Auditory Organ Research Articles

Fgfr3 mutation disrupts chondrogenesis and bone ossification in zebrafish model mimicking CATSHL syndrome partially via enhanced Wnt/β-catenin signaling.

CATSHL syndrome, characterized by camptodactyly, tall stature and hearing loss, is caused by loss-of-function mutations of fibroblast growth factor receptors 3 (FGFR3) gene. Most manifestations of patients with CATSHL syndrome start to develop in the embryonic stage, such as skeletal overgrowth, craniofacial abnormalities, however, the pathogenesis of these phenotypes especially the early maldevelopment remains incompletely understood. Furthermore, there are no effective therapeutic targets for this skeleton dysplasia.Methods: We generated fgfr3 knockout zebrafish by CRISPR/Cas9 technology to study the developmental mechanisms and therapeutic targets of CATSHL syndrome. Several zebrafish transgenic lines labeling osteoblasts and chondrocytes, and live Alizarin red staining were used to analyze the dynamical skeleton development in fgfr3 mutants. Western blotting, whole mount in situ hybridization, Edu labeling based cell proliferation assay and Wnt/β-catenin signaling antagonist were used to explore the potential mechanisms and therapeutic targets.Results: We found that fgfr3 mutant zebrafish, staring from early development stage, showed craniofacial bone malformation with microcephaly and delayed closure of cranial sutures, chondroma-like lesion and abnormal development of auditory sensory organs, partially resembling the clinical manifestations of patients with CATSHL syndrome. Further studies showed that fgfr3 regulates the patterning and shaping of pharyngeal arches and the timely ossification of craniofacial skeleton. The abnormal development of pharyngeal arch cartilage is related to the augmented hypertrophy and disordered arrangement of chondrocytes, while decreased proliferation, differentiation and mineralization of osteoblasts may be involved in the delayed maturation of skull bones. Furthermore, we revealed that deficiency of fgfr3 leads to enhanced IHH signaling and up-regulated canonical Wnt/β-catenin signaling, and pharmacological inhibition of Wnt/β-catenin could partially alleviate the phenotypes of fgfr3 mutants.Conclusions: Our study further reveals some novel phenotypes and underlying developmental mechanism of CATSHL syndrome, which deepens our understanding of the pathogenesis of CATSHL and the role of fgfr3 in skeleton development. Our findings provide evidence that modulation of Wnt/β-catenin activity could be a potential therapy for CATSHL syndrome and related skeleton diseases.

The role of sperm associated antigen 6 gene in morphological changes of inner ear development and signal regulation of auditory organs in mice

AimIn order to analyze the effects of the deletion of the Sperm Associated Antigen 6 (Spag6) gene on the inner ear and the auditory system of mice. MethodClustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 technology was utilized, and the Spag6 gene knockout mouse model was constructed. Self-breeding was carried out to obtain the F1 generation Spag6 homozygous mouse (Spag−/−), the Spag6 heterozygous mouse (Spag+/−) and the Spag6 wild mouse (Spag+/+) were obtained. Polymerase Chain Reaction (PCR) technology was used to verify the three genotypes of mice. The mean hearing threshold of Spag−/− mice, Spag+/− mice and Spag+/+ mice after different intensity of sound stimulation was detected. The inner ear cochlea tissues of Spag−/− mice and Spag+/+ mice were collected and paraffin sections were made. Morphological differences of inner ear tissues in mice were analyzed by hematoxylin – eosin (HE) staining. Immunofluorescence staining was used to analyze the number of hair cells in the inner ear of mice. Apoptosis of mouse inner ear hair cells was analyzed by TdT-mediated dUTP Nick-End Labeling (TUNEL) staining ResultIt was found that the hearing of Spag−/− mice decreased significantly compared with that of Spag+/+ mice (P < 0.01), and the hearing of Spag+/− mice decreased significantly compared with that of Spag+/− mice (P < 0.05). After HE staining and immunofluorescence staining, hair cells in the inner ear cochlea of Spag−/− mice were found to be defective. The apoptosis detection results of TUNEL staining indicated that the number of apoptosis of hair cells in inner ear cochlea of Spag−/− mice was significantly higher than that of Spag+/+ mice, and the average optical density of Corti apparatus of Spag−/− mice was significantly higher than that of Spag+/+ mice (P < 0.01). ConclusionThe results showed that the loss of the Spag6 gene accelerated the apoptosis of hair cells in the cochlear tissue of the inner ear of mice, thereby affecting the auditory system of mice. The significance of this study is to lay the foundation for future studies on the effects of Spag6 on deafness.

