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.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, 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.Hair: A filament-like structure consisting of a shaft which projects to the surface of the SKIN from a root which is softer than the shaft and lodges in the cavity of a HAIR FOLLICLE. It is found on most surfaces of the body.Hair Cells, Vestibular: Sensory cells in the acoustic maculae with their apical STEREOCILIA embedded in a gelatinous OTOLITHIC MEMBRANE. These hair cells are stimulated by the movement of otolithic membrane, and impulses are transmitted via the VESTIBULAR NERVE to the BRAIN STEM. Hair cells in the saccule and those in the utricle sense linear acceleration in vertical and horizontal directions, respectively.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.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.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.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.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.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.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.Hair Follicle: A tube-like invagination of the EPIDERMIS from which the hair shaft develops and into which SEBACEOUS GLANDS open. The hair follicle is lined by a cellular inner and outer root sheath of epidermal origin and is invested with a fibrous sheath derived from the dermis. (Stedman, 26th ed) Follicles of very long hairs extend into the subcutaneous layer of tissue under the SKIN.Hearing: The ability or act of sensing and transducing ACOUSTIC STIMULATION to the CENTRAL NERVOUS SYSTEM. It is also called audition.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.Hearing Loss: A general term for the complete or partial loss of the ability to hear from one or both ears.Transcription Factor Brn-3C: A POU domain factor that activates neuronal cell GENETIC TRANSCRIPTION of GENES encoding NEUROFILAMENT PROTEINS, alpha internexin, and SYNAPTOSOMAL-ASSOCIATED PROTEIN 25. Mutations in the Brn-3c gene have been associated with DEAFNESS.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)TurtlesCilia: Populations of thin, motile processes found covering the surface of ciliates (CILIOPHORA) or the free surface of the cells making up ciliated EPITHELIUM. Each cilium arises from a basic granule in the superficial layer of CYTOPLASM. The movement of cilia propels ciliates through the liquid in which they live. The movement of cilia on a ciliated epithelium serves to propel a surface layer of mucus or fluid. (King & Stansfield, A Dictionary of Genetics, 4th ed)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.Cochlear Microphonic Potentials: The electric response of the cochlear hair cells to acoustic stimulation.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.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.Microscopy, Electron, Scanning: Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.Hair Cells, Ampulla: Sensory cells in the ampullary crest of each of the semicircular ducts, with their apical STEREOCILIA embedded in a wedge-shaped gelatinous cupula. These hair cells sense the movement of ENDOLYMPH resulting from angular acceleration of the head, and send signals via the VESTIBULAR NERVE to the brain to maintain balance.Neurons, Efferent: Neurons which send impulses peripherally to activate muscles or secretory cells.Hair Color: Color of hair or fur.Usher Syndromes: Autosomal recessive hereditary disorders characterized by congenital SENSORINEURAL HEARING LOSS and RETINITIS PIGMENTOSA. Genetically and symptomatically heterogeneous, clinical classes include type I, type II, and type III. Their severity, age of onset of retinitis pigmentosa and the degree of vestibular dysfunction are variable.Animals, Newborn: Refers to animals in the period of time just after birth.Gentamicins: A complex of closely related aminoglycosides obtained from MICROMONOSPORA purpurea and related species. They are broad-spectrum antibiotics, but may cause ear and kidney damage. They act to inhibit PROTEIN BIOSYNTHESIS.Hair Diseases: Diseases affecting the orderly growth and persistence of hair.Lateral Line System: Aquatic vertebrate sensory system in fish and amphibians. It is composed of sense organs (canal organs and pit organs) containing neuromasts (MECHANORECEPTORS) that detect water displacement caused by moving objects.Mechanoreceptors: Cells specialized to transduce mechanical stimuli and relay that information centrally in the nervous system. Mechanoreceptor cells include the INNER EAR hair cells, which mediate hearing and balance, and the various somatosensory receptors, often with non-neural accessory structures.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.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.Auditory Threshold: The audibility limit of discriminating sound intensity and pitch.Chickens: Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.Membrane Potentials: The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).Hair Removal: Methods used to remove unwanted facial and body hair.Hair Dyes: Dyes used as cosmetics to change hair color either permanently or temporarily.Large-Conductance Calcium-Activated Potassium Channels: A major class of calcium activated potassium channels whose members are voltage-dependent. MaxiK channels are activated by either membrane depolarization or an increase in intracellular Ca(2+). They are key regulators of calcium and electrical signaling in a variety of tissues.Organ Culture Techniques: A technique for maintenance or growth of animal organs in vitro. It refers to three-dimensional cultures of undisaggregated tissue retaining some or all of the histological features of the tissue in vivo. (Freshney, Culture of Animal Cells, 3d ed, p1)Hair Preparations: Hair grooming, cleansing and modifying products meant for topical application to hair, usually human. They include sprays, bleaches, dyes, conditioners, rinses, shampoos, nutrient lotions, etc.Noise: Any sound which is unwanted or interferes with HEARING other sounds.Mice, Knockout: Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.Acoustic Maculae: The sensory areas on the vertical wall of the saccule and in the floor of the utricle. The hair cells in the maculae are innervated by fibers of the VESTIBULAR NERVE.Mice, Mutant Strains: Mice bearing mutant genes which are phenotypically expressed in the animals.Patch-Clamp Techniques: An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.Electric Capacitance: The ability of a substrate to retain an electrical charge.Gene Expression Regulation, Developmental: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action during the developmental stages of an organism.

*Sound localization in owls

... mammalian anteroventral cochlear nucleus) and the cochlear nucleus angularis (see figure; mammalian posteroventral and dorsal ... The axons of the auditory nerve originate from the hair cells of the cochlea in the inner ear. Different sound frequencies are ... Both parameters are carried by each fiber of the auditory nerve. The fibers of the auditory nerve innervate both cochlear ... These space-specific neurons can thus form a map of auditory space in which the positions of receptive fields in space are ...

*Otic vesicle

... sub-domain eventually gives rise to the support cells and hair cells while the neurogenic sub-domain gives rise to the auditory ... and a larger dorsal and posterior part, the utricle. The dorsal component of the inner ear also consists of what will become ... The anterior end of the otic vesicle gradually elongates as a tube and coils upon itself forming the beginnings of the cochlear ... Dual embryonic origin of the mammalian otic vesicle forming the inner ear. Development. 2011;138(24):5403-5414. doi:10.1242/dev ...

*Interaural time difference

... and dorsal cochlear nucleus (DCN) and each have different neural innervations. The AVCN contains predominant bushy cells, with ... Type I fibres innervate the base of one or two inner hair cells and Type II fibres innervate the outer hair cells. Both leave ... is the main auditory tract in the brainstem connecting SOC to the inferior colliculus. The dorsal nucleus of the lateral ... The article, In vivo coincidence detection in mammalian sound localization generates phase delays, authored by Franken et. al. ...

*Binaural fusion

... where hair cells transform the mechanical signal into an electrical signal. The auditory nerve, also called the cochlear nerve ... projection patterns of the different neuronal populations in the dorsal and ventral cochlear nuclei". Brain Research Bulletin. ... Grothe, Benedikt; Koch, Ursula (2011). "Dynamics of binaural processing in the mammalian sound localization pathway--the role ... it encounters the hair cells that line the basilar membrane of the cochlea in the inner ear. The cochlea receives auditory ...

*Auditory system

Efferent synapses occur on outer hair cells and on afferent (towards the brain) dendrites under inner hair cells The cochlear ... the dorsal cochlear nucleus (DCN), and ventral cochlear nucleus (VCN). The VCN is further divided by the nerve root into the ... The plan view of the human cochlea (typical of all mammalian and most vertebrates) shows where specific frequencies occur along ... which is what elicits the hair cells' electrical responses. Inner hair cells, like the photoreceptor cells of the eye, show a ...

*Slit-Robo

... restriction force on spiral ganglia neurons to ensure their precise positioning for correct spiral ganglia-cochlear hair cells ... "Biochemical purification of a mammalian slit protein as a positive regulator of sensory axon elongation and branching". Cell. ... In fact Slit2-N, an N-terminal fragment of Slit2, has been shown to induce Dorsal Root Ganglion (DRG) elongation and branching ... During the developmental of mouse peripheral auditory system, Slit/Robo signaling imposes a ...

*Sound localization

The sound localization mechanisms of the mammalian auditory system have been extensively studied. The auditory system uses ... then sends the energy through the oval window and into the cochlea where it is changed into a chemical signal by hair cells in ... This echo cancellation occurs in the Dorsal Nucleus of the Lateral Lemniscus (DNLL).[citation needed] In order to determine the ... the organ of corti, which synapse onto spiral ganglion fibers that travel through the cochlear nerve into the brain. In ...

*Calyx of Held

The calyx of Held is a part of the auditory system, connecting the globular bushy cells (GBCs) of the anteroventral cochlear ... the primary function of the calyx of Held is to allow differentiation between temporal activation of the cochlear hair cells ... and the dorsal cochlear nucleus (DCN). Sufficient FGF levels ensure proper morphology of the cochlear nuclei, while Math5 ... The Calyx of Held is a particularly large synapse in the mammalian auditory central nervous system, so named by Hans Held in ...

*Ear

The cochlea consists of three fluid-filled spaces: the vestibular duct, the cochlear duct, and the tympanic duct. Hair cells ... This bony part is known as the auditory bulla and is formed by the tympanic part of the temporal bone. The skin surrounding the ... The complex geometry of ridges on the inner surface of some mammalian ears helps to sharply focus sounds produced by prey, ... the ear canal originates from the dorsal portion of the first pharyngeal cleft. It is fully expanded by the end of the 18th ...

*Development of the nervous system

ATP release from supporting cells triggers action potentials in inner hair cells. In the auditory system, spontaneous activity ... These mesodermal cells that migrate along the dorsal midline give rise to a structure called the notochord. Ectodermal cells ... Jones, T.A; Jones, S.M; Paggett, K.C (15 October 2001). "Primordial rhythmic bursting in embryonic cochlear ganglion cells". ... The mammalian central nervous system (CNS) is derived from the ectoderm-the outermost tissue layer-of the embryo. In the third ...

