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Encyclopedia > Superior olivary nucleus
Brain: Superior olivary nucleus
Scheme showing the course of the fibers of the lemniscus; medial lemniscus in blue, lateral in red. (Superior olivary nucleus is labeled at center right.)
Latin nucleus olivaris superior
Gray's subject #187 787
NeuroNames hier-565
Dorlands/Elsevier n_11/12582125

The superior olivary nucleus (or superior olive) is a small mass of gray substance situated on the dorsal surface of the lateral part of the trapezoid body. Small in man, but well developed in certain animals, it exhibits the similar structure as the inferior olivary nucleus, and is situated immediately above it. Some of the fibers of the trapezoid body end by arborizing around the cells of this nucleus, while others arise from these cells. Image File history File links Gray713. ... This article needs to be wikified. ... The medial lemniscus, also known as Reils band or Reils ribbon, is a pathway in the brainstem that carries sensory information from the gracile and cuneate nuclei to the thalamus. ... The lateral lemniscus is a tract of axons in the brainstem that carries information about sound from the cochlear nucleus to various brainstem nuclei and ultimately the contralateral inferior colliculus of the midbrain. ... Latin is an ancient Indo-European language originally spoken in Latium, the region immediately surrounding Rome. ... NeuroNames is a system of nomenclature for the brain and related structures. ... Elseviers logo. ... The cerebellum (Latin: little brain) is a region of the brain that plays an important role in the integration of sensory perception and motor output. ... Figure 1a: A human brain, with the cerebellum in purple. ... The trapezoid body is part of the acoustic pathway. ... In anatomy, the olivary bodies or simply olives (Latin oliva) are a pair of prominent oval structures in the medulla oblongata, the lower portion of the brainstem. ...

Contents

Physiology

The superior olivary nucleus plays a number of roles in hearing. The medial superior olive (MSO) is a specialised nucleus that is believed to measure the time difference of arrival of sounds between the ears (the interaural time difference or ITD). The ITD is a major cue for determining the azimuth of low frequency sounds, i.e. localising them on the azimuthal plane - their degree to the left or the right. For the cerebellar structure, see Dentate nucleus. ... // caption The interaural time difference (or ITD) when concerning humans or animals, is the difference in arrival time of a sound between two ears. ... Azimuth is the horizontal component of a direction (compass direction), measured around the horizon, from the north toward the east (i. ...


The lateral superior olive (LSO) is believed to be involved in measuring the level difference of sounds between the ears (the interaural level difference or ILD). The ILD is a major cue in determining the azimuth of high frequency sounds. For the cerebellar structure, see Dentate nucleus. ...


Relationship to auditory system

The superior olivary complex is generally located in the pons, but in human extends from the rostral medulla to the mid-pons[1] and receives projections predominantly from the anteroventral cochlear nucleus via the ventral acoustic stria, although the posteroventral nucleus projects there as well via the intermediate acoustic stria. It is at this site where the first major binaural interactions occur.[2] The superior olivary complex is divided into three parts; the medial, lateral and the Trapezoid body.[3] Position of the pons in the human brain The pons (sometimes pons Varolii after Costanzo Varolio) is a knob on the brain stem. ...


Summary:

  • It is a group of nuclei in the brainstem.
  • It is, in most species, made up of 3 major nuclei: medial superior olive, lateral superior olive and medial nucleus of the Trapezoid body (MNTB).
  • These three nuclei are surrounded by smaller and more diffuse nuclei, collectively called the periolivary nuclei. A subgroup of these periolivary nuclei give rise to the olivocochlear bundle, that termiantes in the inner ear.
  • The superior olivary nucleus receives inputs primarily from bushy cells of the anterior ventral cochlear nuclei (AVCN) bilaterally, and passes on information to the lateral lemnisci. This input occurs primarily via the ventral acoustic stria.
  • The superior olivary nucleus is the first major point where binaural input is combined.

