5-HTTLPR polymorphism of serotonin transporter gene and intellectual environment of professional activity as factors associated with memory changes in aging

Heterogeneity of mental aging is under influence of both genetic and environmental factors. Among the latter, the important role belongs to intellectual activity. The observed relationship of polymorphism 5-HTTLPR serotonin transporter gene with efficiency of cognitive functions and "adaptive" nature of one of its genotypes served as a basis for studying the association of this polymorphism with age-related changes in memory in dependence on the intellectual environment of professional activity. The study involved young and old scientists (Hfl, N = 132) and people not associated with science (HHfl, N = 157). The effectiveness of verbal memory was determined on the base of reported words that were heard in the right and the left ears in dichotic speech test, and on the base of recognition of previously presented syllables; visual memory-on the base of recognition of figures. Regardless of age Hfl subjects showed better verbal memory than HHfl. Higher levels of engagement in mental stimulation in Hfl were associated with less decline of memory for words that were addressed to the left hemisphere. Regardless of other factors carriers S' (S or LG alleles) variant of 5-HTTLPR polymorphism, compared with carries of L/L'(La/La) genotype showed better visual memory. Thus, the initial cognitive potential and engagement in mental stimulation in Hfl contribute to the maintenance of functional activity of the left hemisphere. Visual memory was associated with 5-HTTLPR genotype.