Dorsal cochlear nucleus
Information about Dorsal cochlear nucleus
The dorsal cochlear nucleus (DCN, also known as the "tuberculum acousticum"), is a cortex-like structure on the dorso-lateral surface of the brainstem. Along with the ventral cochlear nucleus, it forms the cochlear nucleus, where all auditory nerve fibers from the cochlea form their first synapse.
The fusiform (also called pyramidal) and giant cells are the principal cells of the DCN. There is no known physiological difference between these two cell types. These cells are the target of two different input systems. The first system arises from the auditory nerve, and carries acoustic information. The second set of inputs is relayed through a set of small cells called "granule" cells in the cochlear nucleus. The granule cells in turn are the target of a number of different inputs, including both those involved in auditory processing and, at least in lower mammals, somatosensory inputs associated with the head, the ear, and the jaw.
Projections from DCN principal cells form the dorsal acoustic stria, which ultimately terminate in the ICC. This projection overlaps with that of the LSO in a well defined manner[1], where they form the primary excitatory input for ICC type O units[2]
While the VCN bushy cells aid in the location of a sound stimulus on the horizontal axis via their inputs to the superior olivary complex, type IV cells may participate in localization of the sound stimulus on the vertical axis. The pinna selectively amplifies frequencies, resulting in reduced sound energy at specific frequencies in certain regions of space. The complicated firing patterns of type IV cells makes them especially suited to detecting these notches, and with the combined power of these two localization systems, an ordinary person can locate where a firework explodes without the use of his eyes.
Somatosensory inputs inhibit type IV cell activity, possibly silencing their activity during head and pinna movements [4]. While this has not been studied extensively, it may play an important role in sound source localization in elevation. A similar effect is seen in the visual system in an effect known as change blindness.
Current auditory models of the DCN employ a two-inhibitor model. Type IV cells receive excitation directly from the auditory nerve, and are inhibited by type II (vertical) cells and a wide band inhibitor (onset-c cells).
| Brain: | ||
|---|---|---|
| Dorsal cochlear nucleus is #4, at upper left | ||
| Latin | nucleus cochlearis posterior | |
| NeuroNames | hier-718 | |
| Dorlands/Elsevier | n_11/12580787 | |
Anatomy
The DCN differs from the ventral portion of the CN as it not only projects to the central nucleus of the Inferior Colliculus (ICC) but also receives efferent innervation from auditory cortex, superior olivary complex and inferior colliculus. The architecture and wiring of the DCN is similar to that of the cerebellum, a concept that currently is important in theories of DCN function. Thus, the DCN is thought to be involved with more complex auditory processing, rather than merely transferring information.The fusiform (also called pyramidal) and giant cells are the principal cells of the DCN. There is no known physiological difference between these two cell types. These cells are the target of two different input systems. The first system arises from the auditory nerve, and carries acoustic information. The second set of inputs is relayed through a set of small cells called "granule" cells in the cochlear nucleus. The granule cells in turn are the target of a number of different inputs, including both those involved in auditory processing and, at least in lower mammals, somatosensory inputs associated with the head, the ear, and the jaw.
Projections from DCN principal cells form the dorsal acoustic stria, which ultimately terminate in the ICC. This projection overlaps with that of the LSO in a well defined manner[1], where they form the primary excitatory input for ICC type O units[2]
Physiology
Principal cells in the DCN have very complex frequency intensity tuning curves. Classified as cochlear nucleus type IV cells[3], the firing rate may be very rapid in response to a low intensity sound at one frequency and then fall below the spontaneous rate with only a small increment in stimulus frequency or intensity. The firing rate may then increase with another increment in intensity or frequency. Type IV cells are excited by wide band noise, and particularly excited by a noise-notch stimulus directly below the cell's best frequency (BF).While the VCN bushy cells aid in the location of a sound stimulus on the horizontal axis via their inputs to the superior olivary complex, type IV cells may participate in localization of the sound stimulus on the vertical axis. The pinna selectively amplifies frequencies, resulting in reduced sound energy at specific frequencies in certain regions of space. The complicated firing patterns of type IV cells makes them especially suited to detecting these notches, and with the combined power of these two localization systems, an ordinary person can locate where a firework explodes without the use of his eyes.
