Cochlea: The part of the inner ear (LABYRINTH) that is concerned with hearing. It forms the anterior part of the labyrinth, as a snail-like structure that is situated almost horizontally anterior to the VESTIBULAR LABYRINTH.Hair Cells, Auditory: Sensory cells in the organ of Corti, characterized by their apical stereocilia (hair-like projections). The inner and outer hair cells, as defined by their proximity to the core of spongy bone (the modiolus), change morphologically along the COCHLEA. Towards the cochlear apex, the length of hair cell bodies and their apical STEREOCILIA increase, allowing differential responses to various frequencies of sound.Organ of Corti: The spiral EPITHELIUM containing sensory AUDITORY HAIR CELLS and supporting cells in the cochlea. Organ of Corti, situated on the BASILAR MEMBRANE and overlaid by a gelatinous TECTORIAL MEMBRANE, converts sound-induced mechanical waves to neural impulses to the brain.Spiral Ganglion: The sensory ganglion of the COCHLEAR NERVE. The cells of the spiral ganglion send fibers peripherally to the cochlear hair cells and centrally to the COCHLEAR NUCLEI of the BRAIN STEM.Cochlear Diseases: Pathological processes of the snail-like structure (COCHLEA) of the inner ear (LABYRINTH) which can involve its nervous tissue, blood vessels, or fluid (ENDOLYMPH).Hair Cells, Auditory, Inner: Auditory sensory cells of organ of Corti, usually placed in one row medially to the core of spongy bone (the modiolus). Inner hair cells are in fewer numbers than the OUTER AUDITORY HAIR CELLS, and their STEREOCILIA are approximately twice as thick as those of the outer hair cells.Hair Cells, Auditory, Outer: Sensory cells of organ of Corti. In mammals, they are usually arranged in three or four rows, and away from the core of spongy bone (the modiolus), lateral to the INNER AUDITORY HAIR CELLS and other supporting structures. Their cell bodies and STEREOCILIA increase in length from the cochlear base toward the apex and laterally across the rows, allowing differential responses to various frequencies of sound.Spiral Ligament of Cochlea: A spiral thickening of the fibrous lining of the cochlear wall. Spiral ligament secures the membranous COCHLEAR DUCT to the bony spiral canal of the COCHLEA. Its spiral ligament fibrocytes function in conjunction with the STRIA VASCULARIS to mediate cochlear ion homeostasis.Hearing: The ability or act of sensing and transducing ACOUSTIC STIMULATION to the CENTRAL NERVOUS SYSTEM. It is also called audition.Ear, Inner: The essential part of the hearing organ consists of two labyrinthine compartments: the bony labyrinthine and the membranous labyrinth. The bony labyrinth is a complex of three interconnecting cavities or spaces (COCHLEA; VESTIBULAR LABYRINTH; and SEMICIRCULAR CANALS) in the TEMPORAL BONE. Within the bony labyrinth lies the membranous labyrinth which is a complex of sacs and tubules (COCHLEAR DUCT; SACCULE AND UTRICLE; and SEMICIRCULAR DUCTS) forming a continuous space enclosed by EPITHELIUM and connective tissue. These spaces are filled with LABYRINTHINE FLUIDS of various compositions.Labyrinth Supporting Cells: Cells forming a framework supporting the sensory AUDITORY HAIR CELLS in the organ of Corti. Lateral to the medial inner hair cells, there are inner pillar cells, outer pillar cells, Deiters cells, Hensens cells, Claudius cells, Boettchers cells, and others.Evoked Potentials, Auditory, Brain Stem: Electrical waves in the CEREBRAL CORTEX generated by BRAIN STEM structures in response to auditory click stimuli. These are found to be abnormal in many patients with CEREBELLOPONTINE ANGLE lesions, MULTIPLE SCLEROSIS, or other DEMYELINATING DISEASES.Stria Vascularis: A layer of stratified EPITHELIUM forming the endolymphatic border of the cochlear duct at the lateral wall of the cochlea. Stria vascularis contains primarily three cell types (marginal, intermediate, and basal), and capillaries. The marginal cells directly facing the ENDOLYMPH are important in producing ion gradients and endochoclear potential.Cochlear Nerve: The cochlear part of the 8th cranial nerve (VESTIBULOCOCHLEAR NERVE). The cochlear nerve fibers originate from neurons of the SPIRAL GANGLION and project peripherally to cochlear hair cells and centrally to the cochlear nuclei (COCHLEAR NUCLEUS) of the BRAIN STEM. They mediate the sense of hearing.Round Window, Ear: Fenestra of the cochlea, an opening in the basal wall between the MIDDLE EAR and the INNER EAR, leading to the cochlea. It is closed by a secondary tympanic membrane.Cochlear Microphonic Potentials: The electric response of the cochlear hair cells to acoustic stimulation.Deafness: A general term for the complete loss of the ability to hear from both ears.Perilymph: The fluid separating the membranous labyrinth from the osseous labyrinth of the ear. It is entirely separate from the ENDOLYMPH which is contained in the membranous labyrinth. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1396, 642)Endolymph: The lymph fluid found in the membranous labyrinth of the ear. