The works provides a morphological analysis of lesions in central upper median reticular nucleus (nucleus raphe) of the midbrain and basal Meinert nucleus in patients with Alzheimer disease. Cytoarchitectonic investigation was performed on the series of 20 microns-thick frontal sections of the brain stained with cresyl violet. The neuronal cross-sectional areas were numerically assessed. Marked individual structural features of these nuclei were characteristic of normals, and not age-related. These structures were largely involved into the Alzheimer disease.