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 Pathways: NEURAL PATHWAYS and connections within the CENTRAL NERVOUS SYSTEM, beginning at the hair cells of the ORGAN OF CORTI, continuing along the eighth cranial nerve, and terminating at the AUDITORY CORTEX.Labyrinthine 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 Tests: Part of an ear examination that measures the ability of sound to reach the brain.Endolymphatic 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 Nucleus: A part of the MEDULLA OBLONGATA situated in the olivary body. It is involved with motor control and is a major source of sensory input to the CEREBELLUM.Stereocilia: 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.

3D MRI of the membranous labyrinth. An age related comparison of MR findings in patients with labyrinthine fibrosis and in persons without inner ear symptoms. (1/1700)

PURPOSE: We compared MRI of the membranous labyrinth in patients with chronic non-neoplastic inner ear disease and MR signs of labyrinthine fibrosis and controls depending on their age, in order to establish whether there were any MR differences regarding patient age groups, control age groups and between the patients and controls themselves. MATERIALS AND METHODS: Clinical ENT examinations as well as a T2* weighted 3D CISS (Constructive Interference in Steady State) sequence with a slice thickness of 0.7 mm were performed. Our collective was subdivided as follows: 0-19 years (10 controls, 3 patients with chronic non-neoplastic inner ear disease), 20-49 years (55 controls, 8 patients), 50 years and older (40 controls, 22 patients). Detectability of labyrinthine structures (e.g. cochlea, vestibule, semicircular canals) and filling defects were evaluated. RESULTS: In the 3 age-groups of the control collective no significant differences were observed in the membranous labyrinth. However differences concerning labyrinthine detectability emerged between controls and patients in both the 20-49 years and 50 years and older age groups. In the patient collective the 3 age groups showed no significant discrepancy in the mean number of lesions. CONCLUSION: Filling defects of the membranous labyrinth on 3D CISS MR images are pathological even in older persons. We would therefore recommend high resolution T2* weighted MRI in the case of suspected labyrinthine fibrosis.  (+info)

Inner ear and kidney anomalies caused by IAP insertion in an intron of the Eya1 gene in a mouse model of BOR syndrome. (2/1700)

A spontaneous mutation causing deafness and circling behavior was discovered in a C3H/HeJ colony of mice at the Jackson Laboratory. Pathological analysis of mutant mice revealed gross morphological abnormalities of the inner ear, and also dysmorphic or missing kidneys. The deafness and abnormal behavior were shown to be inherited as an autosomal recessive trait and mapped to mouse chromosome 1 near the position of the Eya1 gene. The human homolog of this gene, EYA1, has been shown to underly branchio-oto-renal (BOR) syndrome, an autosomal dominant disorder characterized by hearing loss with associated branchial and renal anomalies. Molecular analysis of the Eya1 gene in mutant mice revealed the insertion of an intracisternal A particle (IAP) element in intron 7. The presence of the IAP insertion was associated with reduced expression of the normal Eya1 message and formation of additional aberrant transcripts. The hypomorphic nature of the mutation may explain its recessive inheritance, if protein levels in homozygotes, but not heterozygotes, are below a critical threshold needed for normal developmental function. The new mouse mutation is designated Eya1(bor) to denote its similarity to human BOR syndrome, and will provide a valuable model for studying mutant gene expression and etiology.  (+info)

Synapses involving auditory nerve fibers in primate cochlea. (3/1700)

The anatomical mechanisms for processing auditory signals are extremely complex and incompletely understood, despite major advances already made with the use of electron microscopy. A major enigma, for example, is the presence in the mammalian cochlea of a double hair cell receptor system. A renewed attempt to discover evidence of synaptic coupling between the two systems in the primate cochlea, postulated from physiological studies, has failed. However, in the outer spiral bundle the narrow and rigid clefts seen between pairs of presumptive afferent fibers suggest the possibility of dendro-dendritic interaction confined to the outer hair cell system. The clustering of afferent processes within folds of supporting cells subjacent to outer hair cells is in contrast to the lack of such close associations in the inner hair cell region. The difference reinforces the suggestion of functional interaction of some sort between the outer hair cell afferent nerve processes.  (+info)

Development of acetylcholine-induced responses in neonatal gerbil outer hair cells. (4/1700)

Cochlear outer hair cells (OHCs) are dominantly innervated by efferents, with acetylcholine (ACh) being their principal neurotransmitter. ACh activation of the cholinergic receptors on isolated OHCs induces calcium influx through the ionotropic receptors, followed by a large outward K+ current through nearby Ca2+-activated K+ channels. The outward K+ current hyperpolarizes the cell, resulting in the fast inhibitory effects of efferent action. Although the ACh receptors (AChRs) in adult OHCs have been identified and the ACh-induced current responses have been characterized, it is unclear when the ACh-induced current responses occur during development. In this study we attempt to address this question by determining the time of onset of the ACh-induced currents in neonatal gerbil OHCs, using whole cell patch-clamp techniques. Developing gerbils ranging in age from 4 to 12 days were used in these experiments, because efferent synaptogenesis and functional maturation of OHCs occur after birth. Results show that the first detectable ACh-induced current occurred at 6 days after birth (DAB) in 12% of the basal turn cells with a small outward current. The fraction of responsive cells and the size of outward currents increased as development progressed. By 11 DAB, the fraction of responsive cells and the current size were comparable with those of adult OHCs. The results indicate that the maturation of the ACh-induced response begins around 6 DAB. It appears that the development of ACh-induced responses occur during the same time period when OHCs develop motility but before the onset of auditory function, which is around 12 DAB when cochlear microphonic potentials can first be evoked with acoustic stimulation in gerbils.  (+info)

Comparing in vitro, in situ, and in vivo experimental data in a three-dimensional model of mammalian cochlear mechanics. (5/1700)

Normal mammalian hearing is refined by amplification of the motion of the cochlear partition. This partition, comprising the organ of Corti sandwiched between the basilar and tectorial membranes, contains the outer hair cells that are thought to drive this amplification process. Force generation by outer hair cells has been studied extensively in vitro and in situ, but, to understand cochlear amplification fully, it is necessary to characterize the role played by each of the components of the cochlear partition in vivo. Observations of cochlear partition motion in vivo are severely restricted by its inaccessibility and sensitivity to surgical trauma, so, for the present study, a computer model has been used to simulate the operation of the cochlea under different experimental conditions. In this model, which uniquely retains much of the three-dimensional complexity of the real cochlea, the motions of the basilar and tectorial membranes are fundamentally different during in situ- and in vivo-like conditions. Furthermore, enhanced outer hair cell force generation in vitro leads paradoxically to a decrease in the gain of the cochlear amplifier during sound stimulation to the model in vivo. These results suggest that it is not possible to extrapolate directly from experimental observations made in vitro and in situ to the normal operation of the intact organ in vivo.  (+info)

Gene disruption of p27(Kip1) allows cell proliferation in the postnatal and adult organ of corti. (6/1700)

Hearing loss is most often the result of hair-cell degeneration due to genetic abnormalities or ototoxic and traumatic insults. In the postembryonic and adult mammalian auditory sensory epithelium, the organ of Corti, no hair-cell regeneration has ever been observed. However, nonmammalian hair-cell epithelia are capable of regenerating sensory hair cells as a consequence of nonsensory supporting-cell proliferation. The supporting cells of the organ of Corti are highly specialized, terminally differentiated cell types that apparently are incapable of proliferation. At the molecular level terminally differentiated cells have been shown to express high levels of cell-cycle inhibitors, in particular, cyclin-dependent kinase inhibitors [Parker, S. B., et al. (1995) Science 267, 1024-1027], which are thought to be responsible for preventing these cells from reentering the cell cycle. Here we report that the cyclin-dependent kinase inhibitor p27(Kip1) is selectively expressed in the supporting-cell population of the organ of Corti. Effects of p27(Kip1)-gene disruption include ongoing cell proliferation in postnatal and adult mouse organ of Corti at time points well after mitosis normally has ceased during embryonic development. This suggests that release from p27(Kip1)-induced cell-cycle arrest is sufficient to allow supporting-cell proliferation to occur. This finding may provide an important pathway for inducing hair-cell regeneration in the mammalian hearing organ.  (+info)

A changing pattern of brain-derived neurotrophic factor expression correlates with the rearrangement of fibers during cochlear development of rats and mice. (7/1700)

The reorganization of specific neuronal connections is a typical feature of the developing nervous system. It is assumed that the refinement of connections in sensory systems requires spontaneous activity before the onset of cochlear function and selective sensory experience during the ensuing period. The mechanism of refinement through sensory experience is currently postulated as being based on the selective reinforcement of active projections by neurotrophins. We studied a presumed role of neurotrophins for rearrangement of afferent and efferent fibers before the onset of sensory function in the precisely innervated auditory end organ, the cochlea. We observed a spatiotemporal change in the localization of brain-derived neurotrophic factor (BDNF) protein and mRNA, which correlated with the reorganization of fibers. Thus, BDNF decreased in target hair cells during fiber retraction and was subsequently upregulated in neurons, target hair cells, and adjacent supporting cells concomitant with the formation of new synaptic contacts. Analysis of the innervation pattern in BDNF gene-deleted mice by immunohistochemistry and confocal microscopy revealed a failure in the rearrangement of fibers and a BDNF dependency of distinct neuronal projections that reorganize in control animals. Our data suggest that, before the onset of auditory function, a spatiotemporal change in BDNF expression in sensory, epithelial, and neuronal cells may guide the initial steps of refinement of the innervation pattern.  (+info)

Dose dependent protection by lipoic acid against cisplatin-induced ototoxicity in rats: antioxidant defense system. (8/1700)

This study investigated the alterations that occur in auditory brainstem-evoked responses (ABRs) concurrent with changes in cochlear concentrations of glutathione (GSH), lipid peroxidation, and antioxidant enzyme activity in cisplatin-induced ototoxicity and in dose-dependent otoprotection by an antioxidant lipoate. Male Wistar rats were divided into different groups and were treated as follows, with: (1) vehicle (saline) control; (2) cisplatin (16 mg/kg, i.p.); (3) lipoate (100 mg/kg, i.p.) plus saline; (4) cisplatin plus lipoate (25 mg/kg); (5) cisplatin plus lipoate (50 mg/kg), and (6) cisplatin plus lipoate (100 mg/kg). Post-treatment ABRs were evaluated after three days, the rats were sacrificed, and cochleae were harvested and analyzed. The cisplatin-injected rats showed ABR threshold elevations above the pre-treatment thresholds. Rats treated with lipoate plus cisplatin did not show significant elevation of hearing thresholds. Cisplatin administration resulted in a depletion of cochlear GSH concentration (69% of control), whereas, cisplatin-plus-lipoate treatment increased GSH concentration close to control value. Cisplatin-treated rats showed a decrease in cochlear superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione reductase (GR) activities (57, 78, 59, and 58% of control, respectively), and an increase in malondialdehyde (MDA) concentration (196% of control). Cochlear SOD, CAT, GSH-Px, and GR activities and MDA concentrations were restored in the rats injected with cisplatin plus graded doses of lipoate than those with cisplatin alone. It is concluded that cisplatin-induced ototoxicity is related to impairment of the cochlear antioxidant defense system, and the dose-dependent otoprotection conferred by an antioxidant lipoate against cisplatin ototoxicity is associated with sparing of the cochlear antioxidant defense system.  (+info)