Somatosensory inputs inhibit type IV cell activity, possibly silencing their activity during head and pinna movements [4]. While this has not been studied extensively, it may play an important role in sound source localization in elevation. A similar effect is seen in the visual system in an effect known as change blindness.
Current auditory models of the DCN employ a two-inhibitor model. Type IV cells receive excitation directly from the auditory nerve, and are inhibited by type II (vertical) cells and a wide band inhibitor (onset-c cells).
References
1. ^ Oliver, D. L., G. E. Beckius, et al. (1997). "Simultaneous anterograde labeling of axonal layers from lateral superior olive and dorsal cochlear nucleus in the inferior colliculus of cat." J Comp Neurol 382(2): 215-29.
2. ^ Davis, K. A. (2002). "Evidence of a functionally segregated pathway from dorsal cochlear nucleus to inferior colliculus." J Neurophysiol 87(4): 1824-35.
3. ^ Shofner, W. P. and E. D. Young (1985). "Excitatory/inhibitory response types in the cochlear nucleus: relationships to discharge patterns and responses to electrical stimulation of the auditory nerve." J Neurophysiol 54(4): 917-39.
4. ^ Young, E. D., I. Nelken, et al. (1995). "Somatosensory effects on neurons in dorsal cochlear nucleus." J Neurophysiol 73(2): 743-65.
2. ^ Davis, K. A. (2002). "Evidence of a functionally segregated pathway from dorsal cochlear nucleus to inferior colliculus." J Neurophysiol 87(4): 1824-35.
3. ^ Shofner, W. P. and E. D. Young (1985). "Excitatory/inhibitory response types in the cochlear nucleus: relationships to discharge patterns and responses to electrical stimulation of the auditory nerve." J Neurophysiol 54(4): 917-39.
4. ^ Young, E. D., I. Nelken, et al. (1995). "Somatosensory effects on neurons in dorsal cochlear nucleus." J Neurophysiol 73(2): 743-65.
The ventral cochlear nucleus (or anterior, or accessory ), placed between the two divisions of the cochlear nerve, is on the ventral aspect of the inferior peduncle.
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The cochlear nuclei consist of:
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- (a) the dorsal cochlear nucleus, corresponding to the tuberculum acusticum on the dorso-lateral surface of the inferior peduncle; and
- (b) the ventral or accessory cochlear nucleus
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Latin}}}
Official status
Official language of: Vatican City
Used for official purposes, but not spoken in everyday speech
Regulated by: Opus Fundatum Latinitas
Roman Catholic Church
Language codes
ISO 639-1: la
ISO 639-2: lat
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Official status
Official language of: Vatican City
Used for official purposes, but not spoken in everyday speech
Regulated by: Opus Fundatum Latinitas
Roman Catholic Church
Language codes
ISO 639-1: la
ISO 639-2: lat
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NeuroNames is a system of nomenclature for the human and/or macaque brain.
It is maintained by the University of Washington and is a part of a tool called "BrainInfo". BrainInfo helps one identify structures in the brain.
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It is maintained by the University of Washington and is a part of a tool called "BrainInfo". BrainInfo helps one identify structures in the brain.
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Elsevier, the world's largest publisher of medical and scientific literature, forms part of the Reed Elsevier group. Based in Amsterdam, the company has substantial operations in the UK, USA and elsewhere.
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The inferior colliculi (Latin, lower hill) together with the superior colliculi form the eminences of the corpora quadrigemina, and also part of the tectal region of the midbrain.
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The primary auditory cortex is the region of the brain that is responsible for processing of auditory (sound) information.
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Function of the Primary Auditory Cortex
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superior olivary nucleus (or superior olivary complex or superior olive) is a small mass of gray substance situated on the dorsal surface of the lateral part of the trapezoid body.
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The inferior colliculi (Latin, lower hill) together with the superior colliculi form the eminences of the corpora quadrigemina, and also part of the tectal region of the midbrain.
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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. Many neural pathways link the cerebellum with the motor cortex—which sends information to the muscles causing them
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The cochlear nuclei consist of:
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- (a) the dorsal cochlear nucleus, corresponding to the tuberculum acusticum on the dorso-lateral surface of the inferior peduncle; and
- (b) the ventral or accessory cochlear nucleus
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superior olivary nucleus (or superior olivary complex or superior olive) is a small mass of gray substance situated on the dorsal surface of the lateral part of the trapezoid body.
