Met Allele of BDNF Gene is Protective Factor Against Age-Related Decline in Left Hemisphere Short-Term Verbal Memory

Since brain-derived neurotrophic factor (BDNF) is crucial for neuroplasticity of adult brain, functional polymorphism Val66Met of the BDNF gene may contribute to cognitive heterogeneity in later life. Initially, the Met allele was considered as “risk” allele due to its role in reducing BDNF release leading to detrimental effects in neurodegenerative diseases. Recently, impact of the Met allele is reconsidered as neuroprotective in aging due to negative effect of Val allele form of proBDNF. We explored whether the Met allele protects against the age-related decline in hemispheric efficacy of short-term verbal memory and whether this effect is moderated by high intellectual environment of professional activity (science vs non-science) in younger (
$\mathrm{N}=251$
, 18-35 years) and high-functional older (
$\mathrm{N}=124$
, 55-80 years) adults. Regardless of intellectual environment, genotypes of the BDNF gene showed different age-associated trends in recall of the right-ear presented words (addressed to the left hemisphere): significant downtrend in Val/Val (younger>older) and no age-related difference in Met carriers. Negative correlation between recalled right- and left-presented words in all groups except older Met-carriers may suggest changed hemispheric communication in the last group. The results bring evidence that the Met allele may act to prevent age-related decline in left hemisphere short-term verbal memory.