hypothalamus physiology trait Any measurable characteristic related to the functions of or processes in the ventral and medial region of the diencephalon forming the walls of the ventral half of the third ventricle, which is normally involved in the functions of the autonomic (visceral motor) nervous system and, through its vascular link with the anterior lobe of the pituitary gland, in endocrine mechanisms. Trait.ontology VT:0005645 brain physiology trait neuroendocrine gland physiology trait