*Vocal learning

... but the auditory pathway is not unique to vocal learners. Ear hair cells project to cochlear ganglia neurons to auditory ... A descending auditory feedback pathway exists projecting from the dorsal nidopallium to the intermediate arcopallium to shell ... "Vocalizations" in this case refers only to sounds generated by the vocal organ (mammalian larynx or avian syrinx) as opposed to ... An auditory pathway that is used for auditory learning brings auditory information into the vocal pathway, ...
Regeneration of sensory hair cells in the mature avian inner ear was first described just over 20 years ago. Since then, it has been shown that many other non-mammalian species either continually produce new hair cells or regenerate them in response to trauma. However, mammals exhibit limited hair cell regeneration, particularly in the auditory epithelium. In birds and other non-mammals, regenerated hair cells arise from adjacent non-sensory (supporting) cells. Hair cell regeneration was initially described as a proliferative response whereby supporting cells re-enter the mitotic cycle, forming daughter ...
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 ...
OBJECTIVE/HYPOTHESIS: Hair cells of the mammalian auditory system do not regenerate, and therefore their loss leads to irreversible hearing loss. Aminoglycosides, among other substances, can irreversibly damage hair cells. Somatostatin, a peptide with hormone/neurotransmitter properties, has neuroprotective effects by binding to its receptor. In this study, we tested whether somatostatin can protect hair cells from gentamicin-induced damage in vitro. STUDY DESIGN: This study confirmed the expression of somatostatin receptor mRNA within the cochlea and analyzed the effect of somatostatin on gentamicin-induced hair cell damage and death in vitro. METHODS: Expression of somatostatin receptor mRNA in the rat cochlea was analyzed by reverse ...
TY - JOUR. T1 - Letter to the Editor regarding "Effects of caffeic acid on cisplatin-induced hair cell damage in HEI-OC1 auditory cells". AU - Kim, Shin Hye. AU - Choi, June. AU - Park, Moo Kyun. PY - 2016/2/1. Y1 - 2016/2/1. UR - http://www.scopus.com/inward/record.url?scp=84969724108&partnerID=8YFLogxK. UR - http://www.scopus.com/inward/citedby.url?scp=84969724108&partnerID=8YFLogxK. U2 - 10.1016/j.ijporl.2015.12.010. DO - 10.1016/j.ijporl.2015.12.010. M3 - Letter. C2 - 26786961. AN - SCOPUS:84969724108. VL - 81. JO - International Journal of Pediatric Otorhinolaryngology. JF - International Journal of Pediatric Otorhinolaryngology. SN - 0165-5876. ER - ...
Postembryonic production of hair cells, the highly specialized receptors for hearing, balance and motion detection, occurs in a precisely controlled manner in select species, including avians. Notch1, Delta1 and Serrate1 mediate cell specification in several tissues and species. We examined expression of the chicken homologs of these genes in the normal and drug-damaged chick inner ear to determine if signaling through this pathway changes during hair cell regeneration. In untreated post-hatch chicks, Delta1 mRNA is abundant in a subpopulation of cells in the utricle, which undergoes continual postembryonic hair cell production, but it is absent from all cells in the basilar papilla, which is mitotically quiescent. By 3 days after drug-induced hair cell injury, Delta1 ...
Death of sensory hair cells in the inner ear results in two global health problems that millions of people around the world suffer: hearing loss and balance disorders. Hair cells convert sound vibrations and head movements into electrical signals that are conveyed to the brain, and as a result of aging, exposure to noise, modern drugs or genetic predisposition, hair cells die. In mammals, the great majority of hair cells are produced during embryogenesis, and hair cells that are lost after birth are not replaceable. However, in the last decades, researches have shown some model organisms that retain the ability to regenerate hair ...
In fish, amphibians, and birds, regeneration of sensory hair cells through asymmetric cell divisions of supporting cells can contribute to recovery of hearing and balance after hair cell loss caused by trauma or toxicity (1, 2). Mammalian hair cells do not spontaneously regenerate, even though supporting cells in vestibular sensory epithelia retain a limited ability to divide (3, 4). Consequently, hair cell death in mammals often leads to permanent impairment of hearing and balance.. As the inner ear develops, hair cell progenitor cells exit from the cell cycle and, like neurons, terminally differentiate. Negative cell cycle regulators apparently maintain ...
The goal of Ruben Stepanyans lab The goal of the labs research is to study hair cell mechanosensitivity and calcium homeostasis in normal and pathological conditions. Mechanosensitivity of hair cells is necessary for our hearing while calcium is an essential modulator of mechano-electrical transduction. During excessively loud sounds and noise a substantial amount of calcium ions enter hair cells through mechanotransduction channels. Therefore it is important for hair cells to be able to buffer and extrude excessive Ca2; compromised calcium balance is a significant factor leading to hair cell death. Outer hair cells, one of the two types of auditory ...
Mature mammals exhibit very limited capacity for regeneration of auditory hair cells, while all non-mammalian vertebrates examined can regenerate them. In an effort to find therapeutic targets for deafness and balance disorders, scientists have examined gene expression patterns in auditory tissues under different developmental and experimental conditions. Microarray technology has allowed the large-scale study of gene expression profiles (transcriptomics) at whole-genome levels, but since mRNA expression does not necessarily correlate with protein expression, other methods, such as microRNA analysis and proteomics, are needed to better understand the process of hair cell regeneration. These technologies and some of the results of them are discussed in this review. Although there is a considerable amount of variability found between studies owing to different ...
Stereocilia are actin-based protrusions on auditory sensory hair cells that are deflected by sound waves to initiate the conversion of mechanical energy to neuronal signals. Stereocilia maintenance is essential because auditory hair cells are not renewed in mammals. This process requires both β-actin and γ-actin as knock-out mice lacking either isoform develop distinct stereocilia pathology during aging. In addition, stereocilia integrity may hinge on immobilizing actin, which outside of a small region at stereocilia tips turns over with a very slow, months-long half-life. Here, we establish that β-actin and the actin crosslinking protein fascin-2 cooperate to maintain stereocilia length and auditory function. We observed that mice expressing mutant fascin-2 (p.R109H) or mice lacking β-actin share a common phenotype ...
During this work we investigated organization, molecular composition and function of hair cell ribbon synapses. We demonstrated RIBEYE, Bassoon and Piccolo to be components of IHC synaptic ribbons. In the present study we showed that anchoring of IHC ribbons is impaired in mouse mutants for the presynaptic scaffolding protein Bassoon. The lack of active, zone-anchored synaptic ribbons reduced the presynaptic readily releasable vesicle pool, and impaired synchronous auditory signalling as revealed by recordings of exocytic IHC capacitance changes and sound-evoked activation of spiral ganglion neurons. Both exocytosis of the hair cell releasable vesicle pool and the number of synchronously activated spiral ganglion neurons co-varied with the number of anchored ribbons during development. Interestingly, ribbon-deficient IHCs were still capable of sustained exocytosis with normal Ca2+-dependence. Endocytic membrane retrieval was ...
Hair cells, the sensory receptors of the auditory, vestibular, and lateral-line organs, may be damaged by a number of agents including aminoglycoside antibiotics and severe overstimulation. In the avian cochlea, lost hair cells can be replaced by regeneration. These new hair cells appear to be derived from a support cell precursor which is stimulated to divide by events associated with hair cell loss. Little is known about the timing and sequencing of events leading to new hair cell production. In this study cell cycle-associated events in the avian cochlea were analyzed at early and late time intervals following a single high dose of gentamicin. This single dose protocol has been shown to consistently result in extensive ...
Exposure to aminoglycoside antibiotics can lead to the generation of toxic levels of reactive oxygen species (ROS) within mechanosensory hair cells of the inner ear that have been implicated in hearing and balance disorders. Better understanding of the origin of aminoglycoside-induced ROS could focus the development of therapies aimed at preventing this event. In this work, we used the zebrafish lateral line system to monitor the dynamic behavior of mitochondrial and cytoplasmic oxidation occurring within the same dying hair cell following exposure to aminoglycosides. The increased oxidation observed in both mitochondria and cytoplasm of dying hair cells was highly correlated with mitochondrial calcium uptake. Application of the mitochondrial uniporter inhibitor Ru360 reduced mitochondrial and cytoplasmic oxidation, suggesting that ...
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 ...
in Ear, Nose, & Throat Journal (1998), 77(4), 276280282-5. Regeneration/repair and protection of auditory hair cells and auditory neurons is an exciting, rapidly evolving field. Simultaneous developments in the fields of otobiology and surgical otology have led ... [more ▼]. Regeneration/repair and protection of auditory hair cells and auditory neurons is an exciting, rapidly evolving field. Simultaneous developments in the fields of otobiology and surgical otology have led to new and exciting possibilities in inner ear medicine and surgery; specifically, the treatment or prevention of a variety of types of hearing losses in the foreseeable future. Sensorineural hearing loss in humans is commonly associated with a loss of auditory hair ...
Wnt signaling is a highly conserved pathway crucial for development and homeostasis of multicellular organisms. Secreted Wnt ligands bind Frizzled receptors to regulate diverse processes such as axis patterning, cell division, and cell fate specification. They also serve to govern self-renewal of somatic stem cells in several adult tissues. The complexity of the pathway can be attributed to the myriad of Wnt and Frizzled combinations as well as its diverse context-dependent functions. In the developing mouse inner ear, Wnt signaling plays diverse roles, including specification of the otic placode and patterning of the otic vesicle. At later stages, its activity governs sensory hair cell specification, cell cycle regulation, and hair cell orientation. In regenerating sensory organs from non-mammalian species, Wnt signaling can also regulate the extent of proliferative ...
Hearing loss is often the result of the death of the mechanosensory hair cells of the inner ear. Hair cells are sensitive to a number of environmental insults including aging, noise trauma, and ototoxic drugs. Ototoxic drugs include the aminoglycoside antibiotics and the antineoplastic agent cisplatin. These ototoxic drugs are highly therapeutic, but significant side effects, including ototoxicity and nephrotoxicity. We have previously shown that induction of heat shock proteins (HSPs) inhibits both aminoglycoside- and cisplatin-induced hair cell death in whole organ cultures of adult mouse utricles (1). In addition overexpression of HSP70 inhibits aminoglycoside-induced hearing loss in vivo (2). Our goal is to translate these findings into a clinical co-therapy aimed at inhibiting ototoxic drug-induced hearing loss in humans. Here we have ...
The site of transduction is in the organ of Corti (spiral organ). It is composed of hair cells held in place above the basilar membrane like flowers projecting up from soil, with their exposed short, hair-like stereocilia contacting or embedded in the tectorial membrane above them. The inner hair cells are the primary auditory receptors and exist in a single row, numbering approximately 3,500. The stereocilia from inner hair cells extend into small dimples on the tectorial membranes lower surface. The outer hair cells are arranged in three or four rows. They number approximately 12,000, and they function to fine tune incoming sound waves. The longer stereocilia that project from the outer ...
Cochlear hair cells are mechanoreceptors of the auditory system and cannot spontaneously regenerate in adult mammals; thus hearing loss due to hair cell damage is permanent. In contrast, hair cells...
The sensory epithelia of the inner ear are composed of mechanosensory hair cells and supporting cells, organised into a checkerboard-like pattern. Hair cells are essential for hearing and their loss after exposure to excessive noise (watch your iPods!) and during ageing is the main cause of deafness in humans. This is because in the mammalian auditory organ, the full complement of hair cells is produced during embryonic development. In contrast, reptiles, fish and birds can regenerate their hair cells throughout adult life. In these species, the supporting cells act as tissue stem cells following ...
Inner ear hair cells. Coloured scanning electron micrograph (SEM) of sensory outer hair cells (stereocilia) from the organ of corti, in the cochlea of the inner ear. These cells are surrounded by a fluid called the endolymph. As sound enters the ear it causes waves to form in the endolymph, which in turn cause these hairs to move. The movement is converted into an electrical signal, which is passed to the brain. Each V-shaped arrangement of hairs lies on the top of a single cell. Magnification: x5,000 when printed 10cm tall. - Stock Image P434/0062
Inner ear hair cells convert the mechanical stimuli of sound, gravity, and head movement into electrical signals. This mechanotransduction process is initiated by opening of cation channels near the tips of hair cell stereocilia. Since the identity of these ion channels is unknown, and mutations in the gene encoding transmembrane channel-like 1 (TMC1) cause hearing loss without vestibular dysfunction in both mice and humans, we investigated the contribution of Tmc1 and the closely related Tmc2 to mechanotransduction in mice. We found that Tmc1 and Tmc2 were expressed in mouse vestibular and cochlear hair cells and that GFP-tagged TMC proteins localized near stereocilia tips. Tmc2 expression was transient in early postnatal mouse cochlear hair ...
Inner ear hair cells convert the mechanical stimuli of sound, gravity, and head movement into electrical signals. This mechanotransduction process is initiated by opening of cation channels near the tips of hair cell stereocilia. Since the identity of these ion channels is unknown, and mutations in the gene encoding transmembrane channel-like 1 (TMC1) cause hearing loss without vestibular dysfunction in both mice and humans, we investigated the contribution of Tmc1 and the closely related Tmc2 to mechanotransduction in mice. We found that Tmc1 and Tmc2 were expressed in mouse vestibular and cochlear hair cells and that GFP-tagged TMC proteins localized near stereocilia tips. Tmc2 expression was transient in early postnatal mouse cochlear hair ...
