[TA] the most medial of the cerebellar nuclei, lying medial to the interpositus nucleus, near the midline, in the white matter underneath the vermis of the cerebellar cortex. It receives the axons of Purkinje cells from all parts of the vermis. Its major projection is to the vestibular nuclei and medullary reticular formation. SYN: nucleus fastigii [TA], nucleus medialis cerebelli*, fastigatum, nucleus tecti, roof nucleus, tectal nucleus.