midbrain morphology trait brain molecular composition trait midbrain molecular composition trait 2026-04-14T19:43:32Z Any measurable or observable characteristic related to the proportions of proteins, minerals, nutrients, gases, or other substances in the middle division of the three primary divisions of the developing chordate brain or the corresponding part of the adult brain (in vertebrates, includes a ventral part containing the cerebral peduncles and a dorsal tectum containing the corpora quadrigemina and that surrounds the aqueduct of Sylvius connecting the third and fourth ventricles). VT:0011289 Trait.ontology