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Koper L, Koretsky IA, Rahmat SJ. The tympanic region of the skull in extant pinnipeds: A pilot study of auditory morphological disparity using linear morphometric principal component analysis. Anat Rec (Hoboken) 2024; 307:3021-3040. [PMID: 38332639 DOI: 10.1002/ar.25387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 12/09/2023] [Accepted: 01/02/2024] [Indexed: 02/10/2024]
Abstract
Pinnipeds are unique semiaquatic taxa possessing adaptations to hear efficiently both in water and on land. Research over the past century is extremely limited on the auditory apparatus morphology of pinnipeds, which include the Families Phocidae (true seals), Otariidae (sea lions/fur seals), and Odobenidae (walruses). Our extensive literature review revealed inaccurate terminology of this region, with details corresponding only to terrestrial taxa, and a severe lack of information due to very few current studies. This demonstrates the need for evaluation and comparison of the auditory morphologies of modern terrestrial and semiaquatic carnivorans in relation to hearing. This initial study compares tympanic bullar morphologies of Phocidae to other pinnipeds and representatives of terrestrial carnivoran families. Morphological correlations of the basicranial auditory region were also compared within phocid subfamilies. Eleven skull measurements and about eleven calculated ratios were included in multiple principal component analyses to determine what areas of the auditory apparatus had the most significant morphological variation. This is the first study using this methodology, especially in reference to the hearing adaptations of pinnipeds, specifically in phocids. Results demonstrate distinct trends in phocid bullar morphology relative to other pinnipeds. Analyses reveal that: (1) phocids generally have different bullar morphology than otariids and odobenids; (2) Neomonachus schauinslandi (Hawaiian monk seal) and Neomonachus tropicalis (Caribbean monk seal) have unique morphology compared to phocids and other pinnipeds. Future work with increased number of specimens will further substantiate these findings and both ontogenetic and sexual variations will be examined.
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Affiliation(s)
- Lindsey Koper
- Laboratory of Evolutionary Biology, Department of Anatomy, College of Medicine, Howard University, Washington, DC, USA
| | - Irina A Koretsky
- Laboratory of Evolutionary Biology, Department of Anatomy, College of Medicine, Howard University, Washington, DC, USA
| | - Sulman J Rahmat
- Laboratory of Evolutionary Biology, Department of Anatomy, College of Medicine, Howard University, Washington, DC, USA
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2
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Mason MJ, Lewis MA. Structure and scaling of the middle ear in domestic dog breeds. J Anat 2024; 245:324-338. [PMID: 38605539 PMCID: PMC11259751 DOI: 10.1111/joa.14049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 03/26/2024] [Accepted: 03/27/2024] [Indexed: 04/13/2024] Open
Abstract
Although domestic dogs vary considerably in both body size and skull morphology, behavioural audiograms have previously been found to be similar in breeds as distinct as a Chihuahua and a St Bernard. In this study, we created micro-CT reconstructions of the middle ears and bony labyrinths from the skulls of 17 dog breeds, including both Chihuahua and St Bernard, plus a mongrel and a wolf. From these reconstructions, we measured middle ear cavity and ossicular volumes, eardrum and stapes footplate areas and bony labyrinth volumes. All of these ear structures scaled with skull size with negative allometry and generally correlated better with condylobasal length than with maximum or interaural skull widths. Larger dogs have larger ear structures in absolute terms: the volume of the St Bernard's middle ear cavity was 14 times that of the Chihuahua. The middle and inner ears are otherwise very similar in morphology, the ossicular structure being particularly well-conserved across breeds. The expectation that larger ear structures in larger dogs would translate into hearing ranges shifted towards lower frequencies is not consistent with the existing audiogram data. Assuming that the audiograms accurately reflect the hearing of the breeds in question, oversimplifications in existing models of middle ear function or limitations imposed by other parts of the auditory system may be responsible for this paradox.
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Affiliation(s)
- Matthew J. Mason
- Department of Physiology, Development & NeuroscienceUniversity of CambridgeCambridgeUK
| | - Madaleine A. Lewis
- Department of Physiology, Development & NeuroscienceUniversity of CambridgeCambridgeUK
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3
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Peacock J, Spellman GM, Field DJ, Mason MJ, Mayr G. Comparative morphology of the avian bony columella. Anat Rec (Hoboken) 2024; 307:1735-1763. [PMID: 37365751 DOI: 10.1002/ar.25278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 06/01/2023] [Accepted: 06/04/2023] [Indexed: 06/28/2023]
Abstract
In birds, the columella is the only bony element of the sound conducting apparatus, conveying vibrations of the cartilaginous extracolumella to the fluid of the inner ear. Although avian columellar morphology has attracted some attention over the past century, it nonetheless remains poorly described in the literature. The few existing studies mostly focus on morphological descriptions in relatively few taxa, with no taxonomically broad surveys yet published. Here we use observations of columellae from 401 extant bird species to provide a comprehensive survey of columellar morphology in a phylogenetic context. We describe the columellae of several taxa for the first time and identify derived morphologies characterizing higher-level clades based on current phylogenies. In particular, we identify a derived columellar morphology diagnosing a major subclade of Accipitridae. Within Suliformes, we find that Fregatidae, Sulidae, and Phalacrocoracidae share a derived morphology that is absent in Anhingidae, suggesting a secondary reversal. Phylogenetically informed comparisons allow recognition of instances of homoplasy, including the distinctive bulbous columellae in suboscine passerines and taxa belonging to Eucavitaves, and bulging footplates that appear to have evolved at least twice independently in Strigiformes. We consider phylogenetic and functional factors influencing avian columellar morphology, finding that aquatic birds possess small footplates relative to columellar length, possibly related to hearing function in aquatic habitats. By contrast, the functional significance of the distinctive bulbous basal ends of the columellae of certain arboreal landbird taxa remains elusive.
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Affiliation(s)
- John Peacock
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Garth M Spellman
- Department of Zoology, Denver Museum of Nature and Science, Denver, Colorado, USA
| | - Daniel J Field
- Department of Earth Sciences, University of Cambridge, Cambridge, UK
- Museum of Zoology, University of Cambridge, Cambridge, UK
| | - Matthew J Mason
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Gerald Mayr
- Ornithological Section, Senckenberg Research Institute and Natural History Museum Frankfurt, Frankfurt am Main, Germany
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4
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Stoessel A, David R, Bornitz M, Ossmann S, Neudert M. Auditory thresholds compatible with optimal speech reception likely evolved before the human-chimpanzee split. Sci Rep 2023; 13:20732. [PMID: 38007561 PMCID: PMC10676368 DOI: 10.1038/s41598-023-47778-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 11/18/2023] [Indexed: 11/27/2023] Open
Abstract
The anatomy of the auditory region of fossil hominins may shed light on the emergence of human spoken language. Humans differ from other great apes in several features of the external, middle and inner ear (e.g., short external ear canal, small tympanic membrane, large oval window). However, the functional implications of these differences remain poorly understood as comparative audiometric data from great apes are scarce and conflicting. Here, we measure the sound transfer function of the external and middle ears of humans, chimpanzees and bonobos, using laser-Doppler vibrometry and finite element analysis. This sound transfer function affects auditory thresholds, which relate to speech reception thresholds in humans. Unexpectedly we find that external and middle ears of chimpanzees and bonobos transfer sound better than human ones in the frequency range of spoken language. Our results suggest that auditory thresholds of the last common ancestor of Homo and Pan were already compatible with speech reception as observed in humans. Therefore, it seems unlikely that the morphological evolution observed in the bony auditory region of fossil hominins was driven by the emergence of spoken language. Instead, the peculiar human configuration may be a by-product of morpho-functional constraints linked to brain expansion.
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Affiliation(s)
- Alexander Stoessel
- Institute of Zoology and Evolutionary Research, Friedrich Schiller University Jena, Erbertstr. 1, 07743, Jena, Germany.
- Max Planck Institute for Evolutionary Anthropology, 04103, Leipzig, Germany.
| | - Romain David
- Centre for Human Evolution Research, The Natural History Museum, Cromwell Rd, South Kensington, London, SW7 5BD, UK.
| | - Matthias Bornitz
- Department of Otorhinolaryngology, Head and Neck Surgery, Carl Gustav Carus Faculty of Medicine, TU Dresden, Fetscherstr. 74, 01307, Dresden, Germany
| | - Steffen Ossmann
- Department of Otorhinolaryngology, Head and Neck Surgery, Carl Gustav Carus Faculty of Medicine, TU Dresden, Fetscherstr. 74, 01307, Dresden, Germany
| | - Marcus Neudert
- Department of Otorhinolaryngology, Head and Neck Surgery, Carl Gustav Carus Faculty of Medicine, TU Dresden, Fetscherstr. 74, 01307, Dresden, Germany.
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Yeon EK, Son HO, Sung HJ, Choi JW. Bilateral Congenital Ossicular Anomalies: Are the Anomalies Symmetric for Both Ears? Otolaryngol Head Neck Surg 2023; 169:1028-1034. [PMID: 37003293 DOI: 10.1002/ohn.341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/08/2023] [Accepted: 03/17/2023] [Indexed: 04/03/2023]
Abstract
OBJECTIVE To evaluate whether bilateral congenital ossicular anomalies (COAs) differ regarding ossicular anomalies and hearing loss severities between the ears of the individual. STUDY DESIGN Retrospective case review. SETTING Tertiary referral academic center. METHODS Between March 2012 and December 2022, 7 consecutive patients (14 ears) with surgically confirmed bilateral COAs were included in the study. Preoperative pure-tone thresholds, COA classification according to the Teunissen and Cremers system, surgical procedures, and postoperative audiometric results were compared between the 2 ears of each patient. RESULTS The median age of the patients was 11.5 (range: 6-25) years. Both ears of each patient were categorized based on the same classification. Three patients possessed class III COAs and the other 4 had class I COAs. The interaural differences in preoperative bone and air conduction thresholds were within 15 dB for all patients. Differences in postoperative air-bone gaps between ears were not statistically significant. The surgical procedures required for ossicular reconstruction were almost identical for both ears. CONCLUSION The severity of ossicular abnormalities and hearing loss in patients with bilateral COAs were symmetrical between ears, thereby enabling prediction of the characteristics of the contralateral ear based on the findings observed in 1 ear. These symmetric clinical features can aid surgeons when operating on the contralateral ear.