Renewed proliferation in adult mouse cochlea and regeneration of hair cells

The adult mammalian inner ear lacks the capacity to divide or regenerate. Damage to inner ear generally leads to permanent hearing loss in humans. Here, we present that reprogramming of the adult inner ear induces renewed proliferation and regeneration of inner ear cell types. Co-activation of cell cycle activator Myc and inner ear progenitor gene Notch1 induces robust proliferation of diverse adult cochlear sensory epithelial cell types. Transient MYC and NOTCH activities enable adult supporting cells to respond to transcription factor Atoh1 and efficiently transdifferentiate into hair cell-like cells. Furthermore, we uncover that mTOR pathway participates in MYC/NOTCH-mediated proliferation and regeneration. These regenerated hair cell-like cells take up the styryl dye FM1-43 and are likely to form connections with adult spiral ganglion neurons, supporting that Myc and Notch1 co-activation is sufficient to reprogram fully mature supporting cells to proliferate and regenerate hair cell-like cells in adult mammalian auditory organs.

Vascular endothelial growth factor is required for regeneration of auditory hair cells in the avian inner ear

Hair cells in the auditory organ of the vertebrate inner ear are the sensory receptors that convert acoustic stimuli into electrical signals that are conveyed along the auditory nerve to the brainstem. Hair cells are highly susceptible to ototoxic drugs, infection, and acoustic trauma, which can cause cellular degeneration. In mammals, hair cells that are lost after damage are not replaced, leading to permanent hearing impairments. By contrast, supporting cells in birds and other non-mammalian vertebrates regenerate hair cells after damage, which restores hearing function. The cellular mechanisms that regulate hair cell regeneration are not well understood. We investigated the role of vascular endothelial growth factor (VEGF) during regeneration of auditory hair cells in chickens after ototoxic injury. Using RNA-Seq, immunolabeling, and in situ hybridization, we found that VEGFA, VEGFC, VEGFR1, VEGFR2, and VEGFR3 were expressed in the auditory epithelium, with VEGFA expressed in hair cells and VEGFR1 and VEGFR2 expressed in supporting cells. Using organotypic cultures of the chicken cochlear duct, we found that blocking VEGF receptor activity during hair cell injury reduced supporting cell proliferation as well as the numbers of regenerated hair cells. By contrast, addition of recombinant human VEGFA to organ cultures caused an increase in both supporting cell division and hair cell regeneration. VEGF’s effects on supporting cells were preserved in isolated supporting cell cultures, indicating that VEGF can act directly upon supporting cells. These observations demonstrate a heretofore uncharacterized function for VEGF signaling as a critical positive regulator of hair cell regeneration in the avian inner ear.

Cochlear Surface Preparation in the Adult Mouse.

