Given our findings that the LHb is required for maternal behavior in the naturally parturient mouse dam and the wealth of evidence that the LHb, as a critical regulator of reward signaling, is also involved in the pathophysiology of depression and anxiety (Matsumoto and Hikosaka, 2007; Sartorius and Henn, 2007; L-M. This evidence concerns the gene LHB and depressive disorder.