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Affiliation(s)
- Eun-Kyeong Yeon
- Department of Pediatrics, Chungnam National University College of Medicine, Daejeon, South Korea
| | - Hyo One Son
- Department of Otorhinolaryngology-Head and Neck Surgery, Chungnam National University College of Medicine, Daejeon, South Korea
| | - Hanwool John Sung
- Department of Otorhinolaryngology-Head and Neck Surgery, Chungnam National University College of Medicine, Daejeon, South Korea
| | - Jin Woong Choi
- Department of Otorhinolaryngology-Head and Neck Surgery, Chungnam National University College of Medicine, Daejeon, South Korea
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Cao C, Song J, Su R, Wu X, Wang Z, Hou M. Structure-constrained deep feature fusion for chronic otitis media and cholesteatoma identification. MULTIMEDIA TOOLS AND APPLICATIONS 2023:1-21. [PMID: 37362730 PMCID: PMC10157598 DOI: 10.1007/s11042-023-15425-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 03/19/2023] [Accepted: 04/18/2023] [Indexed: 06/28/2023]
Abstract
Chronic suppurative otitis media (CSOM) and middle ear cholesteatoma (MEC) were two most common chronic middle ear disease(MED) clinically. Accurate differential diagnosis between these two diseases is of high clinical importance given the difference in etiologies, lesion manifestations and treatments. The high-resolution computed tomography (CT) scanning of the temporal bone presents a better view of auditory structures, which is currently regarded as the first-line diagnostic imaging modality in the case of MED. In this paper, we first used a region-of-interest (ROI) network to find the area of the middle ear in the entire temporal bone CT image and segment it to a size of 100*100 pixels. Then, we used a structure-constrained deep feature fusion algorithm to convert different characteristic features of the middle ear in three groups as suppurative otitis media (CSOM), middle ear cholesteatoma (MEC) and normal patches. To fuse structure information, we introduced a graph isomorphism network that implements a feature vector from neighbourhoods and the coordinate distance between vertices. Finally, we construct a classifier named the "otitis media, cholesteatoma and normal identification classifier" (OMCNIC). The experimental results achieved by the graph isomorphism network revealed a 96.36% accuracy in all CSOM and MEC classifications. The experimental results indicate that our structure-constrained deep feature fusion algorithm can quickly and effectively classify CSOM and MEC. It will help otologist in the selection of the most appropriate treatment, and the complications can also be reduced.
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Affiliation(s)
- Cong Cao
- School of Mathematics and Statistics, Central South University, Changsha, 410083 China
| | - Jian Song
- Department of Otorhinolaryngology of Xiangya Hospital, Central South University, Changsha, 410008 China
- Key Laboratory of Otolaryngology Major Disease Research of Hunan Province, Changsha, 410008 China
- National Clinical Research Centre for Geriatric Disorders, Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, 410008 China
| | - Ri Su
- School of Mathematics and Statistics, Central South University, Changsha, 410083 China
| | - Xuewen Wu
- Department of Otorhinolaryngology of Xiangya Hospital, Central South University, Changsha, 410008 China
- Key Laboratory of Otolaryngology Major Disease Research of Hunan Province, Changsha, 410008 China
- National Clinical Research Centre for Geriatric Disorders, Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, 410008 China
| | - Zheng Wang
- School of Computer Science, Hunan First Normal University, Changsha, 410205 China
| | - Muzhou Hou
- School of Mathematics and Statistics, Central South University, Changsha, 410083 China
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Martonos CO, Gudea AI, Ratiu IA, Stan FG, Bolfă P, Little WB, Dezdrobitu CC. Anatomical, Histological, and Morphometrical Investigations of the Auditory Ossicles in Chlorocebus aethiops sabaeus from Saint Kitts Island. BIOLOGY 2023; 12:biology12040631. [PMID: 37106831 PMCID: PMC10135957 DOI: 10.3390/biology12040631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 03/25/2023] [Accepted: 04/18/2023] [Indexed: 04/29/2023]
Abstract
Otological studies rely on a lot of data drawn from animal studies. A lot of pathological or evolutionary questions may find answers in studies on primates, providing insights into the morphological, pathological, and physiological aspects of systematic biological studies. Our study on auditory ossicles moves from a pure morphological (macroscopic and microscopic) investigation of auditory ossicles to the morphometrical evaluation of several individuals as well as to some interpretative data regarding some functional aspects drawn from these investigations. Particularities from this perspective blend with metric data and point toward comparative elements that might also serve as an important reference in further morphologic and comparative studies.
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Affiliation(s)
- Cristian Olimpiu Martonos
- Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, 400372 Cluj-Napoca, Romania
- School of Veterinary Medicine, Ross University, Basseterre P.O. Box 334, Saint Kitts and Nevis
| | - Alexandru Ion Gudea
- Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, 400372 Cluj-Napoca, Romania
| | - Ioana A Ratiu
- Faculty of Medicine and Pharmacy, University of Oradea, 410087 Oradea, Romania
| | - Florin Gheorghe Stan
- Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, 400372 Cluj-Napoca, Romania
| | - Pompei Bolfă
- School of Veterinary Medicine, Ross University, Basseterre P.O. Box 334, Saint Kitts and Nevis
| | - William Brady Little
- School of Veterinary Medicine, Ross University, Basseterre P.O. Box 334, Saint Kitts and Nevis
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Zeyl JN, Snelling EP, Joo R, Clusella-Trullas S. Scaling of ear morphology across 127 bird species and its implications for hearing performance. Hear Res 2023; 428:108679. [PMID: 36587457 DOI: 10.1016/j.heares.2022.108679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 12/04/2022] [Accepted: 12/18/2022] [Indexed: 12/24/2022]
Abstract
The dimensions of auditory structures among animals of varying body size can have implications for hearing performance. Larger animals often have a hearing range focused on lower frequencies than smaller animals, which may be explained by several anatomical mechanisms in the ear and their scaling relationships. While the effect of size on ear morphology and hearing performance has been explored in some mammals, anurans and lizards, much less is known about the scaling relationships for the single-ossicle, internally-coupled ears of birds. Using micro- and nano-CT scans of the tympanic middle and inner ears of 127 ecologically and phylogenetically diverse bird species, spanning more than 400-fold in head mass (2.3 to 950 g), we undertook phylogenetically-informed scaling analyses to test whether 12 morphological traits, of functional importance to hearing, maintain their relative proportions with increasing head mass. We then extended our analysis by regressing these morphological traits with measures of hearing sensitivity and range to better understand morphological underpinnings of hearing performance. We find that most auditory structures scale together in equal proportions, whereas columella length increases disproportionately. We also find that the size of several auditory structures is associated with increased hearing sensitivity and frequency hearing limits, while head mass did not explain these measures. Although both birds and mammals demonstrate proportional scaling between auditory structures, the consequences for hearing in each group may diverge due to unique morphological predictors of auditory performance.
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Affiliation(s)
- Jeffrey N Zeyl
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa.
| | - Edward P Snelling
- Department of Anatomy and Physiology, and Centre for Veterinary Wildlife Research, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | - Rocío Joo
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Davie, FL, USA; Global Fishing Watch, Washington, DC 20036, USA
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Heffner RS, Koay G, Heffner HE, Mason MJ. Hearing in African pygmy hedgehogs (Atelerix albiventris): audiogram, sound localization, and ear anatomy. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:653-670. [PMID: 36282301 DOI: 10.1007/s00359-022-01579-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 08/21/2022] [Accepted: 09/24/2022] [Indexed: 12/14/2022]
Abstract
The behavioral audiogram and sound localization performance, together with the middle and inner ear anatomy, were examined in African pygmy hedgehogs Atelerix albiventris. Their auditory sensitivity at 60 dB SPL extended from 2 to 46 kHz, revealing a relatively narrow hearing range of 4.6 octaves, with a best sensitivity of 21 dB at 8 kHz. Their noise-localization acuity around the midline (minimum audible angle) was 14°, matching the mean of terrestrial mammals. The African pygmy hedgehog was not able to localize low-frequency pure tones or a 3-kHz amplitude-modulated tone when forced to rely on the interaural phase-difference cue, a trait shared by at least nine other mammals. The middle ear of Atelerix has a configuration including an ectotympanic which is not fused to the surrounding bones, a substantial pars flaccida, a synostosed malleo-ectotympanic articulation and a 'microtype' malleus. The hearing and sound localization of A. albiventris is compared to that of a broad range of other mammals. It is shown that a malleus morphology like that of Atelerix, including a stiff articulation with the ectotympanic, is a consistent feature of other mammals that do not hear frequencies below 400 Hz.
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Affiliation(s)
- Rickye S Heffner
- Department of Psychology, University of Toledo, Toledo, OH, 43606, USA.
| | - Gimseong Koay
- Department of Psychology, University of Toledo, Toledo, OH, 43606, USA
| | - Henry E Heffner
- Department of Psychology, University of Toledo, Toledo, OH, 43606, USA
| | - Matthew J Mason
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
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Morphological and Morphometrical Aspects of the Auditory Ossicles in the European Badger (Meles Meles). Vet Sci 2022; 9:vetsci9090483. [PMID: 36136699 PMCID: PMC9504775 DOI: 10.3390/vetsci9090483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 09/05/2022] [Accepted: 09/07/2022] [Indexed: 11/30/2022] Open
Abstract
Simple Summary The little-described morphology of the ear ossicles in the badger provides some interesting morphological features alongside some metrical data. For the malleus, we notice the standard framing into the known shape, with the mentioned presence at the level of the column of all three processes (lateral, rostral and medial), from which the rostral one is the most developed. The malleal manubrium is long and triangularly shaped on a cross-section. For the incus we notice the overall shape of a biradicular molar with the existence of the two crura in acute angulation, while the long crus is continuing with the lenticular process. The presence of a bony blade that links to the lenticular process is also noted. For the stapes, the almost equal two crura and the quite round intercrural foramen is described. Abstract Given the scarce morphological data regarding the middle ear anatomy of this species, the paper attempts to describe the morphological and morphometrical data of the auditory ossicles in the badger. The study was performed using the standard morphological investigations and provides a complete morphological description of the ossicular assembly (malleus, incus and stapes) with some comparative features and attempts to provide a complete set of standardized metrical data for each ossicle. A more-detailed attempt to compare some functional aspects in the light of combined metrical ratios is also implied.
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11
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Racca JM, Jones LL, Dwyer RT, Ferguson M, Sunderhaus L, Hood LJ, Gifford RH. Changes in Acoustic Absorbance Pre- and Post-Cochlear Implantation. Am J Audiol 2022; 31:380-391. [PMID: 35549520 PMCID: PMC9524757 DOI: 10.1044/2022_aja-21-00146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Until recently, there has been little investigation on the effects of cochlear implantation on the transmission of acoustic stimuli through the middle-ear system. Recent studies have shown that cochlear implantation decreases low-frequency acoustic absorbance, consistent with a stiffer middle-ear system postsurgery. The objectives of this study are (a) to investigate the time course of changes in acoustic absorbance post-cochlear implantation in the implanted ear and (b) to compare changes in acoustic absorbance between implanted and nonimplanted ears over time. METHOD Seventeen adult cochlear implant (CI) recipients within 6 months of device activation participated in this study. Wideband acoustic absorbance was measured in both ears at one to six different time points from pre-implantation up to 6-month postactivation. Analyses examined (a) changes in acoustic absorbance as compared to pre-implantation and (b) differences in acoustic absorbance between implanted and nonimplanted ears over time. RESULTS Acoustic absorbance in the implanted ear decreased postsurgery for frequencies lower than 1.5 kHz and persisted through at least 6-month postactivation. We also observed that the spectral range of decreased acoustic absorbance in the implanted ear decreased with longer time postsurgery. Differences in acoustic absorbance between implanted and nonimplanted ears occurred over a broad spectral range at the activation time point and persisted through at least 3-month postactivation, though for a narrower spectral range at the later time point. CONCLUSIONS Cochlear implantation increased middle-ear stiffness as indicated by decreased acoustic absorbance of low-frequency acoustic power. The findings of this study are consistent with those of previous studies and may have important implications toward understanding spatial hearing and programming of acoustic components for CI-combined electric and binaural acoustic stimulation patients.
