110 pathways were significantly affected by the downregulated genes (p < 0.05) in the hippocampus, including tight junction, gap junction, focal adhesion, systemic lupus erythematosus, regulation of actin cytoskeleton, long-term depression, alcoholism, prostate cancer, neurotrophin signalling pathway, MAPK signalling pathway, estrogen signalling pathway, vascular smooth muscle contraction, viral carcinogenesis, GnRH signalling pathway, leukocyte transendothelial migration(Fig. 3f). The gene discussed is BDNF; the disease is alcohol dependence.