BDNF and Alzheimer disease: According to previous AD animal experiments, rTMS reverses Aβ42-induced depletion of nerve growth factor and brain-derived neurotrophic factor (BDNF) in the hippocampus, increases BDNF binding affinity for TrkB in the prefrontal cortex, enhances hippocampal LTP, and reduces Aβ precursor proteins in the hippocampus12–15.