 Deep brain stimulation of the major afferent bundle (i.e., stria medullaris thalami) of the lateral habenula has been used for treatment of depression where it is severe, protracted and therapy-resistant.Methyl-D-aspartate (NMDA) receptor-dependent burst firing in the lateral habenula has been associated with depression in animal studies, and it has been shown that the general anesthetic ketamine blocks this firing by acting as a receptor antagonist.Ketamine has been the subject of numerous studies after having shown fast-acting antidepressant effects in humans.