Nitric oxide (NO) has been implicated as a mediator of vasodilation and neurotransmission in the mammalian cochlea. This is demonstrated by the presence of nitric oxide synthase (NOS) and nitric oxide (NO) in the blood vessels and the organ of Corti in the cochlea. It is not certain if the neurons in the spiral ganglion produce NO since no fluorescent signal could be detected by 4,5-diaminofluorescein diacetate (DAF-2DA), a fluorescent indicator of NO. To determine if NO/peroxynitrite plays any role in neurodestruction observed in ischemic cochlea of the guinea pig, the effects of NO donors, such as S-nitrosocysteine (S-NC) and nitroglycerine (NTG); peroxynitrite generators, such as 3-morpholinosydnonimine (SIN-1); peroxynitrite inhibitors, such as superoxide dismutase plus catalase (SOD/Cat); and NOS inhibitors, such as NG-nitro-L-arginine methyl ether (L-NAME) were tested on normal and ischemic cochleae. The level of NO in the cochlea after 20 to 120 minutes of ischemia was indicated by ...
TY - JOUR. T1 - Intra-tympanic delivery of short interfering RNA into the adult mouse cochlea. AU - Oishi, Naoki. AU - Chen, Fu Quan. AU - Zheng, Hong Wei. AU - Sha, Su Hua. PY - 2013/2/1. Y1 - 2013/2/1. N2 - Trans-tympanic injection into the middle ear has long been the standard for local delivery of compounds in experimental studies. Here we demonstrate the advantages of the novel method of intra-tympanic injection through the otic bone for the delivery of compounds or siRNA into the adult mouse cochlea. First, a fluorescently-conjugated scrambled siRNA probe was applied via intra-tympanic injection into the middle ear cavity and was detected in sensory hair cells and nerve fibers as early as 6 h after the injection. The fluorescent probe was also detected in other cells of the organ of Corti, the lateral wall, and in spiral ganglion cells 48 h after the injection. Furthermore, intra-tympanic delivery of Nox3 siRNA successfully reduced immunofluorescence associated with Nox3 in outer hair ...
In the chicken basilar papilla it has been reported that overexpression of activated β-catenin induces ectopic HC formation (Stevens et al., 2003) and, more recently, it has been shown that canonical Wnt activation can induce proliferation within dissociated epithelial cells of the avian utricle (Alvarado et al., 2011). The role for this pathway during mammalian cochlear development, however, was unknown. Although multiple transgenic canonical Wnt reporter mice have been generated (listed on the Wnt homepage http://www.stanford.edu/group/nusselab/cgi-bin/wnt/), inconsistencies existed as to the exact spatiotemporal pattern of endogenous Wnt/β-catenin activity (Barolo, 2006). In the inner ear, Qian et al. (Qian et al., 2007) reported no Wnt/β-catenin activity in the otocyst and developing cochlea using the BAT-gal mouse (Maretto et al., 2003), whereas Laine et al. (Laine et al., 2010) identified low-level activity in cochleae of the same BAT-gal strain as well as in the TOP-gal reporter ...
Authors: Suh, Myung Whan , Shin, Dong Hoon , Lee, Ho Sun , Park, Ji Yeong , Kim, Chong Sun , Oh, Seung Ha Article Type: Research Article Abstract: Unlike mammals, avian cochlear hair cells can regenerate after acoustic overstimulation. The WDR1 gene is one of the genes suspected to play an important role in this difference. In an earlier study, we found that the WDR1 gene is over-expressed in the chick cochlea after acoustic overstimulation. The aim of this study was to compare the expression of WDR1 before and after acoustic overstimulation in the chick vestibule. Seven-day-old chicks were divided into three groups: normal …group, damage group, and regeneration group. The damage and regeneration group was exposed to 120 dB SPL white noise for 5-6 hours. The damage group was euthanized shortly after the impulse, but the regeneration group was allowed to recover for 2 days. The utricle, saccule, and the three ampullae of each semicircular canal were dissected and immunohistochemically stained ...
By using a device that provides high-resolution images of the inner ear, researchers are learning about the mechanics of hearing. In order to develop therapies for hearing loss, its important to understand the functions of different areas of the cochlea, and until now, that hasnt been very easy.. Because the cochlea is so small and difficult to access, researchers havent been able to study it very easily without causing damage to the ear. But by using this technology (OCT, or optical coherence tomography), researchers at Texas A&M and Stanford have been able to gather information about the way the cochlea converts vibrations into nerve impulses to create sound without having to open the bone around it.. The concept has been proven in mice, and researchers have been able to gather measurements without causing any damage to the mouse cochlea or surrounding tissues. A prototype device has been developed for human use. If researchers can map the human cochlea and determine what happens to the ...
Maturation of neurotransmission in the developing rat cochlea: immunohistochemical evidence from differential expression of synaptophysin and synaptobrevin 2
Cochlea: The cochlea contains the sensory organ of hearing. It bears a striking resemblance to the shell of a snail and in fact takes its name from the Greek word for this object. The cochlea is a spiral tube that is…
By using a device that provides high-resolution images of the inner ear, researchers are learning about the mechanics of hearing. In order to develop therapies for hearing loss, its important to understand the functions of different areas of the cochlea, and until now, that hasnt been very easy.. Because the cochlea is so small and difficult to access, researchers havent been able to study it very easily without causing damage to the ear. But by using this technology (OCT, or optical coherence tomography), researchers at Texas A&M and Stanford have been able to gather information about the way the cochlea converts vibrations into nerve impulses to create sound without having to open the bone around it.. The concept has been proven in mice, and researchers have been able to gather measurements without causing any damage to the mouse cochlea or surrounding tissues. A prototype device has been developed for human use. If researchers can map the human cochlea and determine what happens to the ...
The risks and efficacy of transplanting two varieties of stem cells into mouse cochlea have been evaluated by Japanese researchers.
The cochlea is a fluid-filled structure in the middle ear. The sound waves are translated to fluid waves in the cochlea that are then sensed by nerves connected to fine hairs that float in the fluid and is then sent on to the brain for interpretation. This is the area that a human "cochlear implant" stimulates to help correct hearing loss. The feline cochlea has 3 complete turns while the human cochlea only has 2.75 turns. They have 10,000 more auditory nerves than humans. Near the cochlea is another fluid- and carbonate crystal-filled structure called the vestibular apparatus that is in charge of balance.. Cats are exquisitely adept at locating prey. They can distinguish between two different sound sources 8 cm apart (shorter than the length of an iPhone) at 2 yards and 40cm apart (about 1 foot, or a little longer than 3 iPhones) at 20 yards. They can hear a rustling mouse 20-30 yards away. They can hear 10 distinct octaves of notes vs. humans 8.5 octaves. They even hear one octave above their ...
You may find this publication the answer to your problems. Brain Research Protocols Volume 6, Issue 3, February 2001, Pages 159-166 Cryoembedding and sectioning of cochleas for immunocytochemistry and in situ hybridization Donna S. Whitlon, Renee Szakaly, Mary A. Greiner Abstract Current emphasis on biochemical and molecular aspects of cochlear anatomy underscores the necessity for high quality cryostat sections of the inner ear. The large volume of fluid space within the cochlea makes cryoembedding and sectioning of the organ more problematic than that of other, more homogeneous tissues. Our method for cryoembedding of cochleas for immunocytochemistry and in situ hybridization uses slow infiltration with increasing concentrations of sucrose followed by degassed embedding medium before final orientation and freezing. This method permits high quality cryosections to be cut which preserve overall structure and cellular resolution. Author Keywords: Cryosections; Cochlea; Immunocytochemistry; In ...
The cochlea receives its main blood supply from the basilar artery, via the anterior inferior cerebellar artery and the spiral modiolar artery. It is of clinica...
The observed disorganization and expansion of the organ of Corti, in addition to the proliferation following ectopic β-catenin activation, suggested changes in the adhesion complexes within the epithelium. In addition to roles in proliferation and differentiation, β-catenin plays a role in cell adhesion by binding to the cytoplasmic tail of cadherins at the plasma membrane (Ozawa et al., 1989). Similar to β-catenin, E-cadherin is expressed within the cell membranes of the cochlear sensory epithelium (Whitlon, 1993; Leonova and Raphael, 1997; Simonneau et al., 2003). When we overexpressed β-catenin in the cochlea after initiation of tamoxifen at E13.5 in the Sox2-CreER;β-cateninflox(exon3) mouse, elongation of the sensory epithelium proceeded into the apical region (Fig. 8A) as expected, and staining for EdU as well as Ki67, a cell proliferation marker, were observed (Fig. 8B), but E-cadherin expression within the cell membranes was decreased (Fig. 8C,E). The cochlea contained multiple rows ...
Our aims are to identify the molecular mechanisms that regulate the expression of Fgf20 during the embryonic development of the cochlea; to determine how FGF20 regulates sensory progenitor cell growth and the differentiation of cochlear outer hair and supporting cells in the organ of Corti; and to identify the specific genes and pathways that act downstream of FGF20 during cochlear development using Next Gen mRNA sequencing. We are testing the hypothesis that FGF signaling can enhance sensory cell regeneration following ototoxic damage.. 2. Regulation of neuronal excitability by intracellular FGFs.. We are studying a unique subfamily of FGFs that act intracellularly (iFGFs) in neurons and cardiomyocytes and that are important for regulating cell excitability through interactions with voltage gated sodium channels. Disruption of FGF14, one of four iFGFs, results in an anatomically normal mouse with severe neurobehavioral phenotypes including ataxia, seizure, paroxysmal dystonia and cognitive ...
Sounds pass from the outer ear through to the inner ear, which contains the cochlea and auditory nerve. The cochlea is a coiled, spiral tube containing a large number of sensitive hair cells. The auditory nerve transmits sound signals to the brain.. If part of the cochlea is damaged, it will stop sending information to your brain. The brain may then actively "seek out" signals from parts of the cochlea that still work. These signals might then become over-represented in the brain, which may cause the sounds of tinnitus.. In older people, damage to the cochlea often occurs naturally with age. In younger people, it can be caused by repeated exposure to excessive noise.. ...
Sounds pass from the outer ear through to the inner ear, which contains the cochlea and auditory nerve. The cochlea is a coiled, spiral tube containing a large number of sensitive hair cells. The auditory nerve transmits sound signals to the brain.. If part of the cochlea is damaged, it will stop sending information to your brain. The brain may then actively "seek out" signals from parts of the cochlea that still work. These signals might then become over-represented in the brain, which may cause the sounds of tinnitus.. In older people, damage to the cochlea often occurs naturally with age. In younger people, it can be caused by repeated exposure to excessive noise.. ...
Figure 1. Vangl2 is asymmetrical localized in the organ of Corti. A, Schematic diagram illustrating a surface view of the OC in the mammalian cochlea. Proximal-to-distal and basal-to-apical axes are indicated. The OC comprises a single row of IHCs and three rows of OHCs (O1-O3) that extend along the basal-to-apical axis. Individual hair cells are separated by specific types of supporting cells including IPh cells located between IHCs, Deiters cells (D1-D3), located between OHCs and OPs, located between OHCs in OHC1 and IPs, which create a space between the row of IHC and OHC1. Finally, the proximal edge of IHCs is contacted by a row of border cells (BC). Each HC has a stereociliary bundle (red) located on its lumenal surface. Each bundle is oriented such that its central vertex is located closest to the distal edge of the epithelium. B, Affinity-purified Vangl2 antibody recognizes a band ∼65 kDa in lysates from HEK293 transfected with an untagged Vangl2 construct (lane 1), cochlea (lane2), and ...
The avian cochlea has a remarkable ability to regenerate sensory hair cells after injury, and a major goal of our research is to understand the molecular basis of this regenerative process. An ongoing study, conducted in collaboration with the Lovett lab (Dept. of Genetics), is using Next-Gen sequencing to profile the transcriptome of the chick cochlea throughout the time course of regeneration. Additional data suggest that the lack of FGF signaling in the mature mammalian ear may be one factor that limits regenerative ability in mammals. We are presently collaborating with the Orntiz lab (Dept. of Developmental Biology) to determine whether reactivating FGF signaling in the injured mouse cochlea can evoke some degree of sensory repair ...
Department of Physiology, Medical School, University Walk, Bristol. 1. Outer hair cells from the cochlea of the guinea-pig were isolated and their motile properties studied in short-term culture by the whole-cell variant of the patch recording technique. 2. Cells elongated and shortened when subjected to voltage steps. Cells from both high- and low-frequency regions of the cochlea responded with an elongation when hyperpolarized and a shortening when depolarized. The longitudinal motion of the cell was measured by a differential photosensor capable of responding to motion frequencies 0-40 kHz. 3. Under voltage clamp the length change of the cell was graded with command voltage over a range +/- 2 microns (approximately 4% of the length) for cells from the apical turns of the cochlea. The mean sensitivity of the movement was 2.11 nm/pA injected current, or 19.8 nm/mV membrane polarization. 4. The kinetics of the cell length change during a voltage step were measured. Stimulated at their basal end, ...
Chris - We all take our ears for granted, I think. How do they actually work?Bob - Basically, sound is vibration in the air and it is picked up by the floppy bit on the side of your head. This is called the pinna. Sound is then transmitted to the inner ear, inside of which theres a membrane which is thin and stiff at one end and wobbly at the other end. The thin, stiff bit
