When genetics prevail: brain stimulation fails to overcome learning deficits from brain-derived neurotrophic factor...

The dorsolateral prefrontal cortex (DLPFC) is a key contributor to memory categorization. Brain-Derived Neurotrophic Factor (BDNF) Val66Met polymorphism affects the efficacy of neuronal plasticity induction. We investigated whether DLPFC-transcranial direct current stimulation (tDCS) influences categorization performance, and whether BNDF genotype modulates this effect.

Sixty-two healthy individuals were randomized to receive 10 min of either anodal right DLPFC-tDCS at 1 mA, or sham tDCS during the training phase of a prototype distortion task. Categorization performance was assessed during, shortly after, and the morning following the stimulation. Val66Met polymorphism status was determined through BNDF genotyping.

Val66Met carriers showed poorer categorization ability than Val/Val homozygotes (p < 0.0001). tDCS did not enhance categorization performance overall, or reduce genotype-associated differences with these specific stimulation parameters. However, tDCS extinguished the prototype effect of the categorization task observed in our sample.

Our findings underscore the importance of BDNF polymorphism in category learning. 1 mA anodal right DLPFC over the right DLPFC does not improve performance or offset genotype differences under tested conditions.

BDNF Val66Met polymorphism influences category learning, and low-intensity tDCS does not counteract this effect, emphasizing the need to refine stimulation protocols for genotype-specific cognitive enhancement.