In
neuroanatomy,
habenula (diminutive of Latin
habena meaning
rein) originally denoted the stalk of the
pineal gland (pineal habenula; pedunculus of pineal body), but gradually came to refer to a neighboring group of nerve cells with which the pineal gland was believed to be associated, the habenular nucleus. The habenular nucleus is a set of well-conserved structures in all
vertebrate animals.