The Role of Cannabinoid Receptor tyep 1(CB1) in habenular circuits: Habenular nucleus expresses CB1 intensively, and CB1 mRNA especially locates in median hebenular nucleus (MHb). Lots of studies reveal that lateral habenular nucleus (LHb) mediates negative emotions, but we know little about MHb. CB1 is a good entry point to decipher the functions of MHb. We apply stereotaxic injection technology to deliver AAV to MHb of CB1-FLOX mice, AAV can express Cre recombinase, and get the mice of specific CB1 deletion in the MHb. We are studying all kinds of behaviors with the mice, try to discover the role of CB1 in MHb.