In this study, we identified that the expression of BDNF in AD brain neurons is controlled by miR-132, miR-206, miR-30a-5p, miR-195, miR-10a, miR-322, and miR-613; in stroke, the expression of BDNF in brain neurons is controlled by miR-124, miR-210, miR-922, miR-9, miR-10b-5p, and miR-155; in PD brain neurons, the expression of BDNF is controlled by miR-494-3p, miR-30a-5p, miR-7, and miR-210-3p; and in depression brain neurons, it is controlled by miR-206, miR-124, and miR-155. The gene discussed is BDNF; the disease is Alzheimer disease.