J:173382 Basch ML, Ohyama T, Segil N, Groves AK, Canonical Notch Signaling Is Not Necessary for Prosensory Induction in the Mouse Cochlea: Insights from a Conditional Mutant of RBPj{kappa}. J Neurosci. 2011 Jun 1;31(22):8046-58 ...
In chapter 3, "The Sense of Sensibility," author Wendy Jones uses scenes from one of Jane Austens most celebrated novels to illustrate the functioning of the bodys stress response system.. 0 Comments. ...
In chapter 3, "The Sense of Sensibility," author Wendy Jones uses scenes from one of Jane Austens most celebrated novels to illustrate the functioning of the bodys stress response system.. 0 Comments. ...
Subject: Re: physiological or ecological basis of auditory sharpness From: Eckard Blumschein ,Eckard.Blumschein(at)E-TECHNIK.UNI-MAGDEBURG.DE, Date: Tue, 17 Sep 2002 08:15:58 +0200 Yes, undoubtedly, high CFs are required for localization. I would like to mention a nice tutorial by Duda: http://www-engr.sjsu.edu/~knapp/HCIROD3D/3D_psych/reverb.htm He includes an explanation of IED (interaural envelope delay) and Franssen effect, and he summarizes: With some risk of oversimplification, we can generalize and say that in reverberant environments it is the high-frequency energy, not the low-frequency energy, that is important for localization. The question was: What might be the basis of (the extremely unpleasant) auditory sharpness evoked by spectral components... As we understand from the tutorial, the basal turn of cochlea is designed for localization of single events like clicks or bat calls rather than for recognition of any continuous tone. Maybe, Duda intentionally wrote high-frequency ...
Theres much more to our ears than meets the eye! The human ear contains a chain of important links that work together to help us hear the world around us. From the ears tiny bones to its fluid-filled cochlea, each part is important. In this title, young readers will learn about the small wonders inside the human ear.
TY - JOUR. T1 - Regeneration of Stereocilia of Hair Cells by Forced Atoh1 Expression in the Adult Mammalian Cochlea. AU - Yang, Shi Ming. AU - Chen, Wei. AU - Guo, Wei Wei. AU - Jia, Shuping. AU - Sun, Jian He. AU - Liu, Hui Zhan. AU - Young, Wie Yen. AU - He, David Z.Z.. PY - 2012/9/27. Y1 - 2012/9/27. N2 - The hallmark of mechanosensory hair cells is the stereocilia, where mechanical stimuli are converted into electrical signals. These delicate stereocilia are susceptible to acoustic trauma and ototoxic drugs. While hair cells in lower vertebrates and the mammalian vestibular system can spontaneously regenerate lost stereocilia, mammalian cochlear hair cells no longer retain this capability. We explored the possibility of regenerating stereocilia in the noise-deafened guinea pig cochlea by cochlear inoculation of a viral vector carrying Atoh1, a gene critical for hair cell differentiation. Exposure to simulated gunfire resulted in a 60-70 dB hearing loss and extensive damage and loss of ...
TY - JOUR. T1 - Electrically stimulated increases in cochlear blood flow. T2 - I. frequency and intensity effects. AU - Sillman, Jonathon S.. AU - LaRouere, Michael J.. AU - Masta, Robert I.. AU - Miller, Josef M.. AU - Nuttall, Alfred L.. PY - 1989/4. Y1 - 1989/4. N2 - Charge-balanced, sinusoidal current was passed differentially between the apex and round window of the guinea pig cochlea. Cochlear blood flow was measured using a laser Doppler flow monitor. Systemic blood pressure was monitored from a cannula within the common carotid artery. Electrical stimulation increased cochlear blood flow, while systemic blood pressure was unaffected. A cochlear blood flow response parameter, normalized for transient changes in systemic blood pressure, was defined. The magnitude of the response parameter was found to be frequency selective and was also found to be an increasing function of current intensity, with maximum responses obtained with 500 Hz sinusoids. This cochlear blood flow response was not ...
TY - JOUR. T1 - Targeted PCR Array Analysis of Genes in Innate Immunity and Glucocorticoid Signaling Pathways in Mice Cochleae Following Acoustic Trauma. AU - Maeda, Yukihide. AU - Kariya, Shin. AU - Omichi, Ryotaro. AU - Noda, Yohei. AU - Sugaya, Akiko. AU - Fujimoto, Shohei. AU - Nishizaki, Kazunori. PY - 2018/8/1. Y1 - 2018/8/1. N2 - Aim: To comprehensively analyze cochlear gene expressions related to innate immunity and glucocorticoid signaling at onset of acute noise-induced hearing loss (NIHL). Background: Recent studies suggested innate immunity is involved in the cochlear pathology of NIHL. Glucocorticoids may modulate immune actions in cochleae. Methods: Mice were exposed to 120 dB-octave band noise for 2 hours. Twelve hours later, a targeted PCR array analyzed cochlear expressions of 84 key genes in inflammation and immune pathways and 84 genes in the glucocorticoid signaling pathway. Real-time RT-PCR was used to analyze expression of two immune-related genes, Ccl12 and Glycam1, in ...
Afferent synapses between inner hair cells (IHCs) and spiral ganglion neurons in the cochlea translate sound information into a discrete spike code, providing us the opportunity to directly observe the output of the cochlea. The availability of mutant strains with genetic hearing impairment makes the mouse a valuable species to investigate the molecular mechanisms of cochlear function. In this thesis, mouse was used as a model species to study cochlear sound encoding by recording single unit activities from auditory nerve fibers (ANFs) in vivo. First, developmental changes of ANF responses before and after hearing onset were characterized as an introduction on how normal ANF responses mature during the early postnatal age. Spontaneous bursting activity from ANFs/cochlear nucleus neurons was observed before hearing onset. After hearing onset, the average spontaneous and evoked spike rates of single ANFs increased, while tuning threshold and frequency selectivity improved between p14-15 to p20-21. ...
Our knowledge of the fine structure of the Human Spiral Ganglion (HSG) is still inadequate and new treatment techniques for deafness using electric stimulation, call for further information and studies on the neuronal elements of the human cochlea. This thesis presents results of analyses of human cochlear tissue and specimens obtained during neurosurgical transpetrosal removal of life-threatening meningeomas. The use of surgical biopsies produced a well-preserved material suitable for ultrastructural and immunohistochemical studies on the human inner ear. The SG was studied with respect to fine structure, using TEM technique and the immunostaining pattern of synaptophysin, which is an integral membrane protein of neuronal synaptic vesicles. The immunostaining patterns of the tight junctional protein ZO-1 and the gap junctional proteins Cx26 and Cx43 in the human cochlea were also studied. The ultrastructural morphology revealed an absence of myelination pattern in the HSG, thus differing from ...
The mechanism of hearing loss arises from trauma to stereocilia of the cochlea, the principal fluid filled structure of the inner ear. The pinna combined with the middle ear amplifies sound pressure levels by a factor of twenty, so that extremely high sound pressure levels arrive in the cochlea, even from moderate atmospheric sound stimuli. Underlying pathology to the cochlea are reactive oxygen species, which play a significant role in noise-induced necrosis and apoptosis of the stereocilia. Exposure to high levels of noise have differing effects within a given population, and the involvement of reactive oxygen species suggests possible avenues to treat or prevent damage to hearing and related cellular structures.. The elevated sound levels cause trauma to the cochlear structure in the inner ear, which gives rise to irreversible hearing loss. A very loud sound in a particular frequency range can damage the cochleas hair cells that respond to that range thereby reducing the ears ability to ...
Ben Creisler [email protected] A new paper (in open access) that may be of interest: Eric G. Ekdale (2015) Form and function of the mammalian inner ear. Journal of Anatomy (advance online publication) DOI: 10.1111/joa.12308 http://onlinelibrary.wiley.com/doi/10.1111/joa.12308/abstract http://onlinelibrary.wiley.com/doi/10.1111/joa.12308/epdf The inner ear of mammals consists of the cochlea, which is involved with the sense of hearing, and the vestibule and three semicircular canals, which are involved with the sense of balance. Although different regions of the inner ear contribute to different functions, the bony chambers and membranous ducts are morphologically continuous. The gross anatomy of the cochlea that has been related to auditory physiologies includes overall size of the structure, including volume and total spiral length, development of internal cochlear structures, including the primary and secondary bony laminae, morphology of the spiral nerve ganglion, and the nature of cochlear ...
The K+ circulation in the cochlea is thought to be tightly regulated in the inner compartment of the cochlea by a transport network in the stria vascularis of the cochlea (Wangemann 2006). In the OHC case, K+ passes through the transduction channels and is released into the intercellular space of organ of Corti through several types of K+ channel at the base of the hair cell. These channels include KCNQ4 channels (Kharkovets et al. 2006) and calcium-activated SK and BK channels (Marcotti et al. 2004). From there, K+ is taken up by the supporting cells via the K-Cl cotransporters (Boettger et al. 2002). The supporting cells of the organ of Corti form an extensive epithelial tissue gap-junction system that is essential for buffering extracellular K+ ions in the organ of Corti into the perilymph (Kikuchi et al. 2000). From perilymph, K+ is actively pumped by the K+/Na+ ATPase and K+/Na+/2Cl− cotransporter back into the type II fibrocytes of the spiral ligament and from there back via the stria ...
This study was designed to determine whether the sympathetic nervous system exerts a protective or enhancing effect in acoustic overstimulation. The compound action potential of the cochlea (CAP) was recorded in guinea pigs while the cervical sympathetic nervous system (SNS) was electrically stimulated or after it was surgically eliminated. The stimulation or the elimination of the cervical SNS has no effect on the threshold of CAP. The threshold shift in CAP after acoustic overstimulation (110, 115, or 130 dB SPL for 10 min) was measured in the cervical SNS stimulation group, in the cervical SNS elimination group, and in the control group. When the animal was under insufficient sedation, there was no difference among these three groups. However, the CAP threshold shift was significantly smaller in the cervical SNS stimulation group than in the other two groups when the animals were sufficiently sedated. The cervical SNS stimulation had some protective effect on the susceptibility to acoustic trauma
On the basis of recent advances in auditory physiology, new tests of cochlear function have been developed using measures of otoacoustic emissions. In the present report, the clinical potential for each of the four basic emission types is examined. In addition, the practical advantages of examining the ear with two specific types of evoked emissions, transiently evoked and distortion-product otoacoustic emissions, are reviewed in detail. Finally, the future role of tests of otoacoustic emissions in the diagnosis of hearing impairment is discussed. The current view is that evoked emissions hold promise as an essential part of the clinical examination of the auditory system.. ...
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Kiluchi, T. (1995) Gap junction in the rat cochlea immunohisto-chemical and ultrastructural analysis. Anatomy and Embryology, 2, 101-118.
Prevention of auditory hair cell death offers therapeutic potential to rescue hearing. Pharmacological blockade of JNK/c-Jun signaling attenuates injury-induced hair cell loss, but with unsolved mechanisms. We have characterized the c-Jun stress response in the mouse cochlea challenged with acoustic overstimulation and ototoxins, by studying the dynamics of c-Jun N-terminal phosphorylation. It occurred acutely in glial-like supporting cells, inner hair cells and in the cells of the cochlear ion trafficking route, and was rapidly downregulated after exposures. Notably, death-prone outer hair cells lacked c-Jun phosphorylation. As phosphorylation was triggered also by non-traumatic noise levels and as none of the cells showing this activation were lost, c-Jun phosphorylation is a biomarker for cochlear stress rather than an indicator of a death-prone fate of hair cells. Preconditioning with a mild noise exposure before a stronger traumatizing noise exposure attenuated the cochlear c-Jun stress ...
TY - JOUR. T1 - Short-term plasticity and modulation of synaptic transmission at mammalian inhibitory cholinergic olivocochlear synapses. AU - Katz, Eleonora. AU - Elgoyhen, Ana Belén. PY - 2014/12/2. Y1 - 2014/12/2. N2 - The organ of Corti, the mammalian sensory epithelium of the inner ear, has two types of mechanoreceptor cells, inner hair cells (IHCs) and outer hair cells (OHCs). In this sensory epithelium, vibrations produced by sound waves are transformed into electrical signals. When depolarized by incoming sounds, IHCs release glutamate and activate auditory nerve fibers innervating them and OHCs, by virtue of their electromotile property, increase the amplification and fine tuning of sound signals. The medial olivocochlear (MOC) system, an efferent feedback system, inhibits OHC activity and thereby reduces the sensitivity and sharp tuning of cochlear afferent fibers. During neonatal development, IHCs fire Ca2+ action potentials which evoke glutamate release promoting activity in the ...
Sensorineural hearing loss (sometimes called "nerve deafness") occurs when the cilia (hair cells) of the inner ear (the cochlea) do not function properly. In an undamaged ear, the pressure from sound waves goes into your pinna (the outer ear, the part you can see), makes the eardrum move back and forth, is passed along the small bones of the middle ear (the smallest bones in your body!), and then transfers to the middle ear, where those sound waves cause actual waves in the fluid-filled cochlea. The waves of fluid cause the hair cells to move. This sets off a beautiful chemical chain reaction, which ultimately causes stimulation of the auditory nerve (cranial nerve VIII), which sends the sensation of "sound" to the brain. The hair cells in the cochlea are tonotopically arranged, meaning that each region corresponds to different tones, going from high frequency sounds at the basal end to low frequency sounds at the apex of the cochlea, which looks like a snail shell. Think of a piano keyboard ...