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Affiliation(s)
- Jordan M. Racca
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN,Department of Radiology, Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN
| | - Laura L. Jones
- Department of Audiology, MedStar Georgetown University Hospital, Washington, DC
| | - Robert T. Dwyer
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN,Advanced Bionics LLC, Valencia, CA
| | - Mary Ferguson
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN
| | - Linsey Sunderhaus
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN
| | - Linda J. Hood
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN
| | - René H. Gifford
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN
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12
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Scarpitti EA, Calede JJM. Ecological correlates of the morphology of the auditory bulla in rodents: Application to the fossil record. J Anat 2022; 240:647-668. [PMID: 34747041 PMCID: PMC8930836 DOI: 10.1111/joa.13579] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 10/19/2021] [Accepted: 10/21/2021] [Indexed: 11/27/2022] Open
Abstract
For rodents, hearing is essential to survival. It enables predator evasion, prey detection, and conspecific recognition; it is also likely to be constrained by the physical environment. The resulting hypothetical link between tympanic bulla morphology and ecology has never been investigated across a broad array of rodent species before. Such link may enable the determination of the ecological affinities of many fossil species only known from partial skulls. In this study, we used geometric morphometrics to quantify the shape of the auditory bulla of 197 specimens representing 91 species from 17 families of extant rodents across four different locomotory modes. We used landmarks and semi-landmarks on the ventral and lateral views of the skull to capture morphological characteristics of the bulla and external auditory meatus (EAM). Our results demonstrate an association between bullar morphology and locomotion in rodents. Bullar shape enables the correct classification of 76% of the species in our training set. Fossorial taxa, in particular, show a characteristic morphology including an asymmetric bulla with a dorsally located and laterally expanded EAM that has a small opening diameter. A phylogenetically informed flexible discriminant analysis shows a weak phylogenetic effect on tympanic morphology. There is no evidence for differences in bullar hypertrophy across locomotory categories. The application of this approach to select fossil rodents from the Oligo-Miocene shows broad agreements with prior studies and yields new locomotory inferences for 14 fossil species, including the first proposed locomotion for members of the family Florentiamyidae. Such results call for the timing of burrowing diversification in rodents to be reevaluated.
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Affiliation(s)
| | - Jonathan J. M. Calede
- School of Earth SciencesThe Ohio State UniversityColumbusOhioUSA
- Department of Evolution, Ecology, and Organismal BiologyThe Ohio State UniversityMarionOhioUSA
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13
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Aquatic birds have middle ears adapted to amphibious lifestyles. Sci Rep 2022; 12:5251. [PMID: 35347167 PMCID: PMC8960762 DOI: 10.1038/s41598-022-09090-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 03/16/2022] [Indexed: 11/21/2022] Open
Abstract
Birds exhibit wide variation in their use of aquatic environments, on a spectrum from entirely terrestrial, through amphibious, to highly aquatic. Although there are limited empirical data on hearing sensitivity of birds underwater, mounting evidence indicates that diving birds detect and respond to sound underwater, suggesting that some modifications of the ear may assist foraging or other behaviors below the surface. In air, the tympanic middle ear acts as an impedance matcher that increases sound pressure and decreases sound vibration velocity between the outside air and the inner ear. Underwater, the impedance-matching task is reversed and the ear is exposed to high hydrostatic pressures. Using micro- and nano-CT (computerized tomography) scans of bird ears in 127 species across 26 taxonomic orders, we measured a suite of morphological traits of importance to aerial and aquatic hearing to test predictions relating to impedance-matching in birds with distinct aquatic lifestyles, while accounting for allometry and phylogeny. Birds that engage in underwater pursuit and deep diving showed the greatest differences in ear structure relative to terrestrial species. In these heavily modified ears, the size of the input areas of both the tympanic membrane and the columella footplate of the middle ear were reduced. Underwater pursuit and diving birds also typically had a shorter extrastapedius, a reduced cranial air volume and connectivity and several modifications in line with reversals of low-to-high impedance-matching. The results confirm adaptations of the middle ear to aquatic lifestyles in multiple independent bird lineages, likely facilitating hearing underwater and baroprotection, while potentially constraining the sensitivity of aerial hearing.
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Buffenstein R, Amoroso V, Andziak B, Avdieiev S, Azpurua J, Barker AJ, Bennett NC, Brieño‐Enríquez MA, Bronner GN, Coen C, Delaney MA, Dengler‐Crish CM, Edrey YH, Faulkes CG, Frankel D, Friedlander G, Gibney PA, Gorbunova V, Hine C, Holmes MM, Jarvis JUM, Kawamura Y, Kutsukake N, Kenyon C, Khaled WT, Kikusui T, Kissil J, Lagestee S, Larson J, Lauer A, Lavrenchenko LA, Lee A, Levitt JB, Lewin GR, Lewis Hardell KN, Lin TD, Mason MJ, McCloskey D, McMahon M, Miura K, Mogi K, Narayan V, O'Connor TP, Okanoya K, O'Riain MJ, Park TJ, Place NJ, Podshivalova K, Pamenter ME, Pyott SJ, Reznick J, Ruby JG, Salmon AB, Santos‐Sacchi J, Sarko DK, Seluanov A, Shepard A, Smith M, Storey KB, Tian X, Vice EN, Viltard M, Watarai A, Wywial E, Yamakawa M, Zemlemerova ED, Zions M, Smith ESJ. The naked truth: a comprehensive clarification and classification of current 'myths' in naked mole-rat biology. Biol Rev Camb Philos Soc 2022; 97:115-140. [PMID: 34476892 PMCID: PMC9277573 DOI: 10.1111/brv.12791] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 12/17/2022]
Abstract
The naked mole-rat (Heterocephalus glaber) has fascinated zoologists for at least half a century. It has also generated considerable biomedical interest not only because of its extraordinary longevity, but also because of unusual protective features (e.g. its tolerance of variable oxygen availability), which may be pertinent to several human disease states, including ischemia/reperfusion injury and neurodegeneration. A recent article entitled 'Surprisingly long survival of premature conclusions about naked mole-rat biology' described 28 'myths' which, those authors claimed, are a 'perpetuation of beautiful, but falsified, hypotheses' and impede our understanding of this enigmatic mammal. Here, we re-examine each of these 'myths' based on evidence published in the scientific literature. Following Braude et al., we argue that these 'myths' fall into four main categories: (i) 'myths' that would be better described as oversimplifications, some of which persist solely in the popular press; (ii) 'myths' that are based on incomplete understanding, where more evidence is clearly needed; (iii) 'myths' where the accumulation of evidence over the years has led to a revision in interpretation, but where there is no significant disagreement among scientists currently working in the field; (iv) 'myths' where there is a genuine difference in opinion among active researchers, based on alternative interpretations of the available evidence. The term 'myth' is particularly inappropriate when applied to competing, evidence-based hypotheses, which form part of the normal evolution of scientific knowledge. Here, we provide a comprehensive critical review of naked mole-rat biology and attempt to clarify some of these misconceptions.
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Affiliation(s)
| | - Vincent Amoroso
- Department of Biological SciencesUniversity of Illinois at ChicagoChicagoIL60607U.S.A.
| | - Blazej Andziak
- Graduate Center City University of New York365 Fifth AvenueNew YorkNY10016U.S.A.
| | | | - Jorge Azpurua
- Department of AnesthesiologyStony Brook University101 Nicolls RoadStony BrookNY11794U.S.A.
| | - Alison J. Barker
- Max Delbrück Center for Molecular MedicineRobert‐Rössle‐Str 10Berlin‐Buch13092Germany
| | - Nigel C. Bennett
- Mammal Research Institute, Department of Zoology and EntomologyUniversity of PretoriaPretoria0002South Africa
| | - Miguel A. Brieño‐Enríquez
- Department of Obstetrics, Gynecology & Reproductive MedicineMagee‐Womens Research Institute204 Craft AvenuePittsburghPA15213U.S.A.
| | - Gary N. Bronner
- Department Biological SciencesRondeboschCape Town7701South Africa
| | - Clive Coen
- Reproductive Neurobiology, Division of Women's HealthSchool of Medicine, King's College LondonWestminster Bridge RoadLondonSE1 7EHU.K.
| | - Martha A. Delaney
- Zoological Pathology ProgramUniversity of Illinois3505 Veterinary Medicine Basic Sciences Building, 2001 S Lincoln AvenueUrbanaIL6180U.S.A.
| | - Christine M. Dengler‐Crish
- Department of Pharmaceutical SciencesNortheast Ohio Medical University4209 State Route 44RootstownOH44272U.S.A.
| | - Yael H. Edrey
- Northwest Vista College3535 N. Ellison DriveSan AntonioTX78251U.S.A.
| | - Chris G. Faulkes
- School of Biological and Chemical SciencesQueen Mary University of LondonMile End RoadLondonE1 4NSU.K.
| | - Daniel Frankel
- School of EngineeringNewcastle UniversityMerz CourtNewcastle Upon TyneNE1 7RUU.K.
| | - Gerard Friedlander
- Université Paris DescartesFaculté de Médecine12 Rue de l'École de MédecineParis5006France
| | - Patrick A. Gibney
- Cornell University College of Veterinary MedicineIthacaNY14853U.S.A.
| | - Vera Gorbunova
- Departments of BiologyUniversity of Rochester402 Hutchison HallRochesterNY14627U.S.A.
| | - Christopher Hine
- Cleveland ClinicLerner Research Institute9500 Euclid AvenueClevelandOH44195U.S.A.
| | - Melissa M. Holmes
- Department of PsychologyUniversity of Toronto Mississauga3359 Mississauga Road NorthMississaugaONL5L 1C6Canada
| | | | - Yoshimi Kawamura
- Department of Aging and Longevity ResearchKumamoto University1‐1‐1 HonjoKumamoto860‐0811Japan
| | - Nobuyuki Kutsukake
- Department of Evolutionary Studies of BiosystemsThe Graduate University for Advanced StudiesHayama240‐0193Japan
| | - Cynthia Kenyon
- Calico Life Sciences LLC1170 Veterans BlvdSouth San FranciscoCA94080U.S.A.
| | - Walid T. Khaled
- The School of the Biological SciencesUniversity of CambridgeTennis Court RoadCambridgeCB2 1PDU.K.
| | - Takefumi Kikusui
- Companion Animal Research, School of Veterinary MedicineAzabu UniversitySagamihara252‐5201Japan
| | - Joseph Kissil
- Department of Cancer BiologyThe Scripps Research InstituteScripps FloridaJupiterFL33458U.S.A.
| | - Samantha Lagestee
- Department of Biological SciencesUniversity of Illinois at ChicagoChicagoIL60607U.S.A.
| | - John Larson
- Department of Biological SciencesUniversity of Illinois at ChicagoChicagoIL60607U.S.A.
| | - Amanda Lauer
- Department of OtolaryngologyJohns Hopkins School of MedicineBaltimoreMD21205U.S.A.
| | - Leonid A. Lavrenchenko
- A.N. Severtsov Institute of Ecology and EvolutionRussian Academy of SciencesLeninskii pr. 33Moscow119071Russia
| | - Angela Lee
- Graduate Center City University of New York365 Fifth AvenueNew YorkNY10016U.S.A.
| | - Jonathan B. Levitt
- Biology DepartmentThe City College of New York138th Street and Convent AvenueNew YorkNY10031U.S.A.
| | - Gary R. Lewin
- Max Delbrück Center for Molecular MedicineRobert‐Rössle‐Str 10Berlin‐Buch13092Germany
| | | | - TzuHua D. Lin
- Calico Life Sciences LLC1170 Veterans BlvdSouth San FranciscoCA94080U.S.A.
| | - Matthew J. Mason
- The School of the Biological SciencesUniversity of CambridgeTennis Court RoadCambridgeCB2 1PDU.K.