Inner ear hair cells convert the mechanical stimuli of sound, gravity, and head movement into electrical signals. This mechanotransduction process is initiated by opening of cation channels near the tips of hair cell stereocilia. Since the identity of these ion channels is unknown, and mutations in the gene encoding transmembrane channel-like 1 (TMC1) cause hearing loss without vestibular dysfunction in both mice and humans, we investigated the contribution of Tmc1 and the closely related Tmc2 to mechanotransduction in mice. We found that Tmc1 and Tmc2 were expressed in mouse vestibular and cochlear hair cells and that GFP-tagged TMC proteins localized near stereocilia tips. Tmc2 expression was transient in early postnatal mouse cochlear hair ...
Inner ear hair cells convert the mechanical stimuli of sound, gravity, and head movement into electrical signals. This mechanotransduction process is initiated by opening of cation channels near the tips of hair cell stereocilia. Since the identity of these ion channels is unknown, and mutations in the gene encoding transmembrane channel-like 1 (TMC1) cause hearing loss without vestibular dysfunction in both mice and humans, we investigated the contribution of Tmc1 and the closely related Tmc2 to mechanotransduction in mice. We found that Tmc1 and Tmc2 were expressed in mouse vestibular and cochlear hair cells and that GFP-tagged TMC proteins localized near stereocilia tips. Tmc2 expression was transient in early postnatal mouse cochlear hair ...
Inner ear hair cells convert the mechanical stimuli of sound, gravity, and head movement into electrical signals. This mechanotransduction process is initiated by opening of cation channels near the tips of hair cell stereocilia. Since the identity of these ion channels is unknown, and mutations in the gene encoding transmembrane channel-like 1 (TMC1) cause hearing loss without vestibular dysfunction in both mice and humans, we investigated the contribution of Tmc1 and the closely related Tmc2 to mechanotransduction in mice. We found that Tmc1 and Tmc2 were expressed in mouse vestibular and cochlear hair cells and that GFP-tagged TMC proteins localized near stereocilia tips. Tmc2 expression was transient in early postnatal mouse cochlear 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 ...
One of the most common complaints of adults visiting an audiology clinic is difficulty in understanding speech in the presence of background noise. Performance in noise is often attributed to sensorineural hearing loss. However, there are many individuals with normal hearing who report difficulty hearing in background noise, which demonstrates how inadequate a typical audiometric evaluation is in evaluating the demands of speech comprehension in complex listening situations. It is also unclear which anatomical structures are responsible for our performance in background noise. Discovering the roles of inner hair cells (IHCs), outer hair cells (OHCs), and auditory neurons in speech understanding in quiet and in the presence of background noise is currently a hot topic in the scientific community.. Previous studies have suggested that the eighth cranial nerve, ...
Inner ear hair cells. Coloured scanning electron micrograph (SEM) of sensory hair cells in the cochlea of the inner ear. The crescent-shaped arrangements of hairs across top are the stereocilia. Each crescent lies atop a single cell. Magnification: x1000 when printed at 10 centimetres wide. - Stock Image F004/3259
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 ...
Link to Pubmed [PMID] - 26568308. Elife 2015;4. We show that a cage-shaped F-actin network is essential for maintaining a tight spatial organization of Cav1.3 Ca(2+) channels at the synaptic ribbons of auditory inner hair cells. This F-actin network is also found to provide mechanosensitivity to the Cav1.3 channels when varying intracellular hydrostatic pressure. Furthermore, this F-actin mesh network attached to the synaptic ribbons directly influences the efficiency of otoferlin-dependent exocytosis and its sensitivity to intracellular hydrostatic pressure, independently of its action on the Cav1.3 channels. We propose a new mechanistic model for vesicle exocytosis in auditory hair cells where the rate of vesicle recruitment to the ribbons is directly controlled by a synaptic F-actin network and changes in intracellular hydrostatic ...
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. ...
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. ...
TY - JOUR. T1 - Use of organotypic cultures of Cortis organ to study the protective effects of antioxidant molecules on cisplatin-induced damage of auditory hair cells. AU - Kopke, Richard D.. AU - Liu, Wei. AU - Gabaizadeh, Ramin. AU - Jacono, Andrew. AU - Feghali, Joseph. AU - Spray, David. AU - Garcia, Phil. AU - Steinman, Howard. AU - Malgrange, Bridgitte. AU - Ruben, Robert J.. AU - Rybak, Leonard. AU - Van De Water, Thomas R.. PY - 1997/9/1. Y1 - 1997/9/1. N2 - Hypothesis: Cisplatin causes the generation of reactive oxygen species (ROS), which interferes with the antioxidant defense system of Cortis organ and results in damage to the hair cells. Background: Cisplatin is a widely used chemotherapeutic agent with the dose-limiting side effect of ototoxicity. Evidence is accumulating that cisplatin interferes with the antioxidant defense system of Cortis ...
We measured robust MET currents in both IHCs and OHCs of Myo3a−/−Myo3b−/− mice. The amplitude and sensitivity of these MET currents were smaller and more variable from cell to cell than those of control hair cells, but their kinetics and adaptation characteristics were normal, which appears to rule out an implication of these myosins in MET adaptation (Schneider et al., 2006). Incidentally, MET also occurred in the supernumerary stereocilia of circular OHC bundles, which display inward current responses when deflected in the direction opposite to the kinocilium. The MET currents of Myo3a−/−Myo3b−/− hair cells were consistent with an altered mechanical response of hair bundles due to their abnormal shapes, whereas the MET channels are otherwise properly functioning. Finally, the absence of an abnormal auditory phenotype in ...
CRITIQUE: Hair Cell Micromechanics and Otoacoustic Emissions is replete with highly detailed explanations of hair cell motility and the chemical and genetic forces behind it. It is an excellent guide for the scientist and clinician seeking a better understanding of hair cell mechanics. This books highly focused collection of scientific works successfully makes the argument toward the goal of expanding clinical applications. Although the body of the book is about hair cell mechanics and the heart is otoacoustic emissions, the reader will find that the soul is in the discussion of how OAEs can be utilized in the clinic. The innovative concepts presented here are worthy not just for scientific informations sake, but as valuable tools necessary to expand the audiologists prominence in the clinical arena. This book demonstrates that, audiologically, we live in an exciting time as ...
OHCs and inner hair cells (IHCs), do not regenerate once they are damaged or lost. For this reason, progressive loss of OHCs, in addition to loss of IHCs, leads to much of the etiology of age-related hearing loss.. "… attempts to direct stem cells towards hair cell fates have, so far, resulted only in the formation of immature cells that lack many of the markers of mature IHCs or OHCs," note the authors.. In order for scientists to research and develop treatments for age-related hearing loss, it is important to first gain a better understanding of the maturation process in the cells involved.. In light of this, researchers identified a set of OHC-enriched genes through RNA sequencing. They honed in on the gene Ikzf2 (which encodes Helios), because it was markedly enriched at all tested maturation timepoints, ...
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
TY - JOUR. T1 - Multi-isotope imaging mass spectrometry reveals slow protein turnover in hair-cell stereocilia. AU - Zhang, Duan Sun. AU - Piazza, Valeria. AU - Perrin, Benjamin J.. AU - Rzadzinska, Agnieszka K.. AU - Poczatek, J. Collin. AU - Wang, Mei. AU - Prosser, Haydn M.. AU - Ervasti, James M.. AU - Corey, David P.. AU - Lechene, Claude P.. PY - 2012/1/26. Y1 - 2012/1/26. N2 - Hair cells of the inner ear are not normally replaced during an animals life, and must continually renew components of their various organelles. Among these are the stereocilia, each with a core of several hundred actin filaments that arise from their apical surfaces and that bear the mechanotransduction apparatus at their tips. Actin turnover in stereocilia has previously been studied by transfecting neonatal rat hair cells in culture with a β-actin-GFP fusion, ...
A 3,673-bp murine cDNA predicted to encode a glycosylphosphatidylinositol-anchored protein of 1,088 amino acids was isolated during a study aimed at identifying transcripts specifically expressed in the inner ear. This inner ear-specific protein, otoancorin, shares weak homology with megakaryocyte potentiating factor/mesothelin precursor. Otoancorin is located at the interface between the apical surface of the inner ear sensory epithelia and their overlying acellular gels. In the cochlea, otoancorin is detected at two attachment zones of the tectorial membrane, a permanent one along the top of the spiral limbus and a transient one on the surface of the developing greater epithelial ridge. In the vestibule, otoancorin is present on the apical surface of nonsensory cells, where they contact the otoconial membranes and cupulae. The identification of the mutation (IVS12+2T>C) in the corresponding gene OTOA in one consanguineous Palestinian family affected by nonsyndromic ...
Institutions: MRC Mammalian Genetics Unit and Mouse Genome Centre, MRC Institute of Hearing Research Genetic deafness is highly prevalent in the human population, affecting 1 in 2000 births. Many of these show primary abnormalities of the sensory epithelia of the inner ear, as do several mouse mutants. In the whirler (wi) mutant the stereocilia of the inner hair cells of the cochlear duct are considerably shorter than wild-type while outer hair cell stereocilia take on a more rounded U shape compared to the normal V or W shape. Cloning of the defective gene underlying wi will provide insight into the molecular processes involved in normal development of stereocilia as well as providing valuable insights into the causes of neuroepithelial deafness. The wi non-recombinant region is contained within a minimal tiling path consisting of 2 BACs and a PAC. One of the BACs has been ...
Na+ concentrations in endolymph should be controlled to maintain hair cell function since the transduction channels of hair cells are cation-permeable but not K+-selective. membrane saccular extramacular epithelium semicircular canal duct epithelium and endolymphatic sac. ENaC activity is usually controlled by a number of signal pathways but most notably by genomic regulation of channel numbers in the membrane via glucocorticoid signaling. Nonselective cation channels in the apical membrane of outer sulcus epithelial cells and vestibular transitional cells mediate Na+ and parasensory K+ absorption. The K+-mediated transduction current in hair cells is also accompanied by a Na+ flux since the transduction channels are nonselective cation channels. Cation absorption by all of ...
TY - JOUR. T1 - Hematopoietic stem cells prevent hair cell death after transient cochlear ischemia through paracrine effects. AU - Yoshida, Tadashi. AU - Hata, Ryuji. AU - Hakuba, Nobuhiro. AU - Cao, Fang. AU - Zhu, Pengxiang. AU - Sakanaka, Masahiro. AU - Gyo, Kiyofumi. PY - 2007/11/13. Y1 - 2007/11/13. N2 - Background and aims: Idiopathic sudden hearing loss (ISHL) is usually unilateral and can be anything within a range of a slight impairment of hearing to virtual deafness. One of the most common etiologies for ISHL is circulatory disturbance (most often vertebrobasilar ischemia). Vertebrobasilar ischemia (VBI) causes deafness because most of the auditory system including the inner ears is supplied from the vertebrobasilar system. ISHL of vascular cause is important for neurologists to recognize, because it sometimes appears as a warning sign of impending vertebrobasilar ischemic stroke. Previously, we ...
To understand the basic biological property of hair cells (HCs) from lower vertebrates, we examined transcriptomes of adult zebrafish HCs. GFP-labeled HCs were isolated from the utricle, saccule, and lagena, the three inner-ear sensory epithelia of a pou4f3 promoter-driven GAP-GFP line of transgenic zebrafish. 2,000 HCs and 2,000 non-sensory cells from the inner ear were individually collected by suction pipet technique. RNA sequencing was performed and the resulting sequences were mapped, analyzed, and compared. Comparisons allow us to identify enriched genes in HCs, which may underlie HC specialization.
Recessive mutations at the mouse pirouette (pi) locus result in hearing loss and vestibular dysfunction due to neuroepithelial defects in the inner ear. Using a positional cloning strategy, we have identified mutations in the gene Grxcr1 (glutaredoxin cysteine-rich 1) in five independent allelic strains of pirouette mice. We also provide sequence data of GRXCR1 from humans with profound hearing loss suggesting that pirouette is a model for studying the mechanism of nonsyndromic deafness DFNB25. Grxcr1 encodes a 290 amino acid protein that contains a region of similarity to glutaredoxin proteins and a cysteine-rich region at its C terminus. Grxcr1 is expressed in sensory epithelia of the inner ear, and its encoded protein is localized along the length of stereocilia, the actin-filament-rich mechanosensory structures at the apical surface of auditory and vestibular hair cells. The precise architecture of ...
We used electron tomography of frog saccular hair cells to reconstruct presynaptic ultrastructure at synapses specialized for sustained transmitter release. Synaptic vesicles at inhibited synapses were abundant in the cytoplasm and covered the synaptic body at high density. Continuous maximal stimul …
A team of UH researchers led by Brian McDermott, PhD, Assistant Professor, Otolaryngology, Genetics and Genome Sciences and Neuroscience, School of Medicine, published the cover article in the January 1, 2014, issue of the Journal of Neuroscience based on their work studying mechanosensitive hair bundles in zebrafish. Zebrafish provide a useful model for studying hearing loss, as the hair cells are very similar to human cells, and their development can be studied from the larval stage in the optically transparent fish. Using these models, Dr. McDermotts team demonstrated that the protein ACF7 links hair cell microtubules to actin on the cuticular plate. The work provides new insight into the cytoskeleton and genesis of hair cells and, potentially, could help reveal ...