Auditory processing in the cochlea depends on the integrity of the mechanosensory hair cells. Over a lifetime, hearing loss can be acquired from numerous etiologies such as exposure to excessive noise, the use of ototoxic medications, bacterial or viral ear infections, head injuries, and the aging process. Loss of sensory hair cells is a common pathological feature of the varieties of acquired hearing loss. Additionally, the inner hair cell synapse can be damaged by mild insults. Therefore, surface preparations of cochlear epithelia, in combination with immunolabeling techniques and confocal imagery, are a very useful tool for the investigation of cochlear pathologies, including losses of ribbon synapses and sensory hair cells, changes in protein levels in hair cells and supporting cells, hair cell regeneration, and determination of report gene expression (i.e., GFP) for verification of successful transduction and identification of transduced cell types. The cochlea, a bony spiral-shaped structure in the inner ear, holds the auditory sensory end organ, the organ of Corti (OC). Sensory hair cells and surrounding supporting cells in the OC are contained in the cochlear duct and rest on the basilar membrane, organized in a tonotopic fashion with high-frequency detection occurring in the base and low-frequency in the apex. With the availability of molecular and genetic information and the ability to manipulate genes by knockout and knock-in techniques, mice have been widely used in biological research, including in hearing science. However, the adult mouse cochlea is miniscule, and the cochlear epithelium is encapsulated in a bony labyrinth, making microdissection difficult. Although dissection techniques have been developed and used in many laboratories, this modified microdissection method using cell and tissue adhesive is easier and more convenient. It can be used in all types of adult mouse cochleae following decalcification.

What determines the number of auditory sensilla in the tympanal hearing organs of Tettigoniidae? Perspectives from comparative neuroanatomy and evolutionary forces

Insects have evolved complex receptor organs for the major sensory modalities. For the sense of hearing, the tympanal organ of Tettigoniidae (bush crickets or katydids) shows remarkable convergence to vertebrate hearing by impedance conversion and tonotopic frequency analysis. The main auditory receptors are scolopidial sensilla in thecrista acustica. Morphological studies established that the numbers of auditory sensilla are species-specific. However, the factors determining the specific number of auditory sensilla are not well understood. This review provides an overview of the functional organization of the auditory organ in Tettigoniidae, including the diversification of thecrista acusticasensilla, a list of species with the numbers of auditory sensilla, and a discussion of evolutionary forces affecting the number of sensilla in thecrista acusticaand their sensitivity. While all species of Tettigoniidae studied so far have acrista acustica, the number of sensilla varies on average from 15–116. While the relative differences or divergence in sensillum numbers may be explained by adaptive or regressive changes, it is more difficult to explain a specific number of sensilla in thecrista acusticaof a specific species (like for the model speciesAncistrura nigrovittata,Copiphora gorgonensis,Gampsocleis gratiosa,Mecopoda elongata,Requena verticalis, orTettigonia viridissima): sexual and natural selection as well as allometric relationships have been identified as key factors influencing the number of sensilla. Sexual selection affects the number of auditory sensilla in thecrista acusticaby the communication system and call patterns. Further, positive allometric relationships indicate positive selection for certain traits. Loss of selection leads to evolutionary regression of the auditory system and reduced number of auditory sensilla. This diversity in the auditory sensilla can be best addressed by comparative studies reconstructing adaptive or regressive changes in thecrista acustica.

Reproductive-state dependent changes in saccular hair cell density of the vocal male plainfin midshipman fish

The plainfin midshipman fish (Porichthys notatus) is a nocturnal, seasonally breeding, intertidal-nesting teleost fish that produces social acoustic signals for intraspecific communication. Type I or “nesting” males produce agonistic and reproductive-related acoustic signals including a multiharmonic advertisement call during the summer breeding season. Previous work showed that type I male auditory sensitivity of the saccule, the primary midshipman auditory end organ, changes seasonally with reproductive state such that reproductive males become more sensitive and better suited than nonreproductive males to detect the dominant frequencies contained within type I vocalizations. Here, we examine whether reproductive type I males also exhibit reproductive-state dependent changes in hair cell (HC) density in the three putative auditory end organs (saccule, lagena, and utricle). We show that saccular HC density was greater in reproductive type I males compared to nonreproductive type I males, and that the increase in HC density occurs throughout the saccular epithelium in both the central and marginal epithelia regions. We also show as saccular HC density increases there is a concurrent decrease in saccular support cell (SC) density in reproductive type I males with no overall change in total cell density (i.e., HC + SC). In contrast, we did not observe any seasonal changes in HC density in the utricle or lagena between nonreproductive and reproductive type I males. In addition, we compare the saccular HC densities in reproductive type I males with that of reproductive females and show that females have greater saccular HC densities, which suggest a sexually dimorphic difference in HC receptor density between the two sexual phenotypes, at least during the summer breeding season.