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Stapes: One of the three ossicles of the middle ear. It transmits sound vibrations from the INCUS to the internal ear (Ear, Internal see LABYRINTH).Otoacoustic Emissions, Spontaneous: Self-generated faint acoustic signals from the inner ear (COCHLEA) without external stimulation. These faint signals can be recorded in the EAR CANAL and are indications of active OUTER AUDITORY HAIR CELLS. Spontaneous otoacoustic emissions are found in all classes of land vertebrates.Tectorial Membrane: A membrane, attached to the bony SPIRAL LAMINA, overlying and coupling with the hair cells of the ORGAN OF CORTI in the inner ear. It is a glycoprotein-rich keratin-like layer containing fibrils embedded in a dense amorphous substance.Scala Tympani: The lower chamber of the COCHLEA, extending from the round window to the helicotrema (the opening at the apex that connects the PERILYMPH-filled spaces of scala tympani and SCALA VESTIBULI).Hearing Loss: A general term for the complete or partial loss of the ability to hear from one or both ears.Hearing Loss, Noise-Induced: Hearing loss due to exposure to explosive loud noise or chronic exposure to sound level greater than 85 dB. The hearing loss is often in the frequency range 4000-6000 hertz.Cochlear Duct: A spiral tube that is firmly suspended in the bony shell-shaped part of the cochlea. This ENDOLYMPH-filled cochlear duct begins at the vestibule and makes 2.5 turns around a core of spongy bone (the modiolus) thus dividing the PERILYMPH-filled spiral canal into two channels, the SCALA VESTIBULI and the SCALA TYMPANI.Auditory Threshold: The audibility limit of discriminating sound intensity and pitch.Temporal Bone: Either of a pair of compound bones forming the lateral (left and right) surfaces and base of the skull which contains the organs of hearing. It is a large bone formed by the fusion of parts: the squamous (the flattened anterior-superior part), the tympanic (the curved anterior-inferior part), the mastoid (the irregular posterior portion), and the petrous (the part at the base of the skull).Chinchilla: A genus of the family Chinchillidae which consists of three species: C. brevicaudata, C. lanigera, and C. villidera. They are used extensively in biomedical research.Acoustic Stimulation: Use of sound to elicit a response in the nervous system.Hearing Loss, Sensorineural: Hearing loss resulting from damage to the COCHLEA and the sensorineural elements which lie internally beyond the oval and round windows. These elements include the AUDITORY NERVE and its connections in the BRAINSTEM.Gerbillinae: A subfamily of the Muridae consisting of several genera including Gerbillus, Rhombomys, Tatera, Meriones, and Psammomys.Guinea Pigs: A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.Cochlear Implantation: Surgical insertion of an electronic hearing device (COCHLEAR IMPLANTS) with electrodes to the COCHLEAR NERVE in the inner ear to create sound sensation in patients with residual nerve fibers.Tympanic Membrane: An oval semitransparent membrane separating the external EAR CANAL from the tympanic cavity (EAR, MIDDLE). It contains three layers: the skin of the external ear canal; the core of radially and circularly arranged collagen fibers; and the MUCOSA of the middle ear.Noise: Any sound which is unwanted or interferes with HEARING other sounds.Vestibulocochlear Nerve: The 8th cranial nerve. The vestibulocochlear nerve has a cochlear part (COCHLEAR NERVE) which is concerned with hearing and a vestibular part (VESTIBULAR NERVE) which mediates the sense of balance and head position. The fibers of the cochlear nerve originate from neurons of the SPIRAL GANGLION and project to the cochlear nuclei (COCHLEAR NUCLEUS). The fibers of the vestibular nerve arise from neurons of Scarpa's ganglion and project to the VESTIBULAR NUCLEI.Cochlear Implants: Electronic hearing devices typically used for patients with normal outer and middle ear function, but defective inner ear function. In the COCHLEA, the hair cells (HAIR CELLS, VESTIBULAR) may be absent or damaged but there are residual nerve fibers. The device electrically stimulates the COCHLEAR NERVE to create sound sensation.Ear, Middle: The space and structures directly internal to the TYMPANIC MEMBRANE and external to the inner ear (LABYRINTH). Its major components include the AUDITORY OSSICLES and the EUSTACHIAN TUBE that connects the cavity of middle ear (tympanic cavity) to the upper part of the throat.Ear Canal: The narrow passage way that conducts the sound collected by the EAR AURICLE to the TYMPANIC MEMBRANE.Presbycusis: Gradual bilateral hearing loss associated with aging that is due to progressive degeneration of cochlear structures and central auditory pathways. Hearing loss usually begins with the high frequencies then progresses to sounds of middle and low frequencies.Auditory PathwaysLabyrinthine Fluids: Fluids found within the osseous labyrinth (PERILYMPH) and the membranous labyrinth (ENDOLYMPH) of the inner ear. (From Gray's Anatomy, 30th American ed, p1328, 1332)Vestibule, Labyrinth: An oval, bony chamber of the inner ear, part of the bony labyrinth. It is continuous with bony COCHLEA anteriorly, and SEMICIRCULAR CANALS posteriorly. The vestibule contains two communicating sacs (utricle and saccule) of the balancing apparatus. The oval window on its lateral wall is occupied by the base of the STAPES of the MIDDLE EAR.Neurons, Efferent: Neurons which send impulses peripherally to activate muscles or secretory cells.Evoked Potentials, Auditory: The electric response evoked in the CEREBRAL CORTEX by ACOUSTIC STIMULATION or stimulation of the AUDITORY PATHWAYS.Sound: A type of non-ionizing radiation in which energy is transmitted through solid, liquid, or gas as compression waves. Sound (acoustic or sonic) radiation with frequencies above the audible range is classified as ultrasonic. Sound radiation below the audible range is classified as infrasonic.Endolymphatic Hydrops: An accumulation of ENDOLYMPH in the inner ear (LABYRINTH) leading to buildup of pressure and distortion of intralabyrinthine structures, such as COCHLEA and SEMICIRCULAR CANALS. It is characterized by SENSORINEURAL HEARING LOSS; TINNITUS; and sometimes VERTIGO.Cochlear Nucleus: The brain stem nucleus that receives the central input from the cochlear nerve. The cochlear nucleus is located lateral and dorsolateral to the inferior cerebellar peduncles and is functionally divided into dorsal and ventral