The cochlear nuclei consist of: (a) the lateral cochlear nucleus, corresponding to the tuberculum acusticum on the dorso-lateral surface of the inferior peduncle; and (b) the ventral or accessory cochlear nucleus, placed between the two divisions of the nerve, on the ventral aspect of the inferior peduncle. ...

Medial superior olive (MSO)

The medial superior olive is thought to help locate the position of a sound on the azimuth axis.[3] The azimuth axis is the angle from a certain direction, ie: 32 degrees from north. One’s first instincts may be to think that this nucleus includes vertical information, but this is not the case. The fusiform cells do not project to anything in the level of the pons, and only come into play at the inferior colliculus. Only horizontal data is present, but it does come from two different ear sources, which aids in the localizing of sound on the azimuth axis.[4] The way in which the superior olive does this is by measuring the differences in time between two ear signals recording the same stimulus. Traveling around the head takes about 700 μs, and it is assumed that the medial superior olive is able to detect this. In fact, it is observed that people can detect interaural differences down to 10 microseconds.[4] The nucleus is tonotopically organized, but the azimuthal receptive field projection is “most likely a complex, nonlinear map.”[3] For the cerebellar structure, see Dentate nucleus. ...


The projections of the ipsilateral medial superior olive terminate densely in the central nucleus of the inferior colliculus. The majority of these axons are considered to be “round shaped” or type R. These R axons are mostly glutamatergic and contain round synaptic vesicles and form asymmetric synaptic junctions.[2] The paired inferior colliculi together with the superior colliculi form the eminences of the corpora quadrigemina. ...

  • This is the largest of the nuclei and in human contains approximately 15,500 neurons (Kulesza, 2007).
  • Each MSO receives low-frequency bilateral inputs from the right and left AVCNs.
  • The output is to the ipsilateral lateral lemniscus and ultimately to the inferior colliculus.
  • The MSO responds better to binaural stimuli.
  • Its main function involves detection of differences in arrival time of sounds to the two ears which is part of localization process (ITD).

Lateral superior olive (LSO)

This olive has similar functions to the medial superior olive, but employs intensity to hone in on a sound source.[5] This is the part of the brain stem that labels the louder sound from the left ear as being on the left hand side. The lateral olive receives input from both cochlear nuclei, although the contralateral projections are received indirectly through the nucleus of trapezoid body. The contralateral and ipsilateral inputs are in stark opposition to one another, and thusly the cells in the lateral superior olive fire accordingly when one lateral input is greater than the other. Binomial name L. 19th century illustration The Olive (Olea europaea) is a species of small tree in the family Oleaceae, native to coastal areas of the eastern Mediterranean region, from Lebanon and the maritime parts of Asia Minor and northern Iran at the south end of the Caspian Sea. ...


The projections from the contralateral lateral superior olive go to the central nucleus of the inferior colliculus. The types of axonal projections are both round (or R), as seen above, and also a small amount of pleomorphic or PL axons. Pleomorphic is a synonym for polymorphic or protean, and means the axons are capable of being found in many forms.[6] The pleomorphic axons are mostly inhibitory, with the neurotransmitters glycine and GABA at their disposal, stored inside pleomorphic synaptic vesicles. These axons form symmetrical synapses with the neurons of the inferior colliculus and terminate in a less dense fashion. This page is a candidate to be copied to Wiktionary. ... For the plant, see Glycine (plant). ... Gaba may refer to: Gabâ or gabaa (Philippines), the concept of negative karma of the Cebuano people GABA, the gamma-amino-butyric acid neurotransmitter GABA receptor, in biology, receptors with GABA as their endogenous ligand Gaba 1 to 1, an English conversational school in Japan Marianne Gaba, a US model...


The projections of the ipsilateral lateral superior olive project equal proportions of round and pleomorphic axons. The densities of the axons termination spots of this olivary pathway are not uniform, and contributes the highest density of PL axons to the inferior colliculus.