A mathematical model of cochlear processing is developed to account for the nonlinear dependence of frequency selectivity on intensity in inner hair cell and auditory nerve fiber responses. The model describes the transformation from acoustic stimulus to intracellular hair cell potentials in the cochlea. It incorporates a linear formulation of basilar membrane mechanics and subtectorial fluid-cilia displacement coupling, and simplified description of the inner hair cell nonlinear transduction process. The analysis at this stage is restricted to low-frequency single tones. The computed responses to single tone inputs exhibit the experimentally observed nonlinear effects of increasing intensity such as the increase in the bandwidth of frequency selectivity and the downward shift of the best frequency. In the model, the first effect is primarily due to the saturating effect of ...
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, ...
0108] In an embodiment, the polypeptide product which is encoded by the nucleic acid molecule may be a neurotrophic factor. In one embodiment the nucleic acid may encode a neurotrophic factor for spiral ganglion cells or cochlear hair cells. As used herein a "neurotrophic factor" is a polypeptide possessing at least one activity selected from promoting the growth and survival of developing neurons, maintaining/supporting mature neurons, and/or directing neural growth towards the source of the neurotrophic factor, and/or supporting the survival of spiral ganglion cells, and/or supporting the survival of cochlear hair cells. According to an embodiment, the neurotrophic factor is a polypeptide possessing at least one activity selected from promoting or maintaining neurite ...
TY - JOUR. T1 - Mutation screening of the PCDH15 gene in Spanish patients with usher syndrome type I. AU - Jaijo, Teresa. AU - Oshima, Aki. AU - Aller, Elena. AU - Carney, Carol. AU - Usami, Shin Ichi. AU - Millán, José M.. AU - Kimberling, William J.. PY - 2012/6/23. Y1 - 2012/6/23. N2 - Purpose: PCDH15 codes for protocadherin-15, a cell-cell adhesion protein essential in the morphogenesis and cohesion of stereocilia bundles and in the function or preservation of photoreceptor cells. Mutations in the PCDH15 gene are responsible for Usher syndrome type I (USH1F) and non-syndromic hearing loss (DFNB23). The purpose of this work was to perform PCDH15 mutation screening to identify the genetic cause of the disease in a cohort of Spanish patients with Usher syndrome type I and establish phenotype-genotype correlation. Methods: Mutation analysis of PCDH15 included additional exons recently identified and was performed by direct sequencing. The screening was performed in 19 ...
Inner ear structures are compared among three major genera of the deep-sea fish family Melamphaidae (bigscales and ridgeheads). Substantial interspecific variation is found in the saccular otoliths, including the presence of a unique otolithic spur in the genera Melamphaes and Poromitra. The variation in the saccular otolith is correlated with an increase in the number of hair bundle orientation groups on the sensory epithelia from the genera Scopelogadus to Poromitra to Melamphaes. The diverse structural variations found in the saccule may reflect the evolutionary history of these species. The sensory hair cell bundles in this family have the most variable shapes yet encountered in fish ears. In the saccule, most of the hair bundles are 15-20 μm high, an exceptional height for fish otolithic end organs. These bundles have large numbers of stereovilli, including some that reach the length of the kinocilium. ...
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, ...
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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 ...
To generate Ih activation curves with minimal contamination, tail currents were measured at −74 mV, near the reversal potential for the potassium-selective inward rectifier, IK1. The tail current was sampled at the moment of the step to −74 mV and plotted against prepulse potential. Conductance was calculated by dividing the Ih tail current by the difference (30 mV) between the step potential (−74 mV) and the experimentally determined reversal potential (−44 mV, as measured from type II hair cells in the presence of 500 μm BaCl2, which blocked IK1). Type II vestibular hair cells had a maximum conductance of 4.4 ± 2.6 nS, a half-activation voltage (V1/2) of −99 ± 6 mV, and a slope factor (S) of 8.5 ± 1.9 mV (n = 41; Fig. 2C). Under our experimental conditions, the conductance of Ih was slightly larger than previously reported in mouse vestibular ...
The effects of micro-gravity on the biophysical properties of frog labyrinthine hair cells have been examined by analysing calcium and potassium currents in isolated cells by the patch-clamp technique. The entire, anaesthetised frog was exposed to vector-free gravity in a "random positioning machine" (RPM) and the functional modification induced on single hair cells, dissected from the crista ampullaris, were subsequently studied in vitro. The major targets of microgravity exposure were the calcium/potassium current system and the IA kinetic mechanism. The amplitude of ICa was significantly reduced in micro-gravity conditioned cells. The delayed current, IKD (a complex of IKV and IKCa), was drastically reduced, mostly in its IKCa component. Micro-gravity also affected IKD kinetics by shifting the ...
Hairs form and develop in scalp. To be able to prevent hair loss and for the hair remains healthy; it plays an important role to protect scalp against the negative conditions which may arise and meet its needs.. NHTLAB Tablet with its special formulation, fights many factors which cause hair loss and aims at normalizing life cycle of hair and stopping the hair loss. Efficiency of NHTLAB Tablet on hair and scalp briefly is as follows:. Increases the production of the cells which are found in hair follicles and produce new hairs, and supports the formation of new hairs,. Supports hair transplantation after ...
The ribbon synapse is a type of neuronal synapse characterized by the presence of an electron-dense structure, the synaptic ribbon, that holds vesicles close to the active zone. It is characterized by a tight vesicle-calcium channel coupling that promotes rapid neurotransmitter release and sustained signal transmission. Ribbon synapses undergo a cycle of exocytosis and endocytosis in response to graded changes of membrane potential. It has been proposed that most ribbon synapses undergo a special type of exocytosis based on coordinated multivesicular release. This interpretation has recently been questioned at the inner hair cell ribbon synapse, where it has been instead proposed that exocytosis is described by uniquantal (i.e., univesicular) release shaped by a flickering vesicle fusion pore. These unique features specialize the ribbon synapse to enable extremely fast, precise and sustained neurotransmission, which is critical for the perception of complex senses such as ...
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
At least 30 million Americans suffer from significant hearing loss and balance disorders, Lovett says. One-third of people above age 65 and half of people above age 75 have significant hearing loss. About 80 percent of these problems result from the loss of, or damage to, sensory hair cells. "The cochlea and utricle function nearly identically in birds and humans," says Mark E. Warchol, Ph.D., associate research scientist at the Central Institute for the Deaf and a research associate professor of otolaryngology and of anatomy and neurobiology at Washington University and a co-author of the paper. "But key differences exist between them allow birds to regenerate these cells. If we can understand those differences, perhaps we can learn how to replace lost or damaged sensory hair cells in humans ...
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The Snail/Gfi1 (SNAG) family of zinc finger proteins is a group of transcriptional repressors. Gfi1 is expressed in the hematopoietic and nervous system. Consequently, mutations of Gfi1 cause defects in hematopoiesis and inner ear development. In the Gfi1P2A/P2A mouse strain, a point mutation has been inserted in the SNAG domain that replaces a proline at amino acid position 2 by alanine (P2A). This completely abrogates the activity of Gfi1 as transcriptional repressor. Commercial Opportunities Gfi1 and its paralogue Gfi1b have overlapping, however differential functions in hematopoiesis. Loss of Gfi1 in mice affects pre-T-cell differentiation, the development of neutrophil granulocytes and inner ear hair cells, whereas in contrast loss of Gfi1b impairs the development of erythroid cells and megacaryocytes. Therefore, Gfi1P2A/P2A mice can be used as a model to study and treat deafness as a consequence of ...
Androgenetic Alopecia). The most common type of hair loss seen in women is androgenetic alopecia, also known as female pattern alopecia or baldness. This is seen as hair thinning predominantly over the top and sides of the head. It affects approximately one-third of all susceptible women, but is most commonly seen after menopause, although it may begin as early as puberty. Normal hair fall is approximately 100-125 hairs per day. Fortunately, these hairs are replaced. True hair loss occurs when lost hairs are not regrown or when the daily hair shed exceeds 125 hairs. Genetically, hair loss can come from either parents side of the family.. There are two different types of ...
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But what are hair follicles anyway? Essentially, a follicle is a cell-lined sac from which strands of hair grow. Oil glands called the sebaceous glands are attached to the follicles and produce a fatty substance called sebum that cimbs up the follicle to our scalp. There the sebum oils our skin and hair.. But when hair follicles dont get enough nourishment, they can die. They simply become thinner and thinner until they eventually fall off our heads. When this happens, our scalp loses hair and we see baldness.. But when our hair thins out this doesnt necessarily mean our hair follicles are dead. Sometimes, for many different reasons, our hair follicles go into a resting phase and new hair growth temporarily ...
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Propecia Hair Gets Worse Before It Gets Better. FollicleRx - Promotes Healthy Hair GrowthWe are going to review FollicleRx, a product that promotes healthy hair follicles, but first we must discuss about hair loss and hair itself. Hair is a significant Depression And Hair Loss - Hair Loss Hell BlogGreat post linking D and hair loss! Looking back I realize the worse the PPD the more the hair fallout, a vicious cycle for sure. Now Im older and the genetic form Basics Of Hair Loss - Hair Sciences AcademyOn the other hand, any woman with the Hypothyroid Hair Loss Trigger, its ...
Tragi hairs can be numerous in some people and also very prominent. This condition is more often found in men than women. In some extreme cases, the ear hair can be quite long, recorded as being 5.2 inches by the Guinness World Records in 2003 for Radhakant Baijpai. Since then, the 64-year-old (in 2015) grocers ear hair has continued to grow to almost 10 inches long.. Ear hair is generally identified as the terminal hair developing from the follicles inside the ear canal. However, in its broader sense, ear hair may include the fine vellus hair covering much of the ear (particularly at the prominent parts of the anterior ear), as well as the terminal, or tragi hair.. Hair growth within the ear canal itself is ...
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by Carolyn Y. Johnson / Globe StaffA year ago, I wrote about promising work toward developing a drug that could help treat hearing loss. A group of researchers at Massachusetts Eye and Ear Infirmary had discovered that an experimental drug originally developed with the intent of treating Alzheimers disease could regenerate the delicate hair cells inside ears and restore rudimentary hearing when administered to deaf mice.
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 ...
Hair dying traces its roots to antiquity with evidence of use in ancient Egypt and the Roman Empire. Today, hair dying is an estimated $7 billion industry worldwide. Altering the natural color of hair is popular with both men and women but does have some health risks.. Hair has two major parts - the hair follicle and the hair shaft. The hair follicle is located at the root of the hair and attaches each hair to the scalp. The hair shaft sticks out of the follicle. Hair follicles contain living cells, but hair shafts do not. Hair color comes ...
DISCUSSION. Although the ototoxic effects of aminoglycosides were first described in the 1940s, the underlying mechanisms remain unclear. Hearing damage associated with aminoglycoside use can include permanent hearing loss and tinnitus secondary to the degradation of sensorineural hair cells of the cochlea and/or vestibule. Damage to cochlear hair cells is thought to be mediated by oxidative stress, starting at the base where high-frequency sounds are decoded and advancing to the apex6,8,13,14,15. In the present study, we identified hearing complaints after aminoglycoside use in 27% of medical records analyzed, similar to what has been described in the literature (27.8%)11. Higher frequencies of TB and hearing complaints among male subjects in our study were also consistent with previous reports. This finding may be related to the increased tendency for ...
The precise mechanical behavior of the basilar membrane (BM) at low frequencies is still unknown. To address this issue we use an in vitro preparation of the guinea pig temporal bone to investigate the mechanical behaviour of the organ of Corti at the apex of the cochlea. Confocal laser interferometry is used to record the nanometre displacements of both Hensens cells (HeC) and the BM in response to sound and electrical stimulation. We show that at low frequencies, the BM exhibits greatly reduced sound-evoked movement (similar to 35dB less) and no current-evoked movement, when compared to the HeC at the same position along the spiral. The BM best frequency is found to be an average of 52Hz (0.35 octave) higher than the HeC best frequency. In addition, we demonstrate that BM motion is not affected by inhibition of somatic electromotility or by blocking the mechanoelectrical transduction channels. We therefore propose that the BM primarily acts as a passive support structure ...
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 ...
Male pattern baldness or Androgenic alopecia is a common problem where the patients are misled by improper marketing by beneficiaries. Male pattern baldness follows a genetic pattern commonly. However the onset could be advanced by external factors like improper nutrition, unhealthy parlour procedures, dandruff, cheap shampoos etc. Hair Transplantation Chennai as a result in permanent restoration lost hair surgically. Hair transplantation does not halt the on-going hair loss. Therefore medical management is an essential part of hair restoration procedure. Patients experiencing early thinning or hair loss should start medical treatment. Currently there are only two FDA approved medication in various combinations. This included Minoxidil and Fenestride. These medications help to prevent ...