| | - Dan McCloskey
- College of Staten Island in the City University of New York2800 Victory BlvdStaten IslandNY10314U.S.A.
| | - Mary McMahon
- Calico Life Sciences LLC1170 Veterans BlvdSouth San FranciscoCA94080U.S.A.
| | - Kyoko Miura
- Department of Aging and Longevity ResearchKumamoto University1‐1‐1 HonjoKumamoto860‐0811Japan
| | - Kazutaka Mogi
- Companion Animal Research, School of Veterinary MedicineAzabu UniversitySagamihara252‐5201Japan
| | - Vikram Narayan
- Calico Life Sciences LLC1170 Veterans BlvdSouth San FranciscoCA94080U.S.A.
| | | | - Kazuo Okanoya
- Department of Life SciencesThe University of Tokyo7‐3‐1 HongoTokyo153‐8902Japan
| | | | - Thomas J. Park
- Department of Biological SciencesUniversity of Illinois at ChicagoChicagoIL60607U.S.A.
| | - Ned J. Place
- Cornell University College of Veterinary MedicineIthacaNY14853U.S.A.
| | - Katie Podshivalova
- Calico Life Sciences LLC1170 Veterans BlvdSouth San FranciscoCA94080U.S.A.
| | | | - Sonja J. Pyott
- Groningen Department of OtorhinolaryngologyUniversity Medical CenterPostbus 30.001GroningenRB9700The Netherlands
| | - Jane Reznick
- Cologne Excellence Cluster for Cellular Stress Responses in Aging‐Associated Diseases (CECAD)University Hospital CologneJoseph‐Stelzmann‐Street 26Cologne50931Germany
| | - J. Graham Ruby
- Calico Life Sciences LLC1170 Veterans BlvdSouth San FranciscoCA94080U.S.A.
| | - Adam B. Salmon
- Barshop Institute for Longevity and Aging StudiesUniversity of Texas Health Science Center4939 Charles Katz Dr.San AntonioTX78229U.S.A.
| | - Joseph Santos‐Sacchi
- Department of NeuroscienceYale University School of Medicine200 South Frontage Road, SHM C‐303New HavenCT06510U.S.A.
| | - Diana K. Sarko
- Department of AnatomySchool of Medicine, Southern Illinois University975 S. NormalCarbondaleIL62901U.S.A.
| | - Andrei Seluanov
- Departments of BiologyUniversity of Rochester402 Hutchison HallRochesterNY14627U.S.A.
| | - Alyssa Shepard
- Department of Cancer BiologyThe Scripps Research InstituteScripps FloridaJupiterFL33458U.S.A.
| | - Megan Smith
- Calico Life Sciences LLC1170 Veterans BlvdSouth San FranciscoCA94080U.S.A.
| | - Kenneth B. Storey
- Department of BiologyCarleton University1125 Colonel By DriveOttawaONK1S 5B6Canada
| | - Xiao Tian
- Department of Genetics – Blavatnik InstituteHarvard Medical School77 Avenue Louis PasteurBostonMA02115U.S.A.
| | - Emily N. Vice
- Department of Biological SciencesUniversity of Illinois at ChicagoChicagoIL60607U.S.A.
| | - Mélanie Viltard
- Fondation pour la recherche en PhysiologieUniversité Catholique de LouvainClos Chapelle‐aux‐Champs 30Woluwe‐saint Lambert1200Belgium
| | - Akiyuki Watarai
- Companion Animal Research, School of Veterinary MedicineAzabu UniversitySagamihara252‐5201Japan
| | - Ewa Wywial
- Biology DepartmentThe City College of New York138th Street and Convent AvenueNew YorkNY10031U.S.A.
| | - Masanori Yamakawa
- Department of Evolutionary Studies of BiosystemsThe Graduate University for Advanced StudiesHayama240‐0193Japan
| | - Elena D. Zemlemerova
- A.N. Severtsov Institute of Ecology and EvolutionRussian Academy of SciencesLeninskii pr. 33Moscow119071Russia
| | - Michael Zions
- Graduate Center City University of New York365 Fifth AvenueNew YorkNY10016U.S.A.
| | - Ewan St. John Smith
- The School of the Biological SciencesUniversity of CambridgeTennis Court RoadCambridgeCB2 1PDU.K.
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Carnosaurs as Apex Scavengers: Agent-based simulations reveal possible vulture analogues in late Jurassic Dinosaurs. Ecol Modell 2021. [DOI: 10.1016/j.ecolmodel.2021.109706] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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In-air hearing in Hawaiian monk seals: implications for understanding the auditory biology of Monachinae seals. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 207:561-573. [PMID: 34145465 PMCID: PMC8222047 DOI: 10.1007/s00359-021-01498-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 06/01/2021] [Accepted: 06/04/2021] [Indexed: 11/17/2022]
Abstract
The auditory biology of Monachinae seals is poorly understood. Limited audiometric data and certain anatomical features suggest that these seals may have reduced sensitivity to airborne sounds compared to related species. Here, we describe the in-air hearing abilities of a Hawaiian monk seal (Neomonachus schauinslandi) trained to participate in a psychophysical paradigm. We report absolute (unmasked) thresholds for narrowband signals measured in quiet conditions across the range of hearing and masked thresholds measured in the presence of octave-band noise at two frequencies. The behavioral audiogram indicates a functional hearing range from 0.1 to 33 kHz and poor sensitivity, with detection thresholds above 40 dB re 20 µPa. Critical ratio measurements are elevated compared to those of other seals. The apparently reduced terrestrial hearing ability of this individual—considered with available auditory data for a northern elephant seal (Mirounga angustirostris)—suggests that hearing in Monachinae seals differs from that of the highly sensitive Phocinae seals. Exploration of phylogenetic relationships and anatomical traits support this claim. This work advances understanding of the evolution of hearing in amphibious marine mammals and provides updated information that can be used for management and conservation of endangered Hawaiian monk seals.
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Pleštilová L, Hrouzková E, Burda H, Meheretu Y, Šumbera R. Ear morphology in two root-rat species (genus Tachyoryctes) differing in the degree of fossoriality. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 207:469-478. [PMID: 33956210 DOI: 10.1007/s00359-021-01489-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 04/20/2021] [Accepted: 04/24/2021] [Indexed: 11/30/2022]
Abstract
It is supposed that the subterranean lifestyle in mammals is reflected in ear morphology and tuning of hearing to low frequencies. We studied two root-rat species to see if their ear morphology reflects the difference in the amount of their surface activity. Whereas the more subterranean Tachyoryctes splendens possesses shorter pinnae as expected, it has smaller bullae compared to the more epigeic Tachyoryctes macrocephalus. The ratio between the eardrum and the stapedial footplate area and the ratio between the mallear and the incudal lever were lower in T. splendens (19.3 ± 0.3 and 1.9 ± 0.0, respectively) than in T. macrocephalus (21.8 ± 0.6 and 2.1 ± 0.1), probably reflecting the latter's higher surface activity. The cochlea in both species has 3.5 coils, yet the basilar membrane is longer in the smaller T. splendens (13.0 ± 0.5 versus 11.4 ± 0.7 mm), which indicates its wider hearing range and/or higher sensitivity (to some frequencies). In both root-rat species, the highest density of outer hair cells (OHC) was in the apical part of the cochlea, while the highest density of inner hair cells (IHC) was in its middle part. This OHC density pattern corresponds with good low-frequency hearing, whereas the IHC pattern suggests sensitivity to higher frequencies.
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Affiliation(s)
- Lucie Pleštilová
- Department of Zoology, Faculty of Science, University of South Bohemia, Branišovská, 1760, 37005, České Budějovice, Czech Republic.
| | - Ema Hrouzková
- Department of Zoology, Faculty of Science, University of South Bohemia, Branišovská, 1760, 37005, České Budějovice, Czech Republic
| | - Hynek Burda
- Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, 16521, Praha, Czech Republic
| | - Yonas Meheretu
- Department of Biology, College of Natural and Computational Sciences, University of Mekelle, Mekelle, Ethiopia
| | - Radim Šumbera
- Department of Zoology, Faculty of Science, University of South Bohemia, Branišovská, 1760, 37005, České Budějovice, Czech Republic
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Lin X, Meenderink SWF, Stomackin G, Jung TT, Martin GK, Dong W. Forward and Reverse Middle Ear Transmission in Gerbil with a Normal or Spontaneously Healed Tympanic Membrane. J Assoc Res Otolaryngol 2021; 22:261-274. [PMID: 33591494 DOI: 10.1007/s10162-020-00779-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 11/19/2020] [Indexed: 11/25/2022] Open
Abstract
Tympanic membranes (TM) that have healed spontaneously after perforation present abnormalities in their structural and mechanical properties; i.e., they are thickened and abnormally dense. These changes result in a deterioration of middle ear (ME) sound transmission, which is clinically presented as a conductive hearing loss (CHL). To fully understand the ME sound transmission under TM pathological conditions, we created a gerbil model with a controlled 50% pars tensa perforation, which was left to heal spontaneously for up to 4 weeks (TM perforations had fully sealed after 2 weeks). After the recovery period, the ME sound transmission, both in the forward and reverse directions, was directly measured with two-tone stimulation. Measurements were performed at the input, the ossicular chain, and output of the ME system, i.e., at the TM, umbo, and scala vestibuli (SV) next to the stapes. We found that variations in ME transmission in forward and reverse directions were not symmetric. In the forward direction, the ME pressure gain decreased in a frequency-dependent manner, with smaller loss (within 10 dB) at low frequencies and more dramatic loss at high frequency regions. The loss pattern was mainly from the less efficient acoustical to mechanical coupling between the TM and umbo, with little changes along the ossicular chain. In the reverse direction, the variations in these ears are relatively smaller. Our results provide detailed functional observations that explain CHL seen in clinical patients with abnormal TM, e.g., caused by otitis media, that have healed spontaneously after perforation or post-tympanoplasty, especially at high frequencies. In addition, our data demonstrate that changes in distortion product otoacoustic emissions (DPOAEs) result from altered ME transmission in both the forward and reverse direction by a reduction of the effective stimulus levels and less efficient transfer of DPs from the ME into the ear canal. This confirms that DPOAEs can be used to assess both the health of the cochlea and the middle ear.
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Affiliation(s)
- Xiaohui Lin
- VA Loma Linda Healthcare System, Loma Linda, CA, 92374, USA
| | | | | | - Timothy T Jung
- VA Loma Linda Healthcare System, Loma Linda, CA, 92374, USA.,Department of Otolaryngology - Head and Neck Surgery, Loma Linda University Health, Loma Linda, CA, 92350, USA
| | - Glen K Martin
- VA Loma Linda Healthcare System, Loma Linda, CA, 92374, USA.,Department of Otolaryngology - Head and Neck Surgery, Loma Linda University Health, Loma Linda, CA, 92350, USA
| | - Wei Dong
- VA Loma Linda Healthcare System, Loma Linda, CA, 92374, USA. .,Department of Otolaryngology - Head and Neck Surgery, Loma Linda University Health, Loma Linda, CA, 92350, USA.
