| Brain: Inferior olivary nucleus | ||
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| Microcircuitry of the cerebellum. Excitatory synapses are denoted by (+) and inhibitory synapses by (-). MF: Mossy fiber. DCN: Deep cerebellar nuclei. IO: Inferior olive. CF: Climbing fiber. GC: Granule cell. PF: Parallel fiber. PC: Purkinje cell. GgC: Golgi cell. SC: Stellate cell. BC: Basket cell. |
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| Transverse section of medulla oblongata below the middle of the olive. (Inferior olivary nucleus labeled at center right.) | ||
| Gray's | subject #187 781 | |
| Part of | Olivary body | |
| NeuroNames | hier-696 | |
| MeSH | Olivary+Nucleus | |
The inferior olivary nucleus is the largest nucleus situated in the olivary body, part of the medulla oblongata.
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Function
It is closely associated with the cerebellum, meaning that is involved in control and coordination of movements[1], and likely also sensory processing and cognitive tasks.
There is some evidence that it is stimulated by ghrelin.[2]
Anatomy
It consists of a gray folded lamina arranged in the form of an incomplete capsule, opening medially by an aperture called the hilum.
Emerging from the hilum are numerous fibers that collectively constitute the peduncle of the olive. The axons, also known as olivocerebellar fibers, leave the olivary nucleus, exit through the hilum, and decussate with those from the opposite olive in the raphe.
Then, as internal arcuate fibers, they pass partly through and partly around the opposite olive and enter the inferior peduncle to be distributed to the cerebellar hemisphere of the opposite side from which they arise.
The fibers are smaller than the internal arcuate fibers connected with the medial lemniscus.
Fibers passing in the opposite direction from the cerebellum to the olivary nucleus are often described as the CTT, but their existence is doubtful.
Much uncertainty exists also with regard to the connections of the olive and the spinal cord.
Important connections between the cerebrum and the olive of the same side exist, but the exact pathway is unknown.
Many collaterals from the reticular formation and from the pyramids enter the inferior olivary nucleus.
Removal of one cerebellar hemisphere is followed by atrophy of the opposite olivary nucleus.
Pathology
Hypertrophy has been associated with progressive supranuclear palsy.[3]
Additional images
 Section of the medulla oblongata at about the middle of the olive. |
 Diagram showing the course of the arcuate fibers. |
 Sagittal section through right cerebellar hemisphere. The right olive has also been cut sagitally. |
_section_description_2.JPG) Human brain frontal (coronal) section |
References
- ^ "Medical Neurosciences". http://www.neuroanatomy.wisc.edu/virtualbrain/BrainStem/06Olive.html.
- ^ Zhang W, Lin TR, Hu Y, Fan Y, Zhao L, Mulholland MW (2003). "Activation of c-fos expression in the rat inferior olivary nucleus by ghrelin". Neurosci. Lett. 353 (3): 157–60. doi:. PMID 14665405. http://linkinghub.elsevier.com/retrieve/pii/S0304394003011248.
- ^ Hanihara T, Amano N, Takahashi T, Itoh Y, Yagishita S (1998). "Hypertrophy of the inferior olivary nucleus in patients with progressive supranuclear palsy". Eur. Neurol. 39 (2): 97–102. doi:. PMID 9520070. http://content.karger.com/produktedb/produkte.asp?typ=fulltext&file=ene39097.
External links
This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated.
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