WordNet

any bundle of nerve fibers running to various organs and tissues of the body (同)nervus
a remedy for hearing loss or deafness
of or relating to the science of acoustics; "acoustic properties of a hall" (同)acoustical
the study of the physical properties of sound
control of your emotions; "this kind of tension is not good for my nerves"

PrepTutorEJDIC

〈C〉『神経』 / 〈C〉《複数形で》『神経過敏』,いらだち / 〈U〉『勇気』,度胸(courage) / 〈U〉《時にa ~》厚かましさ,ずぶとさ;無礼 / 〈C〉葉脈;(昆虫の)翅脈(しみゃく) / 〈人,特に自分〉‘に'力を与える,‘を'元気づける
音響の;聴覚の / (特に楽器が電気的に増幅・変化されていない)自然音を出す
《単数扱い》音響学 / 《複数扱い》(劇場などの)音響効果

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/11/08 06:26:33」(JST)

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The cochlear nerve (also auditory or acoustic nerve) is one of two parts of the vestibulocochlear nerve, a cranial nerve present in amniotes. The cochlear nerve carries auditory sensory information from the cochlea of the inner ear directly to the brain. The other portion of the vestibulocochlear nerve is the vestibular nerve, which carries spatial orientation information to the brain from the semicircular canals.

Anatomy and connections

In terms of anatomy, an auditory nerve fiber is either bipolar or unipolar, with its distal projection being called the peripheral process, and its central projection being called the axon; these two projections are also known as the "peripheral axon" and the "central axon", respectively. The peripheral process is sometimes referred to as a dendrite, although that term is somewhat inaccurate. Unlike the typical dendrite, the peripheral process generates and conducts action potentials, which then "jump" across the cell body (or soma) and continue to propagate along the central axon. In this respect, auditory nerve fibers are somewhat unique in that action potentials pass through the soma. Both the peripheral process and the axon are myelinated.

In humans, the number of nerve fibers within the cochlear nerve averages around 30,000.^[1] The number of fibers varies significantly across species; for example, the domestic cat has some 50,000 fibers. The peripheral axons of auditory nerve fibers form synaptic connections with the hair cells of the cochlea via ribbon synapses using the neurotransmitter glutamate. The central axons form synaptic connections with cells in the cochlear nucleus of the brainstem. The cell bodies of the cochlear nerve lie within the cochlea and collectively form the spiral ganglion, named for the spiral shape it inherits from the cochlea. The terms "cochlear nerve fiber" and "spiral ganglion cell" are used, to some degree, interchangeably, although the former may be used to more specifically refer to the central axons of the cochlear nerve. These central axons exit the cochlea at its base and form a nerve trunk, which, in humans, is approximately one inch long. The cochlear nerve projects centrally to the brainstem, where its fibers synapse with the cell bodies of the cochlear nucleus. A good anatomical description of human auditory nerve fibers is provided by Spoendlin and Schrott (1985). Important earlier work was done by Schuknecht.

Types of neurons

In mammals, cochlear nerve fibers are classified as either type I or type II.

Type I neurons make up 90-95% of the neurons and innervate the inner hair cells. They have relatively large diameters, are bipolar, and are myelinated. Each type I axon innervates only a single inner hair cell, but each inner hair cell is innervated by up to 30 such nerve fibers, depending on species and location within the cochlea.
Type II neurons make up the remaining 5-10% of the neurons and innervate the outer hair cells. They have relatively small diameters, are unipolar, and are unmyelinated.

Cochlear nuclear complex

In mammals, the axons from each cochlear nerve terminate in the cochlear nuclear complex that is ipsilaterally located in the medulla of the brainstem. The cochlear nucleus is the first 'relay station' of the central auditory system and receives mainly ipsilateral afferent input.

The three major components of the cochlear nuclear complex are (see figure below):

the dorsal cochlear nucleus (DCN)
the anteroventral cochlear nucleus (AVCN)
the posteroventral cochlear nucleus (PVCN)

Each of the three cochlear nuclei are tonotopically organized. The axons from the low-frequency region of the cochlea project to the ventral portion of the dorsal cochlear nucleus and the ventrolateral portions of the anteroventral cochlear nucleus. The axons from the high-frequency region project to the dorsal portion of the anteroventral cochlear nucleus and the uppermost dorsal portions of the dorsal cochlear nucleus. The axons from the intermediate frequency region project to intermediate targets, such that tonotopy is preserved between the cochlea and the cochlear nuclei.

