Red Nucleus

Anatomy

• In the midbrain tegmentum, at the level of the superior colliculus, dorsomedial to the substantia nigra; appears dark on T2-weighted MRI because of its iron content.
• Magnocellular (rubrospinal tract) and parvocellular (rubro-olivary tract) parts; in humans the parvocellular part predominates.
• Input: from the contralateral dentate nucleus via the superior cerebellar peduncle, and from motor and premotor cortex.
• Oculomotor nerve fibers pass through the nucleus.

Functions

• Relaying cerebellar output to the motor system.
• Contribution to motor learning and error correction through the rubro-olivary loop.
• Rubrospinal tract: small in humans, contributes to arm and hand movements.

Connections and chemistry

• Dentate nucleus (contralateral) → red nucleus (superior cerebellar peduncle)
• Red nucleus → inferior olive (rubro-olivary tract) → cerebellum
• Red nucleus → spinal cord (rubrospinal tract)
• Motor and premotor cortex → red nucleus

Development

Developmental course through childhood and adolescence.

• Brain iron increases with age; iron in the red nucleus and substantia nigra rises quickly in childhood and adolescence.

Clinical

• Holmes (rubral) tremor: a slow, coarse tremor at rest, with posture and with movement, after midbrain lesions.
• Findings related to low ferritin and brain iron are being studied in restless legs syndrome and ADHD.
• The “face of the giant panda” MRI sign in the midbrain in Wilson disease (around the red nucleus and substantia nigra).

Assessment

Neuropsychological tasks and measures that probe this region's function.

• Cerebellar examination: finger–nose, intention tremor
• Eye movements (oculomotor nerve)
• Iron-sensitive MRI (SWI): imaging of the red nucleus and substantia nigra

Lesions and damage

Clinical findings expected with damage or dysfunction.

• Benedikt syndrome: ipsilateral oculomotor nerve palsy, contralateral tremor and ataxia.
• Claude syndrome: ipsilateral oculomotor nerve palsy, contralateral cerebellar ataxia.

In the model

How this structure is defined in the 3D model, and the data source.

CIT168 red nucleus probability map (right/left).

References

Full citations for the card; links go to the paper (DOI) or a PubMed search.

1. Hallgren B, Sourander P. The effect of age on the non-haemin iron in the human brain. J Neurochem 1958;3(1):41–51. DOI: 10.1111/j.1471-4159.1958.tb12607.x
2. Konofal E et al. Iron deficiency in children with attention-deficit/hyperactivity disorder. Arch Pediatr Adolesc Med 2004;158(12):1113–1115. DOI: 10.1001/archpedi.158.12.1113
3. Raina GB et al. Holmes tremor: clinical description, lesion localization, and treatment in a series of 29 cases. Neurology 2016;86(10):931–938. DOI: 10.1212/WNL.0000000000002440