Thalamus

**Semantic type:** Body Part, Organ, or Organ Component

**Definition:** An ovoid mass composed predominantly of gray substance and associated laminae of white substance. The thalamus is divided into anterior, medial, and lateral parts. The function of the thalamus is to relay sensory impulses and cerebellar and basal ganglia projections to the cerebral cortex. The thalamus is positioned within the posterior part of the diencephalon forming most of each lateral wall of the third ventricle.

**Synonyms:** - BRAIN, THALAMUS - Dorsal Thalamus - THALAMUS - dorsal plus ventral thalamus - thalamus