- The caudal part of the prosencephalon composed of the epithalamus, thalamus, and hypothalamus. [G. dia, through, + enkephalos, brain]
* * *di·en·ceph·a·lon .dī-ən-'sef-ə-.län, .dī-(.)en-, -lən n the posterior subdivision of the forebrain called also betweenbrain, interbraindi·en·ce·phal·ic -sə-'fal-ik adj
* * *n.an anatomical division of the forebrain, consisting of the epithalamus, thalamus (dorsal thalamus), hypothalamus, and ventral thalamus (subthalamus). See brain.
* * *di·en·ceph·a·lon (di″ən-sefґə-lon) [dia- + encephalon] 1. [TA] the caudal part of the prosencephalon, which largely bounds the third ventricle and connects the mesencephalon to the cerebral hemispheres; each lateral half is divided by the hypothalamic sulcus into a dorsal part, comprising the epithalamus, dorsal thalamus, and metathalamus, and a ventral part, comprising the ventral thalamus (subthalamus) and hypothalamus. Called also interbrain. See Plate 9. See also brainstem. 2. the posterior of the two brain vesicles formed by specialization of the prosencephalon in the developing embryo. diencephalic adj
Diencephalon. Posterior (dorsal) (A) and anterior (inferior) (B) views of the base of the brain, showing the diencephalon in relation to the mesencephalon (midbrain) and rhombencephalon (hindbrain).
Medical dictionary. 2011.