LEARNING UP-REGULATES BRAIN-DERIVED NEUROTROPHIC FACTOR MESSENGER-RIBONUCLEIC-ACID - A MECHANISM TO FACILITATE ENCODING AND CIRCUIT MAINTENANCE

Brain-derived neurotrophic factor (BDNF) promotes neuron survival, enh ances sprouting, protects neurons against insult, and may be involved in several aspects of learning and memory. In this study, rats trained to locate a submerged platform in a water maze had elevated levels of BDNF messenger ribonucleic acid (mRNA) in the hippocampus (p < .05), a structure associated with spatial memory. BDNF mRNA expression incre ased after 3 and 6 days but not after 1 day of training in the water m aze. A yoked control group that swam without the platform present, to control for physical activity, showed a trend for elevated. BDNF mRNA at an intermediate level between the learning and sedentary groups. Ot her cortical and subcortical areas did not show a significant increase in BDNF mRNA after learning or activity (p > .05). These findings sug gest that learning can impact BDNF mRNA expression localized to the br ain areas involved in the processing of spatial information. Furthermo re, behaviors such as physical activity and learning may help maintain and protect neurons at risk in aging and neurodegenerative disease vi a increased BDNF expression.