May play a role in the specification and maintenance of basal forebrain identity. First detectable at early gastrula stages. Expressed in the anterior-most region of the open neural plate and midanterior and midlateral anterior ridge. By late neurula stages, expressed in the derivatives of these regions namely, in the anterior and rostral ventrolateral part of the forebrain neuroepithelium, primordium striatum, optic stalk, chiasmatic ridge and the anterior hypothalamus. At tailbud stages the expression extends laterally and caudally with the enlargement of the forebrain ventricle. Expression in the tadpole stage embryos is specific to the optic disk, optic stalk and anterior hypothalamus. Belongs to the EMX homeobox family.