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Ankamreddy H, Bok J, Groves AK. Uncovering the secreted signals and transcription factors regulating the development of mammalian middle ear ossicles. Dev Dyn 2020; 249:1410-1424. [PMID: 33058336 DOI: 10.1002/dvdy.260] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 10/11/2020] [Accepted: 10/11/2020] [Indexed: 12/22/2022] Open
Abstract
The mammalian middle ear comprises a chain of ossicles, the malleus, incus, and stapes that act as an impedance matching device during the transmission of sound from the tympanic membrane to the inner ear. These ossicles are derived from cranial neural crest cells that undergo endochondral ossification and subsequently differentiate into their final functional forms. Defects that occur during middle ear development can result in conductive hearing loss. In this review, we summarize studies describing the crucial roles played by signaling molecules such as sonic hedgehog, bone morphogenetic proteins, fibroblast growth factors, notch ligands, and chemokines during the differentiation of neural crest into the middle ear ossicles. In addition to these cell-extrinsic signals, we also discuss studies on the function of transcription factor genes such as Foxi3, Tbx1, Bapx1, Pou3f4, and Gsc in regulating the development and morphology of the middle ear ossicles.
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Affiliation(s)
| | - Jinwoong Bok
- Department of Anatomy, Yonsei University College of Medicine, Seoul, South Korea.,Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, South Korea
| | - Andrew K Groves
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
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21
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Assemat A, Mourlam MJ, Weppe R, Maugoust J, Antoine P, Orliac MJ. The ossicular chain of Cainotheriidae (Mammalia, Artiodactyla). J Anat 2020; 237:250-262. [PMID: 32255213 PMCID: PMC7369187 DOI: 10.1111/joa.13190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 03/03/2020] [Accepted: 03/04/2020] [Indexed: 11/30/2022] Open
Abstract
This work describes an unparalleled sample of isolated fossil auditory ossicles of cainotheriid artiodactyls from the Paleogene karstic infillings of Dams (Tarn-et-Garonne, Quercy, France). This collection comprises a total of 18 mallei, 28 incudes and three stapedes. It allows the documentation of both intra- and interspecific variability of ossicular morphology within Cainotheriidae. We show that despite considerable intraspecific variability, the malleus, the incus and the stapes appear to be taxonomically informative at the Cainotheriidae scale. This work further provides the first description of a reconstructed ossicular chain of a terrestrial Paleogene artiodactyl species, found in a basicranium of the late Oligocene cainotheriine Caenomeryx filholi (Pech Desse locality).
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Affiliation(s)
- Alexandre Assemat
- Institut des Sciences de l’EvolutionCNRS, IRD, EPHE, Université de MontpellierMontpellierFrance
| | - Mickaël J. Mourlam
- Institut des Sciences de l’EvolutionCNRS, IRD, EPHE, Université de MontpellierMontpellierFrance
| | - Romain Weppe
- Institut des Sciences de l’EvolutionCNRS, IRD, EPHE, Université de MontpellierMontpellierFrance
| | - Jacob Maugoust
- Institut des Sciences de l’EvolutionCNRS, IRD, EPHE, Université de MontpellierMontpellierFrance
| | - Pierre‐Olivier Antoine
- Institut des Sciences de l’EvolutionCNRS, IRD, EPHE, Université de MontpellierMontpellierFrance
| | - Maeva Judith Orliac
- Institut des Sciences de l’EvolutionCNRS, IRD, EPHE, Université de MontpellierMontpellierFrance
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22
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Péus D, Dobrev I, Pfiffner F, Sim JH. Comparison of sheep and human middle-ear ossicles: anatomy and inertial properties. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2020; 206:683-700. [PMID: 32564138 PMCID: PMC7392934 DOI: 10.1007/s00359-020-01430-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 05/25/2020] [Accepted: 06/01/2020] [Indexed: 12/30/2022]
Abstract
The sheep middle ear has been used in training to prepare physicians to perform surgeries and to test new ways of surgical access. This study aimed to (1) collect anatomical data and inertial properties of the sheep middle-ear ossicles and (2) explore effects of these features on sound transmission, in comparison to those of the human. Characteristic dimensions and inertial properties of the middle-ear ossicles of White-Alpine sheep (n = 11) were measured from high-resolution micro-CT data, and were assessed in comparison with the corresponding values of the human middle ear. The sheep middle-ear ossicles differed from those of human in several ways: anteroinferior orientation of the malleus handle, relatively small size of the incus with a relatively short distance to the lenticular process, a large area of the articular surfaces at the incudostapedial joint, and a relatively small moment of inertia along the anterior-posterior axis. Analysis in this study suggests that structure and orientation of the middle-ear ossicles in the sheep are conducive to an increase in the hinge-like ossicular-lever-action around the anterior-posterior axis. Considering the substantial anatomical differences, outcomes of middle-ear surgeries would presumably be difficult to assess from experiments using the sheep middle ear.
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Affiliation(s)
| | - Ivo Dobrev
- Department of Otorhinolaryngology, Head and Neck, Surgery University Hospital Zurich, Zurich, Switzerland.,University of Zurich, Zurich, Switzerland
| | - Flurin Pfiffner
- Department of Otorhinolaryngology, Head and Neck, Surgery University Hospital Zurich, Zurich, Switzerland.,University of Zurich, Zurich, Switzerland
| | - Jae Hoon Sim
- Department of Otorhinolaryngology, Head and Neck, Surgery University Hospital Zurich, Zurich, Switzerland. .,University of Zurich, Zurich, Switzerland.
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Le Maître A, Grunstra NDS, Pfaff C, Mitteroecker P. Evolution of the Mammalian Ear: An Evolvability Hypothesis. Evol Biol 2020; 47:187-192. [PMID: 32801400 PMCID: PMC7399675 DOI: 10.1007/s11692-020-09502-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 05/12/2020] [Indexed: 11/29/2022]
Abstract
Encapsulated within the temporal bone and comprising the smallest elements of the vertebrate skeleton, the ear is key to multiple senses: balance, posture control, gaze stabilization, and hearing. The transformation of the primary jaw joint into the mammalian ear ossicles is one of the most iconic transitions in vertebrate evolution, but the drivers of this complex evolutionary trajectory are not fully understood. We propose a novel hypothesis: The incorporation of the bones of the primary jaw joint into the middle ear has considerably increased the genetic, regulatory, and developmental complexity of the mammalian ear. This increase in the number of genetic and developmental factors may, in turn, have increased the evolutionary degrees of freedom for independent adaptations of the different functional ear units. The simpler ear anatomy in birds and reptiles may be less susceptible to developmental instabilities and disorders than in mammals but also more constrained in its evolution. Despite the tight spatial entanglement of functional ear components, the increased "evolvability" of the mammalian ear may have contributed to the evolutionary success and adaptive diversification of mammals in the vast diversity of ecological and behavioral niches observable today. A brief literature review revealed supporting evidence for this hypothesis.
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Affiliation(s)
- Anne Le Maître
- Department of Evolutionary Biology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
- Department of Palaeontology, University of Vienna, Vienna, Austria
- PALEVOPRIM - UMR 7262CNRS INEE, Université de Poitiers, Poitiers, France
| | - Nicole D. S. Grunstra
- Department of Evolutionary Biology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
- KLI Institute for Evolution and Cognition Research, Klosterneuburg, Austria
- Mammal Collection, Natural History Museum Vienna, Vienna, Austria
| | - Cathrin Pfaff
- Department of Palaeontology, University of Vienna, Vienna, Austria
| | - Philipp Mitteroecker
- Department of Evolutionary Biology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
- KLI Institute for Evolution and Cognition Research, Klosterneuburg, Austria
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24
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Zeyl JN, den Ouden O, Köppl C, Assink J, Christensen-Dalsgaard J, Patrick SC, Clusella-Trullas S. Infrasonic hearing in birds: a review of audiometry and hypothesized structure-function relationships. Biol Rev Camb Philos Soc 2020; 95:1036-1054. [PMID: 32237036 DOI: 10.1111/brv.12596] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 03/13/2020] [Accepted: 03/17/2020] [Indexed: 12/15/2022]
Abstract
The perception of airborne infrasound (sounds below 20 Hz, inaudible to humans except at very high levels) has been documented in a handful of mammals and birds. While animals that produce vocalizations with infrasonic components (e.g. elephants) present conspicuous examples of potential use of infrasound in the context of communication, the extent to which airborne infrasound perception exists among terrestrial animals is unclear. Given that most infrasound in the environment arises from geophysical sources, many of which could be ecologically relevant, communication might not be the only use of infrasound by animals. Therefore, infrasound perception could be more common than currently realized. At least three bird species, each of which do not communicate using infrasound, are capable of detecting infrasound, but the associated auditory mechanisms are not well understood. Here we combine an evaluation of hearing measurements with anatomical observations to propose and evaluate hypotheses supporting avian infrasound detection. Environmental infrasound is mixed with non-acoustic pressure fluctuations that also occur at infrasonic frequencies. The ear can detect such non-acoustic pressure perturbations and therefore, distinguishing responses to infrasound from responses to non-acoustic perturbations presents a great challenge. Our review shows that infrasound could stimulate the ear through the middle ear (tympanic) route and by extratympanic routes bypassing the middle ear. While vibration velocities of the middle ear decline towards infrasonic frequencies, whole-body vibrations - which are normally much lower amplitude than that those of the middle ear in the 'audible' range (i.e. >20 Hz) - do not exhibit a similar decline and therefore may reach vibration magnitudes comparable to the middle ear at infrasonic frequencies. Low stiffness in the middle and inner ear is expected to aid infrasound transmission. In the middle ear, this could be achieved by large air cavities in the skull connected to the middle ear and low stiffness of middle ear structures; in the inner ear, the stiffness of round windows and cochlear partitions are key factors. Within the inner ear, the sizes of the helicotrema and cochlear aqueduct are expected to play important roles in shunting low-frequency vibrations away from low-frequency hair-cell sensors in the cochlea. The basilar papilla, the auditory organ in birds, responds to infrasound in some species, and in pigeons, infrasonic-sensitive neurons were traced back to the apical, abneural end of the basilar papilla. Vestibular organs and the paratympanic organ, a hair cell organ outside of the inner ear, are additional untested candidates for infrasound detection in birds. In summary, this review brings together evidence to create a hypothetical framework for infrasonic hearing mechanisms in birds and other animals.
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Affiliation(s)
- Jeffrey N Zeyl
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch, 7600, South Africa
| | - Olivier den Ouden
- R&D Seismology and Acoustics, Royal Netherlands Meteorological Institute (KNMI), Ministry of Infrastructure, Public Works and Water Management, De Bilt, 3730 AE, The Netherlands.,Faculty of Civil Engineering and Geosciences, Department of Geoscience and Engineering, Delft University of Technology, Delft, 2628 CN, The Netherlands
| | - Christine Köppl
- Cluster of Excellence "Hearing4all" and Department of Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, 26129, Germany
| | - Jelle Assink
- R&D Seismology and Acoustics, Royal Netherlands Meteorological Institute (KNMI), Ministry of Infrastructure, Public Works and Water Management, De Bilt, 3730 AE, The Netherlands
| | | | - Samantha C Patrick
- School of Environmental Sciences, University of Liverpool, Liverpool, L69 3GP, UK
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25
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Yancey KL, Manzoor NF, Haynes DS, Bennett ML, O'Malley M, Rivas A. Audiometric Outcomes and Middle Ear Disease following Cerebrospinal Fluid Leak Repair. Otolaryngol Head Neck Surg 2020; 162:942-949. [PMID: 32204657 DOI: 10.1177/0194599820911720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To investigate audiometric outcomes and incidence of chronic ear disease following lateral skull base repair (LSBR) of cerebrospinal fluid (CSF) leaks. STUDY DESIGN Retrospective review. SETTING Tertiary skull base center. SUBJECTS AND METHODS Consecutive adults undergoing LSBR of CSF leaks between 2012 and 2018 were reviewed. Audiometric data included mean air conduction pure-tone average (PTA), air-bone gap (ABG), speech recognition threshold (SRT), and word recognition score (WRS). The incidence and management of the following were collected: effusion, retraction, otitis media and externa, perforation, and cholesteatoma. RESULTS Seventy-three patients underwent transmastoid (n = 5), middle cranial fossa (n = 2), or combined approach (n = 67) for repair of spontaneous leaks (sCSFLs, n = 41) and those occurring in the setting of chronic ear disease (ceCSFLs, n = 32). ABG decreased 7.23 dB (P = .01) in sCSFL patients. Perforations (P = .01) were more likely in ceCSFL. No sCSFL patient developed a cholesteatoma, perforation, or infection. Effusions (n = 7) were transient, and retractions (n = 2) were managed conservatively in the sCSFL cohort. Eight ceCSFL patients required tubes, 3 underwent tympanoplasties with (n = 2) and without (n = 1) ossicular chain reconstruction (OCR), and 1 had tympanomastoidectomy with OCR. CONCLUSION Lateral skull base repair of CSF leaks maintained or improved hearing. Patients with preexisting chronic ear disease were more likely to require additional intervention to sustain adequate middle ear aeration compared to the sCSFL cohort. LSBR of sCSFL does not appear to increase risk for developing chronic ear disease.
