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Neal J, Rodrigues S, Denton JSS, Bronson A. Skeletal labyrinth morphology of four species of living elasmobranchs. Anat Rec (Hoboken) 2024. [PMID: 39324429 DOI: 10.1002/ar.25582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 08/20/2024] [Accepted: 09/12/2024] [Indexed: 09/27/2024]
Abstract
Despite detailed descriptions of cranial anatomy in representatives of most major chondrichthyan groups, the inner ear has been described infrequently and most often from the soft tissue of the membranous labyrinth. However, skeletal labyrinth morphology has been linked with ecology in several groups of vertebrates, and shark skeletal labyrinths bear several specializations for detecting low frequency sounds. Without description of these structures across a broad sample of taxa, future exploration of the ecomorphology of ear shape is not possible. We used high-resolution CT scanning to generate three-dimensional models of the endocranial anatomy in four elasmobranchs: the Nurse Shark (Ginglymostoma cirratum), the Japanese Tope Shark (Hemitriakis japanica), the Horn Shark (Heterodontus francisci), and the Zebra Shark (Stegostoma tigrinum). Major differences are apparent between the skeletal labyrinths of these taxa, which might be ascribed to either phylogenetic history or lifestyle. In particular, the size of the skeletal labyrinth relative to the cranium dramatically differs among these chondrichthyans, as does the diameter and angle of the semicircular canals and the size of the canals relative to the vestibule. Based on the separation of the anterior and posterior semicircular canals, and the lack thereof in S. tigrinum, the degree of specialization for low frequency sound detection may also vary.
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Affiliation(s)
- Jordyn Neal
- Department of Biological Science, California State University Fullerton, Fullerton, California, USA
| | - Samantha Rodrigues
- Department of Biological Sciences, California State Polytechnic University Humboldt, Arcata, California, USA
| | - John S S Denton
- Florida Museum of Natural History, University of Florida, Gainesville, Florida, USA
- Department of Ichthyology, American Museum of Natural History, New York, New York, USA
| | - Allison Bronson
- Department of Biological Sciences, California State Polytechnic University Humboldt, Arcata, California, USA
- Division of Paleontology, American Museum of Natural History, New York, New York, USA
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Chang RK, Okihiro MS. A practical guide to necropsy of the elasmobranch chondrocranium and causes of mortality in wild and aquarium-housed California elasmobranchs. Front Vet Sci 2024; 11:1410332. [PMID: 38938914 PMCID: PMC11208305 DOI: 10.3389/fvets.2024.1410332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Accepted: 06/04/2024] [Indexed: 06/29/2024] Open
Abstract
Elasmobranchs are common, iconic species in public aquaria; their wild counterparts are key members of marine ecosystems. Post-mortem examination is a critical tool for disease monitoring of wild elasmobranchs and for management of those under human care. Careful necropsy of the head, with a focus on clinically relevant anatomy, can ensure that proper samples are collected, increasing the chance of presumptive diagnoses prior to slower diagnostic workup. Immediate feedback from a thorough head necropsy allows for faster management decisions, often identifying pathogens, routes of pathogen entry, and pathogenesis, which are current shortcomings in published literature. This article proposes a protocol for necropsy of the elasmobranch chondrocranium, emphasizing unique anatomy and careful dissection, evaluation, and sampling of the endolymphatic pores and ducts, inner ears, brain, and olfactory system as part of a complete, whole-body necropsy. Extensive use of cytology and microbiology, along with thorough sample collection for histology and molecular biology, has proven effective in identifying a wide range of pathogens and assisting with characterization of pathogenesis. The cause of mortality is often identified from a head necropsy alone, but does not replace a thorough whole-body dissection. This protocol for necropsy and ancillary diagnostic sample collection and evaluation was developed and implemented in the necropsy of 189 wild and aquarium-housed elasmobranchs across 18 species over 13 years (2011-2023) in California. Using this chondrocranial approach, meningoencephalitis was determined to be the primary cause of mortality in 70% (118/168) of stranded wild and aquarium-housed elasmobranchs. Etiology was largely bacterial or protozoal. Carnobacterium maltaromaticum bacterial meningoencephalitis occurred in salmon sharks (Lamna ditropis), shortfin mako sharks (Isurus oxyrinchus), common thresher sharks (Alopias vulpinus), and one Pacific electric ray (Tetronarce californica). Miamiensis avidus was the most common cause of protozoal meningoencephalitis and found almost exclusively in leopard sharks (Triakis semifasciata) and bat rays (Myliobatis californica) that stranded in San Francisco Bay. Bacterial pathogens were found to use an endolymphatic route of entry, while protozoa entered via the nares and olfactory lamellae. Trauma was the second most common cause of mortality and responsible for 14% (24/168) of wild shark strandings and deaths of aquarium-housed animals.