Intracellular recordings were made from the low frequency region (third turn) of the guinea pig cochlea. Response characteristics are compared to gross potentials obtained from the organ of Corti fluid space. Inner hair cells (IHCs) possess relatively low (median, -32 mV) initial membrane potentials, whereas that of outer hair cells (OHCs) is higher (median, -53.5 mV). In response to tone burst stimuli, both cell types produce a combination of AC and DC responses. The latter are depolarizing for IHCs but may be of either polarity for OHCs. In terms of their AC responses, IHCs are about 12 dB more sensitive than OHCs. At low sound levels these cells are more linear than high frequency hair cells (Russell, I. J., and P. M. Sellick (1978) J. Physiol. (Lond.) 284: 261-290), judging from the relation between AC and DC response components. At high sound levels pronounced response saturation is seen. The overall tuning properties of the two hair cell types are rather similar, even though IHCs exhibit ...
Neurons in the developing auditory system fire bursts of action potentials before the onset of hearing. This spontaneousactivity promotes the survival and maturation of auditory neurons and the refinement of synaptic connections in auditory nuclei; however, the mechanisms responsible for initiating this activity remain uncertain. Previous studies indicate that inner supporting cells (ISCs) in the developing cochlea periodically release ATP, which depolarizes inner hair cells (IHCs), leading to bursts of action potentials in postsynaptic spiral ganglion neurons (SGNs). To determine when purinergic signaling appears in the developing cochlea and whether it is responsible for initiating auditory neuron activity throughout the prehearing period, we examined spontaneousactivity from ISCs, IHCs, and SGNs in cochleae acutely isolated from rats during the first three postnatal weeks. We found that ATP was released from ISCs within the cochlea from birth until the onset of hearing, which led to periodic ...
Mechanical responses in the basal turn of the guinea-pig cochlea are measured with low-level broad-band noise as the acoustical stimulus [for details see de Boer and Nuttall, J. Acoust. Soc. Am. 101, 3583-3592 (1997)]. Results are interpreted within the framework of a classical three-dimensional model of the cochlea that belongs to a very wide class of nonlinear models. The use of linear-systems analysis for this class of nonlinear models has been justified earlier [de Boer, Audit. Neurosci. 3, 377-388 (1997)]. The data are subjected to inverse analysis with the aim to recover the effective basilar-membrane impedance. This is a parameter function that, when inserted into the model, produces a model response, the resynthesized response, that is similar to the measured response. With present-day solution methods, resynthesis leads back to an almost perfect replica of the original response in the spatial domain. It is demonstrated in this paper that this also applies to the response in the frequency
Photograph of a receptor cell, known as an outer hair cell (OHC), in the mammalian cochlea with its large nucleus (N) located at the base of the cell. Receptor cells in the cochlea have structures known as stereocilia (S) at their apex. These structures convert the mechanical energy of sound to an electrochemical signal that can be processed by the peripheral and central auditory nerves. Outer hair cells have an additional feature; they can contract and extend in response to hyper- and depolarization of the cell. Their motility is regulated by signals from the brain, thereby allowing for the fine-tuning of mechanical signals that impinge on the cochlea. The photo was taken at a magnification of 7100 X using an electron microscope by Margaret Harvey, Senior Biological Scientist. Check out the link to see an outer hair cells response to music: https://www.youtube.com/watch?v=c91ubWbScs4 ...
About 95 percent of sound input to the brain comes from the ears inner hair cells.. "These inner hair cells are like spark plugs in an 8-cylinder engine," says Salvi. "A car wont run well if you remove half of those spark plugs, but people can still present with normal hearing thresholds if theyve lost half or even three-quarters of their inner hair cells.". Ear damage reduces the signal that goes the brain. That results in trouble hearing, but thats not whats happening here, because the brain "has a central gain control, like a radio, the listener can turn up the volume control to better hear a distant station." Salvi says.. Sound is converted to neural activity by the inner hair cells in the auditory part of the ear, called the cochlea.. Sound-evoked neural activity then travels from the cochlea to the auditory nerve and into the central auditory pathway of the brain. Halfway up the auditory pathway the information is relayed into a structure known as the inferior colliculus, before ...
The researchers show that this is due to a molecular signalling pathway in the cochlea, mediated by a chemical compound called ATP, released by the cochlear tissue with noise and activating specific ATP receptors in the cochlear cells.. "Interestingly, if the pathway is removed, such as by genetic manipulations, this adaptive mechanism doesnt occur and the ear becomes very vulnerable to longer term noise exposure and the effects of age, eventually resulting in permanent hearing loss.". "In other words the adaptive mechanism also protects the ear," says Professor Thorne.. The second paper, done in collaboration with United States colleagues, reveals a new genetic cause of deafness in humans which involves exactly the same mechanism.. People (two families in China) who had a mutation in the ATP receptor showed a rapidly progressing hearing loss which was accelerated if they worked in noisy environments.. "This work is important because it shows that our ears naturally adapt to their environment, ...
INTRODUCTION: the aim of this study was to investigate cochlear functions in patients with hyperemesis gravidarum (HG). METHODES: twenty-nine HG patients (58 ears) and 31 healthy control subjects (62 ears) were included. Audiometry testings at 250 and 500 Hz and 1, 2, 4, 8, 10, 12, 14, 16 kHz were performed to the patients and controls. RESULTS: mean age of patients with HG was 26,5 4,4 years and the mean age of control group was 28,0 4,2 years. At the time of the tests mean gestational age of the HG group and controls were 9 and 11 weeks respectively. No differences were observed between the groups in tympanic membrane status, orother otolaringological evaluations. No significant differences were observed in audiometric tests at any frequencies between the groups (p values for all>0.05). CONCLUSION: there was not a difference between pregnant cases with HG and cases with normal pregnancy in terms of audimetric tests. Cochlear functions are not affectedremarkably in women with HG.
Omics group organizes Cochlea national symposiums, conferences across the globe in association with popular Cochlea associations and companies. OMICS group planned its conferences, and events in america, europe, middle east and asia pacific. locations which are popular with international conferences, symposiums and events are china, canada, dubai, uae, france, spain, india, australia, italy, germany, singapore, malaysia, brazil, south korea, san francisco, las vegas, san antonio, omaha, orlando, raleigh, santa clara, chicago, philadelphia, baltimore, united kingdom, valencia, dubai, beijing, hyderabad, bengaluru and mumbai
During normal hearing, sound waves travel through the ear canal and strike the eardrum causing it to vibrate. The eardrum is attached to three tiny bones in the middle ear. The last bone, the stapes, pushes on a fluid-filled chamber in the inner ear, called the cochlea. This fluid movement causes sensitive hair cells within the cochlea to bend. When the hair cells bend, they generate an electrical signal that is sent to the brain. Disease, damage, or deformity of the cochlear hair cells is a common cause of hearing impairment or deafness. These malfunctioning hair cells may send intermittent or unclear signals to the auditory nerve, or send no signal at all. A device called a cochlear implant can restore hearing by replacing these damaged structures with a wire that is implanted in the cochlea. In order to stimulate the hearing process, sound waves are first received by a microphone unit, or speech processor, that hangs over the back of the ear. Within the processor, sound is filtered and ...
The rate of longitudinal flow of perilymph has been measured using an ionic tracer technique. Spread of the tracer trimethylphenylammonium (TMPA) along the perilymphatic scalae was monitored with ion-selective microelectrodes following injection of a
Wild-type (right) Kcnq1tm1Kpfe/Kcnq1tm1Kpfe (left) comparisons of the midmodular sections of the cochlea at P0 (A), P3 (B) and P70 (C). Note the collapse of Reissners membrane at P3 (B) and degeneration of inner and outer hair cells at P70 (C). D-F: Details of the saccule at P0 (D), P8 (E) and P70 (F ...
Rattay, F., Lutter, P., and Naves Leao, R. (2000)."The electrically stimulated cochlea: Calculation of the potential distribution in the inner ear and the excitation of the auditory nerve". Presented at the 3rd Mathmod, IMACS Symposium on Math. Modelling, Vienna ...
Cochlea, filled with fluids called perilymph and endolymph, a spiral-shaped cavity in the ear that translates sound waves into electrical nerve impulses and sends them to the cerebral cortex for interpretation. - Stock Image P434/0097
The cochlea is arranged like a rolled-up piano keyboard, as shown in box A in the figure below. Lining the cochlea are many thousands of hair cells that convert the sound into electrical signals. Cochlear implants only have up to a couple of dozen electrodes, each of which performs a similar function to a hair…
This site contains information on the otoacoustic emissions, details on available OAE hardware and software and on-line OAE lectures and white papers
Will we be able to restore hearing loss? It was recently found that we as humans do possess an ability to regenerate cells in our intestines. A similarity between these cells in the intestine and cells found in the cochlea led researchers to discover a drug that could regenerate cochlea cells.
Animals are able to detect, perceive, and react to a wide range of stimuli in their environment. Although sensory information always flows from peripheral sensory organs into the central nervous system, each system exhibits specialized features, highlighted by differences at the circuit level. For instance, in the cochlea, sound information is organized according to frequency and must be communicated with exquisite speed and precision, thereby permitting animals to localize sounds based on miniscule differences in timing. In the retina, on the other hand, a wide variety of neuronal subtypes cooperate to detect and encode aspects of the visual scene, such as the onset of light or direction-selective motion. Accordingly, neurons in the cochlea and retina exhibit fundamentally distinct morphologies and patterns of connectivity. Spiral ganglion neurons (SGNs), the primary sensory neurons of the inner ear, have quite simple bipolar shapes, with unbranched peripheral processes projecting like spokes ...
Low incidence disabilities in education and what medical supports are available - Assignment Example There are specialized interventions that cater for students with hearing impairments in the society. This involves cochlear implants that provide a sense of sound to low incidence students that have a problem with hearing. The surgical electronic device is essential for students with partial damages on the sensory hair cells in the cochlea. Its relevance in hearing is evident in different ways. In this case, adults benefit immediately through experiencing improvement in the first three months of implantation. The children may improve at a slower pace since they need a lot of training during implantations process. In general, victims who undergo cochlea implantation perceive loud, medium and soft sounds as they understand speech through lip reading (Niparko, 2009). At the same time, there are autism interventions that involve communication and behavioral strategies. In most cases, this treatment ...
We suggest that one role of regulated surface AMPAR expression is to limit excitotoxicity that might be induced during acoustic overstimulation. Intense acoustic stimulation can produce histological signs thought to be associated with excitotoxicity, which include vacuolization in the auditory nerve terminals and in the satellite cells near the ganglion cell bodies (Sun et al. 2001; Wang et al. 2002). The noise exposure we employed normally induces removal of surface AMPARs and does not induce signs of excitotoxicity. But when the removal of surface AMPARs was blocked with myr-Dyn, these same stimuli generated excitotoxic responses. In neuronal cultures from the CNS, excitotoxicity can be observed as a calpain-mediated cell death (Bano et al. 2005; Lankiewicz et al. 2000). We showed that a brief exposure to glutamate receptor agonists at concentrations that induce surface AMPAR removal without generating cell death can induce cell death when removal of surface AMPARs is blocked by ...
Susan wrote: actually, thats not quite true. one of the beauties of the critical band theory is that it *does* address the shape and size of the filters. fletcher, in his original theory, assumed they were symmetrical, but did not know for sure. when patterson and moore created psychophysical tuning curves they were asymmetrical, so patterson controlled for off-freq listening by using notched noise. when he did that, it forced the subjects to listen to the filter centered on fs and the bands were shown to be symmetrical. - Actually, what I said is accurate. However, the response suggests the literature I made reference to may not well known or how it shows CB theory has a weakness. The work I made reference to agrees with the Fletcher and Patterson work in that there is a mechanism (yes, probably peripheral) that aids in the selectivity of the auditory system. What the data also shows, however, is that the auditory system processes information OUTSIDE the critical band and it affects the ...
Acoustic trauma is an injury to the inner ear thats often caused by exposure to a high-decibel noise. This injury can occur after exposure to a single, very loud noise or from exposure to noises at a lower decibel over a long period of time. Learn about the symptoms and treatment options for acoustic trauma.
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Hello friends. I am saddened to say that my T has worsened again recently - acoustic trauma from prolonged exposure to a loud speaker in a pub setting...
Throughout the day I have been losing more low frequency hearing, and I really dont know why whatsoever (possibly road noise?), but it could be the...