The future of otology

The field of otology is increasingly at the forefront of innovation in science and medicine. The inner ear, one of the most challenging systems to study, has been rendered much more open to inquiry by recent developments in research methodology. Promising advances of potential clinical impact have occurred in recent years in biological fields such as auditory genetics, ototoxic chemoprevention and organ of Corti regeneration. The interface of the ear with digital technology to remediate hearing loss, or as a consumer device within an intelligent ecosystem of connected devices, is receiving enormous creative energy. Automation and artificial intelligence can enhance otological medical and surgical practice. Otology is poised to enter a new renaissance period, in which many previously untreatable ear diseases will yield to newly introduced therapies. This paper speculates on the direction otology will take in the coming decades. Making predictions about the future of otology is a risky endeavour. If the predictions are found wanting, it will likely be because of unforeseen revolutionary methods.

개념적 혼성 이론을 통한 ‘微’형 신조어 의미 분석 - ‘微德’, ‘微耳’을 중심으로

In this paper, the ‘微X’-type neologism of 2010 to 2016 was analyzed through conceptual blending theory to examine its blending process. The ‘微X’-type neologism has been steadily create every year, and there are many. The ‘微X’-type neologism can be divided into the ‘微(微博/微信)X’-type and ‘微(small)X’-type according to the meaning of ‘微’. Among the ‘微(微博/微信)X’-type neologism, ‘微德’ in 2016 was analyzed. Among the ‘微(small)X’-type neologism, ‘微耳’ in 2016 was analyzed. ‘微德’’s Input space 1 and input space 2 were construct with the ‘human personality cognitive model’ and ‘weixin use cognitive model’ and as a result, the user"s language using Weissin represents the user’s personality, and the use of a word containing the metaphor ‘Man is the vessel of character has positive results. Input space 1 of ‘微耳’ was also constructed, including an ear cognitive model and a aesthetic aspect of the ear, and input space 2 was constructed with an auditory organ frame.’

Drug-induced Stress Granule Formation Protects Sensory Hair Cells in Mouse Cochlear Explants During Ototoxicity

Stress granules regulate RNA translation during cellular stress, a mechanism that is generally presumed to be protective, since stress granule dysregulation caused by mutation or ageing is associated with neurodegenerative disease. Here, we investigate whether pharmacological manipulation of the stress granule pathway in the auditory organ, the cochlea, affects the survival of sensory hair cells during aminoglycoside ototoxicity, a common cause of acquired hearing loss. We show that hydroxamate (-)-9, a silvestrol analogue that inhibits eIF4A, induces stress granule formation in both an auditory cell line and ex-vivo cochlear cultures and that it prevents ototoxin-induced hair-cell death. In contrast, preventing stress granule formation using the small molecule inhibitor ISRIB increases hair-cell death. Furthermore, we provide the first evidence of stress granule formation in mammalian hair cells in-vivo triggered by aminoglycoside treatment. Our results demonstrate that pharmacological induction of stress granules enhances cell survival in native-tissue, in a clinically-relevant context. This establishes stress granules as a viable therapeutic target not only for hearing loss but also other neurodegenerative diseases.

Research of influence of working conditions on workers in foundries

The working conditions of workers in foundries and their impact on occupational illness are considered. The results of the distribution of occupational diseases in the casting departments and according to professions working in foundries are given. It was found that the working conditions of foundrymen lead to such occupational diseases as silicosis and dust bronchitis, vibration disease and neuritis of the auditory organ. It is noted that about 60% of vibration disease, about 40% of neuritis of the auditory organ, about 80% of silicosis and dust bronchitis from the total number of similar occupational diseases in machine-building enterprises account for workers in foundries.