Can we heal hearing loss, ringing and vertigo naturally? Studies show that with the right nutrients, we can help repair hearing and ringing in the ears; and even vertigo maybe remedied by simple physical positions or "maneuvers".. Hearing is the ability to perceive sound by detecting vibrations and changing pressure through the ear. The inner and outer hair cells of the ear are very important and if damaged, hearing loss can occur. According to the NeuroScience Department at the U of WI, "When you are exposed to loud music or noise, it is your hair cells which are damaged. Hearing loss occurs because loud sounds are really just large pressure waves (like when you stand next to a subwoofer and can "feel" the bass). These large pressure waves bend the stereocilia too far, sometimes to the point where they are damaged. This kills the hair ...
Most hair dyes in the stores are chemical based and using them is dangerous to health but all thanks to natural hair practice, today, we can dye or color our hair to different shades with out fear of adverse effects as is with the chemical store bought products.. Henna is a natural hair dye that even comes with a lot of benefits for hair. It is also one of the ingredients that is used for a lot of beauty reasons. Henna has been one of the best hair care ingredients available to us. Since ancient times, henna has been used as a hair dye.. However, it would be interesting to know that henna has numerous other hair benefits. Apart from coloring your hair, henna is also good for treating other ...
Female-pattern baldness is different than that of male pattern baldness. The hair thins all over the head, in a diffused manner but the frontal hairline does not regress. There may be a moderate loss of hair on the crown, but this rarely progresses to total or near baldness as it may in men.. Female-pattern baldness hair loss is permanent. The hair loss is usually mild to moderate. No treatment is required if the person is comfortable with her appearance. It can be treated with medication or hair restoration. Some women however lose hair in a pattern similar to men.. Failure to grow a new hair is closely linked with genetic predisposition, aging, and levels of endocrine hormones. Changes in the levels of the androgens can affect ...
Can Methotrexate Cause Curly Hair. The Girl With Arthritis: My Methotrexate HairMy Methotrexate Hair which can also cause hair loss. It did. but I heard that buy viagra with paypal cancer patients who took chemo and lost their hair get curly hair as methotrexate and hair coloring , Arthritis Informationmethotrexate and hair CathyWhy did you stop. Are you saying i cant color my hair now. I have lots of long curly hair and it would cost a fortune for me Would you take methotrexate for this? - CurlTalkHome CurlTalk Life Non-hair discussion Would you take methotrexate for this? 3C curly/wavy/kinky hair. Mercury ...
Hearing is a unique sensory feature providing the individual with acoustic information about the surrounding environment. Humans rely on hearing to localize potential dangers and it is essential for communication and social interaction. Hearing impairment is the most common sensory deficit and affects approximately 360 million people world-wide according to the World Health Organization. Therefore, it is of great importance to understand the underlying mechanisms that enable hearing. At inner hair cell ribbon synapses, which are the first relay station of the auditory pathway, CaV1.3 calcium channels are presynaptic key elements modulating calcium-influx exocytosis coupling. In order to indefatigably respond to incoming sound waves, these CaV1.3 channels exhibit weak inactivation kinetics, but the underlying mechanisms are not understood. In the course of this study, a mutation in the gene encoding for calcium binding protein 2 (CaBP2) was shown to cause ...
Stereocilin is a protein that in humans is encoded by the STRC gene. This gene encodes a protein that is associated with the hair bundle of the sensory hair cells in the inner ear. The hair bundle is composed of stiff microvilli called stereocilia and is involved with mechanoreception of sound waves. This gene is part of a tandem duplication on chromosome 15; the second copy is a pseudogene. Mutations in this gene cause autosomal recessive non-syndromic deafness. GRCh38: Ensembl release 89: ENSG00000242866 - Ensembl, May 2017 GRCm38: Ensembl release 89: ENSMUSG00000033498 - Ensembl, May 2017 "Human PubMed Reference:". "Mouse PubMed Reference:". Verpy E, Masmoudi S, Zwaenepoel I, Leibovici M, Hutchin TP, Del Castillo I, Nouaille S, Blanchard S, Laine S, Popot JL, Moreno F, Mueller RF, Petit C (Nov 2001). "Mutations in a new gene encoding a protein of the ...
Release of neurotrophin-3 (NT3) and brain-derived neurotrophic factor (BDNF) from hair cells in the cochlea is essential for the survival of spiral ganglion neurons (SGNs). Loss of hair cells associated with a sensorineural hearing loss therefore results in degeneration of SGNs, potentially reducing the performance of a cochlear implant. Exogenous replacement of either or both neurotrophins protects SGNs from degeneration after deafness. We previously incorporated NT3 into the conducting polymer polypyrrole (Ppy) synthesized with para-toluene sulfonate (pTS) to investigate whether Ppy/pTS/NT3-coated cochlear implant electrodes could provide both neurotrophic support and electrical stimulation for SGNs. Enhanced and controlled release of NT3 was achieved when Ppy/pTS/NT3-coated electrodes were subjected to electrical stimulation. Here we ...
The vomeronasal organ (VNO) is a chemosensory structure involved in the detection of pheromones in most mammals. The VNO sensory epithelium contains both neurons and supporting cells. Data suggest that vomeronasal neurons represent the pheromonal transduction sites, whereas scarce information is available on the functional properties of supporting cells. To begin to understand their role in VNO physiology, we have characterized with patch-clamp recording techniques the electrophysiological properties of supporting cells isolated from the neuroepithelium of the mouse VNO. Supporting cells were distinguished from neurons by their typical morphology and by the lack of immunoreactivity for Ggamma8 and OMP, two specific markers for vomeronasal neurons. Unlike glial cells in other tissues, VNO supporting cells ...
Platelet-rich plasma (PRP) is what we use to treat hair loss here at The Beauty Medics because its such an effective yet entirely natural treatment. PRP contains essential proteins known as growth factors that naturally stimulate the hair to start growing again by targeting the damaged hair follicles.. The great thing is that PRP is in your own blood, and thats what Dr. Bokhari and his team will use here to treat your hair loss. Your blood has two key components, red blood cells and plasma, and the plasma contains the platelets we use to stimulate hair growth and reverse any balding.. If you think it sounds too good to be true, youll be delighted to hear that numerous scientific studies have found PRP therapy to be effective in treating hair loss. A peer review of 14 ...
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 ...
TAPES, BONDS, HAIR EXTENSIONS. We have a full line of tapes, bonds and other products either specifically for hair loss or good for long term maintenance of a hair system.. We use a new system for hair extensions - we believe is the best method in use today. Previous methods are more cumbersome and bulky. We also found hair weaving to be extremely time consuming and leaves a thick ridge along the weaving path. In addition, we no longer do or recommend hair weaving due to the risk of traction alopecia.. Check out the PHOTOS on this website of our new hair extension process and youll see the natural and beautiful results.. USEFUL LINKS:. Maria Jaggard Salon - Additional Information on Maria Jaggard Salon products & services. www.MariaJaggard.com. Wikipedia Reference on ...
Scalp is where the hair is formed and grown. In order to prevent hair loss and maintain healthy hairs, protecting scalp against possible negative outcomes and procuring its needs play a major role. Hair loss is an incidence which occurs when one or more phenomenon effect the scalp negatively. Depending on the phenomenon which occurred; life cycle of the hair starts to deteriorate. To prevent hair loss; scalp should be protected against the factors which cause hair loss. NHTLAB SHAMPOO, thanks to its special formulation; fights against many reasons which cause hair loss and aims at normalizing the life cycle of the hair and stop hair loss. NHTLAB Shampoos effects on scalp and ...
The most common type hair problems diagnosed in females is Androgenetic alopecia inherited. However, this is most common cause of hair problems in males as well. Androgenic alopecia in females is seen as hair thinning which means the number of hair on female head heavily reduces. Since the reason of hair loss varies individual to individual and hence proper medical help is of utmost importance.. Some other common causes of hair problems of females are mentioned here:. 1.Alopecia areata- This is patchy loss of hair from the scalp. Sometime eyebrows and other hair bearing parts begin losing hair. This type of hair loss is considered to be due to autoimmune.. 2.Traction ...
Several studies have demonstrated a link between diabetes and the dysfunction of the inner ear. Few studies, however, have reported the signalling mechanisms involved in metabolic control in human inner ear cells. Knowledge of the expression and role of the insulin receptor and downstream signalling components in the inner ear is sparce. Our immunohistochemistry approach has shown that the insulin receptor, insulin receptor substrate 1 (IRS1), protein kinase B (PKB) and insulin-sensitive glucose transporter (GLUT4) are expressed in the sensory epithelium of the human saccule, which also exhibits expression of a calcium-sensitive cAMP/cGMP phosphodiesterase 1C (PDE1C) and the vasopressin type 2 receptor. IRS1 and PDE1C are selectively expressed in sensory epithelial hair cells, whereas the other components are expressed in sensory epithelial supporting cells or in both cell ...
Several studies have noted an association between age and dizziness.6-8 ,12 ,14 The US NHANES reported that age was significantly associated with vestibular dysfunction.6 GNT-HIS also reported that moderate-to-severe dizziness or vertigo increased with age and the prevalence reached 37% in the age group 60 years and older.14 Hannaford et al7 showed that problems of balance increased with age. Our study also showed that the prevalence of dizziness and vestibular dysfunction in the 60-69 years and more than 70 years age segments is significantly higher than for those in the 40-49 years age segment. In multivariable analysis, dizziness and objective vestibular dysfunction assessed by the modified Romberg test showed a significant association with age (tables 1 and 2). The increase in prevalence with age can be explained by changes associated with the ageing of the vestibular system such as reduction of vestibular hair cells, degeneration of the ...
The findings shown that proanthocyanidins induced the growth of hair by converting your hair-cycle activity from your resting telogen hair cycle phase for the active growing anagen hair cycle phase. In line with Natural News, because hair consists of protein, fat, water and carbohydrates, a protein deficiency might result in weak hair or baldness. This is often particularly true for vegetarians. Adding protein to your diet may help to enrich the fitness of the hair. But additionally, there are certain medications that causes such a thinning hair, on top of that. Calcium channel blockers are certainly one such medication. Once conditions have improved, the hair is likely to re-grow. ...
Last week, I put up a post about good moisturizers for low porosity hair. This time, I want to talk about high porosity hair (you didnt think I would leave this out did you?). If you dont know how to test the difference, read this post. Unlike low porosity hair, high porosity hair absorbs moisture really well. However, it also loses moisture easily. Because the hair cuticles are often open, its hard for high porous hair to retain moisture. High porous hair can be attributed to heat damage, poor hair maintenance, harsh hair dyes or just good ole genes. Its usually thin and can break easily if not properly maintained. High porosity hair needs heavier products and sealants to ...
FRIDAY, April 29, 2016 (HealthDay News) -- Black women who like to wear their hair pulled back tightly may be increasing their risk of hair loss, new research suggests. A team of researchers from Johns Hopkins School of Medicine in Baltimore reviewed 19 studies and found a "strong association" between scalp-pulling hair styles and traction alopecia, which is gradual hair loss from damage to the hair follicle from tension at the hair root.. Traction alopecia is the most common type of hair loss among black American women, affecting about one out of three, the researchers said.. The study did not prove a definitive cause-and-effect connection. But, styles linked with this type of hair loss include braids, tight ponytails, dreadlocks, weaves ...
Both topical minoxidil and oral finasteride can be used to slow or even halt the loss of hair due to male pattern baldness, or androgenic alopecia. Both medications should also be used to slow the hair follicle miniaturation process that eventually results in hair loss. Shock loss is a phenomenon oberserved in some post-transplant patients, in which existing hair in the thinning regions that was transplanted is partially lost. Here are our thoughts about preventing post-transplant shock loss.. 1. Finasteride is effective at reducing the amount of shedding of normal hairs in the thinning zones after hair transplantation. 2. The timing of hair transplantation is important - if you are a young person experiencing early hair loss and have a ...
Loss of hair is a very natural and common phenomenon. According to experts, losing about 100 strands of hair approximately in a day is quite common. Therefore, there is nothing to worry about. Losing hair in bulks can be a real cause of concern, as this might harm your physical appearance.. As per various studies released by doctors and hair care experts, it has been observed that onions form to be a major ingredient which can augment growth of healthy hair follicles to a large extent. Considered to be one of the best of natural remedies, onions are suggested by doctors to be used on scalp in case you suffer from issues related to hair loss.. Besides, using such natural ingredients, hair care experts suggest that, you take proper care of your ...
Melanotan 2 (a.k.a. Melanotan II) is a synthetic (man-made) member of the melanocortin family of naturally occurring proteins. The melanocortins are hormones and signaling peptides critical to the production of melanin (pigment molecule and in the regulation of homeostatis, appetite, and sexual arousal. Melanocortins mediate their effects by binding to melanocortin receptors.. The Effects of Melanocortins. Melanocortin (MC) receptors are found on cells throughout the body. Five different MC receptors, labeled (1) through (5), have been identified thus far. Understanding how those receptors work has allowed scientists to explore the effects of melanocortin and thus melanotan 2. Here are the effects of each MC receptor.. MC(1): MC(1) is found in melanocytes, skin cells that are responsible for the production of melanin, the pigment that imparts a dark color to the skin. It is also found on hair ...