p] So, Laxmi, Nayan, Trishul and I, have all decided to take on this once in a lifetime challenge! Absolutely bonkers yet absolutely dedicated to the cause. To see the expression on a child when they first hear a sound is heart warming, something we all take for granted. [/p][p] [b]"Let every deaf child speak" - imagine growing up in a world unable to hear.[/b][/p][p] - Did you know 800 children are born deaf every year in Pune?[/p][p] - 650 of those children do not have the ability to receive a proper education in Pune[/p][p] - These children are born deaf but they are not born [b]mute[/b][/p][p] [b]"Early detection and intervention can help these children speak and lead a normal life" - Dr Avinash M.Wachasunder M.S. (ENT) Practicing ENT surgeon[/b][/p][p] Cochlea Pune for hearing and speech has been a growing charitable trust who specialise in supporting congenitally born deaf children from the age of 0 through to 6 years.[/p][p] Through early detection and intervention, the Cochlea team has ...
Asari, H., Pearlmutter, B. A., Zador, A. M. (July 2006) Sparse representations for the cocktail party problem. Journal of Neuroscience, 26 (28). pp. 7477-7490. ISSN 02706474 ...
ShareThis[88] Ketten, D. R., and D. Wartzok, Three-dimensional reconstructions of the dolphin ear, Sensory Abilities of Cetaceans: Field and Laboratroy Evidence, Proc. NATO ASI Ser. A, Life Sci., vol. 196, New York and London, Plenum Press, pp. 81-105, 09-Aug-1999, 1990. Get PDF: Full Text.pdf (format PDF / 1017 KB) ...
An ImageJ PlugIn that can automatically calculate the frequencies on different points along the cochlea. Please read the Users Manual for step by step instructions on how to install and use the PlugIn. ...
Complete Cochlear Coverage allows our cochlear implants to stimulate the full length of the cochlea, which provides a richer, more natural sound quality.
This site contains information on the otoacoustic emissions, details on available OAE hardware and software and on-line OAE lectures and white papers
Plasmid pEJS614_pTetR-P2A-BFPnls/sgNS from Dr. Erik Sontheimers lab contains the inserts Non-specific sgRNA and TetR-P2A-BFP and is published in Nature Methods (2018) This plasmid is available through Addgene.
So, Ive taken 3 months break from IVF treatment after I spent all last year cycling which resulted in lots of outcomes from overstimulation, blighted ovum/miscarry..you name it...we went thru it. So, I decided March 014 would be the month
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Conchae is a snail shaped organ which has 2 1/2 (2S) turns. The oval window opens into the vestibule to cochlea through the scala vestibule.The bony part of the cochlea make turns around a central pillar called modiolus. The modiolus at its upper end diverge into Y shaped membranes called vestibular membrane and basilar membrane. On the one side of the modiolus and vestibular membrane lie the scala vestibuli. On the other side of modiolus and basilar membrane lies the scala tympani. Scala vestibuli and tympani communicates with each other only at the apex of cochlea which is helicotrema. Between the vestibular membrane and basilar membrane lies the membranous cochlea which is called scala media (cochlear duct). On the internal surface of basilar membrane lies coiled and arranged in coiled form cells called hair cells and supporting cells. Hair cells are further divided into inner and outer hair cells. Inner hair cells are arranged in 1 layer, while outer hair cells are arranged in 3 layers. ...
Conchae is a snail shaped organ which has 2 1/2 (2S) turns. The oval window opens into the vestibule to cochlea through the scala vestibule.The bony part of the cochlea make turns around a central pillar called modiolus. The modiolus at its upper end diverge into Y shaped membranes called vestibular membrane and basilar membrane. On the one side of the modiolus and vestibular membrane lie the scala vestibuli. On the other side of modiolus and basilar membrane lies the scala tympani. Scala vestibuli and tympani communicates with each other only at the apex of cochlea which is helicotrema. Between the vestibular membrane and basilar membrane lies the membranous cochlea which is called scala media (cochlear duct). On the internal surface of basilar membrane lies coiled and arranged in coiled form cells called hair cells and supporting cells. Hair cells are further divided into inner and outer hair cells. Inner hair cells are arranged in 1 layer, while outer hair cells are arranged in 3 layers. ...
The hair cells of the inner ear seem to be specified properly as they express many of the typical hair cell markers such as myosin VI/VIIa, Math1 and Brn3c. Thus, Gfi1 is not required for the specification of hair cells as they are formed in both the vestibule and the cochlea. However, the loss of Gfi1 seems to affect the vestibular and cochlear hair cells differently. In the vestibule, the hair cells are morphologically abnormal at the earliest stages of hair cell differentiation and at all subsequent stages. In addition, hair cells are not specifically localized to a lumenal monolayer, and are more variable in size and shape. This disorganization of hair cells in the vestibule may account for the ataxic behavior of the mice. In the cochlea, Gfi1 is required for the organization and maintenance of both inner and outer hair cells. Although the mutant hair cells seem to be specified in the developing organ of Corti as early as E15.5 and express typical hair cell markers, they are disorganized. In ...
Located in the petrous portion of the temporal bone, the cochlea is a spiral tube which is a part of the inner ear, resembling a snail shell. The inner walls of the cochlea are lined with a fine layer of epithelium tissue as a thin membrane divides the spiralled tube along its length into two spaces which are filled with fluids; these tubes are the scala vestibuli and the scala tympani. In between the scala vestibuli and the scala tympani, there is a third yet smaller spiraling tube called scala media or cochlear duct, contains the organ of Corti. This special sensitive organ lies along the length of the membrane and is composed of neuroepithelial hair cells, which are special sensory receptor for hearing. The cochlea and the vestibular system make up the labyrinth of the inner ear. ...
Looking for online definition of Nerve of cochlea within spiral lamina in the Medical Dictionary? Nerve of cochlea within spiral lamina explanation free. What is Nerve of cochlea within spiral lamina? Meaning of Nerve of cochlea within spiral lamina medical term. What does Nerve of cochlea within spiral lamina mean?
Low-frequency hearing is critically important for speech and music perception, but no mechanical measurements have previously been available from inner ears with intact low-frequency parts. These regions of the cochlea may function in ways different from the extensively studied high-frequency regions, where the sensory outer hair cells produce force that greatly increases the sound-evoked vibrations of the basilar membrane. We used laser interferometry in vitro and optical coherence tomography in vivo to study the low-frequency part of the guinea pig cochlea, and found that sound stimulation caused motion of a minimal portion of the basilar membrane. Outside the region of peak movement, an exponential decline in motion amplitude occurred across the basilar membrane. The moving region had different dependence on stimulus frequency than the vibrations measured near the mechanosensitive stereocilia. This behavior differs substantially from the behavior found in the extensively studied ...
Looking for basilar membrane of cochlear duct? Find out information about basilar membrane of cochlear duct. structure composed mostly of lipid lipids, a broad class of organic products found in living systems. Most are insoluble in water but soluble in nonpolar... Explanation of basilar membrane of cochlear duct
Cochlear implants were created for adults and children that suffer from a form of hearing loss known as sensorineural hearing loss. In sensorineural hearing loss there is usually damage to the tiny hair like cells in the cochlea. The cochlea is the tiny snail shaped coil in your inner ear that transmits sound signals to the auditory nerve. When the tiny hair like cells in your cochlea are damaged they are unable to transmit the sound signals to the auditory nerve. The cochlear implant circumvents the cochleas tiny hair like cells and directly stimulates the auditory nerve.. So how does the cochlear implant work? First a tiny receiver is implanted just under your skin behind the ear. This receiver is then connected to tiny electrodes that have been placed in the cochlea. You are then fitted with an external auditory speech processor, a transmitter and a battery pack. The microphone looks like a hearing aid and is worn behind the ear or it can be worn somewhere else on your body depending on your ...
There are several types of hearing disorders. Some children with hearing disorders can hear a little, while others hear nothing at all. Some children with hearing disorders may be able to hear sounds well, but they will not be able to understand what they are hearing. Hearing takes place when sound waves enter the ear. Sound waves are created by any type of noise. The waves move through special bones in the ear and reach certain nerves. These nerves, then, send signals to the brain. So anything that keeps the sound waves from moving through the ear or the nerve signals from reaching the brain causes a hearing loss.
en] Peripherin is an intermediate filament protein that is expressed in peripheral and enteric neurons. In the cochlear nervous system, peripherin expression has been extensively used as a differentiation marker by preferentially labeling the type II neuronal population at adulthood, but yet without knowing its function. Since the expression of peripherin has been associated in time with the process of axonal extension and during regeneration of nerve fibers in other systems, it was of interest to determine whether peripherin expression in cochlear neurons was a static phenotypic trait or rather prone to modifications following nerve injury. In the present study, we first compared the expression pattern of peripherin and beta III-tubulin from late embryonic stages to the adult in rat cochlea. The staining for both proteins was seen before birth within all cochlear neurons. By birth, and for 2 or 3 days, peripherin expression was gradually restricted to the type II neuronal population and their ...
3D surface reconstruction from histology slides of the cochlea (scala vestibuli, scala tympani and scala media) of a Chinchilla (Chinchilla lanigera) using AMIRA® Visualization Software. Specimen courtesy of Massachusetts Eye and Ear Infirmary (MEEI).
When the stapes, a small bone that is part of the middle ear, is stimulated to remove from the oval window, a K+ rich fluid called endolymph rushes into the cochlea. This change in fluid amount causes a bend in the basilar membrane, which in turn, bends the reticular lamina, rods of Corti, and the tectorial membrane. This bending also causes the stereocilia to bend back and forth on the hair cells. On the tip of each stereocilia is a channel called transient receptor potential A1 channels or TRPA1, which allows for the inflow of K+ into the hair cell. Each TRPA1 channel is connected to one other by a link known as the tip link. This link can be thought of as a string that opens and closes a door. As the stereocilia bend each way, the "doors" to the channels open allowing K+ into the hair cell or close preventing K+ overflow. When K+ enters the hair cell, depolarization occurs. This unique physiological property is due to the extremely high concentration of K+ in the endolymph which results in a ...
Introduction and Objective]: The cochleogram is a graphic record which represents hair cells along the length of the basilar membrane and relates cell damage with frequency specific values in hearing thresholds. The purpose of this study is to design a simple and robust method to quantitatively determine the distribution of the inner and outer hair cells at the organ of Corti in the mouse cochlea. [Materials and Methods]: Six male CBA/CaOlaHsd mice with normal auditory brainstem responses were sacrificed at 2months of age. The cochleae from both ears (n=12) were extracted, fixed and decalcified, and then divided in two parts (apical-middle and basal), obtaining around 80% of the whole extent of the basilar membrane. The organ of Corti (OC) was isolated and phalloidin-stained in multiwall glass slides. Using a fluorescence microscope and stereological software, the total length of the OC was divided into equidistant 5% sectors1. The number of inner (IHC) and outer (OHC) hair cells in randomly ...
Galloni P, Lovisolo GA, Mancini S, Parazzini M, et al. (2005): The authors conducted a series of experiments to test the response of the cochlear outer hair cell (OHC) activity. OHC motility causes emissions spontaneously and in response to external stimuli. These otoacoustic emisssions (OAE) can be recorded and are used as a simple and non-invasive way to analyze OHC function. The authors focussed on distortion products otoacoustic emission (DPOAE), which are evoked by stimulation with two pure tones of different frequencies.. The authors used Sprague-Dawley rats in their experiments to test the effect of radiofrequency radiation (RFR), at 900 MHz frequency, on DPOAE. A variety of different protocols were used. These included different SAR levels (1 or 2 W/kg), modulation (GSM or CW), exposure time (2 or 3 h/day, 1 or 4 weeks), and EM source (horn or loop antenna). No changes in the OAE parameters, measured before and after the exposure, were seen.. ...
The influence of carbon dioxide (CO2) on cochlear blood flow (CBF), blood pressure (SBP) and skin blood flow (SBF) was studied in anaesthetized guinea pigs. A transient acute respiratory acidosis was produced by inhalation of CO2 and oxygen (O2) gas mixtures. The blood flows were measured by laser Doppler flowmetry (LDF). High CO2 increased CBF and SBP, and decreased SBF in a dose-dependent manner. The responses of CBF, SBP and SBF to high CO2 were reversible. Our results indicate that high CO2 (and low pH) dilates the smooth muscle of the blood vessels, resulting in an increase in CBF. CO2 also activates the sympathetic nervous system in the whole body, producing an increase in SBP. The distribution of alpha- adrenergic fibres/receptors is abundant in skin and scarce in the cochlea. The constrictive effect on blood vessels is much greater in the skin than in the cochlea, thus our results showed a decrease in SBF during stimulation with higher CO2.. ...
It seems we have come full circle regarding our understanding of the cellular basis of audition in the cochlea. As early as the 1950s, the spiral ganglion was proposed to play the primary role in the ability to understand speech, leading to the development of the cochlear implant, which is arguably the most clinically successful biotechnological implant available in any field.. However, the discovery of otoacoustic emissions in the 1970s and outer hair cells motile abilities in the 1980s led to a paradigm shift that attributed to outer hair cells a primary role in the fine-tuning of the speech signal essential for understanding spoken language. More recently, several strong lines of evidence in animal models have suggested a significant part for the spiral ganglion to play in speech understanding, particularly in the presence of background noise.. Moderate noise exposure that causes a loss of up to 50 percent of spiral ganglion cells results in no permanent changes in distortion product ...