Implications of the Tympanal Hearing Organ and Ultrastructure of Chaetotaxy for the Higher Classification of Embioptera

Several slowly evolving characters are evaluated with the main objective of reinforcing the higher classification of Embioptera. An embiopteran femoral auditory organ, described here for the first time, exhibits differences in shape and position that provide diagnostic criteria for higher taxonomic groups in the order. New characters on silk ejectors, bladders, and various types of leg setae are also discussed within a taxonomic framework. The utility of these new traits and their different conditions, for identifying monophyletic groups, was tested by a preliminary phylogenetic analysis.

Flowers respond to pollinator sound within minutes by increasing nectar sugar concentration.

Can plants sense natural airborne sounds and respond to them rapidly? We show that Oenothera drummondii flowers, exposed to playback sound of a flying bee or to synthetic sound signals at similar frequencies, produce sweeter nectar within 3 min, potentially increasing the chances of cross pollination. We found that the flowers vibrated mechanically in response to these sounds, suggesting a plausible mechanism where the flower serves as an auditory sensory organ. Both the vibration and the nectar response were frequency‐specific: the flowers responded and vibrated to pollinator sounds, but not to higher frequency sound. Our results document for the first time that plants can rapidly respond to pollinator sounds in an ecologically relevant way. Potential implications include plant resource allocation, the evolution of flower shape and the evolution of pollinators sound. Finally, our results suggest that plants may be affected by other sounds as well, including anthropogenic ones.

The Study of the Possibility of Usage of the Sokolov’s Criteria for Assessing the Results of Directed Influence on the Auditory System of a Biological Object

In this work the possibility of using the Sokolov criterion for assessing the results of directed influence on the auditory organ of a biological object was considered. Guinea pigs were used as a test object because the structure of their auditory organ is largely similar to a human one. As an effect of directed influence on the auditory canal the impact of oto-active drugs on test specimens was used, which was estimated via implementation of distortion product otoacoustic emission. To evaluate the possibility of using the criterion arrays of experimental results that have not yet been processed have been used. Study represents comparatory analysis of two groups of data sets – pre- and post-criterion application. The comparison was made in two categories — the mean value and the confidence interval.Ref.8, fig.7.

Noise pollution is one of the causes of occupational diseases

People lose hearing more often than we can imagine. Loss of hearing or deafness today is one of the most common occupational diseases not only in Ukraine but also in the world. Every day we are accompanied by a whole range of the most diverse sources of noise - household appliances at home and in the office, neighbors repairs, televisions, the road to work - metro, people in public transport or loud headphones music. And this can not be avoided, because each of us lives in a society, co-exists with other its representatives. All our life – a global communication. Many experiments found that noise is a general biologic stimulus and under certain conditions can affect all human life systems. The influence of noise on the human auditory organ is most fully studied. Intense noise, especially at high frequencies – 4000 Hz or more, with daily exposure leads to a professional illness – hearing loss, the symptom of which is the slow loss of hearing on both ears. According to official statistics of the World Health Organization, more than 5% of the Earth's population suffers from a disabling hearing loss. That is, such loss results not only in the deterioration of hearing quality, but also has certain social consequences, namely:&#x0D; &#x0D; more than 360 million people around the world have hearing problems (about 328 million adults and 32 million children);&#x0D; 1.1 billion teenagers and young people are at risk of hearing loss mainly due to listening to high-volume music as well as excessive noise levels;&#x0D; more than a third of people lose hearing as a result of excessive noise levels in the workplace. The rest is congenital deafness, loss of hearing due to various diseases and injuries;&#x0D; an average of almost ten years is passed before hearing impaired people turn to a doctor;&#x0D; studies have shown that about 1/3 of people over 65 years have hearing problems.&#x0D;

Wnt/\u03b2-catenin interacts with the FGF pathway to promote proliferation and regenerative cell proliferation in the zebrafish lateral line neuromast