parts. It is tonotopically organized, performs the first stage of central auditory processing, and projects (directly or indirectly) to higher auditory areas including the superior olivary nuclei, the medial geniculi, the inferior colliculi, and the auditory cortex.Petrous Bone: The dense rock-like part of temporal bone that contains the INNER EAR. Petrous bone is located at the base of the skull. Sometimes it is combined with the MASTOID PROCESS and called petromastoid part of temporal bone.Otologic Surgical Procedures: Surgery performed on the external, middle, or internal ear.Ear Ossicles: A mobile chain of three small bones (INCUS; MALLEUS; STAPES) in the TYMPANIC CAVITY between the TYMPANIC MEMBRANE and the oval window on the wall of INNER EAR. Sound waves are converted to vibration by the tympanic membrane then transmitted via these ear ossicles to the inner ear.Labyrinth Diseases: Pathological processes of the inner ear (LABYRINTH) which contains the essential apparatus of hearing (COCHLEA) and balance (SEMICIRCULAR CANALS).Mechanotransduction, Cellular: The process by which cells convert mechanical stimuli into a chemical response. It can occur in both cells specialized for sensing mechanical cues such as MECHANORECEPTORS, and in parenchymal cells whose primary function is not mechanosensory.Mice, Inbred CBAEfferent Pathways: Nerve structures through which impulses are conducted from a nerve center toward a peripheral site. Such impulses are conducted via efferent neurons (NEURONS, EFFERENT), such as MOTOR NEURONS, autonomic neurons, and hypophyseal neurons.Vibration: A continuing periodic change in displacement with respect to a fixed reference. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Acoustics: The branch of physics that deals with sound and sound waves. In medicine it is often applied in procedures in speech and hearing studies. With regard to the environment, it refers to the characteristics of a room, auditorium, theatre, building, etc. that determines the audibility or fidelity of sounds in it. (From Random House Unabridged Dictionary, 2d ed)Hearing Disorders: Conditions that impair the transmission of auditory impulses and information from the level of the ear to the temporal cortices, including the sensorineural pathways.Vestibulocochlear Nerve Diseases: Pathological processes of the VESTIBULOCOCHLEAR NERVE, including the branches of COCHLEAR NERVE and VESTIBULAR NERVE. Common examples are VESTIBULAR NEURITIS, cochlear neuritis, and ACOUSTIC NEUROMA. Clinical signs are varying degree of HEARING LOSS; VERTIGO; and TINNITUS.Meniere Disease: A disease of the inner ear (LABYRINTH) that is characterized by fluctuating SENSORINEURAL HEARING LOSS; TINNITUS; episodic VERTIGO; and aural fullness. It is the most common form of endolymphatic hydrops.Ear: The hearing and equilibrium system of the body. It consists of three parts: the EXTERNAL EAR, the MIDDLE EAR, and the INNER EAR. Sound waves are transmitted through this organ where vibration is transduced to nerve signals that pass through the ACOUSTIC NERVE to the CENTRAL NERVOUS SYSTEM. The inner ear also contains the vestibular organ that maintains equilibrium by transducing signals to the VESTIBULAR NERVE.Saccule and Utricle: Two membranous sacs within the vestibular labyrinth of the INNER EAR. The saccule communicates with COCHLEAR DUCT through the ductus reuniens, and communicates with utricle through the utriculosaccular duct from which the ENDOLYMPHATIC DUCT arises. The utricle and saccule have sensory areas (acoustic maculae) which are innervated by the VESTIBULAR NERVE.Animals, Newborn: Refers to animals in the period of time just after birth.Audiometry: The testing of the acuity of the sense of hearing to determine the thresholds of the lowest intensity levels at which an individual can hear a set of tones. The frequencies between 125 and 8000 Hz are used to test air conduction thresholds and the frequencies between 250 and 4000 Hz are used to test bone conduction thresholds.Interferometry: Measurement of distances or movements by means of the phenomena caused by the interference of two rays of light (optical interferometry) or of sound (acoustic interferometry).Audiometry, Pure-Tone: Measurement of hearing based on the use of pure tones of various frequencies and intensities as auditory stimuli.Anatomy, Regional: The anatomical study of specific regions or parts of organisms, emphasizing the relationship between the various structures (e.g. muscles, nerves, skeletal, cardiovascular, etc.).Kanamycin: Antibiotic complex produced by Streptomyces kanamyceticus from Japanese soil. Comprises 3 components: kanamycin A, the major component, and kanamycins B and C, the minor components.Hearing TestsEndolymphatic Sac: The blind pouch at the end of the endolymphatic duct. It is a storage reservoir for excess ENDOLYMPH, formed by the blood vessels in the membranous labyrinth.Inferior Colliculi: The posterior pair of the quadrigeminal bodies which contain centers for auditory function.Olivary NucleusStereocilia: Mechanosensing organelles of hair cells which respond to fluid motion or fluid pressure changes. They have various functions in many different animals, but are primarily used in hearing.Tinnitus: A nonspecific symptom of hearing disorder characterized by the sensation of buzzing, ringing, clicking, pulsations, and other noises in the ear. Objective tinnitus refers to noises generated from within the ear or adjacent structures that can be heard by other individuals. The term subjective tinnitus is used when the sound is audible only to the affected individual. Tinnitus may occur as a manifestation of COCHLEAR DISEASES; VESTIBULOCOCHLEAR NERVE DISEASES; INTRACRANIAL HYPERTENSION; CRANIOCEREBRAL TRAUMA; and other conditions.