Link to Pubmed [PMID] - 25122888. J. Neurosci. 2014 Aug;34(33):10853-69. The hair cell ribbon synapses of the mammalian auditory and vestibular systems differ greatly in their anatomical organization and firing properties. Notably, vestibular Type I hair cells (VHC-I) are surrounded by a single calyx-type afferent terminal that receives input from several ribbons, whereas cochlear inner hair cells (IHCs) are contacted by several individual afferent boutons, each facing a single ribbon. The specificity of the presynaptic molecular mechanisms regulating transmitter release at these different sensory ribbon synapses is not well understood. Here, we found that exocytosis during voltage activation of Ca(2+) channels displayed higher Ca(2+) sensitivity, 10 mV more negative half-maximum activation, and a smaller dynamic range in VHC-I than in IHCs. VHC-I had a larger number of Ca(2+) channels per ribbon (158 vs 110 in IHCs), but their Ca(2+) current density was twofold smaller because of a smaller open ...
Here, we defined the role of oestrogen signalling in the cochlea as essential for normal glutamatergic synapses in the cochlea. Both oestrogen and progesterone are known to be neuroprotective against stroke and glutamate toxicity in the central nervous system (CNS) when bound to their receptors (Singer et al, 1996; Liu et al, 2012). 17‐β‐Estradiol and its receptors have been reported to enhance synaptic function in the hippocampus, acting locally at PSDs, where Esr1 and Esr2 are also expressed (Adams & Morrison, 2003), controlling the expression of key post‐synaptic proteins upon activation and translocation of the receptor into the nucleus (Akama & McEwen, 2003; Liu et al, 2008; Pinaud & Tremere, 2012). In the auditory system, oestrogen is known to control central and peripheral auditory processing (Hultcrantz et al, 2006). Esr1 and Esr2 are expressed in both IHCs and OHCs (Motohashi et al, 2010), and they protect against neuropathy following acoustic trauma (Meltser et al, 2008; ...
The inner ear is an organ located deep within the temporal bone, which is the bone of the skull on both sides of the head above and to the sides of the outer ear. The inner ear has two main structures: the semicircular canals and the cochlea.. The semicircular canals do not contribute to hearing, but assist in maintaining balance as we move. The cochlea is the hearing organ of the inner ear, which is a fluid-filled structure that looks like a snail. The cochlea changes the mechanical vibrations from the tympanic membrane and the ossicles into a sequence of electrical impulses. Sensory cells, called hair cells, bend in the cochlea as the fluid is disrupted by the mechanical vibrations. This bending of the hair cells causes electrical signals to be sent to the brain by way of the auditory nerve. The cochlea is arranged by frequency, much like a piano, and encodes sounds from 20Hz (low pitch) to 20,000Hz (high pitch) in humans.. ...
... The long-awaited third edition of the successful text, Hearing Disorders is a collection of easy-to-read essays about the diagnosis, treatment and management of ear diseases and hearing disorders. Twenty-four free-standing chapters were written by a multidisciplinary group of authors, who are recognized experts in their respective areas. This clinically oriented...Find out more
This image from the lab of Patricia White, Assistant Professor of Neurobiology and Anatomy, shows a cross section of a young mouses cochlea -- the fluid-filled, inner ear structure that contains the receptor organ for hearing. Sensory hair cells are shown in pink and supporting cells in green. The sensory hair cells translate the fluid vibration of sounds into electrical impulses that are carried to the brain by sensory nerves. Age-related and noise-induced loss of hair cells in the cochlea of our inner ear is a major cause of hearing loss. So why cant mammals replace these cells as other vertebrates do? Why do surrounding supporting cells simply expand to create a scar that is insensitive to sound vibrations? Whites lab is investigating those questions, especially in light of the fact that purified immature mammalian supporting cells can divide and differentiate into new sensory hair cells under certain conditions in culture. Moreover, even mature mammalian supporting cells can differentiate ...
Registered in inner ear. Three semicircular canals loop in three planes at right angles to each other, responsible for transduction of movement messages. Method: hair cells deformed by gelatinous membrane. Vestibular apparatus, gives us perception of gravity and movement. Due to physical response, not chemical binding.. Cochlea: bony, coil shaped part of inner ear, where hearing occurs.. Sound enters through auditory canal, vibrates tympanic membrane,moving three bones of middle ear (malleus, incus, and stapes)against oval window opening in front of cochlea. Cochlea has three fluid filled ducts, one of these the organ of Corti. Sound waves in air go to vibration in organ of Corti; fluid tickles hair cells, which register the movement along basilar membrane in cochlea. Different sound frequencies move different portions of basilar membrane. Hearing loss due to loss of hair cells.Humans normally smell more than 300 odors in a day(Facts and Truth).. Transduction of sound accomplished throgh ...
Natures fastest motors are the cochlear outer hair cells (OHCs). These sensory cells use a membrane protein, Slc26a5 (prestin), to generate mechanical force at high frequencies, which is essential for explaining the exquisite hearing sensitivity of mammalian ears. Previous studies suggest that Slc26a5 continuously diffuses within the membrane, but how can a freely moving motor protein effectively convey forces critical for hearing? To provide direct evidence in OHCs for freely moving Slc26a5 molecules, we created a knockin mouse where Slc26a5 is fused with YFP. These mice and four other strains expressing fluorescently labeled membrane proteins were used to examine their lateral diffusion in the OHC lateral wall. All five proteins showed minimal diffusion, but did move after pharmacological disruption of membrane-associated structures with a cholesterol-depleting agent and salicylate. Thus, our results demonstrate that OHC lateral wall structure constrains the mobility of plasma membrane ...
TY - JOUR. T1 - Dynamic firing properties of type I spiral ganglion neurons. AU - Davis, Robin. AU - Crozier, Robert A.. PY - 2015/7/2. Y1 - 2015/7/2. N2 - Spiral ganglion neurons, the first neural element in the auditory system, possess complex intrinsic properties, possibly required to process frequency-specific sensory input that is integrated with extensive efferent regulation. Together with their tonotopically-graded sizes, the somata of these neurons reveal a sophisticated electrophysiological profile. Type I neurons, which make up ~95 % of the ganglion, have myriad voltage-gated ion channels that not only vary along the frequency contour of the cochlea, but also can be modulated by regulators such as voltage, calcium, and second messengers. The resultant developmentally- and tonotopically-regulated neuronal firing patterns conform to three distinct response modes (unitary, rapid, and slow) based on threshold and accommodation. This phenotype, however, is not static for any individual type ...
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Inner-ear hair cell differentiation requires Atoh1 function, while Eya1, Six1, and Sox2 are coexpressed in sensory progenitors and mutations in these genes cause sensorineural hearing loss. However, how these genes are linked functionally and the transcriptional networks controlling hair cell induct …
Hearing loss is the fastest growing and one of the most prevalent chronic conditions today affecting 600 million people worldwide. Furthermore, hearing impairment is one of the most common birth defects in humans and numerous forms are due to defects in the developmental pathways responsible for formation of the cochlea - the hearing organ. In addition to its basic biological function, the complex development of the cochlea enables us to study organogenesis, pluripotency, plasticity, cell fate specification, differentiation and pattern formation - processes that are essential aspects of development for all biological systems.. Many cases of acquired hearing impairment are attributed to damage or loss of inner ear hair cells - cells that are responsible for detecting sound in our environment, and inner ear neurons - cells that are responsible for transmitting sound information from the hair cells to the brain. In addition to congenital abnormalities, hair cell loss can be caused by disease such ...
The developing auricle is first noticeable around the sixth week of gestation in the human fetus, developing from the auricular hillocks, which are derived from the first and second pharyngeal arches. These hillocks develop into the folds of the auricle and gradually shift upwards and backwards to their final position on the head. En route accessory auricles (also known as preauricular tags) may be left behind. The first three hillocks are derived from the 1st branchial arch and form the tragus, crus of the helix, and helix, respectively. Cutaneous sensation to these areas is via the trigeminal nerve, the attendant nerve of the 1st branchial arch. The final three hillocks are derived from the second branchial arch and form the antihelix, antitragus, and lobule, respectively. These portions of the ear are supplied by the cervical plexus and a small portion by the facial nerve. This explains why vesicles are classically seen on the auricle in herpes infections of the facial nerve (Ramsay Hunt ...
The gustatory cortex is the primary receptive area for taste. The word taste is used in a technical sense to refer specifically to sensations coming from taste buds on the tongue. The five qualities of taste detected by the tongue include sourness, bitterness, sweetness, saltiness, and the protein taste quality, called umami. In contrast, the term flavor refers to the experience generated through integration of taste with smell and tactile information. The gustatory cortex consists of two primary structures: the anterior insula, located on the insular lobe, and the frontal operculum, located on the frontal lobe. Similarly to the olfactory cortex, the gustatory pathway operates through both peripheral and central mechanisms.[clarification needed] Peripheral taste receptors, located on the tongue, soft palate, pharynx, and esophagus, transmit the received signal to primary sensory axons, where the signal is projected to the nucleus of the solitary tract in the medulla, or the gustatory nucleus of ...
The human ear canal is divided into two parts. The elastic cartilage part forms the outer third of the canal; its anterior and lower wall are cartilaginous, whereas its superior and back wall are fibrous. The cartilage is the continuation of the cartilage framework of pinna. The cartilaginous portion of the ear canal contains small hairs and specialized sweat glands, called apocrine glands, which produce cerumen (ear wax). The bony part forms the inner two thirds. The bony part is much shorter in children and is only a ring (annulus tympanicus) in the newborn. The layer of epithelium encompassing the bony portion of the ear canal is much thinner and therefore, more sensitive in comparison to the cartilaginous portion. Size and shape of the canal vary among individuals. The canal is approximately 2.5 centimetres (1 in) long and 0.7 centimetres (0.28 in) in diameter.[2] It has a sigmoid form and runs from behind and above downward and forward. On the cross-section, it is of oval shape. These are ...
... named for the spiral shape it shares with the cochlea. These central axons exit the cochlea at its base and form a nerve trunk ... The cochlear nerve carries auditory sensory information from the cochlea of the inner ear directly to the brain. The other ... The peripheral axons of auditory nerve fibers form synaptic connections with the hair cells of the cochlea via ribbon synapses ... The axons from the low-frequency region of the cochlea project to the ventral portion of the dorsal cochlear nucleus and the ...
... and then to the oval window in the fluid-filled cochlea. Hence, it ultimately converts and amplifies vibration in air to ...
CochleaEdit. The retinoblastoma protein is involved in the growth and development of mammalian hair cells of the cochlea, and ... In studies where the gene for Rb is deleted in mice cochlea, hair cells continue to proliferate in early adulthood. Though this ... Suppressing function of the retinoblastoma protein in the adult rat cochlea has been found to cause proliferation of supporting ...
Cross-section of cochlea. Perilymph is located in the scala tympani and scala vestibuli - the aqua regions at the top and ...
Lyon, R. F.; Mead, C. (1988). "An analog electronic cochlea". IEEE Transactions on Acoustics, Speech, and Signal Processing. 36 ... Wen, Bo; Boahen, Kwabena (December 2009). "A Silicon Cochlea With Active Coupling". IEEE Transactions on Biomedical Circuits ... In 1988, Richard F. Lyon and Carver Mead described the creation of an analog cochlea, modelling the fluid-dynamic traveling- ... Richard F. Lyon, "A Computational Model of Filtering, Detection, and Compression in the Cochlea", Proceedings IEEE ...
In the mammalian cochlea, amplification occurs in the outer hair cells of the Organ of Corti. These cells sit directly above a ... These waves exert a pressure on the basilar and tectorial membranes of the cochlea which vibrate in response to sound waves of ... Sound waves enter the scala vestibuli of the cochlea and travel throughout it, carrying with them various sound frequencies. ... The Physical Basis of the Action of the Cochlea Kemp 1978 : Stimulated acoustic emissions from within the human auditory system ...
... cochlea Reeve, 1849: synonym of Turritella cochlea Reeve, 1849 Turritella acicula Stimpson, 1851: synonym of Turritellopsis ... Turritella cochlea Reeve, 1849. Retrieved through: World Register of Marine Species on 19 May 2010. Turritella columnaris ... 1951 Turritella cochlea Reeve, 1849 Turritella columnaris Kiener, 1843 Turritella communis Risso, 1826 Turritella concava ...
During this period he published a paper with Carver Mead describing an analog cochlea which modeled the propagation of sound in ... Lyon, R. F.; Mead, C. (1988). "An analog electronic cochlea". IEEE Trans. on Acoustics, Speech, and Signal Processing. 36: 1119 ... Hamilton, Tara Julia (6 February 2009). "The silicon cochlea: 20 years on" (PDF). The Neuromorphic Engineer. Institute of ... and Compression in the Cochlea", Proceedings IEEE International Conference on Acoustics, Speech, and Signal Processing, Paris, ...