Wnt and FGF are highly conserved signaling pathways found in various organs and have been identified as important regulators of auditory organ development. In this study, we used the zebrafish lateral line system to study the cooperative roles of the Wnt and FGF pathways in regulating progenitor cell proliferation and regenerative cell proliferation. We found that activation of Wnt signaling induced cell proliferation and increased the number of hair cells in both developing and regenerating neuromasts. We further demonstrated that FGF signaling was critically involved in Wnt-regulated proliferation, and inhibition of FGF abolished the Wnt stimulation-mediated effects on cell proliferation, while activating FGF signaling with basic fibroblast growth factor (bFGF) led to a partial rescue of the proliferative failure and hair cell defects in the absence of Wnt activity. Whole-mount in situ hybridization analysis showed that the expression of several FGF pathway genes, including pea3 and fgfr1, was increased in neuromasts after treatment with the Wnt pathway inducer BIO. Interestingly, when SU5402 was used to inhibit FGF signaling, neuromast cells expressed much lower levels of the FGF receptor gene, fgfr1, but produced increased levels of Wnt target genes, including ctnnb1, ctnnb2, and tcf7l2, while bFGF treatment produced no alterations in the expression of those genes, suggesting that fgfr1 might restrict Wnt signaling in neuromasts during proliferation. In summary, our analysis demonstrates that both the Wnt and FGF pathways are tightly integrated to modulate the proliferation of progenitor cells during early neuromast development and regenerative cell proliferation after neomycin-induced injury in the zebrafish neuromast.

Building a Sound Wall in the Cochlea: Development of the Stria Vascularis

The stria vascularis is a specialized epithelial structure of the mammalian cochlea that produces endolymph, the potassium‐rich fluid responsible for the positive endocochlear potential of the cochlear lumen. This positive extracellular potential is the major driving force for proper signal transduction by sensory cells in the ear, and thus normal hearing. The stria vascularis is the “battery” of the auditory organ: it is localized in the lateral wall of the cochlea, and consists of a multilayered highly vascularized epithelium. It is composed of three main cell types with distinct embryonic origins: the marginal cells derived from the otic epithelium , the intermediate cells which are specialized melanocyte‐like cells derived from migratory neural crest cells, and the basal cells that are derived from otic mesenchyme. Mesoderm‐derived blood vessels are interspersed between these cells throughout the stria. Defects in the development of the stria vascularis are part of a number of inheritable deafness syndromes in humans, including Hirschsprung disease and Waardenburg, Jervell and Lange‐Nielsen, Bartter and SeSAME syndromes. Strial degeneration is estimated to cause more than 30% of age related hearing loss or presbycusis, which affects between 25–40% of the population over 65 years and over 60% of the population over 80 years old. The causes of strial atrophy remain poorly understood. Over the past decade, a great effort has been made to understand the development of the sensory cells in the mammalian cochlea with the aim of applying their developmental principles to regenerative therapies. By contrast, very little is known about the developmental potential of the stria vascularis, or even the mechanisms of strial degeneration due to aging. Our focus is to uncover the normal development of the stria, the cellular interactions that lead to its formation, and the potential for regeneration in cases of congenital strial deafness.Support or Funding InformationHearing Health FoundationThe Hartwell FoundationNIDCD R01DC015785This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Cricket tympanal organ revisited: morphology, development and possible functions of the adult-specific chitin core beneath the anterior tympanal membrane.

Vertebrates and insects are phylogenetically separated by millions of years but have commonly developed tympanal membranes for efficiently converting airborne sound to mechanical oscillation in hearing. The tympanal organ of the field cricket Gryllus bimaculatus, spanning 200μm, is one of the smallest auditory organs among animals. It indirectly links to two tympana in the prothoracic tibia via tracheal vesicles. The anterior tympanal membrane is smaller and thicker than the posterior tympanal membrane and it is thought to have minor function as a sound receiver. Using differential labeling of sensory neurons/surrounding structures and three-dimensional reconstructions, we revealed that a shell-shaped chitin mass and associated tissues are hidden behind the anterior tympanal membrane. The mass, termed the epithelial core, is progressively enlarged by discharge of cylindrical chitin from epithelial cells that start to aggregate immediately after the final molt and it reaches a plateau in size after 6days. The core, bridging between the anterior tracheal vesicle and the fluid-filled chamber containing sensory neurons, is supported by a taut membrane, suggesting the possibility that anterior displacements of the anterior tracheal vesicle are converted into fluid motion via a lever action of the core. The epithelial core did not exist in tympanal organ homologs of meso- and metathoracic legs or of nymphal legs. Taken together, the findings suggest that the epithelial core, a potential functional homolog to mammalian ossicles, underlies fine sound frequency discrimination required for adult-specific sound communications.