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The pinna (Latin for feather) is the visible part of the ear that resides outside of the head (this may also be referred to as the auricle or auricula).
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Purpose
The purpose of the pinna is to collect sound...... Click the link for more information.
In visual perception, change blindness is the phenomenon where a person viewing a visual scene apparently fails to detect large changes in the scene. For change blindness to occur, the change in the scene typically has to coincide with some visual, disruption such as a saccade (eye
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In animals, the brain or encephalon (Greek for "in the skull"), is the control center of the central nervous system, responsible for behavior. The brain is located in the head, protected by the skull and close to the primary sensory apparatus of vision, hearing,
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The rhombencephalon (or hindbrain) is a developmental categorization of portions of the central nervous system in vertebrates.
The rhombencephalon can be subdivided in a variable number of transversal swellings called rhombomeres.
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The rhombencephalon can be subdivided in a variable number of transversal swellings called rhombomeres.
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The myelencephalon is a developmental categorization of a portion of the central nervous system. The myelencephalon is composed of the medulla oblongata; contains a portion of the fourth ventricle; as well as the glossopharyngeal nerve (CN IX), vagus nerve (CN X), accessory nerve
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The medulla oblongata is the lower portion of the brainstem.
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Location
By anatomical terms of location, it is rostral to the spinal cord and caudal to the pons, which is in turn ventral to the cerebellum...... Click the link for more information.
arcuate nucleus is a group of neurons located on the anterior surface of the medullary pyramids. They receive fibers from the corticospinal tract and send their axons through the external arcuate fibers and striae medullares to the cerebellum via the inferior cerebellar peduncle.
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The interior district of the medulla oblongata is named the pyramid and lies between the anterior median fissure and the antero-lateral sulcus.
Its upper end is slightly constricted, and between it and the pons the fibers of the abducent nerve emerge; a little below the
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Its upper end is slightly constricted, and between it and the pons the fibers of the abducent nerve emerge; a little below the
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pyramidal decussation.
Having crossed the middle line, they pass down in the posterior part of the lateral funiculus as the lateral cerebrospinal fasciculus.
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Having crossed the middle line, they pass down in the posterior part of the lateral funiculus as the lateral cerebrospinal fasciculus.
Additional images
Diagrams of the medulla spinalis.
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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. They contain the olivary nuclei.
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The inferior olivary nucleus is the largest nucleus situated in the olivary body, part of the medulla oblongata.
It consists of a gray folded lamina arranged in the form of an incomplete capsule, opening medially by an aperture called the hilum.
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It consists of a gray folded lamina arranged in the form of an incomplete capsule, opening medially by an aperture called the hilum.
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The anterior median fissure (ventral or ventromedian fissure) contains a fold of pia mater, and extends along the entire length of the medulla oblongata: it ends at the lower border of the pons in a small triangular expansion, termed the foramen cecum.
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The ventral respiratory group (VRG) is a column of neurons located in the ventrolateral region of the medulla, extending from the caudal facial nucleus to -400μm obex.
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The solitary nucleus and tract are structures in the brainstem that carry and receive visceral sensation and taste from the facial (VII), glossopharyngeal (IX), vagus (X) cranial nerves, as well as the cranial part of the accessory nerve (XI).
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The solitary tract (Latin: tractus solitarius) is a compact fiber bundle that extends longitudinally through the posterolateral region of the medulla. The solitary tract is surrounded by the nucleus of the solitary tract, and descends to the upper cervical segments
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The hypoglossal nucleus is a cranial nerve nucleus, and it extends the length of the medulla, and being a motor nucleus, is close to the midline. In the open medulla, it is visible as what is known as the hypoglossal trigone
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The dorsal nucleus of the vagus nerve (or posterior motor nucleus of vagus) is a cranial nerve nucleus for the vagus nerve that arises from the floor of the fourth ventricle.
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The nucleus ambiguus (literally "ambiguous nucleus") is a region of histologically disparate cells located just dorsal (posterior) to the inferior olivary nucleus in the lateral portion of the upper (rostral) medulla.
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