Cochlear amplifier: The cochlear amplifier is a positive feedback mechanism within the cochlea that provides acute sensitivity in the mammalian auditory system. The main component of the cochlear amplifier is the Outer Hair Cell (OHC) which increases the amplitude and frequency selectivity of sound vibrations using electromechanical feedback.Electrical tuning: Electrical tuning is a mechanism by which vertebrates such as frogs and reptiles, which lack a long cochlea, discriminate sound. Mammals have long cochleae, and are able to distinguish different sounds by mechanisms such as mechanical tuning, in which the stiffness and length of hair cells’ stereocilia makes a given cell best suited to respond to a certain type of stimulus.Organ of Corti: The organ of Corti (or spiral organ) is the organ in the inner ear found only in mammals that contains auditory sensory cells, or "hair cells."Definition of Organ of Corti - Merriam Webster - Retrieved 30 April 2012.Spiral ganglionPirouette (dressage)Hair cell: Hair cells are the sensory receptors of both the auditory system and the vestibular system in all vertebrates. In mammals, the auditory hair cells are located within the organ of Corti on a thin basilar membrane in the cochlea of the inner ear.Ultrasonic hearing: Ultrasonic hearing is a recognised auditory effect which allows humans to perceive sounds of a much higher frequency than would ordinarily be audible using the physical inner ear, usually by stimulation of the base of the cochlea through bone conduction. Human hearing is recognised as having an upper bound around 17-20 kHz, depending on the person, but ultrasonic sinusoids as high as 120 kHz have been reported as successfully perceived.Membranous labyrinth: The receptors for the senses of equilibrium and hearing are housed within a collection of fluid filled tubes and chambers known as the membranous labyrinth. The membranous labyrinth is lodged within the bony labyrinth and has the same general form; it is, however, considerably smaller and is partly separated from the bony walls by a quantity of fluid, the perilymph.Auditory brainstem response: The auditory brainstem response (ABR) is an auditory evoked potential extracted from ongoing electrical activity in the brain and recorded via electrodes placed on the scalp. The resulting recording is a series of vertex positive waves of which I through V are evaluated.Stria vascularis of cochlear duct: The upper portion of the spiral ligament contains numerous capillary loops and small blood vessels, and is termed the stria vascularis. It produces endolymph for the scala media, one of the three fluid-filled compartments of the cochlea.Cochlear nerve: The cochlear nerve (also auditory or acoustic nerve) is a nerve in the head that carries signals from the cochlea of the inner ear to the brain. It is part of the vestibulocochlear nerve, the 8th cranial nerve which is found in higher vertebrates; the other portion of the 8th cranial nerve is the vestibular nerve which carries spatial orientation information from the semicircular canals.Round window: The round window is one of the two openings into the inner ear. It is closed off from the middle ear by the round window membrane, which vibrates with opposite phase to vibrations entering the inner ear through the oval window.Endocochlear potential: Endo cochlear presentation is the positive voltage of 80-100mV seen in the cochlear endolymphatic spaces.Within the cochlea the EP varies in the magnitude all along its length.Nonsyndromic deafness: Nonsyndromic deafness is hearing loss that is not associated with other signs and symptoms. In contrast, syndromic deafness involves hearing loss that occurs with abnormalities in other parts of the body.PerilymphEndolymph: Endolymph is the fluid contained in the membranous labyrinth of the inner ear. It is also called Scarpa's fluid, after Antonio Scarpa.Paragorgopis stapes: Paragorgopis stapes is a species of ulidiid or picture-winged fly in the genus Paragorgopis of the family Ulidiidae.stapeshttp://data.Otoacoustic emission: An otoacoustic emission (OAE) is a sound which is generated from within the inner ear. Having been predicted by Thomas Gold in 1948, its existence was first demonstrated experimentally by David Kemp in 1978Kemp DT.Tectorial membrane (cochlea): The tectorial membrane (TM) is one of two acellular gels in the cochlea of the inner ear, the other being the basilar membrane (BM). The TM is located above the sulcus spiralis internus and the spiral organ of Corti and extends along the longitudinal length of the cochlea parallel to the BM.Scala tympaniBone anchored hearing aid: A Bone-anchored hearing aid is a type of hearing aid based on bone conduction. It is primarily suited to people who have conductive hearing losses, unilateral hearing loss and people with mixed hearing losses who cannot otherwise wear 'in the ear' or 'behind the ear' hearing aids.Octave band: If it is required to analyse a source on frequency by frequency basis, it is possible but impractical and time consuming. The whole frequency range is divided into set of frequencies called bands.Reissner's membraneAbsolute threshold of hearing: The absolute threshold of hearing (ATH) is the minimum sound level of a pure tone that an average ear with normal hearing can hear with no other sound present. The absolute threshold relates to the sound that can just be heard by the organism.Mastoid part of the temporal bone: The mastoid portion of the temporal bone forms the posterior part of the temporal bone.Castle of Chinchilla: The Castle of Chinchilla (Spanish: Castillo de Chinchilla) is a castle located in Chinchilla de Monte-Aragón, Spain. It was declared Bien de Interés Cultural in 1931.Electric acoustic stimulationCongenital hearing loss: Congenital hearing loss is a hearing loss present at birth. It can include hereditary hearing loss or hearing loss due to other factors present either in-utero (prenatal) or at the time of birth.Meriones (genus): Meriones is a rodent genus that includes the gerbil most commonly kept as a pet, Meriones unguiculatus. The genus contains most animals referred to as jirds, but members of the genera Sekeetamys, Brachiones, and sometimes Pachyuromys are also known as jirds.Labeo porcellus: Labeo porcellus is fish in genus Labeo.Administrative distance: Administrative distance is the measure used by Cisco routers to select the best path when there are two or more different routes to the same destination from two different routing protocols. Administrative distance defines the reliability of a routing protocol.Tympanic membrane retraction: Tympanic membrane retraction describes a condition in which a part of the ear drum lies deeper within the ear than its normal position. The ear drum comprises two parts, the pars tensa, which is the main part of the ear drum, and the pars flaccida, which is a smaller part of the ear drum located above the pars tensa.Helicopter noise reduction: Helicopter noise reduction is a topic of research into designing helicopters which can be operated more quietly, reducing the public-relations problems with night-flying or expanding an airport. In addition, it is useful for military applications in which stealth is required: long-range propagation of helicopter noise can alert an enemy to an incoming helicopter in time to re-orient defenses.Vestibulocochlear nerve: The vestibulocochlear nerve (auditory vestibular nerve)Kolb, Bryan, and Ian Q. Whishaw.EABR: EABR refers to electrically Evoked Auditory Brain stem Responses in reference to cochlear implants. EABR results are used in the development and refinement of the cochlear implant technology.Middle ear: The middle ear is the portion of the ear internal to the eardrum, and external to the oval window of the cochlea. The mammalian middle ear contains three ossicles, which couple vibration of the eardrum into waves in the fluid and membranes of the inner ear.Ceruminous adenoma: A ceruminous adenoma (also known as adenoma of the ceruminous gland and ceruminoma) is a benign glandular neoplasm which arises from the ceruminous glands located within the external auditory canal. These glands are found within the outer one third to one half of the external auditory canal, more common along the posterior surface; therefore, the tumor develops within a very specific location.PresbycusisLateral lemniscus: 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. Three distinct, primarily inhibitory, cellular groups are located interspersed within these fibers, and are thus named the nuclei of the lateral lemniscus.Residenza Il Castello: Il Castello (Italian term of castle) of Bardine di San Terenzo is located in the Bardine's Valley, in the city of Fivizzano, between the Tuscan-Emilian Apennines and the Apuan Alps, not far from the Tyrrhenian Sea. The Castello, an ancient building dating back to the 12th century, has been long used as the residence of family Nobili.Galvanic vestibular stimulation: Galvanic vestibular stimulation is the process of sending specific electric messages to a nerve in the ear that maintains balance. There are two main groups of receptors in the vestibular system: the three semi-circular canals, and the two otolith organs (the utricle and the saccule).Motor neuron: In neurology, the term motor neuron (or motoneuron) classically applies to neurons located in the central nervous system (or CNS) that project their axons outside the CNS and directly or indirectly control muscles. The motor neuron is often associated with efferent neuron, primary neuron, or alpha motor neurons.Alaris: Alaris is the brand name of the regional rail network run by the Spanish national rail company RENFE that connects the major cities of Madrid and Valencia, and Barcelona and the main cities of the Valencian community. Alaris services currently use ETR 490 trainsets, as well as S-120 and S-130 units.Sound Blaster AudigyDorsal 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 synapses.Petro-occipital fissure: This grooved surface of the foramen magnum is separated on either side from the petrous portion of the temporal bone by the petro-occipital fissure, which is occupied in the fresh state by a plate of cartilage; the fissure is continuous behind with the jugular foramen, and its margins are grooved for the inferior petrosal sinus.Bast fibreEvolution of mammalian auditory ossicles: The evolution of mammalian auditory ossicles is one of the most well-documented and important evolutionary events, demonstrating both numerous transitional forms as well as an excellent example of exaptation, the re-purposing of existing structures during evolution.Neope pulaha: The Veined Labyrinth (Neope pulaha) is a species of satyrine butterfly found in Asia.Mechanotransduction: Mechanotransduction refers to the many mechanisms by which cells convert mechanical stimulus into chemical activity. Mechanotransduction is responsible for a number of senses and physiological processes in the body, including proprioception, touch, balance, and hearing.Amygdalofugal pathway: The amygdalofugal pathway (Latin for "fleeing from the amygdala" and commonly distinguished as the ventral amygdalofugal pathway) is one of the three principal pathways by which fibers leave the amygdala, a limbic structure in the medial temporal lobe of the brain. The other main efferent pathways from the amygdala are the stria terminalis and anterior commissure.Whole body vibration: Whole body vibration (sometimes abbreviated as WBV), is a training method in which the exerciser works out while on a machine that vibrates the body. Vibration training was initially used in the fitness industry, but has expanded to physical therapy, rehabilitation and professional sports.AcousticsUniversal neonatal hearing screening: Universal Neonatal Hearing Screening (UNHS) is an increasingly popular strategy for the early detection of hearing loss. It describes the use of objective testing methodologies (usually otoacoustic emission (OAE) testing or automated auditory brainstem response (AABR) testing) to screen the hearing of the whole population of newborns in a particular target region.Auditory neuropathy: Auditory neuropathy (AN) is a variety of hearing loss in which the outer hair cells within the cochlea are present and functional, but sound information is not faithfully transmitted to the auditory nerve and brain properly.Plas Coch: Plas Coch is an unofficial area in the Wrexham County Borough of Wales. It lies to the north-west part of the Welsh town of Wrexham.Ear: The ear is the organ that detects sound. It not only receives sound, but also aids in balance and body position.Utricle (ear): The utricle, or utriculus, along with the saccule is one of the two otolith organs located in the vertebrate inner ear. The utricle and the saccule are parts of the balancing apparatus (membraneous labyrinth) located within the vestibule of the bony labyrinth (small oval chamber).Minimum audibility curve: Minimum audibility curve is a standardised graph of the threshold of hearing versus frequency for an average human, and is used as the reference level when measuring hearing loss with an audiometer as shown on an audiogram.Angle-resolved low-coherence interferometry: Angle-resolved low-coherence interferometry (a/LCI) is an emerging biomedical imaging technology which uses the properties of scattered light to measure the average size of cell structures, including cell nuclei. The technology shows promise as a clinical tool for in situ detection of dysplatic, or precancerous tissue.Pure tone audiometryKanamycin nucleotidyltransferase: In molecular biology, kanamycin nucleotidyltransferase (KNTase) is an enzyme which is involved in conferring resistance to aminoglycoside antibiotics. It catalyses the transfer of a nucleoside monophosphate group from a nucleotide to kanamycin.Hearing testEndolymphatic sac tumor: An endolymphatic sac tumor is a very uncommon papillary epithelial neoplasm arising within the endolymphatic sac or endolymphatic duct. This tumor shows a very high association with von Hippel-Lindau syndrome (VHL).Brachium of inferior colliculus: The Brachium of inferior colliculus (or inferior brachium) carries auditory afferent fibers from the inferior colliculus of the mesencephalon to the medial geniculate nucleus.Neuroanatomy 5th edition, Nolte.Inferior olivary nucleus: The inferior olivary nucleus is the largest nucleus situated in the olivary body, part of the medulla oblongata.Tinnitus