Mosquito hearing is the most sensitive among arthropods—But is the sound level of a male swarm loud enough to be picked up by the female’s particle-velocity sensor?

Males of many mosquito species aggregate in station-keeping swarms, waiting for the arrival of conspecific females to mate with. We test whether audition could be used by a female to locate male swarms and to assess whether the males are conspecific. The sound level resulting from thousands of wing flaps could be loud enough to be heard at a long range (~1 m) via the antennal flagellum (particle velocity sensor, primarily designed for close-range communication). A mosquito hears a conspecific by adjusting its own wing-beat frequency so that the difference tone between its own and the opposite-sex frequencies falls into a narrow band to which the auditory organ is tuned. Indeed, the antennal flagella produce distortion products resulting in difference tones of the nearby soundscape. Swarms of males were recorded and played-back to females in a 2-m-sided flight chamber. The natural sounds of the males of two species (Anopheles coluzzii and A. gambiae) and related synthetic sounds were played at different sound levels to individual free-flying A. coluzzii females. The mosquitoes’ responses were investigated by analysing changes in three-dimensional-tracked flight trajectories and wing-beat frequencies. The results show that (1) females do respond to the sound of swarming males, (2) a qualitative difference between female and male behaviour, (3) a quantitative effect of the sound stimulus of conspecific males, and (4) verification of previous results suggesting the importance of the first harmonic of their wing beats in mosquito acoustic communication.

Determination of Resonant Frequencies of an Acoustical System of the Human by Means of Objective Methods of a Research of Hearing

Different pathological processes lead to changes of human auditory system characteristics. Nowadays, hearing diagnosis is not surprising and does not cause unnecessary questions, because most people understand the importance of health care and know about problems that can arise if they are not warned in advance. In the world there are many methods and programs for objective diagnosis of human hearing. Today, among hearing diagnosing objective methods, multifrequency acoustic impedancemetry and otoacoustic emission are most widely used in clinical practice. Comparison of the obtained characteristics in normal and pathological conditions allows us to judge the degree of changes in the auditory organ and diagnose some of its diseases. However, a large discrepancy between intersubject data may overlap deviations from norms. This is the main problem in diagnosis of hearing system. Determination the resonant frequency of human auditory system structural elements in a comprehensive study, using objective methods gives us a possibility to detect changes in ear conductive system more accurately. Significant changes in the resonance frequency of human middle ear make it possible to detect an existing pathology at a functional level. Resonant frequency shift (to one or the other side) may indicate the presence of otosclerosis, auditory ossicles chain break, etc. In this work, the parameters of the human middle ear were obtained theoretically, based on a two-circuit model of the human middle ear, and confirmed experimentally, using tympanometry and otoacoustic emission, which eliminate the main problem of hearing diagnostics and offer new diagnostic parameters for sound-conducting ear system diseases diagnosing, namely, value of resonant frequencies. Determining the resonant frequency of human auditory system structures in a comprehensive study using objective methods, allows us to identify changes in ear sound-conducting system. To study human auditory system resonant frequency, an electromechanical model of human middle ear was selected and its main parameters were determined: eardrum and tympanic cavity flexibility, acoustic impedance of air in the tympanic cavity and auditory tube, resonant frequency of first and second circuits of middle ear vibrating system, auditory ossicles weight. Purpose of the study - to search and identify effective ways to improve objective acoustic diagnostic methods and substantiate the choice of tympanometry and otoacoustic emission as the main methods for studying the state of the human auditory system, which allow a detailed assessment of pathological processes. Ref. 10, fig. 2, tabl. 1.`