Sound localization in owls - WikipediaSound localization in owls - Wikipedia

... mammalian anteroventral cochlear nucleus) and the cochlear nucleus angularis (see figure; mammalian posteroventral and dorsal ... The axons of the auditory nerve originate from the hair cells of the cochlea in the inner ear. Different sound frequencies are ... Both parameters are carried by each fiber of the auditory nerve. The fibers of the auditory nerve innervate both cochlear ... These space-specific neurons can thus form a map of auditory space in which the positions of receptive fields in space are ...
more infohttps://en.wikipedia.org/wiki/Sound_localization_in_owls

Inhibitory neurotransmission, plasticity and aging in the mammalian central auditory system | Journal of Experimental BiologyInhibitory neurotransmission, plasticity and aging in the mammalian central auditory system | Journal of Experimental Biology

The auditory nerve carries signals from hair cells of cochlea into cochlear nucleus, where acoustic information projects to ... primary auditory cortex. ABR. auditory brain stem response. CN. cochlear nucleus. DCN. dorsal cochlear nucleus. GABA. gamma ... The pattern of age-related hair cell loss was different between the two strains. Aged FBN rats lost few inner hair cells (IHCs ... 2 displays the modest age-related inner hair cell changes for both strains while outer hair cell changes are more extensive ( ...
more infohttp://jeb.biologists.org/content/211/11/1781.long

Otic vesicle - WikipediaOtic vesicle - Wikipedia

... sub-domain eventually gives rise to the support cells and hair cells while the neurogenic sub-domain gives rise to the auditory ... and a larger dorsal and posterior part, the utricle. The dorsal component of the inner ear also consists of what will become ... The anterior end of the otic vesicle gradually elongates as a tube and coils upon itself forming the beginnings of the cochlear ... Dual embryonic origin of the mammalian otic vesicle forming the inner ear. Development. 2011;138(24):5403-5414. doi:10.1242/dev ...
more infohttps://en.wikipedia.org/wiki/Otic_vesicle

Mechanisms contributing to central excitability changes during hearing loss | PNASMechanisms contributing to central excitability changes during hearing loss | PNAS

The dorsal cochlear nucleus (DCN) is one of the first relays within the central auditory pathway (12). Hyperactivity in the DCN ... a hearing disorder characterized by absent auditory brainstem responses with preserved outer hair cell function. Myelin ... 2003) Bidirectional synaptic plasticity in the cerebellum-like mammalian dorsal cochlear nucleus. Proc Natl Acad Sci USA 100: ... 2004) Cell-specific, spike timing-dependent plasticities in the dorsal cochlear nucleus. Nat. Neurosci 7:719-725. ...
more infohttp://www.pnas.org/content/109/21/8292

000259 - JE/LeJ000259 - JE/LeJ

The primary influence of the jerker gene appears to be on the apical hair cells, not development of neural structures. ... A small minority of homozygotes have been found to have embryonic neural tube defects or a dorsal enlargement of the head. JE/ ... Auditory brainstem response is totally absent in homozygotes while heterozygous mice undergo a progressive impairment with age ... The abnormal behavior and deafness are associated with postnatal degeneration of the sensory cells of the cochlea and the ...
more infohttps://www.jax.org/strain/000259

Supra-Threshold Hearing and Fluctuation Profiles: Implications for Sensorineural and Hidden Hearing Loss | SpringerLinkSupra-Threshold Hearing and Fluctuation Profiles: Implications for Sensorineural and Hidden Hearing Loss | SpringerLink

An important topic in contemporary auditory science is supra-threshold hearing. Difficulty hearing at conversational speech ... Dallos P (1985) Response characteristics of mammalian cochlear hair cells. J Neurosci 5:1591-1608Google Scholar ... Cant NB, Benson CG (2003) Parallel auditory pathways: projection patterns of the different neuronal populations in the dorsal ... Mechanoelectrical transduction in auditory hair cells. In: Eatock RA, Fay RR (eds) Vertebrate hair cells. Springer, New York, ...
more infohttps://link.springer.com/article/10.1007%2Fs10162-018-0669-5

Complexin-I Is Required for High-Fidelity Transmission at the Endbulb of Held Auditory Synapse | Journal of NeuroscienceComplexin-I Is Required for High-Fidelity Transmission at the Endbulb of Held Auditory Synapse | Journal of Neuroscience

... and III/IV as measured by auditory brainstem responses. Complexins were not detectable in cochlear hair cells but CPX I was ... Reciprocal synapses between outer hair cells and their afferent terminals: evidence for a local neural network in the mammalian ... the skull was exposed along the dorsal midsagittal line. Two holes were drilled in the skull 2000-2300 μm caudal to the lambda ... which is restricted to inner ear hair cells. Otoferlin has been suggested to play a role as Ca2+ sensor of hair cell ...
more infohttp://www.jneurosci.org/content/29/25/7991.long

Susan K. McConnells Profile | Stanford ProfilesSusan K. McConnell's Profile | Stanford Profiles

The mammalian auditory sensory epithelium, the organ of Corti, comprises the hair cells and supporting cells that are pivotal ... The primary cause appears to be reduced precursor cell proliferation in the early cochlear duct. Thus, during development, ... in the mouse telencephalon results in a loss of all dorsal midline cell types without affecting the specification of cortical ... Progenitor cells in the mammalian forebrain can undergo either symmetric or asymmetric cell divisions by varying their cleavage ...
more infohttps://profiles.stanford.edu/susan-mcconnell

From placode to polarization: new tunes in inner ear development | DevelopmentFrom placode to polarization: new tunes in inner ear development | Development

Math1 gene transfer generates new cochlear hair cells in mature guinea pigs in vivo. J. Neurosci. 23,4395 -4400. ... Zheng, W., Huang, L., Wei, Z. B., Silvius, D., Tang, B. and Xu, P. X. (2003). The role of Six1 in mammalian auditory system ... E) As development continues, the cochlear duct begins to coil and the semicircular canals (SSC) begin to form in the dorsal ... but in the organ of Corti the hair cells and supporting cells are organized into rows (Fig. 2). Hair cells perceive sound and/ ...
more infohttp://dev.biologists.org/content/131/17/4119

Audition | Institute for Mathematics and its ApplicationsAudition | Institute for Mathematics and its Applications

Differential Sensitivity of Dorsal and Ventral Cochlear Nucleus Neur ons to Pinna Cues for Sound Direction. Thomas Imig ( ... hair cells and the eighth nerve;. * information processing in the brainstem, mid-brain, and cortex; ... biologists and engineers who work on different aspects of the auditory system. The entire auditory system will be covered, ... Anatomy and Physiology of the Mammalian Brainstem. Donata Oertel (University of Wisconsin, Madison) ...
more infohttps://ima.umn.edu/1998-1999/W3.8-12.99

Frontiers | Making sense of Wnt signaling-linking hair cell regeneration to development | Frontiers in Cellular NeuroscienceFrontiers | Making sense of Wnt signaling-linking hair cell regeneration to development | Frontiers in Cellular Neuroscience

