Principal inferior olivary nucleus
Nucleus olivaris inferior principalis
- Latin synonym: Nucleus olivaris inferior
- Synonym: Inferior olivary nucleus
- Related terms: Principal olivary nucleus
Definition
The principal inferior olivary nucleus, the largest component of the inferior olivary complex, is a distinctive structure within the medulla oblongata. Shaped like a crumpled bag with its hilum (opening) oriented medially, this nucleus is responsible for creating the surface prominence known as the olive. It works in close association with the dorsal and medial accessory olivary nuclei, collectively forming the inferior olivary complex.
Connections:
Afferent fibers: It receives input from the spinal cord (via the spinoolivary tract), cerebellum, and cerebral cortex.
Efferent fibers: Its output fibers decussate (cross the midline) and travel to the cerebellum through the inferior cerebellar peduncle as olivocerebellar fibers.
Function: The principal inferior olivary nucleus plays a critical role in coordinating voluntary muscle movement by contributing to the cerebellar circuitry involved in motor learning and timing of muscle actions.
References
Snell, R.S. (2010). ‘Chapter 5: The Brainstem’, in Clinical Neuroanatomy. (7th ed.) Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins, pp.204.