Within the inner ear sits the cochlea. The cochlea is a snail-shaped formation that enables sound transmission via a ... The cochlea is a complex structure, consisting of three layers of fluid. The scala vestibuli and scala media are separated by ... When a sound is presented to the human ear, the time taken for the wave to travel through the cochlea is only 5 milliseconds. ... They are non-linear, level-dependent and the bandwidth decreases from the base to apex of the cochlea as the tuning on the ...
The Cochlea. New York: Springer. pp. 435-502. ISBN 978-0-387-94449-4. OCLC 33243443. Warr, WB.; Beck, JE.; Neely, ST. (1997). " ... The MOCS gives rise to a frequency-specific innervation of the cochlea, in that MOC fibres terminate on the outer hair cells at ... In the cats without efferent input to the cochlea, elevated thresholds of the AN, a decreased sharpness of the tuning curves, ... The olivocochlear system is a component of the auditory system involved with the descending control of the cochlea. Its nerve ...
Their hearing can be measured at the round window as cochlear microphonics and summating potential (of the cochlea), and ... Johnstone, J. R. & Johnstone, B. M. (1969). "Electrophysiology of the lizard cochlea". Experimental Neurology. 24 (1): 99-109. ...
The basilar membrane is widest (0.42-0.65 mm) and least stiff at the apex of the cochlea, and narrowest (0.08-0.16 mm) and most ... Deiters cells M. Holmes and J. D. Cole, "Pseudoresonance in the cochlea, ' in: Mechanics of Hearing, E. de Boer and M. A. ... In: Altschuler, R.A., Hoffman, D.W., Bobbin, R.P. (Eds.), Neurobiology of Hearing: The Cochlea. Raven Press, New York, pp. 109- ... The basilar membrane within the cochlea of the inner ear is a stiff structural element that separates two liquid-filled tubes ...
The Cochlear Duct (or Scala Media) is an endolymph filled cavity inside the cochlea, located in between the tympanic duct and ... Cross section of the cochlea. Cross section at avatar.com.au. ...
The tectorial membrane (TM) is one of two acellular membranes in the cochlea of the inner ear, the other being the basilar ... This raises the possibility that the TM may be involved in the longitudinal propagation of energy in the intact cochlea. Floor ... Cross αsection of the cochlea. Thalmann, I.; Thallinger, G.; Comegys, T.H.; Thalmann, R. (1986). "Collagen - The Predominant ... and traditionally was neglected or downplayed in many models of the cochlea. However, recent genetic , mechanical and ...
Neurons whose cell bodies lie in the spiral ganglion are strung along the bony core of the cochlea, and send fibers (axons) ... The cell bodies of the spiral ganglion neurons are found in the modiolus, the conical shaped central axis in the cochlea. ... Diagrammatic longitudinal section of the cochlea Organ of corti This article incorporates text in the public domain from the ... ISBN 0-387-97800-3. H Spoendlin (1972). "Innervation densities of the cochlea". Acta Otolaryngol. JB Nadol Jr (1990). "Synaptic ...
Cross section of the cochlea. Histology and Virtual Microscopy Learning Resources University of Michigan Medical School; ...
Iupiter et cochlea - mentioned under Zeus and the Tortoise 58. Satyrus et homo - The Satyr and the Traveller 59. Mures et feles ... cochleae. 33. cornix et hirundo. 34. Mercurius et statuarius - The Statue of Hermes 35. Pater et filii - The Farmer and his ...
Diagrammatic longitudinal section of the cochlea. This article incorporates text in the public domain from the 20th edition of ...
The cochlea and vestibule, viewed from above. Transverse section of the cochlear duct of a fetal cat. Interior of right osseous ... The vestibular duct or scala vestibuli is a perilymph-filled cavity inside the cochlea of the inner ear that conducts sound ... Diagrammatic longitudinal section of the cochlea. Tympanic duct Slide from University of Kansas Diagram at Indiana University ...
The cochlea thus acts as an 'acoustic prism', distributing the energy of each Fourier component of a complex sound at different ... One such mechanism is the opening of ion channels in the hair cells of the cochlea in the inner ear. Air pressure changes in ... At the end of the ossicular chain, movement of the stapes footplate within the oval window of the cochlea, in turn, generates a ... Hair cells in the cochlea are stimulated when the basilar membrane is driven up and down by differences in the fluid pressure ...
The cochlea consists of three fluid-filled spaces: the vestibular duct, the cochlear duct, and the tympanic duct. Hair cells ... The cochlea is a spiral shell-shaped organ responsible for the sense of hearing. These structures together create the ... The development of inner ear structures such as the cochlea is regulated by Dlx5/Dlx6, Otx1/Otx2 and Pax2, which in turn are ... In 1961, he was awarded the Nobel Prize in Physiology or Medicine for his research on the function of the cochlea in the ...
Histology: A Test and Atlas[page needed] Raphael Y, Altschuler RA (June 2003). "Structure and innervation of the cochlea". ...
Cochlea Oval window This article incorporates text in the public domain from the 20th edition of Grays Anatomy (1918) Colletti ... It allows fluid in the cochlea to move, which in turn ensures that hair cells of the basilar membrane will be stimulated and ... The membrane vibrates with opposite phase to vibrations entering the cochlea through the oval window as the fluid in the ... It therefore travelled "backwards" around the cochlea but still gave useful hearing as the hair cells were still deflected in ...
The cochlea contains the spiral organ of Corti, which is the receptor organ for hearing. It consists of tiny hair cells that ... This action is passed onto the cochlea, which is a fluid-filled snail-like structure that contains the receptor organ for ... it transmits pressure waves of sound through the fluid of the cochlea, sending the organ of Corti in the cochlear duct into ...
The cochlea is a spiral tube that is… ... The cochlea contains the sensory organ of hearing. It bears a ... In human ear: Cochlea. The cochlea contains the sensory organ of hearing. It bears a striking resemblance to the shell of a ... human cochlea and semicircular canalsDissection of the human cochlea and semicircular canals.. Courtesy of Lars-Goran Johnsson ... inner ear, which contains the cochlea. The cochlea is a complex coiled structure. It consists of a long membrane, known as the ...
The spiral ganglion is one of the two ganglion parts that make up the acoustic nerve complex (a group of ganglion cells closely applied to the cranial edge of the auditory vesicle). The spiral ganglion fibers create the cochlear nerve.. ...
The membrane is joined to the bony shelf of the cochlea and passes like a roof over the receptor cells, making contact with the ...
It lies between the two bony compartments and ends as a closed sac at the apex of the cochlea. ...
Download this Cochlea photo now. And search more of iStocks library of royalty-free stock images that features Animal photos ... Cochlea - Stock image. .... Animal, Eyestalk, One Animal, The Natural World, Animal Antenna. ...
Sound, in a form of a mechanical wave, enters the cochlea at the round window. The cochlea is filled with fluid and the ... but rather into a natural crevice in the cochlea that allows for the hydrodynamic nature of the cochlea to be maintained. Still ... As a result of facilitated activity of the SGC in one cochlea only and stimulation through a very limited number of stimulating ... The cochlear implant can include an electrode array that is implantable in the cochlea of the implantee and which is adapted to ...
The cochlea is a portion of the inner ear that looks like a snail shell (cochlea is Greek for snail.) The cochlea receives ... The name cochlea derives from Ancient Greek κοχλίας (kōhlias), meaning spiral, snail shell. The cochlea (plural is cochleae) ... The cochlea and vestibule, viewed from above. Cross-section of the cochlea. Bony labyrinth Membranous labyrinth Cochlear ... Kay The Cochlea By Peter Dallos, Arthur N. Popper, Richard R. Fay Cochlea at the US National Library of Medicine Medical ...
Turritella cochlea is a species of sea snail, a marine gastropod mollusk in the family Turritellidae. Reeve, 1849 Conch. Icon. ... Turritella cochlea Reeve, 1849. Retrieved through: World Register of Marine Species on 17 May 2010.. ...
Euophrys cochlea is a jumping spider species in the genus Euophrys that lives in South Africa. Wesołowska, W.; Azarkina, G. N ... doi:10.11646/zootaxa.3789.1.1. World Spider Catalog (2017). "Euophrys cochlea Wesolowska, Azarkina & Russell-Smith, 2014". ...
Carelia cochlea was a species of small, air-breathing, land snails, terrestrial pulmonate gastropod mollusks in the family ... Carelia cochlea. 2006 IUCN Red List of Threatened Species. Downloaded on 6 August 2007.. ...
The modiolus is a conical shaped central axis in the cochlea. It consists of spongy bone and the cochlea turns approximately ...
"Heteropsammia cochlea. Corals of the World - Photos, maps and information about corals and reefs". coral.aims.gov.au. Retrieved ... Heteropsammia cochlea, also known as walking dendro, is a species of small lonely coral belonging to the Dendrophylliidae ... Heteropsammia cochlea. The IUCN Red List of Threatened Species 2008: e.T133679A3861285. doi:10.2305/IUCN.UK.2008.RLTS. ...
Spiral ligament of cochlea definition at Dictionary.com, a free online dictionary with pronunciation, synonyms and translation ...
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Artificial cochlea tells tones apart. TRN March 9/16, 2005. TRN Categories: MicroElectroMechanical Systems (MEMS); Applied ... This micromechanical microphone mimics the cochlea, the tapered part of the biological ear that distinguishes different ...
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The actual coiling or spiral nature of the cochlea occurred to save space inside the skull. The longer the cochlea, the higher ... Dugdale, DC (2012). "Hearing and the Cochlea". MedlinePlus. Manley, GA (August 2012). "Evolutionary Paths to Mammalian Cochleae ... The size of cochlea has been measured throughout its evolution based on the fossil record. In one study, the basal turn of the ... Humans have long cochleae, but the space devoted to each frequency range is quite large (2.5mm per octave), resulting in a ...
Segmentation of Cochlea in 3D » Segmentation of a Knee Bone in 3D » Component Analysis & Selection in 3D » ... Segmentation of Cochlea in 3D The Wolfram Language includes a variety of 3D segmentation techniques such as clustering, region ... Extract the cochlea by selecting the largest component and multiply the selected segment by the original volume to visualize ... Apply image foresting segmentation and connected components to obtain an initial segmentation of a cochlea. ...
In chapter 3, "The Sense of Sensibility," author Wendy Jones uses scenes from one of Jane Austens most celebrated novels to illustrate the functioning of the bodys stress response system.. 0 Comments. ...
But a cochlea implant looks a bit like a normal hearing aid. Its worn behind the ear and theres a microphone attached to it. ... As a result of damage or losing certain parts of the cochlea, in the same way that phantom pain hurts, the tinnitis is the ... Lets have a listen to what a piece of music would sound like if youre listening to it with a cochlea implant. [sound] That ... Chris - So when we lose them and we want to restore them using this cochlea implant technology, how does that work? What does ...
Lgr5-positive supporting cells generate new hair cells in the postnatal cochlea.. Bramhall NF1, Shi F2, Arnold K3, Hochedlinger ... The prevalence of hearing loss after damage to the mammalian cochlea has been thought to be due to a lack of spontaneous ... These data suggest that the neonatal mammalian cochlea has some capacity for hair cell regeneration following damage alone and ... Lgr5-Positive Supporting Cells Generate New Hair Cells in the Postnatal Cochlea ...
cochleae. (. I. ) Quantification of EdU+ cells in WT, Sox2CreERT2/+. , and Sox2GFP/+. cochleae. (. J. ) P28 Sox2CreERT2/+. mice ... cochlea. Mechanistically, Sox2haplo or damaged neonatal cochleae showed lower levels of Sox2 and Hes5, but not of Wnt target ... cochlea. (. D. ) Schematic of EdU administration to Sox2CreERT2/+. mice, Sox2GFP/+. mice, and WT littermates (once daily, P2-P4 ... cochleae compared with expression in WT littermates. (. F. ) Confocal images show no EdU+ hair cells or supporting cells in the ...
... we stained the cochleae of mouse and rat with the antibodies used in this study (Figures 6(c) and 6(d)). In the mouse cochlea, ... revealed the same expression patterns of KIAA1199 in the common marmoset cochlea. (c) Immunohistochemistry with the cochleae of ... Distinct Expression Pattern of a Deafness Gene, KIAA1199, in a Primate Cochlea. Makoto Hosoya,1 Masato Fujioka,1 Hideyuki Okano ... Figure 1: Expression of KIAA1199 in the cochlea of the common marmoset. (a and b) KIAA1199 expression is observed in the ...
  • It allows fluid in the cochlea to move, which in turn ensures that hair cells of the basilar membrane will be stimulated and that audition will occur. (wikipedia.org)
  • The membrane vibrates with opposite phase to vibrations entering the cochlea through the oval window as the fluid in the cochlea is displaced when pressed by the stapes at the oval window. (wikipedia.org)
  • Cochlea Oval window This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918) Colletti V, Soli SD, Carner M, Colletti L (2006). (wikipedia.org)
  • The evolution of the human cochlea is a major area of scientific interest because of its favourable representation in the fossil record. (wikipedia.org)
  • KIAA1199 was later identified by cDNA microarray analysis as a cochlea-specific gene that was abundantly expressed in the human cochlea [ 4 ], and the protein it encodes has been found to play a central role in hyaluronan binding and depolymerization [ 5 ]. (hindawi.com)
  • The electrical, acoustical, and mechanical elements of the cochlea are explicitly integrated into a transmission-line model to develop a physiological interpretation of the human cochlea insofar. (diva-portal.org)
  • The human cochlea contains on the order of 3,500 inner hair cells and 12,000 outer hair cells at birth. (wikipedia.org)
  • Current research involving glial cells in the human cochlea proposes that these cells are the common precursor to both mature Schwann cells and satellite glial cells. (wikipedia.org)
  • he conceptualised using a seashell to replicate the human cochlea, and grass blades (which were flexible at the tip and gradually increasing in stiffness) to represent electrodes. (wikipedia.org)
  • In 2006 Manoussaki and her NIH collaborators published a paper proposing that the helical shape of the cochlea enhances low-frequency sounds through an effect analogous to the well-known "whispering gallery effect" in which soft sounds that travel along curved walls in a large chamber remain loud enough that they can be heard clearly on the opposite side of the room. (innovations-report.com)