... cell cycle regulation, and hair cell orientation. In regenerating sensory organs from non-mammalian species, Wnt signaling can ... At later stages, its activity governs sensory hair cell specification, cell cycle regulation, and hair cell orientation. In ... This review describes the current knowledge of the roles of Wnt signaling and Wnt-responsive cells in hair cell development and ... This review describes the current knowledge of the roles of Wnt signaling and Wnt-responsive cells in hair cell development and ...
more infohttps://www.frontiersin.org/articles/10.3389/fncel.2015.00066/full

The role of Six1 in mammalian auditory system development | DevelopmentThe role of Six1 in mammalian auditory system development | Development

H) In E15.5 cochlea, Six1 is expressed weakly in the supporting cells and first appeared in the inner hair cell (arrowhead) in ... BrdU-positive cells were largely reduced in the dorsal region of Six1-/- otic vesicle (OV, above arrowheads in D). (E) The ... double heterozygotes showing severe cochlear defects (arrows), absence of posterior ampulla (asterisk) and truncated posterior ... hair cells. It is also expressed in some cells in the GER. In addition, it is expressed in the thinner part of the cochlea duct ...
more infohttps://dev.biologists.org/content/130/17/3989.figures-only

JoVE | Peer Reviewed Scientific Video Journal - Methods and ProtocolsJoVE | Peer Reviewed Scientific Video Journal - Methods and Protocols

Mammalian cochlear hair cells are terminally differentiated and are not regenerated when they are lost. In non-mammalian ... and the hair cells of the utricle are similar in both structure and function to the hair cells in the auditory organ, the organ ... This can be performed in adult animals with a traumatic injury to the dorsal column. Here, we describe methods for ... Since there is no cell line that satisfactorily represents mammalian hair cells, research on hair cells relies on primary organ ...
more infohttps://www.jove.com/visualize/abstract/23240046/depletion-resident-macrophages-does-not-alter-sensory-regeneration

Table of Contents - October 24, 2012, 32 (43) | Journal of NeuroscienceTable of Contents - October 24, 2012, 32 (43) | Journal of Neuroscience

Hair Cell Replacement in Adult Mouse Utricles after Targeted Ablation of Hair Cells with Diphtheria Toxin Justin S. Golub, Ling ... The Dorsal Raphe Modulates Sensory Responsiveness during Arousal in Zebrafish Tohei Yokogawa, Markus C. Hannan and Harold A. ... Mammalian Target of Rapamycin Signaling Is a Key Regulator of the Transit-Amplifying Progenitor Pool in the Adult and Aging ... Emergence of Selectivity and Tolerance in the Avian Auditory Cortex C. Daniel Meliza and Daniel Margoliash ...
more infohttp://www.jneurosci.org/content/32/43

Frontiers | GLAST Deficiency in Mice Exacerbates Gap Detection Deficits in a Model of Salicylate-Induced Tinnitus | Frontiers...Frontiers | GLAST Deficiency in Mice Exacerbates Gap Detection Deficits in a Model of Salicylate-Induced Tinnitus | Frontiers...

Salicylate caused greater auditory threshold shifts (near 15 dB) in GLAST KO mice than in wild-type mice across all tested ... Auditory brainstem responses (ABR) and distortion products of otoacoustic emission (DPOAE) were performed to evaluate the ... Auditory brainstem responses (ABR) and distortion products of otoacoustic emission (DPOAE) were performed to evaluate the ... Salicylate caused greater auditory threshold shifts (near 15 d... ... is expressed in support cells from the cochlea and buffers the ...
more infohttps://www.frontiersin.org/articles/10.3389/fnbeh.2016.00158/full

Noise-Induced Neural Degeneration and Therapeutic Effect of Antioxidant DrugsNoise-Induced Neural Degeneration and Therapeutic Effect of Antioxidant Drugs

... hair cells and spiral ganglion cells in spite of clear recovery of cochlear thresholds and no loss of inner and outer hair ... especially in the dorsal cochlear nucleus (DCN). Pathological changes induced by noise exposure in the central auditory system ... Excitotoxicity, synaptic repair, and functional recovery in the mammalian cochlea: a review of recent findings. Ann N Y Acad ... induce cell death by producing free radicals, and contribute to injury and deaths of hair cells and spiral ganglion cells [178 ...
more infohttps://www.ejao.org/journal/view.php?number=6&viewtype=pubreader

StateMaster - Encyclopedia: Lateral lemniscusStateMaster - Encyclopedia: Lateral lemniscus

Hair cells are the sensory cells of both the auditory system and the vestibular system in all vertebrates. ... Section through ... The Dorsal Cochlear Nucleus (DCN) has input from the LL and output to the contralateral LL via the ipsilateral and ... This article refers to a bone in the mammalian ear. ... The stapes or stirrup is the stirrup-shaped small bone or ossicle in ... The organ of Corti is the organ in the inner ear of mammals that contains auditory sensory cells, or hair cells. // Structure ...
more infohttp://www.statemaster.com/encyclopedia/Lateral-lemniscus

Inhibitory Amino Acid Synapses and Pathways in the Ventral Cochlear Nucleus | SpringerLinkInhibitory Amino Acid Synapses and Pathways in the Ventral Cochlear Nucleus | SpringerLink

Hair cells can, for example, respond to tones by oscillations of membrane potential at rates as high as many hundred... ... The processing of auditory information requires neurons to fire at a rapid rate. ... The processing of auditory information requires neurons to fire at a rapid rate. Hair cells can, for example, respond to tones ... In: Merchán M.A., Juiz J.M., Godfrey D.A., Mugnaini E. (eds) The Mammalian Cochlear Nuclei. NATO ASI series (Series A, Life ...
more infohttps://link.springer.com/chapter/10.1007/978-1-4615-2932-3_17

Cells  | Free Full-Text | The Myc Road to Hearing Restoration | HTMLCells | Free Full-Text | The Myc Road to Hearing Restoration | HTML

Regeneration of lost organ of Corti hair cells through forced cell cycle re-entry of supporting cells or through manipulation ... We will summarize the recently published work describing the early and late effects of N-Myc and L-Myc on hair cell formation ... Direct successful alterations to the cell cycle result in cell death whereas regulation of upstream genes is insufficient to ... specifically the balance of proliferation and differentiation required to form and to maintain hair cells. ...
more infohttps://www.mdpi.com/2073-4409/1/4/667/htm

Cochlear Nucleus as a Generator of Tinnitus-Related Signals - Oxford HandbooksCochlear Nucleus as a Generator of Tinnitus-Related Signals - Oxford Handbooks

Because the cochlear nucleus is the first processing center in the brain receiving cochlear input, it is the first brainstem ... Research published over the last 30 years demonstrates changes in neural circuitry and activity in the cochlear nucleus that ... Tinnitus most commonly begins with alterations of input from the ear resulting from cochlear trauma or overstimulation of the ... Changes in the tonotopic map of the dorsal cochlear nucleus in hamsters with hair cell loss and radial nerve bundle ...
more infohttps://www.oxfordhandbooks.com/view/10.1093/oxfordhb/9780190849061.001.0001/oxfordhb-9780190849061-e-8?rskey=nk8P0V&result=17

Feature detection (nervous system) - WikipediaFeature detection (nervous system) - Wikipedia

... like in auditory systems of other vertebrates, primary sensory afferent neurons, which receive inputs from hair cells from a ... Beyond pyramidal cells and spherical cells, a more complex feature detector exists in the dorsal torus semicurcularis of the ... Oertel D, Fay RR, Popper AN (2002). Integrative functions in the mammalian auditory pathway. New York: Springer-Verlag. pp. 385 ... Auditory nerve fibers take this slightly-processed sensory information to the cochlear nucleus where information either ...
more infohttps://en.m.wikipedia.org/wiki/Feature_detection_

Protocols and Video Articles Authored by Bernd FritzschProtocols and Video Articles Authored by Bernd Fritzsch

... is the molecular motor responsible for cochlear amplification by mammalian cochlea outer hair cells and has the unique combined ... is a basic helix-loop-helix transcription factor necessary for the specification of inner ear hair cells and central auditory ... Nov, 2002 , Pubmed ID: 12429503 The dorsal skin of the crawfish frog, Rana areolata, is associated with numerous prominent ... hair cells and supporting cells in the mammalian inner ear. Cross-regulation of Atoh1 and Neurog1 results in hair cell changes ...
more infohttps://www.jove.com/author/Bernd_Fritzsch

ORBi: Browsing ORBiORBi: Browsing ORBi

Mammalian auditory hair cell regeneration/repair and protection: a review and future directions.. Feghali, J. G.; Lefèbvre, ... The field of cochlear implantation has also provided insights into both the short- and long-term effects of cochlear ... fibroblasts had promoted the regeneration of peptidergic axons originating from dorsal root afferents and, to a lesser extent, ... Regeneration/repair and protection of auditory hair cells and auditory neurons is an exciting, rapidly evolving field. ...
more infohttp://orbi.ulg.ac.be/browse?type=author&sort_by=1&order=DESC&rpp=20&etal=3&value=Moonen%2C+Gustave+p000749&offset=200

BrainMind.comBrainMind.com

These cells give rise to axons which form the cochlear division of the 8th cranial nerve; i.e. the auditory nerve. This rope of ... AUDITORY TRANSMISSION FROM THE COCHLEA TO THE TEMPORAL LOBE Within the cochlea of the inner ear are tiny hair cells which serve ... The mammalian auditory system, however, did not evolve from the lateral line but from the vestibular nucleus (chapter 5). The ... The dorsal roof of the midbrain is referred to as the tegmentum (which produces dopamine) whereas more centrally located is the ...
more infohttp://brainmind.com/Midbrain.html

The Endless Bummer: Surf Art By Any Other Name: Moores Law & The Kurzweilian SchtickThe Endless Bummer: Surf Art By Any Other Name: Moore's Law & The Kurzweilian Schtick

