abnormal habenula morphology decreased habenula size 2013-12-04T22:39:39Z MP:0012482 MPheno.ontology csmith decreased habenular nucleus size reduced habenular nucleus reduced habenular nucleus size reduced size of the group of nuclei that makes up the small eminence on the dorsomedial surface of the thalamus, just in front of the dorsal commissure on the lateral edge of the habenular trigone