Summary:

  • The LSO is considerably smaller than the MSO; in human the LSO contains only 5,600 neurons.
  • The LSO receives high-frequency inputs from the ipsilateral AVCN and also from contralateral AVCN via the ipsilateral MNTB. Due to this arrangement, this is another site of binaural integration.
  • Its output is to the lateral lemnisci on both sides (in contrast to MSO) and ultimately to Inferior Colliculus.
  • The LSO is primarily sensitive to high frequencies and therefore to intensity differences between the ears and can detect differences as small as 10 dB.

Medial Nucleus of Trapezoid Body (MNTB)

  • The MNTB is the smallest part of SOC; the presence of the MNTB in the human brainstem is in doubt.
  • The neurones only get high-frequency input from contralateral AVCN, and its output projects to ipsilateral LSO.
  • There are two response types found: a ‘chopper type’ similar to spindle cells in the AVCN and a primary type which is similar to those of Bushy Cells in the AVCN.

See also

In anatomy, the olivary bodies or simply olives (Latin oliva and olivae, singular and plural, respectively) are a pair of prominent oval structures in the medulla oblongata, the lower portion of the brainstem. ...

References

  1. ^ Kulesza RJ, Cytoarchitecture of the human superior olivary complex: Medial and lateral superior olive. Hearing Research 225(2007) 80-90
  2. ^ a b Oliver DL, et al. Axonal projections from the lateral and medial superior olive to the inferior colliculus of the cat: a study using electron microscopic autoradiography. J Comp Neurol. 1995 Sep 11;360(1):17-32
  3. ^ a b c Oliver, Douglas L. et al. Topography of Interaural Temporal Disparity Coding in Projections of Medial Superior Olive to Inferior Colliculus. The Journal of Neuroscience, August 13, 2003, 23(19):7438-7449
  4. ^ a b Kandel, et al Principles of Neuroscience. Fourth ed. pp 591-624. Copyright 2000, by McGraw-Hill Co.
  5. ^ Tsuchitani, C. and J. C. Boudreau (1967). "Encoding of stimulus frequency and intensity by cat superior olive S-segment cells." J Acoust Soc Am 42(4): 794-805.
  6. ^ Medical Online Dictionary http://www.medterms.com/script/main/art.asp?articlekey=4943

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. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant. A garden sign welcomes residents and visitors to Rogers Park as home of Loyola University Chicago. ... The public domain comprises the body of all creative works and other knowledge—writing, artwork, music, science, inventions, and others—in which no person or organization has any proprietary interest. ... An illustration from the 1918 edition Henry Grays Anatomy of the Human Body (or Grays Anatomy as it has more commonly become known) is an anatomy textbook widely regarded as a classic work on human anatomy. ...


  Results from FactBites:
 
IX. Neurology. 4a. The Hind-brain or Rhombencephalon. Gray, Henry. 1918. Anatomy of the Human Body. (10328 words)
The fibers of the abducent nerve pass forward through the entire thickness of the pons on the medial side of the superior olivary nucleus, and between the lateral fasciculi of the cerebrospinal fibers, and emerge in the furrow between the lower border of the pons and the pyramid of the medulla oblongata.
The nucleus of the cochlear nerve consists of: (a) the lateral cochlear nucleus, corresponding to the tuberculum acusticum on the dorso-lateral surface of the inferior peduncle; and (b) the ventral or accessory cochlear nucleus, placed between the two divisions of the nerve, on the ventral aspect of the inferior peduncle.
The cerebellum is connected to the cerebrum, pons, and medulla oblongata; to the cerebrum by the superior peduncle, to the pons by the middle peduncle, and to the medulla oblongata by the inferior peduncles.
Reference Encyclopedia - Olivary nucleus (385 words)
In anatomy, the olivary bodies or simply olives (Latin oliva and olivae, singular and plural, respectively) are a pair of prominent oval structures in the medulla oblongata, the lower portion of the brainstem.
The olivary body is located on the anterior surface of the medulla lateral to the pyramid, from which it is separated by the antero-lateral sulcus and the fibers of the hypoglossal nerve.
The medial accessory olivary nucleus lies between the inferior olivary nucleus and the pyramid, and forms a curved lamina, the concavity of which is directed laterally.
  More results at FactBites »

 
 

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