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What kind of earphones will damage my ears the least?

I am 15 and listen to loud music on my iPod a lot, and the ear doctor told me that the vibrations from the music were killing the tiny hairs on my cochlea, so are there any earphones that would be better for my ears than the ones I use now (standard apple earphones) Thanks :-)

I would say, many studies have indicated that they all are the same. However, the government of France has imposed a limit on all music players sold in the country: they must not be capable of producing more than 100dBA (the threshold of hearing damage during extended listening is 80dB, and the threshold of pain, or theoretically of immediate hearing loss, is 130dB)
So...... since France is nearly (or so I think) is the only nation that limits the dBA of these products, you should buy earphones from France (you are a Brit, you know, shipping wouldn't be expensive)

BUT, instead of all the ruckus, why don't you just lower the volume? My brother is just like you! Honestly, I tried it once (for 1 second!) And my ears hurt like hell! Did you know that a British study revealed that listening to loud music for 5+ hours a week is EXTREMELY DANGEROUS and can result in temporary or PERMANENT hearing impairment or deafness?

Keep it safe!  (+ info)

what is cochlea disorder?

The inner ear structure called the cochlea is a snail-shell like structure divided into three fluid-filled parts. Two are canals for the transmission of pressure and in the third is the sensitive organ of Corti, which detects pressure impulses and responds with electrical impulses which travel along the auditory nerve to the brain. Located in the area of the ear where nerves are contained, its function is to gather electrical signals from sound vibrations and transmit them to your auditory nerve (or hearing nerve). The hearing nerve then sends these signals to the brain, where they're translated into recognizable sounds. If important parts of the cochlea aren't working properly and the hearing nerve isn't being stimulated, there's no way for the electrical signals to get to the brain. Therefore, hearing doesn't occur. (Sometimes referred to as nerve deafness, this is called sensorineural hearing loss.)


It is extremely important to obtain an accurate diagnosis before trying to find a cure. Many diseases and conditions share common symptoms.

The information provided here should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions.

Hope this helps
matador 89  (+ info)

Can a damaged Cochlea be a result of childhood ear infections?

As a child I had lots of ear infections. I also have moderate hearing loss. I was told that I have a problem with my cochlea. I have been thinking and wondering to myself if this was from my childhood or maybe I was born this way.
If you don't have a clue don't post anything. I'm tired of people making posts that are not answers.
I just had the usual antibiotics. I am 23 now. I vaguely remember having the infections. They all happened before I was in kindergarten, possibly earlier.
The reason why I'm asking is because the audiologist told me that my ear drum looks perfectly normal, without any scaring so I never ruptured my ear drum. In the test she ran she found that my middle ear bones work fine as well. I also respond well to my hearing aids which says that my auditory nerves function well. So she narrowed it down and told me that my cochlea is not working as it should.

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Physiologically, what makes people cringe when they hear fingernails on a blackboard?

Is it some kind of latent instinct from time immemorial? Or simply a reaction our cochleas have when exposed to those particular waves?

there is reflex that related to hearing(acoustic reflex) but it is irrelevant to your question.

i believe, it relates to our unconscious, which is induce the feeling of scream caused by pain!  (+ info)

Is there a cure for Hearing Impairment ?

