Differential effects of BDNF val66met in repetitive associative learning paradigms

• BDNF val66met influence on associative learning was tested in two learning domains.
• Met carrier benefitted more from repetitive vocabulary training.
• This was paralleled by a higher reduction of delayed answers.
• This effect was similar in a haptic training, but not for elder subjects.
• BDNF val66met might have differential effects depending on the behavioural task.

In healthy young subjects, the brain derived neurotropic factor (BDNF) val66met polymorphism negatively affects behavioural outcome in short-term motor cortex or hippocampus-based learning paradigms. In repetitive training paradigms over several days this effect can be overcome, in tests involving other brain areas even positive effects were found.To further specify the role of this polymorphism in cognitive processes, we used an associative vocabulary learning paradigm over four consecutive days and tested 38 young healthy subjects and 29 healthy elderly subjects. As a control paradigm, we designed a nonverbal haptic Braille letter-learning paradigm based on the same principles. Behavioural outcome was then associated with the BDNF-genotype.In the vocabulary learning task, met carrier (met/val and met/met) benefitted more from the repetitive training than val/val subjects. This was paralleled by a higher reduction of delayed answers during the course of the study, an effect that was also present in the haptic paradigm. However, in a group of healthy elderly subjects, no similar tendency was found.We conclude that the BDNF val66met polymorphism alters highly circumscribed answer behaviours in young healthy subjects. This might partly explain the high variability of previously published results.