<p>Heterogeneity of mental aging is largely determined by the interaction of environmental and genetic factors. Our previous work on the analysis of age-related changes in the global power of the background EEG showed that only elderly subjects displayed differences associated with the STin2VNTR polymorphism of the serotonin transporter gene and training due to the intellectual saturation of the professional environment (comparison of scientists (Sc) and people whose work was not associated with professional scientific activity (non-scientists, NSc)). In the case of slow rhythms, the greatest differences were observed between homozygous genotypes, with the lowest power values in elderly NSc in the 10/10 genotype group, and in the Sc in the 12/12 group. The aim of the present study was to determine the spatial pattern of current source density (CSD) underlying the power decreases identified in the 10/10 NSc and 12/12 Sc genotypes. The study involved elderly subjects (55–80 years; 38 Sc and 39 NSc). Voxel-by-voxel analysis using eLORETA showed no local features of the decrease in CSD for the 10/10 NSc genotype compared to 12/12 NSc genotype. Thus, the previously noted decrease in slow rhythm power in the 10/10 NSc group is apparently due to a unidirectional diffuse decrease in different areas of the cerebral cortex. In contrast, in carriers of the 12/12 Sc genotype as compared with carriers of the 10/10 Sc genotype, differentiated spatial patterns of decreases in CSD were found at the frequency of the δ rhythm mainly in the precuneus cortex and the inferior and superior parietal lobule of the left hemisphere and, at the frequencies of the α2 and α3 rhythm, in the precuneus cortex and the superior parietal lobule of the right hemisphere. These data may indicate the occurrence of adaptive reorganization of neural networks in elderly scientists carrying the 12/12 genotype associated with cognitive training.</p>