The accessory cuneate nucleus (also lateral cuneate nucleus, or external cuneate nucleus) is a

nucleus Nucleus (: nuclei) is a Latin word for the seed inside a fruit. It most often refers to: *Atomic nucleus, the very dense central region of an atom *Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucleu ...

situated in the caudal

medulla oblongata The medulla oblongata or simply medulla is a long stem-like structure which makes up the lower part of the brainstem. It is anterior and partially inferior to the cerebellum. It is a cone-shaped neuronal mass responsible for autonomic (involun ...

just lateral to the

cuneate nucleus The dorsal column nuclei are a pair of nuclei in the dorsal columns of the dorsal column–medial lemniscus pathway (DCML) in the brainstem. The name refers collectively to the cuneate nucleus and gracile nucleus, which are situated at the l ...

. It relays unconscious

proprioceptive Proprioception ( ) is the sense of self-movement, force, and body position. Proprioception is mediated by proprioceptors, a type of sensory receptor, located within muscles, tendons, and joints. Most animals possess multiple subtypes of propri ...

sensory information from the upper limb and upper trunk to the cerebellum via the cuneocerebellar fibers. The neurons of the ACN (as well as those of the lateral portion of the cuneate nucleus) are functionally homologous with the posterior thoracic nucleus; the cuneocerebellar fibers are therefore the upper body functional equivalent of the

dorsal spinocerebellar tract The spinocerebellar tracts are nerve tracts originating in the spinal cord and terminating in the same side ( ipsilateral) of the cerebellum. The two main tracts are the dorsal spinocerebellar tract, and the ventral spinocerebellar tract. Both of ...

Anatomy

Synapses in the ACN are somatotopically organized.

Afferents

Afferents of the ACN arise from muscle stretch receptors and skin touch receptors of the upper limb; they enter the spinal cord rostral to the posterior thoracic nucleus to ascend in the lateral portion of the

cuneate fasciculus Cuneate means "wedge-shaped", and can apply to: * Cuneate leaf, a leaf shape * Cuneate nucleus The dorsal column nuclei are a pair of nuclei in the dorsal columns of the dorsal column–medial lemniscus pathway (DCML) in the brainstem. The ...

. A minority of the fibers of the

thus synapse in the ACN.

Efferents

Efferents of the ACN form the cuneocerebellar fibers that pass through the ipsilateral

restiform body The inferior cerebellar peduncle is formed by fibers of the restiform body that join with fibers from the much smaller juxtarestiform body. The inferior cerebellar peduncle is the smallest of the three cerebellar peduncles. The upper part of th ...

of the

inferior cerebellar peduncle The inferior cerebellar peduncle is formed by fibers of the restiform body that join with fibers from the much smaller juxtarestiform body. The inferior cerebellar peduncle is the smallest of the three cerebellar peduncles. The upper part of t ...

to terminate in the ipsilateral hemisphere of the cerebellum; a few of its efferents do not join the cuneocerebellar fibers, instead ascending in the contralateral

medial lemniscus The medial lemniscus, also known as Reil's band or Reil's ribbon (for German anatomist Johann Christian Reil), is a large ascending bundle of heavily myelinated axons that decussate in the brainstem The brainstem (or brain stem) is the pos ...

to terminate in the

thalamus The thalamus (: thalami; from Greek language, Greek Wikt:θάλαμος, θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the wikt:dorsal, dorsal part of the diencephalon (a division of ...

Additional images

File:Sobo 1909 665.png

References

External links

NIF Search - Accessory Cuneate Nucleus
via the

Neuroscience Information Framework The Neuroscience Information Framework is a repository of global neuroscience web resources, including experimental, clinical, and translational neuroscience databases, knowledge bases, atlases, and genetic/ genomic resources and provides many aut ...

{{DEFAULTSORT:Accessory Cuneate Nucleus Medulla oblongata