I know that stem cell research holds promising possibilities for regrowing cochlea nerves. But the US has had restrictions on stem cell funding the past 8 years Bush was in office. I have a hearing loss and am curious if any other countries have found a cure.

currently there is cochlear implants these are somewhat controversial and probably something that you should talk over with your doctor and family. But yeah stem cell research is relatively new and it could be a couple of years before something concrete or miraculous comes out.  (+ info)

I was hit directly in my ear, and I suddenly lost my hearing. Is there any medicine I can use to fix this?

I found some information online that said I could have damaged my cochlea. It just happened and I have not been to the doctor yet. What should I do in the mean time to help get my hearing back?

no medicine until you go see a doctor. You could have ruptured your eardrum and have some infection also going on now. You do not want to play with hearing loss so I suggest you go to see a doctor and if you can't afford on go to the hospital. Most hospitals will give you free help once you go over your income. Don't let that stop you. Your hearing is very important.  (+ info)

when you have ear ringing, can the sound of the ear ringing itself hurt your ears?

i have ringing in my right ear, and im wonderind if that constant ring can cause damage, just like a hihgh pitched sound would, or is the ringing just an illusion of sorts(your eardrum isnt actually picking up or making any sound, you just hear it) beacuase im wondering if its actual sound, or an illusion sent to your brain from your cochlea

Yep - What Calli said is pretty much correct. Another way to put it is that the damage is already done, at the nerve level. There isn't actually any real sound causing the ringing sensation, so it can't cause further damage.

One important thing to watch out for - since there has already been some injury to the cilia and nerves, it'll be easier for loud noises to cause more damage. If you like loud music, use firearms or work in a very noisy environment you'd be smart to start wearing something like those foam or soft rubber ear plugs. You can find them in Walgreen's, WalMart or almost any pharmacy. I'm not kidding. I learned the hard way.  (+ info)

I am 23 and hearing loss my whole life I was wondering if the have some new surgeries or a site i can look at?

microscopic hairs on my cochleas are laying down rather than standing erect to catch the full effect of vibrations passing through the ear canal. I was wondering if there is some new and improved surgeries out there (hopefully on the east coast) somewhere to correct this problem. Or at least a website that might lead me in the right direction.

have you researched Cochlear Implants?
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(9/1700) Developmental expression of the TGF beta s in the mouse cochlea.

Mice with targeted disruption of the TGF beta 2 gene display defects in epithelial-mesenchymal tissue interactions in several tissues including the developing cochlea. Specifically, the region of the spiral limbus and the overlying interdental cells, structures putatively involved in endolymphatic fluid homeostasis, display morphogenetic abnormalities. These findings prompted us to explore the pre-natal and post-natal expression of all three mammalian TGF beta genes in the developing mouse inner ear. TGF beta 2 mRNA expression was identified throughout the cochlear epithelium at all of the developmental stages examined. TGF beta 3 mRNA expression was identified in the mesenchymal tissues of the cochlea surrounding the otic epithelium. We found no evidence for compensation by the other two TGF beta isoforms in the cochleas of the TGF beta 2 mutants.  (+info)

(10/1700) 13-cis-Retinoic acid alters neural crest cells expressing Krox-20 and Pax-2 in macaque embryos.

This study investigates hindbrain and associated neural crest (NCC), otocyst, and pharyngeal arch development in monkey embryos following teratogenic exposure to 13-cis-retinoic acid (cRA). cRA was orally administered (5 mg/kg) to pregnant long-tailed macaques (Macaca fascicularis) between gestational days (GD) 12 and 27. Embryos were surgically collected at desired stages during treatment, analyzed for external morphological changes, and processed for immunohistochemistry. Two transiently expressed nuclear proteins, Krox-20 and Pax-2, were used as markers for the target cellular and anatomical structures. Rhombomere (r) expression patterns of Pax-2 (r4/r6) and Krox-20 (r3/r5) were maintained after cRA treatment, but r4 and r5 were substantially reduced in size. In untreated embryos, Krox-20 immunoreactive NCC derived from r5 migrated caudally around the developing otocyst to contribute to the third pharyngeal arch mesenchyme. In cRA-treated embryos, a subpopulation of NCC rostral to the otocyst also showed Krox-20 immunoreactivity, but there was a substantial reduction in Krox-20 post-otic NCC. Pax-2 immunoreactive NCC migrating from r4 to the second pharyngeal arch were substantially reduced in numbers in treated embryos. Alteration in the otic anlage included delayed invagination, abnormal relationship with the adjacent hindbrain epithelium, and altered expression boundaries for Pax-2. cRA-associated changes in the pharyngeal arch region due to cRA included truncation of the distal portion of the first arch and reduction in the size of the second arch. These alterations in hindbrain, neural crest, otic anlage, and pharyngeal arch morphogenesis could contribute to some of the craniofacial malformations in the macaque fetus associated with exposure to cRA.  (+info)

(11/1700) Math1: an essential gene for the generation of inner ear hair cells.

The mammalian inner ear contains the cochlea and vestibular organs, which are responsible for hearing and balance, respectively. The epithelia of these sensory organs contain hair cells that function as mechanoreceptors to transduce sound and head motion. The molecular mechanisms underlying hair cell development and differentiation are poorly understood. Math1, a mouse homolog of the Drosophila proneural gene atonal, is expressed in inner ear sensory epithelia. Embryonic Math1-null mice failed to generate cochlear and vestibular hair cells. This gene is thus required for the genesis of hair cells.  (+info)

(12/1700) Somatic stiffness of cochlear outer hair cells is voltage-dependent.