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Affiliation(s)
- Kristen L Yancey
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University, Nashville, Tennessee, USA
| | - Nauman F Manzoor
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University, Nashville, Tennessee, USA
| | - David S Haynes
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University, Nashville, Tennessee, USA
| | - Marc L Bennett
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University, Nashville, Tennessee, USA
| | - Matthew O'Malley
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University, Nashville, Tennessee, USA
| | - Alejandro Rivas
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University, Nashville, Tennessee, USA
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26
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Potapova EG. Morphological Specificity of the Auditory Capsule of Sciurid (Sciuridae, Rodentia). BIOL BULL+ 2020. [DOI: 10.1134/s1062359019070094] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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27
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Zherebtsova OV, Potapova EG. Pathways and Level of Morphological Adaptations in Modern Diatomyidae and Ctenodactylidae (Rodentia). BIOL BULL+ 2020. [DOI: 10.1134/s1062359019070124] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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28
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Malkemper EP, Mason MJ, Burda H. Functional anatomy of the middle and inner ears of the red fox, in comparison to domestic dogs and cats. J Anat 2020; 236:980-995. [PMID: 32068262 PMCID: PMC7219625 DOI: 10.1111/joa.13159] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 12/28/2019] [Accepted: 01/07/2020] [Indexed: 01/21/2023] Open
Abstract
Anatomical middle and inner ear parameters are often used to predict hearing sensitivities of mammalian species. Given that ear morphology is substantially affected both by phylogeny and body size, it is interesting to consider whether the relatively small anatomical differences expected in related species of similar size have a noticeable impact on hearing. We present a detailed anatomical description of the middle and inner ears of the red fox Vulpes vulpes, a widespread, wild carnivore for which a behavioural audiogram is available. We compare fox ears to those of the well‐studied and similarly sized domestic dog and cat, taking data for dogs and cats from the literature as well as providing new measurements of basilar membrane (BM) length and hair cell numbers and densities in these animals. Our results show that the middle ear of the red fox is very similar to that of dogs. The most obvious difference from that of the cat is the lack of a fully formed bony septum in the bulla tympanica of the fox. The cochlear structures of the fox, however, are very like those of the cat, whereas dogs have a broader BM in the basal cochlea. We further report that the mass of the middle ear ossicles and the bulla volume increase with age in foxes. Overall, the ear structures of foxes, dogs and cats are anatomically very similar, and their behavioural audiograms overlap. However, the results of several published models and correlations that use middle and inner ear measurements to predict aspects of hearing were not always found to match well with audiogram data, especially when it came to the sharper tuning in the fox audiogram. This highlights that, although there is evidently a broad correspondence between structure and function, it is not always possible to draw direct links when considering more subtle differences between related species.
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Affiliation(s)
- Erich Pascal Malkemper
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany.,Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Praha, Czech Republic
| | - Matthew J Mason
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Hynek Burda
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany.,Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Praha, Czech Republic
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29
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Basso AP, Sidorkewicj NS, Casanave EB, Mason MJ. The middle ear of the pink fairy armadillo Chlamyphorus truncatus (Xenarthra, Cingulata, Chlamyphoridae): comparison with armadillo relatives using computed tomography. J Anat 2020; 236:809-826. [PMID: 31997377 DOI: 10.1111/joa.13146] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2019] [Indexed: 11/30/2022] Open
Abstract
The pink fairy armadillo Chlamyphorus truncatus is the smallest extant armadillo and one of the least-known fossorial mammals. The aim of this study was to establish if its middle ear is specially adapted to the subterranean environment, through comparison with more epigeic relatives of the groups Euphractinae (Chaetophractus villosus, Chaetophractus vellerosus, Zaedyus pichiy) and Dasypodinae (Dasypus hybridus). We examined the middle ears using micro-computed tomography and subsequent three-dimensional reconstructions. D. hybridus has a relatively small middle ear cavity, an incomplete bulla and 'ancestral' ossicular morphology. The other species, including Chlamyphorus, have fully ossified bullae and middle ear ossicles, with a morphology between 'transitional' and 'freely mobile', but in all armadillos the malleus retains a long anterior process. Unusual features of armadillo ears include the lack of a pedicellate lenticular apophysis and the presence, in some species, of an element of Paaw within the stapedius muscle. In common with many subterranean mammals, Chlamyphorus has a relatively flattened malleo-incudal articulation and appears to lack a functional tensor tympani muscle. Its middle ear cavity is not unusually enlarged, and its middle ear ossicles seem less robust than those of the other armadillos studied. In comparison with the euphractines, there is no reason to believe that the middle ear of this species is specially adapted to the subterranean environment; some aspects may even be indicative of degeneration. The screaming hairy armadillo, Chaetophractus vellerosus, has the most voluminous middle ear in both relative and absolute terms. Its hypertrophied middle ear cavity likely represents an adaptation to low-frequency hearing in arid rather than subterranean conditions.
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Affiliation(s)
- Ana P Basso
- Cátedra de Anatomía Comparada, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina.,Instituto de Ciencias Biológicas y Biomédicas del Sur (INBIOSUR), Universidad Nacional del Sur y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
| | - Nora S Sidorkewicj
- Cátedra de Anatomía Comparada, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina.,Instituto de Ciencias Biológicas y Biomédicas del Sur (INBIOSUR), Universidad Nacional del Sur y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
| | - Emma B Casanave
- Instituto de Ciencias Biológicas y Biomédicas del Sur (INBIOSUR), Universidad Nacional del Sur y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina.,Cátedra de Fisiología Animal, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - Matthew J Mason
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
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30
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Cai L, Stomackin G, Perez NM, Lin X, Jung TT, Dong W. Recovery from tympanic membrane perforation: Effects on membrane thickness, auditory thresholds, and middle ear transmission. Hear Res 2019; 384:107813. [PMID: 31655347 DOI: 10.1016/j.heares.2019.107813] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 09/20/2019] [Accepted: 10/09/2019] [Indexed: 01/22/2023]
Abstract
Sounds delivered to the ear move the tympanic membrane (TM), which drives the middle-ear (ME) ossicles and transfers the acoustic energy to the cochlea. Perforations of the TM result in hearing loss because of less efficient sound conduction through the ME. The patterns of TM motions, and thus ME sound transmission, vary with frequency and depend on many factors, including the TM thickness. In this study, we measured TM thickness, auditory brainstem responses (ABR), and ME transmission immediately following a controlled pars tensa perforation and after 4 weeks of spontaneous recovery in a gerbil model. It is found that after recovery, the hearing thresholds showed a sloping pattern across frequencies: almost back to normal levels at frequencies between 2 and 8 kHz, sloping loss in the low (<2 kHz) and mid-frequency (8-30 kHz) range, and little restoration at frequencies above 30 kHz. This pattern was confirmed by the measured ME pressure gains. The thickness of the healed TM did not return to normal but was 2-3 times thicker over a significant portion of the membrane. The increased thickness was not limited to the perforated area but expanded into intact regions adjacent to the perforation, which led to an increased thickness in general. Combined, these results suggest that TM thickness is an important factor in determining its vibration patterns and efficiency to transfer sounds to the ossicles and thus influencing ME sound transmission, especially for high-frequency sounds. The results provided both structural and functional observations to explain the conductive hearing loss seen in patients with abnormal TMs, e.g., caused by otitis media, spontaneously healed post-perforation, or repaired via tympanoplasty in the clinic.
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Affiliation(s)
- Lingling Cai
- VA Loma Linda Healthcare System, Loma Linda, CA, 92357, USA; Department of Radiology, Shanghai Ninth People's Hospital, Shanghai JiaoTong University, School of Medicine, Shanghai, China
| | | | - Nicholas M Perez
- VA Loma Linda Healthcare System, Loma Linda, CA, 92357, USA; School of Computer Science and Engineering, California State University San Bernardino, San Bernardino, CA, 92407, USA
| | - Xiaohui Lin
- VA Loma Linda Healthcare System, Loma Linda, CA, 92357, USA
| | - Timothy T Jung
- VA Loma Linda Healthcare System, Loma Linda, CA, 92357, USA; Department of Otolaryngology - Head and Neck Surgery, Loma Linda University Health, Loma Linda, CA, 92350, USA
| | - Wei Dong
- VA Loma Linda Healthcare System, Loma Linda, CA, 92357, USA; Department of Otolaryngology - Head and Neck Surgery, Loma Linda University Health, Loma Linda, CA, 92350, USA.
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31
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Mourlam MJ, Orliac MJ. Early evolution of the ossicular chain in Cetacea: into the middle ear gears of a semi-aquatic protocetid whale. Proc Biol Sci 2019; 286:20191417. [PMID: 31575370 DOI: 10.1098/rspb.2019.1417] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Modifications of the morphology and acoustic properties of the ossicular chain are among the major changes that accompanied the adaptation of Cetacea to the aquatic environment. Thus, data on the middle ear ossicles of early whales are crucial clues to understand the first steps of the emblematic terrestrial/aquatic transition that occurred in that group. Yet, the delicate nature and very small size of these bones make their preservation in the fossil record extremely rare. Due to the scarcity of available data, major questions remain concerning the sound transmission pathways in early non-fully aquatic whales. Virtual reconstruction of a partially complete ossicular chain of an Eocene protocetid whale documents for the first time the three ossicles of a semi-aquatic archaeocete. Contrary to previous hypotheses, these ossicles present different evolutionary patterns, showing that the ossicular chain does not act as a single morphological module. Functional analyses of the different middle ear units highlight a mosaic pattern of terrestrial and aquatic signatures. This integrative anatomical and functional study brings strong evidence that protocetids were adapted to their dual acoustic environment with efficient hearing in both air and water.