References

^ Spoendlin H, Schrott A (1989). "Analysis of the human auditory nerve". Hear Res 43 (1): 25–38. doi:10.1016/0378-5955(89)90056-7. PMID 2613564.

Additional images

Ear anatomy
Cochlear nucleus innervated by a branching auditory nerve fibre
Terminal nuclei of the vestibular nerve, with their upper connections.
Transverse section of the cochlear duct of a fetal cat.
Floor of ductus cochlearis.
Diagrammatic longitudinal section of the cochlea
Organ of corti

External links

Illustration at cytochemistry.net
Gray's page #1059

UpToDate Contents

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1. 前庭神経鞘腫（聴神経腫） vestibular schwannoma acoustic neuroma
2. 幼児および小児における精密な神経学的評価 detailed neurologic assessment of infants and children
3. 成人における詳細な神経学的検査 the detailed neurologic examination in adults
4. 全身性硬化症（強皮症）の神経筋症状 neuromuscular manifestations of systemic sclerosis scleroderma
5. シェーグレン症候群の臨床症状：腺外型疾患 clinical manifestations of sjogrens syndrome extraglandular disease

English Journal

Alpha-synuclein deficiency and efferent nerve degeneration in the mouse cochlea: A possible cause of early-onset presbycusis.

Park SN, Back SA, Choung YH, Kim HL, Akil O, Lustig LR, Park KH, Yeo SW.SourceDepartment of Otolaryngology-Head & Neck Surgery, The Catholic University of Korea, College of Medicine, St. Mary's Hospital, 505 Banpodong, Seochogu, Seoul 137-701, Republic of Korea.
Neuroscience research.Neurosci Res.2011 Nov;71(3):303-10. Epub 2011 Aug 5.
OBJECTIVES/HYPOTHESIS: Efferent nerves under the outer hair cells (OHCs) play a role in the protection of these cells from loud stimuli. Previously, we showed that cochlear α-synuclein expression is localized to efferent auditory synapses at the base of the OHCs. To prove our hypothesis that α-syn
PMID 21840348

Relationship between noise-induced hearing-loss, persistent tinnitus and growth-associated protein-43 expression in the rat cochlear nucleus: does synaptic plasticity in ventral cochlear nucleus suppress tinnitus?

Kraus KS, Ding D, Jiang H, Lobarinas E, Sun W, Salvi RJ.SourceCenter for Hearing and Deafness, State University of New York at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14214, USA.
Neuroscience.Neuroscience.2011 Oct 27;194:309-25. Epub 2011 Jul 28.
Aberrant, lesion-induced neuroplastic changes in the auditory pathway are believed to give rise to the phantom sound of tinnitus. Noise-induced cochlear damage can induce extensive fiber growth and synaptogenesis in the cochlear nucleus, but it is currently unclear if these changes are linked to tin
PMID 21821100

Japanese Journal

内視鏡下に摘出しえた鼻腔神経鞘腫例

洲崎真吾,高木大,中丸裕爾,福田諭
耳鼻咽喉科臨床 104(3), 181-185, 2011-03-01
… Schwannoma is a neurogenic tumor arising in peripheral nerve sheath Schwann cells. … Most head and neck schwannomas occur as acoustic neurinomas, with sinonasal involvement accounting for 3%. …
NAID 10027794119

披裂軟骨内転術と併用術式の発声機能評価

兒玉成博,讃岐徹治,東家完,湯本英二
音声言語医学 52(2), 149-157, 2011
片側声帯麻痺の嗄声に対する治療として, 披裂軟骨内転術 (以下, 内転術) はよく知られた術式であり, 一般的に他の術式と併用して行われることが多い. これまで併用術式の術後発声機能を経時的に検討した報告はない. 今回, 内転術を単独で行った症例 (内転群) , 内転術に甲状軟骨形成術I型 (以下, I型) を加えた症例 (内転+I型群) , 内転術に頸神経ワナ?反回神経吻合術 (以下, Ansa …
NAID 130000662903

Related Pictures

★リンクテーブル★

リンク元	「聴神経」「nervus vestibulocochlearis」「vestibulocochlear nerve」
関連記事	「acoustic」「nerve」

「聴神経」

Cochlear nerve
	Diagrammatic longitudinal section of the cochlea. (Cochlear nerve is in center, shown as striped.)
	Part of the cochlear division of the acoustic nerve, highly magnified.
Details
Latin	nervus cochlearis
From	Vestibulocochlear nerve
Identifiers
Gray's	p.906
MeSH	A08.800.800.120.910.120
TA	A14.2.01.133
FMA	53431
	Anatomical terms of neuroanatomy