A common genetic variation in the BDNF gene (Val66Met) affects how the brain releases BDNF, and people with this variation tend to have worse memory performance, especially for verbal and spatial tasks.

Source Excerpt

“In the human BDNF gene, a common single nucleotide polymorphism identified with a Met to Val substitution at codon 66 in the pro-domain of BDNF, called rs6265 or Val66Met polymorphism, affects synaptic targeting of BDNF-containing vesicles and activity-dependent neuronal release of BDNF. Met66 homozygous knock-in mice showed a selective impairment in activity-dependent synaptic plasticity in vitro. Additionally, exogenous application of proBDNF in Val-carriers facilitated LTD and inhibited LTP, while not in Met carriers. Because of its frequency in the human population [up to 30% Met carriers in a European sample ] and its association with lower serum levels of BDNF, this single nucleotide polymorphism has been a matter of great interest. This polymorphism has been associated with structural and functional differences in the brain, such as synaptic plasticity and memory performance. Some of these structural changes include volumetric decreases in specific regions -such as the hippocampus, the parahippocampal gyrus, the prefrontal cortex and the amygdala -. The presence of the Met allele is, in turn, associated with poor mnemonic performance on verbal tasks both at short and long delays and also deficits in working and spatial memory tasks.”