  • The first focus of this work aims at defining automatic image processing methods adapted to the spiral shape of the cochlea to study the cochlear shape variability from high-resolution μCT images. (archives-ouvertes.fr)
  • The high-quality, sterling silver jewelry is inspired by the shape of the cochlea, the part of the ear that gives us the ability to interpret sound. (audbling.com)
  • The membrane is joined to the bony shelf of the cochlea and passes like a roof over the receptor cells, making contact with the tips of their hairs. (innerbody.com)
  • Neurons whose cell bodies lie in the spiral ganglion are strung along the bony core of the cochlea, and send fibers (axons) into the central nervous system (CNS). (wikipedia.org)
  • Four rows of hair cells (called stereocilia) are located along the length of the cochlea. (hubpages.com)
  • The canal is one of two main chambers that are created by an elastic membrane that runs the length of the cochlea. (innovations-report.com)
  • Not only does this help to give a better understanding of the structure of the cochlea, but also of the localization. (keyence.com)
  • At the cochlea, this information is converted into electrical impulses that travel by means of the cochlear nerve, which spans from the cochlea to the ventral cochlear nucleus, which is located in the pons of the brainstem. (wikipedia.org)
  • In the common marmoset cochlea, KIAA1199 protein expression was more widespread than in rodents, with all epithelial cells, including hair cells, expressing KIAA1199. (hindawi.com)
  • b ) A cross-sectional view of the common marmoset cochlea duct under low magnification (left). (nih.gov)
  • In conclusion, transient receptor potential vanilloid 4 may function as an osmosensory and a mechanosensory receptor in the cochlea. (ovid.com)
  • A fine fissure in the lower part of the first turn of the cochlea , formed by a spiral lamina which projects from the outer wall of the cochlea but does not quite reach the osseous spiral lamina , thus leaving a narrow gap . (biology-online.org)
  • If the round window were to be absent or rigidly fixed (as can happen in some congenital abnormalities), the stapes footplate would be pushing incompressible fluid against the unyielding walls of the cochlea. (wikipedia.org)
  • It absorbs the pressure that is left after the stapes' footplate sends the pressurized waves into the cochlea and drains it from the system so that theres not limitless pressure going into the cochlea at all times without any release. (wikipedia.org)
  • Although the differentiation of hair cells is known to require the expression of basic helix-loop-helix transcription factor, Atoh1 , the control of cell proliferation in the region of the developing cochlea that will ultimately become the sensory epithelium and the cues that initiate Atoh1 expression remain obscure. (jneurosci.org)
  • Our results demonstrated that when electrodes were completely sealed into the cochlea, the rate of longitudinal volume flow in scala tympani was extremely slow, approximately 1.6 nl/min in the apical direction. (biomedsearch.com)
  • Scala tympani labeled at right, inside cochlea. (wikipedia.org)
  • At the apical end of the cochlea, at an opening known as the helicotrema, the scala vestibuli merges with the scala tympani. (wikipedia.org)
  • c ) The three-dimensional equivalent electrical circuit of the whole cochlea built from the element circuit in ( b ) by its longitudinal electrical coupling in the selected nodes. (royalsocietypublishing.org)
  • This raises the possibility that the TM may be involved in the longitudinal propagation of energy in the intact cochlea. (wikipedia.org)
  • The cochlea thus acts as an 'acoustic prism', distributing the energy of each Fourier component of a complex sound at different locations along its longitudinal axis. (wikipedia.org)
  • Lgr5-positive supporting cells generate new hair cells in the postnatal cochlea. (nih.gov)
  • Sox2 haploinsufficiency results in continued proliferation and formation of supernumerary hair cells in the neonatal cochlea. (jci.org)
  • B ) Whole-mount preparation of cochlea from P4 Sox2 CreERT2/+ R26R tdTomato/+ mice given tamoxifen on P2, showing tdTomato expression in supporting cells and some hair cells. (jci.org)
  • F ) Confocal images show no EdU + hair cells or supporting cells in the P5 WT cochlea. (jci.org)
  • H ) Quantification of extranumerary hair cells in WT, Sox2 CreERT2/+ , and Sox2 GFP/+ cochleae. (jci.org)
  • The sound waves travel through the cochlea and excite hair cells at specific locations along the cochlea, and the information from these cells is picked up by the auditory nerve and carried to the brain. (hubpages.com)
  • The hair-cell concentration of calbindin-D28k but not of parvalbumin-β increased from the low- to high-frequency end of the cochlea. (jneurosci.org)
  • β-Catenin-deleted cochleae displayed disrupted compartment borders containing ectopic hair cell and supporting cell subtypes, whereas inhibiting transcriptional and preserving cell adhesion-mediated activities of β-catenin maintained radial patterning and cell identity. (pnas.org)
  • Here we show that β-catenin is required for specification of hair cell and supporting cell subtypes and radial patterning of the cochlea in vivo. (pnas.org)
  • In the avian cochlea, lost hair cells can be replaced by regeneration. (jneurosci.org)
  • This single dose protocol has been shown to consistently result in extensive morphological damage and hair cell loss in the proximal region of the cochlea while sparing a morphologically undamaged distal cochlear region. (jneurosci.org)
  • Using these markers we found evidence for reversible changes in cell cycle status throughout the cochlea, while progression through S phase and mitosis was restricted to the region of the cochlea which sustained hair cell loss. (jneurosci.org)
  • We used this technique to make, to our knowledge, the first measurements of the tectorial membrane, the structure that overlies the sensory hair cell stereociliary bundles, within a healthy cochlea. (pnas.org)
  • Olivocochlear suppression of outer hair cells in vivo: evidence for combined action of BK and SK2 channels throughout the cochlea. (nih.gov)
  • In the developing cochlea, Wnt/β-catenin signaling positively regulates the proliferation of precursors and promotes the formation of hair cells by up-regulating Atoh1 expression. (frontiersin.org)
  • Altogether, our findings suggest that LGR4 and LGR5 play an important role in the regulation of hair cell differentiation in the embryonic cochlea. (frontiersin.org)
  • The cochlea contains many thousands of hair cells organized in extensive arrays, embedded in an electrically coupled system of supporting cells. (royalsocietypublishing.org)
  • The cochlea also contains a specific population of hair cells, the outer hair cells (OHCs), which is thought to amplify the BM motion. (royalsocietypublishing.org)
  • However, it is unresolved how Notch signaling functions in the hair cell-damaged cochlea and the molecular and cellular changes induced in supporting cells in response to hair cell trauma are poorly understood. (pubmedcentralcanada.ca)
  • Moreover, we provide evidence that Notch signaling is active in the hair cell damaged cochlea and identify Hes1, Hey1, Hey2, HeyL, and Sox2 as targets and potential Notch effectors of this hair cell-independent mechanism of Notch signaling. (pubmedcentralcanada.ca)
  • This causes hair cells inside the cochlea to be susceptible to fluorescence blurring during fluorescence observation, and are therefore observed mainly with laser confocal microscopes. (keyence.com)
  • Actin filaments, stereocilia and hair cells of the bird cochlea. (biologists.org)
  • The cochlea has over 32,000 hair cells. (wikipedia.org)
  • The cochlea contains two cell types, auditory hair cells for mechanotransduction and supporting cells. (wikipedia.org)
  • The lessened severity of Cx30 knockout in comparison to Cx26 knockout is supported by a study examining the time course and patterns of hair cell degeneration in the cochlea. (wikipedia.org)
  • The percent hair cell loss was less widespread and frequent in the cochleas of Cx30 null mice. (wikipedia.org)
  • It uses the same kinds of fluids and detection cells (hair cells) as the cochlea uses, and sends information to the brain about the attitude, rotation, and linear motion of the head. (wikipedia.org)
  • It therefore travelled "backwards" around the cochlea but still gave useful hearing as the hair cells were still deflected in the same way. (wikipedia.org)
  • The outer hair cells mechanically amplify low-level sound that enters the cochlea. (wikipedia.org)
  • He theorized that the placement of each sensory cell (hair cell) along the coil of the cochlea corresponds to a specific frequency of sound (the so-called tonotopy). (wikipedia.org)
  • This inflammation causes a bad blood flow in the exposed blood vessels (vascular stasis), and a bad oxygen supply for the liquid inside the cochlea (endolymphatic hypoxia) Those noxious conditions worsen the damaged hair-cells degeneration. (wikipedia.org)
  • Sox2haplo cochleae had delayed terminal mitosis and ectopic sensory cells, yet normal auditory function. (jci.org)
  • A ) Immunostaining of P5 WT cochlea shows Sox2 expression in Hensen's cells, Deiters' cells, pillar cells, and the lateral portion of the greater epithelial ridge. (jci.org)
  • C ) GFP + supporting cells in the P5 Sox2 GFP/+ cochlea. (jci.org)
  • However, there is a risk of tumor growth associated with transplanting iPS cells into mouse cochleae. (medindia.net)
  • They noted that the number of cells able to be transplanted into cochleae is limited because of the cochleae's tiny size. (medindia.net)
  • Thus, the number of settled cells is low.They also noted the formation of a teratoma (encapsulated tumor) in some cochlea after transplantation with one group of iPS cells. (medindia.net)
  • Stem Cells and the Bird Cochlea-Where Is Everybody? (cshlpress.com)
  • ResultsOrganic cation transporter 2 was found in the supporting cells and in type I spiral ganglion cells in the cochlea of all species studied. (diva-portal.org)
  • The loss of LGR4 function prolonged the proliferation in the mid-basal turn of E13 cochleae, causing an increase in the number of SOX2-positive precursor cells within the pro-sensory domain. (frontiersin.org)
  • It has been demonstrated that INS can be utilized to stimulate spiral ganglion cells in the cochlea. (ovid.com)
  • Deiters cells M. Holmes and J. D. Cole, "Pseudoresonance in the cochlea, ' in: Mechanics of Hearing, E. de Boer and M. A. Viergever (editors), Proceedings of the IUTAM/ICA Symposium, Delft (1983), pp. 45-52. (wikipedia.org)
  • The spiral (cochlear) ganglion is the group of nerve cells that serve the sense of hearing by sending a representation of sound from the cochlea to the brain. (wikipedia.org)
  • Because of their structural specialization, Boettcher cells are believed to play a significant role in the function of the cochlea. (wikipedia.org)
  • Aminoglycoside-induced production of reactive oxygen species may also injure cells of the cochlea. (wikipedia.org)
  • Boettcher cells are located immediately under Claudius cells in the lower turn of the cochlea. (wikipedia.org)
  • Research on the regrowth of cochlea cells may lead to medical treatments that restore hearing. (wikipedia.org)
  • It turns out that it is the curvature of the cochlea, not its size, that is highly correlated to the low-frequency hearing limit," says Daphne Manoussaki, assistant professor of mathematics at Vanderbilt University, who headed the new study with Richard S. Chadwick, a section chief at the National Institute on Deafness and Other Communication Disorders (one of the National Institutes of Health, or NIH). (innovations-report.com)
  • Charles F. Babbs, "Quantitative Reappraisal of the Helmholtz-Guyton Resonance Theory of Frequency Tuning in the Cochlea," Journal of Biophysics , vol. 2011, Article ID 435135, 16 pages, 2011. (hindawi.com)
  • The basal end of the cochlea, where sounds enter from the middle ear, encodes the higher end of the audible frequency range while the apical end of the cochlea encodes the lower end of the frequency range. (wikipedia.org)
  • Ototoxicity in the cochlea may cause hearing loss of the high-frequency pitch ranges or complete deafness, or losses at points between. (wikipedia.org)
  • Element values along the cochlea are tapered in a logarithmic fashion to represent lowering frequency responses with distance. (wikipedia.org)
  • citation needed] Clark's research demonstrated that an electrode bundle with 'graded stiffness' would pass without injury around the tightening spiral of the cochlea to the speech frequency region. (wikipedia.org)
  • Unlike behavioral curves, however, the curves obtained by plotting the sound required to produce an arbitrary amount of electrical potential of the cochlea do not represent auditory thresholds. (britannica.com)
  • The cochlea is essential for sound detection. (pnas.org)
  • There are currently two competing theories established to explain the propagation of sound from the place where it is produced inside the cochlea towards the exit of the cochlea. (hindawi.com)
  • In first steps in hearing, the cochlea converts sound waves coming from the outside of the ear into electrical activity of the auditory nerve. (royalsocietypublishing.org)
  • CHL patients have a problem with the ear (outer, middle or canal) that prohibits air conducted sound from reaching an otherwise functional cochlea. (wikipedia.org)
  • Therefore, the traditional treatment approach has been a prosthetic device called Baha, which replaces the function of the impaired ear by using a well-established principle called bone conduction to re-route sound through the skull bones to the functional cochlea. (wikipedia.org)
  • The waves have to be amplified because the fluid in the cochlea reduces sound. (wikipedia.org)
  • The development of the cochlea has received considerable attention in recent years as a model system for studies of cell interactions in patterning, sensory repair, and regeneration. (jneurosci.org)
  • Studies of the cochlea revealed that the extra neurotrophin-3 had boosted the regeneration of synapses damaged by the noise. (elifesciences.org)
  • Clark showed[clarification needed] that the electrode bundle had to be free-fitting, and the wires needed to be terminated with circumferential bands to reduce friction against the outer wall of the cochlea, and so make it[clarification needed] easier to pass the required distance. (wikipedia.org)
  • Histological reconstructions and microCT of guinea pig cochleae stimulated with an infrared laser suggest that the orientation of the beam from the optical fiber determined the site of stimulation in the cochlea. (ovid.com)
  • However, the stimulation can happen also via direct vibration of the cochlea from the skull. (wikipedia.org)