The mammalian cochlea depends on an amplification process for its sensitivity and frequency-resolving capability. Outer hair cells are responsible for providing this amplification. It is usually assumed that the membrane-potential-driven somatic shape changes of these cells are the basis of the amplifying process. It is of interest to see whether mechanical reactance changes of the cells might accompany their changes in cell shape. We now show that the cylindrical outer hair cells change their axial stiffness as their membrane potential is altered. Cell stiffness was determined by optoelectronically measuring the amplitude of motion of a flexible vibrating fiber as it was loaded by the isolated cell. Voltage commands to the cell were delivered in a tight-seal whole-cell configuration. Cell stiffness was decreased by depolarization and increased by hyperpolarization.  (+info)

(13/1700) Mutation of the Na-K-Cl co-transporter gene Slc12a2 results in deafness in mice.

Hearing impairment is a common human condition, but we know little about the molecular basis of cochlear function. Shaker-with-syndactylism (sy) is a classic deaf mouse mutant and we show here that a second allele, sy(ns), is associated with abnormal production of endolymph, the fluid bathing sensory hair cells. Using a positional candidate approach, we demonstrate that mutations in the gene encoding the basolateral Na-K-Cl co-transporter Slc12a2 (Nkcc1, mBSC2) cause the deafness observed in sy and sy(ns) mice. This finding provides the molecular basis of another link in the chain of K+recycling in the cochlea, a process essential for normal cochlear function.  (+info)

(14/1700) Role of alpha9 nicotinic ACh receptor subunits in the development and function of cochlear efferent innervation.

Cochlear outer hair cells (OHCs) express alpha9 nACh receptors and are contacted by descending, predominately cholinergic, efferent fibers originating in the CNS. Mice carrying a null mutation for the nACh alpha9 gene were produced to investigate its role(s) in auditory processing and development of hair cell innervation. In alpha9 knockout mice, most OHCs were innervated by one large terminal instead of multiple smaller terminals as in wild types, suggesting a role for the nACh alpha9 subunit in development of mature synaptic connections. Alpha9 knockout mice also failed to show suppression of cochlear responses (compound action potentials, distortion product otoacoustic emissions) during efferent fiber activation, demonstrating the key role alpha9 receptors play in mediating the only known effects of the olivocochlear system.  (+info)

(15/1700) Targeted mutagenesis of the POU-domain gene Brn4/Pou3f4 causes developmental defects in the inner ear.

Targeted mutagenesis in mice demonstrates that the POU-domain gene Brn4/Pou3f4 plays a crucial role in the patterning of the mesenchymal compartment of the inner ear. Brn4 is expressed extensively throughout the condensing mesenchyme of the developing inner ear. Mutant animals displayed behavioral anomalies that resulted from functional deficits in both the auditory and vestibular systems, including vertical head bobbing, changes in gait, and hearing loss. Anatomical analyses of the temporal bone, which is derived in part from the otic mesenchyme, demonstrated several dysplastic features in the mutant animals, including enlargement of the internal auditory meatus. Many phenotypic features of the mutant animals resulted from the reduction or thinning of the bony compartment of the inner ear. Histological analyses demonstrated a hypoplasia of those regions of the cochlea derived from otic mesenchyme, including the spiral limbus, the scala tympani, and strial fibrocytes. Interestingly, we observed a reduction in the coiling of the cochlea, which suggests that Brn-4 plays a role in the epithelial-mesenchymal communication necessary for the cochlear anlage to develop correctly. Finally, the stapes demonstrated several malformations, including changes in the size and morphology of its footplate. Because the stapes anlage does not express the Brn4 gene, stapes malformations suggest that the Brn4 gene also plays a role in mesenchymal-mesenchymal signaling. On the basis of these data, we suggest that Brn-4 enhances the survival of mesodermal cells during the mesenchymal remodeling that forms the mature bony labyrinth and regulates inductive signaling mechanisms in the otic mesenchyme.  (+info)

(16/1700) Cross-modal reorganization of callosal connectivity without altering thalamocortical projections.

Mammalian cerebral cortex is composed of a multitude of different areas that are each specialized for a unique purpose. It is unclear whether the activity pattern and modality of sensory inputs to cortex play an important role in the development of cortical regionalization. The modality of sensory inputs to cerebral cortex can be altered experimentally. Neonatal diversion of retinal axons to the auditory thalamus (cross-modal rewiring) results in a primary auditory cortex (AI) that resembles the primary visual cortex in its visual response properties and topography. Functional reorganization could occur because the visual inputs use existing circuitry in AI, or because the early visual inputs promote changes in AI's circuitry that make it capable of constructing visual receptive field properties. The present study begins to distinguish between these possibilities by exploring whether the callosal connectivity of AI is altered by early visual experience. Here we show that early visual inputs to auditory thalamus can reorganize callosal connections in auditory cortex, causing both a reduction in their extent and a reorganization of the pattern. This result is distinctly different from that in deafened animals, which have widespread callosal connections, as in early postnatal development. Thus, profound changes in cortical circuitry can result simply from a change in the modality of afferent input. Similar changes may underlie cortical compensatory processes in deaf and blind humans.  (+info)