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Affiliation(s)
- Mickaël J Mourlam
- Institut des Sciences de l'Évolution, UMR 5554 CNRS, IRD, EPHE, Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier cedex 5, France
| | - Maeva J Orliac
- Institut des Sciences de l'Évolution, UMR 5554 CNRS, IRD, EPHE, Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier cedex 5, France
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32
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Harper T, Rougier GW. Petrosal morphology and cochlear function in Mesozoic stem therians. PLoS One 2019; 14:e0209457. [PMID: 31412094 PMCID: PMC6693738 DOI: 10.1371/journal.pone.0209457] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 06/07/2019] [Indexed: 11/19/2022] Open
Abstract
Here we describe the bony anatomy of the inner ear and surrounding structures seen in three plesiomorphic crown mammalian petrosal specimens. Our study sample includes the triconodont Priacodon fruitaensis from the Upper Jurassic of North America, and two isolated stem therian petrosal specimens colloquially known as the Höövör petrosals, recovered from Aptian-Albian sediments in Mongolia. The second Höövör petrosal is here described at length for the first time. All three of these petrosals and a comparative sample of extant mammalian taxa have been imaged using micro-CT, allowing for detailed anatomical descriptions of the osteological correlates of functionally significant neurovascular features, especially along the abneural wall of the cochlear canal. The high resolution imaging provided here clarifies several hypotheses regarding the mosaic evolution of features of the cochlear endocast in early mammals. In particular, these images demonstrate that the membranous cochlear duct adhered to the bony cochlear canal abneurally to a secondary bony lamina before the appearance of an opposing primary bony lamina or tractus foraminosus. Additionally, while corroborating the general trend of reduction of venous sinuses and plexuses within the pars cochlearis seen in crownward mammaliaforms generally, the Höövör petrosals show the localized enlargement of a portion of the intrapetrosal venous plexus. This new vascular feature is here interpreted as the bony accommodation for the vein of cochlear aqueduct, a structure that is solely, or predominantly, responsible for the venous drainage of the cochlear apparatus in extant therians. Given that our fossil stem therian inner ear specimens appear to have very limited high-frequency capabilities, the development of these modern vascular features of the cochlear endocast suggest that neither the initiation or enlargement of the stria vascularis (a unique mammalian organ) was originally associated with the capacity for high-frequency hearing or precise sound-source localization.
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Affiliation(s)
- Tony Harper
- Center for Functional Anatomy and Evolution, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Guillermo W. Rougier
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky, United States of America
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33
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A Nearly Complete Juvenile Skull of the Marsupial Sparassocynus derivatus from the Pliocene of Argentina, the Affinities of “Sparassocynids”, and the Diversification of Opossums (Marsupialia; Didelphimorphia; Didelphidae). J MAMM EVOL 2019. [DOI: 10.1007/s10914-019-09471-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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34
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Mechanics to pre-process information for the fine tuning of mechanoreceptors. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:661-686. [PMID: 31270587 PMCID: PMC6726712 DOI: 10.1007/s00359-019-01355-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 06/18/2019] [Accepted: 06/20/2019] [Indexed: 11/17/2022]
Abstract
Non-nervous auxiliary structures play a significant role in sensory biology. They filter the stimulus and transform it in a way that fits the animal’s needs, thereby contributing to the avoidance of the central nervous system’s overload with meaningless stimuli and a corresponding processing task. The present review deals with mechanoreceptors mainly of invertebrates and some remarkable recent findings stressing the role of mechanics as an important source of sensor adaptedness, outstanding performance, and diversity. Instead of organizing the review along the types of stimulus energy (force) taken up by the sensors, processes associated with a few basic and seemingly simple mechanical principles like lever systems, viscoelasticity, resonance, traveling waves, and impedance matching are taken as the guideline. As will be seen, nature makes surprisingly competent use of such “simple mechanics”.
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35
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D’Elía G, Fabre PH, Lessa EP. Rodent systematics in an age of discovery: recent advances and prospects. J Mammal 2019. [DOI: 10.1093/jmammal/gyy179] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Affiliation(s)
- Guillermo D’Elía
- Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Pierre-Henri Fabre
- Institut des Sciences de l’Evolution (ISEM, UMR 5554 CNRS-UM2-IRD), Université Montpellier, Montpellier Cedex 5, France
| | - Enrique P Lessa
- Departamento de Ecología y Evolución, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
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36
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Dong W, Stomackin G, Lin X, Martin GK, Jung TT. Distortion product otoacoustic emissions: Sensitive measures of tympanic -membrane perforation and healing processes in a gerbil model. Hear Res 2019; 378:3-12. [PMID: 30709692 DOI: 10.1016/j.heares.2019.01.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 01/13/2019] [Accepted: 01/20/2019] [Indexed: 11/27/2022]
Abstract
Distortion product otoacoustic emissions (DPOAEs) evoked by two pure tones carry information about the mechanisms that generate and shape them. Thus, DPOAEs hold promise for providing powerful noninvasive diagnostic details of cochlear operations, middle ear (ME) transmission, and impairments. DPOAEs are sensitive to ME function because they are influenced by ME transmission twice, i.e., by the inward-going primary tones in the forward direction and the outward traveling DPOAEs in the reverse direction. However, the effects of ME injuries on DPOAEs have not been systematically characterized. The current study focused on exploring the utility of DPOAEs for examining ME function by methodically characterizing DPOAEs and ME transmission under pathological ME conditions, specifically under conditions of tympanic-membrane (TM) perforation and spontaneous healing. Results indicated that DPOAEs were measurable with TM perforations up to ∼50%, and DPOAE reductions increased with increasing size of the TM perforation. DPOAE reductions were approximately flat across test frequencies when the TM was perforated about 10% (<1/8 of pars tensa) or less. However, with perforations greater than 10%, DPOAEs decreased further with a low-pass filter shape, with ∼30 dB loss at frequencies below 10 kHz and a quick downward sloping pattern at higher frequencies. The reduction pattern of DPOAEs across frequencies was similar to but much greater than, the directly measured ME pressure gain in the forward direction, which suggested that reduction in the DPOAE was a summation of losses of ME ear transmission in both the forward and reverse directions. Following 50% TM perforations, DPOAEs recovered over a 4-week spontaneously healing interval, and these recoveries were confirmed by improvements in auditory brainstem response (ABR) thresholds. However, up to 4-week post-perforation, DPOAEs never fully recovered to the levels obtained with normal intact TM, consistent with the incomplete recovery of ABR thresholds and ME transmission, especially at high-frequency regions, which could be explained by an irregularly dense and thickened healed TM. Since TM perforations in patients are commonly caused by either trauma or infection, the present results contribute towards providing insight into understanding ME transmission under pathological conditions as well as promoting the application of DPOAEs in the evaluation and diagnosis of deficits in the ME-transmission system.
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Affiliation(s)
- Wei Dong
- Research Service, VA Loma Linda Healthcare System, Loma Linda, CA 92357, USA; Department of Otolaryngology--Head & Neck Surgery, Loma Linda University Health, Loma Linda, CA 92354, USA.
| | - Glenna Stomackin
- Research Service, VA Loma Linda Healthcare System, Loma Linda, CA 92357, USA
| | - Xiaohui Lin
- Research Service, VA Loma Linda Healthcare System, Loma Linda, CA 92357, USA
| | - Glen K Martin
- Research Service, VA Loma Linda Healthcare System, Loma Linda, CA 92357, USA; Department of Otolaryngology--Head & Neck Surgery, Loma Linda University Health, Loma Linda, CA 92354, USA
| | - Timothy T Jung
- Research Service, VA Loma Linda Healthcare System, Loma Linda, CA 92357, USA; Department of Otolaryngology--Head & Neck Surgery, Loma Linda University Health, Loma Linda, CA 92354, USA
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37
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Boonman A, Zadicario P, Mazon Y, Rabi C, Eilam D. The sounds of silence: Barn owl noise in landing and taking off. Behav Processes 2018; 157:484-488. [DOI: 10.1016/j.beproc.2018.06.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 06/14/2018] [Accepted: 06/18/2018] [Indexed: 11/27/2022]
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38
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Zeyl JN, Johnston CE. Do Body Wall Vibrations Over the Lungs Aid Aerial Hearing in Salamanders? An Investigation into Extratympanic Hearing Mechanisms. HERPETOLOGICA 2017. [DOI: 10.1655/herpetologica-d-16-00076.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Jeffrey N. Zeyl
- Fish Biodiversity Lab, School of Fisheries, Aquaculture, and Aquatic Sciences, College of Agriculture, Auburn University, Auburn, AL 36849, USA
| | - Carol E. Johnston
- Fish Biodiversity Lab, School of Fisheries, Aquaculture, and Aquatic Sciences, College of Agriculture, Auburn University, Auburn, AL 36849, USA
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Gerhardt P, Henning Y, Begall S, Malkemper EP. Audiograms of three subterranean rodent species (genus Fukomys) determined by auditory brainstem responses reveal extremely poor high-frequency hearing. ACTA ACUST UNITED AC 2017; 220:4377-4382. [PMID: 29025871 DOI: 10.1242/jeb.164426] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 10/05/2017] [Indexed: 11/20/2022]
Abstract
Life underground has shaped the auditory sense of subterranean mammals, shifting their hearing range to low frequencies. Mole-rats of the genus Fukomys have, however, been suggested to hear at frequencies up to 18.5 kHz, unusually high for a subterranean rodent. We present audiograms of three mole-rat species, Fukomys anselli, Fukomys micklemi and the giant mole-rat Fukomys mechowii, based on evoked auditory brainstem potentials. All species showed low sensitivity and restricted hearing ranges at 60 dB SPL extending from 125 Hz to 4 kHz (5 octaves) with most-sensitive hearing between 0.8 kHz and 1.4 kHz. The high-frequency cut-offs are the lowest found in mammals to date. In contrast to predictions from middle ear morphology, F. mechowii did not show higher sensitivity than F. anselli in the low-frequency range. These data suggest that the hearing range of Fukomys mole-rats is highly restricted to low frequencies and similar to that of other subterranean mammals.
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Affiliation(s)
- Patricia Gerhardt
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, 45117 Essen, Germany
| | - Yoshiyuki Henning
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, 45117 Essen, Germany
| | - Sabine Begall
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, 45117 Essen, Germany
| | - E Pascal Malkemper
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, 45117 Essen, Germany .,Department of Wildlife Management, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, 16521 Praha 6, Czech Republic
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Koyabu D, Hosojima M, Endo H. Into the dark: patterns of middle ear adaptations in subterranean eulipotyphlan mammals. ROYAL SOCIETY OPEN SCIENCE 2017; 4:170608. [PMID: 28989763 PMCID: PMC5627103 DOI: 10.1098/rsos.170608] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 08/21/2017] [Indexed: 05/06/2023]
Abstract
Evolution of the middle ear ossicles was a key innovation for mammals, enhancing the transmission of airborne sound. Radiation into various habitats from a terrestrial environment resulted in diversification of the auditory mechanisms among mammals. However, due to the paucity of phylogenetically controlled investigations, how middle ear traits have diversified with functional specialization remains unclear. In order to identify the respective patterns for various lifestyles and to gain insights into fossil forms, we employed a high-resolution tomography technique and compared the middle ear morphology of eulipotyphlan species (moles, shrews and hedgehogs), a group that has radiated into various environments, such as terrestrial, aquatic and subterranean habitats. Three-dimensional geometric morphometric analysis was conducted within a phylogenetically controlled framework. Quantitative shapes were found to strongly reflect the degree of subterranean lifestyle and weakly involve phylogeny. Our analyses demonstrate that subterranean adaptation should include a relatively shorter anterior process of the malleus, an enlarged incus, an enlarged stapes footplate and a reduction of the orbicular apophysis. These traits arguably allow improving low-frequency sound transmission at low frequencies and inhibiting the low-frequency noise which disturbs the subterranean animals in hearing airborne sounds.
