BDNF and early-onset autosomal dominant Alzheimer disease: However, intra-hippocampal administration of the ERK inhibitor PD98059 alone or combine with BDNF treatment both showed significant decreases in the time spent in the right quadrant (both P < 0.0001) and the attempts at searching for the platform (both P < 0.05), indicating that blocking the activity of ERK can not only induce cognition impairments but also eliminated the curative effect of BDNF in the Aβ1-42-treated rat model of Alzheimer's disease.