OC: Octopus Cells. Detection of transients.. DCN: Dorsal Cochlear Nucleus. Detection of spectral edges and calibrating for ... MC: Multipolar Cells. Measure spectral energy.. GBC: Globular Bushy Cells. Relays spikes from the auditory nerve to the Lateral ... Feedback signals to modulate outer hair cell function in the cochlea.. VNLL, PON: Ventral Nucleus of the Lateral Lemniscus, ... We still live today with sufficient nuclear weapons (not all of which appear to be well accounted for) to end all mammalian ...
more infohttp://endlessbummerny.blogspot.com/2012/03/surf-art-by-any-other-name-moores-law.html
  • Age-related presynaptic changes in the cochlear nucleus include reduced glycine levels, while in the auditory midbrain and cortex, GABA synthesis and release are altered. (biologists.org)
  • Age-related postsynaptic GABA A R changes in IC and primary auditory cortex (A1) involve changes in the subunit makeup of GABA A Rs. (biologists.org)
  • While the functions of different neuronal types in the CN and the SOC are quite well understood, the nature of the code at the inferior colliculus (IC), medial geniculate (MGB) and primary auditory cortex (A1) levels are less well understood. (biologists.org)
  • For example, simple cells in the visual cortex of the domestic cat ( Felis catus ), respond to edges-a feature which is more likely to occur in objects and organisms in the environment. (wikipedia.org)
  • In the patients, although resting metabolism was decreased to 61% of normal values, bilateral auditory areas 41 and 42 showed activation as seen in the controls, but the temporoparietal junction cortex (BA 22) failed to be activated. (ac.be)
  • Moreover, the auditory association cortex was functionally disconnected from the posterior parietal association area (BA 40), the anterior cingulate cortex (BA 24) and the hippocampus, as revealed by psychophysiological interaction analysis. (ac.be)
  • The efferent auditory system is a descending bundle, which originates from the auditory cortex and terminates at the sensory cells of the organ of Corti. (oae.it)
  • Different sound frequencies are encoded by different fibers of the auditory nerve, arranged along the length of the auditory nerve, but codes for the timing and level of the sound are not segregated within the auditory nerve. (wikipedia.org)
  • In contrast, a decreased membrane resistance of DCN granule cells (multisensory inputs) leads to a reduced maximal firing rate of DCN principal cells that is overcome when additional multisensory fibers are recruited. (pnas.org)
  • DCN FCs integrate the acoustic information from AN fibers with MS signals transmitted via granule cell axons (parallel fibers) ( 17 ⇓ - 19 ). (pnas.org)
  • Responses of FCs are further shaped by feed-forward inhibition, mainly through inhibitory tuberculo-ventral cells activated by AN fibers and cartwheel cells activated by parallel fibers ( 17 , 29 ⇓ - 31 ). (pnas.org)
  • Such difficulty in listeners with normal thresholds has received more attention recently, especially associated with descriptions of synaptopathy, the loss of auditory nerve (AN) fibers as a result of noise exposure or aging. (springer.com)
  • Third, the role of the auditory efferent system, which receives inputs from L/MSR fibers, is revisited in the context of fluctuation-profile coding. (springer.com)
  • The more posterior portion of the midbrain consists of the superior (visual) and inferior (auditory) collicululi which are directly related to the thalamus, and the red nucleus which receives motor fibers from the cerebellum and frontal and parietal lobe. (brainmind.com)
  • The pontine tegmentum and the more dorsal portion of the midbrain tegmentum is also considered part of the reticular formation through which course ascending sensory fibers and descending motor fibers. (brainmind.com)
  • Both the lateral and medial fibers of the OC bundle pass dorsally from their cell bodies through the reticular formation to the floor of the 4th ventricle (Warr 1992). (oae.it)
  • The cochlea's inner hair cells are connected to the brain via myelinated (Type I) fibers, and the outer hair cells are connected to the brain via unmyelinated (Type II) fibers. (hyperacusisresearch.org)
  • Since the Type II fibers are not only small in caliber but few in number (composing only 5% of all hair cell fibers), their physiological responses have proven difficult to characterize. (hyperacusisresearch.org)
  • Nevertheless, aspects of their neuroanatomy have long suggested that these Type II fibers are involved in the sensation of auditory pain. (hyperacusisresearch.org)
  • Like somatic C fibers, unmyelinated type II cochlear afferents differ in size, number, and innervation pattern from type I afferents that encode sound. (pnas.org)
  • Findings of age-related inhibitory changes within mammalian auditory circuits are similar to age and deafferentation plasticity changes observed in other sensory systems. (biologists.org)
  • In addition, inhibitory inputs damp low-frequency, time-locked excitatory signals from both sides of the head as they project onto the dendrites of linearly arrayed cells in the medial superior olivary complex (MSO) ( Masterton and Imig, 1984 ). (biologists.org)
  • In 1953, H.B. Barlow's electrophysiological recordings from excised retina of the frog provided the first evidence for the presence of an inhibitory surround in the receptive field of a frog's retinal ganglion cell. (wikipedia.org)
  • In the same year, Stephen Kuffler published in vivo evidence for an excitatory center, inhibitory surround architecture in the ganglion cells of the mammalian retina which further supported Barlow's suggestion that on-off units can code for behaviorally relevant events. (wikipedia.org)
  • This review summarizes studies addressing several key issues that shape our current thinking about inner ear development, with particular emphasis on early patterning events, sensory hair cell specification and planar cell polarity. (biologists.org)
  • and genes that pattern the sensory epithelium, particularly the specification and polarization of hair cells. (biologists.org)
  • Within the labyrinth, some regions of epithelial cells become specified to develop as the specialized sensory epithelia that will act as the primary transducers of sound, motion and gravity, while other regions retain a simple cuboidal epithelial morphology. (biologists.org)
  • At later stages, its activity governs sensory hair cell specification, cell cycle regulation, and hair cell orientation. (frontiersin.org)
  • In regenerating sensory organs from non-mammalian species, Wnt signaling can also regulate the extent of proliferative hair cell regeneration. (frontiersin.org)
  • The present study characterized the behavior of cochlear macrophages after aminoglycoside ototoxicity and also examined the possible role of macrophages in sensory regeneration. (jove.com)
  • Following ototoxic injury, macrophages appear to migrate out of the hyaline cell region and towards the basilar membrane, congregating immediately below the lesioned sensory epithelium. (jove.com)
  • In order to determine whether recruited macrophages contribute to the regeneration of sensory receptors, we quantified supporting cell proliferation and hair cell recovery after the elimination of most resident macrophages via application of liposomally-encapsulated clodronate. (jove.com)
  • The adult mouse utricle preparation represents a mature sensory epithelium for studies of the molecular signals that regulate the survival, homeostasis, and death of these cells. (jove.com)
  • Hair cell regeneration is mediated by glia-like supporting cells, which contact the basolateral surfaces of hair cells in the sensory epithelium 9, 10 . (jove.com)
  • As also detailed in chapter 5, the anterior most segment of the midbrain and anterior pons, appear to have evolved from sensory-motor, and photosensitive cells. (brainmind.com)
  • Gfi1 protein is expressed in a more restricted pattern in specialized sensory cells of the PNS, including the eye, presumptive Merkel cells, the lung and hair cells of the inner ear. (biologists.org)
  • Therefore, the aim of the current study was to investigate synaptic transmission at this early time point after AOE and determine whether changes in auditory or multisensory (MS) inputs to FCs might contribute to the altered excitability in the DCN. (pnas.org)
  • This finding, together with previous evidence that type II afferents respond weakly to synaptic transmission from cochlear hair cells, and normally are insensitive to sound, supports the identification of type II afferents as cochlear nociceptors, mediating the sensation of painfully loud sound. (pnas.org)
  • The dorsal roof of the midbrain is referred to as the tegmentum (which produces dopamine) whereas more centrally located is the substantia nigra, a major source of corpus striatal dopamine. (brainmind.com)
  • Spanning the medial and lateral lengths of the brainstem and midbrain is a complex reticulum of richly interconnected cells with long ascending and descending axons, collectively referred to as the reticular activating system, which is concerned with generalized and selective arousal and activation of the neuroaxis. (brainmind.com)
  • Once damaged beyond repair, these do not regenerate as they do in nonmammalian vertebrates, suggesting that protective mechanisms should exist to preserve cochlear function. (pnas.org)
  • I am interested in what prevents the hair cells from regenerating after damage in mammals, as they do in birds and lower vertebrates. (washington.edu)
  • The anterior end of the otic vesicle gradually elongates as a tube and coils upon itself forming the beginnings of the cochlear duct. (wikipedia.org)
  • D) Next, the otocyst undergoes elaborate morphogenetic changes, including the dorsal extension of the endolymphatic ducts (ED), which will terminate in the endolymphatic sacs (not shown), in the dorsal region of the developing otocyst and the cochlear duct (CD) in the ventral region. (biologists.org)
  • E) As development continues, the cochlear duct begins to coil and the semicircular canals (SSC) begin to form in the dorsal region of the ear. (biologists.org)
  • The remaining thin, unmyelinated type II afferents extend hundreds of microns along the cochlear duct to contact many outer hair cells. (pnas.org)
  • In control subjects, auditory click stimuli activated bilateral auditory cortices [Brodmann areas (BA) 41 and and the contralateral auditory association cortices (BA 22). (ac.be)
  • J:145172 Benedito R, Trindade A, Hirashima M, Henrique D, da Costa LL, Rossant J, Gill PS, Duarte A, Loss of Notch signalling induced by Dll4 causes arterial calibre reduction by increasing endothelial cell response to angiogenic stimuli. (jax.org)
  • Otic vesicle, or auditory vesicle, consists of either of the two sac-like invaginations formed and subsequently closed off during embryonic development. (wikipedia.org)
  • The central part of the otic vesicle represents the membranous vestibule, and is subdivided by a constriction into a smaller ventral part, the saccule, and a larger dorsal and posterior part, the utricle. (wikipedia.org)
  • Dual embryonic origin of the mammalian otic vesicle forming the inner ear. (wikipedia.org)
  • This framework for understanding neural coding and control mechanisms for supra-threshold hearing suggests strategies for the design of novel hearing aid signal-processing and electrical stimulation patterns for cochlear implants. (springer.com)
  • H(2)(15)O-PET was used to investigate changes in regional cerebral blood flow in response to auditory stimulation in patients in the vegetative state. (ac.be)
  • Thus, despite altered resting metabolism, the auditory primary cortices were still activated during external stimulation, whereas hierarchically higher-order multi- modal association areas were not. (ac.be)
  • Homozygous mutant mice are deaf from birth and have no detectable stimulus-related cochlear potential at any stage. (jax.org)
  • Here, we show that type II afferents are excited during cochlear tissue damage in part by the algogenic cytoplasmic metabolite adenosine triphosphate (ATP). (pnas.org)
  • Despite this extensive arbor, type II afferents are weakly activated by outer hair cell transmitter release and are insensitive to sound. (pnas.org)
  • Here, we show that type II afferents are activated when outer hair cells are damaged. (pnas.org)
  • Here, we provide evidence that unmyelinated type II cochlear afferents can report cochlear trauma, a potential trigger for nocifensive behavior. (pnas.org)
  • Our recent study showed the presence of bursts in DCN fusiform cells (FCs) just a few days after AOE ( 16 ). (pnas.org)
  • The cochlear nucleus (CN) consists of a dorsal and ventral division (DCN, VCN) having three functionally and anatomically segregated outputs (for a review, see Young and Oertel, 2004 ). (biologists.org)
  • Protein expression patterns form several microdomains within the calyx membrane: a synaptic domain facing the hair cell, the heminode abutting the first myelinated internode, and one or two intermediate domains. (pubmedcentralcanada.ca)
  • This response rate firing conveys important information about intensity and frequency and so is maintained throughout the initial processing in the auditory brain stem. (springer.com)
  • A small minority of homozygotes have been found to have embryonic neural tube defects or a dorsal enlargement of the head. (jax.org)
  • We show that Gfi1 mRNA is expressed in many areas that give rise to neuronal cells during embryonic development in mouse, and that Gfi1 protein has a more restricted expression pattern. (biologists.org)
  • The primary influence of the jerker gene appears to be on the apical hair cells, not development of neural structures. (jax.org)
  • Secreted Wnt ligands bind Frizzled receptors to regulate diverse processes such as axis patterning, cell division, and cell fate specification. (frontiersin.org)
  • This response depends on both ionotropic (P2X) and metabotropic (P2Y) purinergic receptors, binding ATP released from nearby supporting cells in response to hair cell damage. (pnas.org)
  • This review describes the current knowledge of the roles of Wnt signaling and Wnt-responsive cells in hair cell development and regeneration. (frontiersin.org)
  • We also discuss possible future directions and the potential application and limitation of Wnt signaling in augmenting hair cell regeneration. (frontiersin.org)
  • Thus adenovirus-mediated gene expression in supporting cells of cultured utricles provides a powerful tool to study the roles of supporting cells as mediators of hair cell survival, death, and regeneration. (jove.com)
  • Auditory brainstem response is totally absent in homozygotes while heterozygous mice undergo a progressive impairment with age. (jax.org)
  • Salicylate caused greater auditory threshold shifts (near 15 dB) in GLAST KO mice than in WT mice across all tested frequencies, despite similarly reduced DPOAE. (frontiersin.org)
  • Gfi1 was first identified as causing interleukin 2-independent growth in T cells and lymphomagenesis in mice. (biologists.org)
  • Furthermore, Gfi1 mutant mice lose all cochlear hair cells just prior to and soon after birth through apoptosis. (biologists.org)