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Affiliation(s)
- Daisuke Koyabu
- The University Museum, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, 113-0033 Tokyo, Japan
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41
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Doyle WJ. A formal description of middle ear pressure-regulation. Hear Res 2017; 354:73-85. [PMID: 28917121 DOI: 10.1016/j.heares.2017.08.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 08/18/2017] [Accepted: 08/21/2017] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Middle ear (ME) pressure-regulation (MEPR) is a homeostatic mechanism that maintains the ME-environment pressure-gradient (MEEPG) within a range optimized for "normal" hearing. OBJECTIVE Describe MEPR using equations applicable to passive, inter-compartmental gas-exchange and determine if the predictions of that description include the increasing ME pressure observed under certain conditions and interpreted by some as evidencing gas-production by the ME mucosa. METHODS MEPR was modeled as the combined effect of passive gas-exchanges between the ME and: perilymph via the round window membrane, the ambient environment via the tympanic membrane, and the local blood via the ME mucosa and of gas flow between the ME and nasopharynx during Eustachian tube openings. The first 3 of these exchanges are described at the species level using the Fick's diffusion equation and the last as a bulk gas transfer governed by Poiseuille's equation. The model structure is a time-iteration of the equation: PMEg(t=(i+1)Δt) = ∑s(PMEs(t=iΔt)+(1/(βMEsVME)∑P(ҚPs(PCs(t=(iΔt)-PMEs(t=(iΔt))). There, PMEg(t=iΔt) and PMEs(t=iΔt) are the ME total and species-pressures at the indexed times, PCs(t=iΔt) is the species-pressure for each exchange-compartment, βMEsVME is the product of the ME species-capacitance and volume, ҚPs is the pathway species-conductance, and ∑S and ∑P are operators for summing the expression over all species or exchange pathways. RESULTS When calibrated to known values, the model predicts the empirically measured ME species-pressures and the observed time-trajectories for total ME pressure and the MEEPG under a wide variety of physiologic, pathologic and non-physiologic conditions. CONCLUSIONS Passive inter-compartmental gas exchange is sole and sufficient to describe MEPR.
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Affiliation(s)
- William J Doyle
- Department of Otolaryngology, University of Pittsburgh, School of Medicine, Pittsburgh, PA, USA.
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Luo W, Yi H, Taylor J, Li JD, Chi F, Todd NW, Lin X, Ren D, Chen P. Cilia distribution and polarity in the epithelial lining of the mouse middle ear cavity. Sci Rep 2017; 7:45870. [PMID: 28358397 PMCID: PMC5372464 DOI: 10.1038/srep45870] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 03/03/2017] [Indexed: 12/15/2022] Open
Abstract
The middle ear conducts sound to the cochlea for hearing. Otitis media (OM) is the most common illness in childhood. Moreover, chronic OM with effusion (COME) is the leading cause of conductive hearing loss. Clinically, COME is highly associated with Primary Ciliary Dyskinesia, implicating significant contributions of cilia dysfunction to COME. The understanding of middle ear cilia properties that are critical to OM susceptibility, however, is limited. Here, we confirmed the presence of a ciliated region near the Eustachian tube orifice at the ventral region of the middle ear cavity, consisting mostly of a lumen layer of multi-ciliated and a layer of Keratin-5-positive basal cells. We also found that the motile cilia are polarized coordinately and display a planar cell polarity. Surprisingly, we also found a region of multi-ciliated cells that line the posterior dorsal pole of the middle ear cavity which was previously thought to contain only non-ciliated cells. Our study provided a more complete understanding of cilia distribution and revealed for the first time coordinated polarity of cilia in the epithelium of the mammalian middle ear, thus illustrating novel structural features that are likely critical for middle ear functions and related to OM susceptibility.
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Affiliation(s)
- Wenwei Luo
- Department of Cell Biology Emory University, Atlanta, USA.,Eye, Ear, Nose, and Throat Hospital, Fudan University, Shanghai, PR China
| | - Hong Yi
- Electronic Microscopy Laboratory, Emory University, Atlanta, USA
| | - Jeannette Taylor
- Electronic Microscopy Laboratory, Emory University, Atlanta, USA
| | - Jian-Dong Li
- Center for Inflammation, Immunity and Infection, Institution for Biomedical Sciences, Georgia State University, Atlanta, USA
| | - Fanglu Chi
- Eye, Ear, Nose, and Throat Hospital, Fudan University, Shanghai, PR China
| | - N Wendell Todd
- Department of Otolaryngology, Emory University, Atlanta, USA
| | - Xi Lin
- Department of Otolaryngology, Emory University, Atlanta, USA
| | - Dongdong Ren
- Eye, Ear, Nose, and Throat Hospital, Fudan University, Shanghai, PR China
| | - Ping Chen
- Department of Cell Biology Emory University, Atlanta, USA
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Mittal R, Debs LH, Nguyen D, Patel AP, Grati M, Mittal J, Yan D, Eshraghi AA, Liu XZ. Signaling in the Auditory System: Implications in Hair Cell Regeneration and Hearing Function. J Cell Physiol 2017; 232:2710-2721. [DOI: 10.1002/jcp.25695] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 11/18/2016] [Indexed: 02/06/2023]
Affiliation(s)
- Rahul Mittal
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Luca H. Debs
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Desiree Nguyen
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Amit P. Patel
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - M'hamed Grati
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Jeenu Mittal
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Denise Yan
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Adrien A. Eshraghi
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Xue Zhong Liu
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
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Ear Structures of the Naked Mole-Rat, Heterocephalus glaber, and Its Relatives (Rodentia: Bathyergidae). PLoS One 2016; 11:e0167079. [PMID: 27926945 PMCID: PMC5142786 DOI: 10.1371/journal.pone.0167079] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 11/08/2016] [Indexed: 11/21/2022] Open
Abstract
Although increasingly popular as a laboratory species, very little is known about the peripheral auditory system of the naked mole-rat, Heterocephalus glaber. In this study, middle and inner ears of naked mole-rats of a range of ages were examined using micro-computed tomography and dissection. The ears of five other bathyergid species (Bathyergus suillus, Cryptomys hottentotus, Fukomys micklemi, Georychus capensis and Heliophobius argenteocinereus) were examined for comparative purposes. The middle ears of bathyergids show features commonly found in other members of the Ctenohystrica rodent clade, including a fused malleus and incus, a synovial stapedio-vestibular articulation and the loss of the stapedius muscle. Heterocephalus deviates morphologically from the other bathyergids examined in that it has a more complex mastoid cavity structure, poorly-ossified processes of the malleus and incus, a ‘columelliform’ stapes and fewer cochlear turns. Bathyergids have semicircular canals with unusually wide diameters relative to their radii of curvature. How the lateral semicircular canal reaches the vestibule differs between species. Heterocephalus has much more limited high-frequency hearing than would be predicted from its small ear structures. The spongy bone forming its ossicular processes, the weak incudo-stapedial articulation, the columelliform stapes and (compared to other bathyergids) reduced cochlear coiling are all potentially degenerate features which might reflect a lack of selective pressure on its peripheral auditory system. Substantial intraspecific differences were found in certain middle and inner ear structures, which might also result from relaxed selective pressures. However, such interpretations must be treated with caution in the absence of experimental evidence.
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Mason MJ. Internally coupled ears in living mammals. BIOLOGICAL CYBERNETICS 2016; 110:345-358. [PMID: 26794500 PMCID: PMC5107206 DOI: 10.1007/s00422-015-0675-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 12/11/2015] [Indexed: 05/22/2023]
Abstract
It is generally held that the right and left middle ears of mammals are acoustically isolated from each other, such that mammals must rely on neural computation to derive sound localisation cues. There are, however, some unusual species in which the middle ear cavities intercommunicate, in which case each ear might be able to act as a pressure-difference receiver. This could improve sound localisation at lower frequencies. The platypus Ornithorhynchus is apparently unique among mammals in that its tympanic cavities are widely open to the pharynx, a morphology resembling that of some non-mammalian tetrapods. The right and left middle ear cavities of certain talpid and golden moles are connected through air passages within the basicranium; one experimental study on Talpa has shown that the middle ears are indeed acoustically coupled by these means. Having a basisphenoid component to the middle ear cavity walls could be an important prerequisite for the development of this form of interaural communication. Little is known about the hearing abilities of platypus, talpid and golden moles, but their audition may well be limited to relatively low frequencies. If so, these mammals could, in principle, benefit from the sound localisation cues available to them through internally coupled ears. Whether or not they actually do remains to be established experimentally.
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Affiliation(s)
- Matthew J Mason
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK.
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Abstract
The diminutive middle ear ossicles (malleus, incus, stapes) housed in the tympanic cavity of the temporal bone play an important role in audition. The few known ossicles of Neandertals are distinctly different from those of anatomically modern humans (AMHs), despite the close relationship between both human species. Although not mutually exclusive, these differences may affect hearing capacity or could reflect covariation with the surrounding temporal bone. Until now, detailed comparisons were hampered by the small sample of Neandertal ossicles and the unavailability of methods combining analyses of ossicles with surrounding structures. Here, we present an analysis of the largest sample of Neandertal ossicles to date, including many previously unknown specimens, covering a wide geographic and temporal range. Microcomputed tomography scans and 3D geometric morphometrics were used to quantify shape and functional properties of the ossicles and the tympanic cavity and make comparisons with recent and extinct AMHs as well as African apes. We find striking morphological differences between ossicles of AMHs and Neandertals. Ossicles of both Neandertals and AMHs appear derived compared with the inferred ancestral morphology, albeit in different ways. Brain size increase evolved separately in AMHs and Neandertals, leading to differences in the tympanic cavity and, consequently, the shape and spatial configuration of the ossicles. Despite these different evolutionary trajectories, functional properties of the middle ear of AMHs and Neandertals are largely similar. The relevance of these functionally equivalent solutions is likely to conserve a similar auditory sensitivity level inherited from their last common ancestor.
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Wannaprasert T. Functional Morphology of the Ear of the Lesser Bamboo Rat (Cannomys badius). MAMMAL STUDY 2016. [DOI: 10.3106/041.041.0301] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Mason MJ. Structure and function of the mammalian middle ear. I: Large middle ears in small desert mammals. J Anat 2015; 228:284-99. [PMID: 26104342 DOI: 10.1111/joa.12313] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2015] [Indexed: 11/26/2022] Open
Abstract
Many species of small desert mammals are known to have expanded auditory bullae. The ears of gerbils and heteromyids have been well described, but much less is known about the middle ear anatomy of other desert mammals. In this study, the middle ears of three gerbils (Meriones, Desmodillus and Gerbillurus), two jerboas (Jaculus) and two sengis (elephant-shrews: Macroscelides and Elephantulus) were examined and compared, using micro-computed tomography and light microscopy. Middle ear cavity expansion has occurred in members of all three groups, apparently in association with an essentially 'freely mobile' ossicular morphology and the development of bony tubes for the middle ear arteries. Cavity expansion can occur in different ways, resulting in different subcavity patterns even between different species of gerbils. Having enlarged middle ear cavities aids low-frequency audition, and several adaptive advantages of low-frequency hearing to small desert mammals have been proposed. However, while Macroscelides was found here to have middle ear cavities so large that together they exceed brain volume, the bullae of Elephantulus are considerably smaller. Why middle ear cavities are enlarged in some desert species but not others remains unclear, but it may relate to microhabitat.
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Affiliation(s)
- Matthew J Mason
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
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