Accessory Cuneate Nucleus

Synonyms

Lateral cuneate nucleus

Definition

Nucleus in the dorsolateral portion of the medulla that receives sensory information likely from touch, pressure, and stretch receptors in the upper extremities. It gives rise to the cuneocerebellar tract which enters the cerebellum via the inferior cerebellar peduncle. The accessory cuneate nucleus is thought to be the equivalent of the dorsal nucleus of Clarke in the lumbar, thoracic, and lower cervical cord which is the source of the dorsal spinocerebellar tract. These nuclei and tracts provide unconscious (as opposed to “conscious”) sensory feedback to the cerebellum in its regulation of individual muscles. Lesions of this nucleus might be expected to produce cerebellar type symptoms of the ipsilateral upper extremity (i.e., ataxia/incoordination of movement), but it is relatively small and isolated lesions are likely to be extremely rare.