as well as about the pathogenesis of neurodegenerative and mental disorders. The article considers the structure and functions of the olfactory tubercle, diagonal band of Broca, and nucleus basalis of Meynert located within the so-called olfactory cortex. Based on numerous literary data, it was demonstrated that despite a relatively simple neural structure, all three these structures are involved in the mechanisms of the most complex mental functions, and the zone of their location is a kind of anatomical bridge between the anterior cingulate and anterior insular cortex, the significance of which in the mental process is difficult to overestimate. Along with the consideration of these issues, the article reveals a historical priority of Volodymyr Betz in the cytoarchitectonic description of the olfactory tubercle. It was also demonstrated that the work of V. Betz can contain information about the structure of the diagonal band and nucleus basalis, previously discovered by P. Broca and T. Meynert, respectively. Consequently, taking into account a significance of the considered part of the brain, cytoarchitectonic data V. Betz on the structure of the olfactory tubercle and adjacent structures can be considered no less important than his other observations recognized by a professional community.</p>