BDNF and Cognitive impairment: BDNF thus may potentially remedy cognition in the 5-HT1AR KO animal independently of hippocampal cellular plasticity changes by rescuing the dysfunction from loss of 5-HT1AR activity directly.33 Ultimately, in either case, encoding a better allocentric map to the hidden platform location may be the mechanism through which Ex rectifies the 5-HT1AR KO cognitive impairment.