BDNF and Alzheimer disease: The molecular biology bases for attenuation of AD progression in rodent models by physical activity are: (a) PA stimulates release of brain BDNF and (b) the β-secretase (BACE1) promoter that stimulates expression of β-secretase, the rate limiting enzyme of the amyloidogenic pathway producing Aβ peptides in the neurons, has a NFκB biding site.