Red nucleus

Last revised by Robab Ghorban Pour on 17 Aug 2021

The red nucleus is one of the brainstem nuclei and part of the extrapyramidal system. The red nuclei are round masses of grey matter, situated within the rostral part of tegmentum of midbrain (the part between the cerebral peduncles and the quadrigeminal plate). It consists of a larger neorubrum and smaller paleorubrum.

Function

It receives afferent fibers from several locations within the diencephalon:

It sends its axons to the olive (rubro-olivary and reticulo-olivary fibers) and spinal cord (rubrospinal tract).  Its action includes the coordination of muscle tone, body position and gait.

Pathology

A lesion of the red nucleus causes resting tremor, abnormal muscle tone and choreoathetosis. As oculomotor nerve fibers travel through the surface of the nucleus, oculomotor nerve palsy could be part of syndromes involving the red nucleus. These are Benedikt syndrome and Claude syndrome, caused by occlusion of perforating branches of posterior cerebral artery. These syndromes present with oculomotor nerve palsy as well as contralateral tremor, hemiataxia and choreiform movements.4