Two C-shaped nuclei located within the medulla just posterior to the pons that make up the largest nuclei within the olivary body. Afferent and efferent fibers travel to and from the nuclei through the hilum. The inferior olivary nucleus forms many connections to the cerebellum through the olivocerebellar tract. Olivocerebellar fibers leave medially through the hilum, decussate, and ascend to the cerebellum via the inferior cerebellar peduncle. At this point, the fibers are deemed climbing fibers that terminate by synapsing onto the cerebellar cortex. The inferior olivary nucleus is implicated in motor control and coordination, particularly pacemaking. Therefore, if defective, essential tremor or progressive supranuclear palsy may result.