BDNF and autism: Studies have shown that after intraperitoneal injection of sodium valproate (VPA) into rats at 12.5 days of gestation to establish an autism rat model, the expression of BDNF in the cerebral cortex of fetal rats can be significantly increased; meanwhile, at 50 days after birth, the expression is significantly reduced, indicating that BDNF is a potential target drug for treating autism (Almeida et al., 2014; Chau et al., 2017).