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Affiliation(s)
- Ri K. Chang
- Monterey Bay Aquarium, Monterey, CA, United States
| | - Mark S. Okihiro
- California Department of Fish and Wildlife, Vista, CA, United States
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Chapuis L, Yopak KE, Radford CA. From the morphospace to the soundscape: Exploring the diversity and functional morphology of the fish inner ear, with a focus on elasmobranchsa). THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 154:1526-1538. [PMID: 37695297 DOI: 10.1121/10.0020850] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 08/21/2023] [Indexed: 09/12/2023]
Abstract
Fishes, including elasmobranchs (sharks, rays, and skates), present an astonishing diversity in inner ear morphologies; however, the functional significance of these variations and how they confer auditory capacity is yet to be resolved. The relationship between inner ear structure and hearing performance is unclear, partly because most of the morphological and biomechanical mechanisms that underlie the hearing functions are complex and poorly known. Here, we present advanced opportunities to document discontinuities in the macroevolutionary trends of a complex biological form, like the inner ear, and test hypotheses regarding what factors may be driving morphological diversity. Three-dimensional (3D) bioimaging, geometric morphometrics, and finite element analysis are methods that can be combined to interrogate the structure-to-function links in elasmobranch fish inner ears. In addition, open-source 3D morphology datasets, advances in phylogenetic comparative methods, and methods for the analysis of highly multidimensional shape data have leveraged these opportunities. Questions that can be explored with this toolkit are identified, the different methods are justified, and remaining challenges are highlighted as avenues for future work.
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Affiliation(s)
- L Chapuis
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, United Kingdom
| | - K E Yopak
- Department of Biology and Marine Biology, Centre for Marine Science, University of North Carolina Wilmington, Wilmington, North Carolina 28403, USA
| | - C A Radford
- Leigh Marine Laboratory, Institute of Marine Science, University of Auckland, Leigh 0985, New Zealand
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Sauer DJ, Yopak KE, Radford CA. Ontogenetic development of inner ear hair cell organization in the New Zealand carpet shark Cephaloscyllium isabellum. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.1034891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
IntroductionThe inner ear hair cells of fishes can provide insight into the early evolution of vertebrate inner ear structure. Fishes represent some of the first vertebrates to evolve auditory capacity, and the same basic structure, the sensory hair cell, provides the fundament for auditory and vestibular function in jawed vertebrates. Despite holding critical basal position in the evolutionary tree of gnathostomes, relatively little is known about inner ear hair cells in elasmobranchs. Specifically, the extent of plasticity in hair cell organization throughout ontogeny among different sensory epithelia and the degree of variation between species is unknown.MethodsIn this study, we characterized the inner ear hair cells of the New Zealand carpet shark Cephaloscyllium isabellum throughout ontogeny by quantifying macular area, number of hair cells, hair cell density, and hair cell orientations in the inner ear maculae from a range of body sizes.ResultsSimilar to other elasmobranchs and bony fishes, macular area and the number of hair cells increased throughout ontogeny in the otolith organs. The orientations of hair cells within each maculae also was consistent with the limited data on other elasmobranchs. However, contrary to expectation, the macula neglecta did not increase in area or hair cell number throughout ontogeny, and hair cell density did not change with body size in any maculae.DiscussionThese findings suggest there may be variation between elasmobranch species in ontogenetic development of hair cell organization that may be related to hearing capabilities throughout life.
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Araújo R, David R, Benoit J, Lungmus JK, Stoessel A, Barrett PM, Maisano JA, Ekdale E, Orliac M, Luo ZX, Martinelli AG, Hoffman EA, Sidor CA, Martins RMS, Spoor F, Angielczyk KD. Inner ear biomechanics reveals a Late Triassic origin for mammalian endothermy. Nature 2022; 607:726-731. [PMID: 35859179 DOI: 10.1038/s41586-022-04963-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 06/10/2022] [Indexed: 01/12/2023]
Abstract
Endothermy underpins the ecological dominance of mammals and birds in diverse environmental settings1,2. However, it is unclear when this crucial feature emerged during mammalian evolutionary history, as most of the fossil evidence is ambiguous3-17. Here we show that this key evolutionary transition can be investigated using the morphology of the endolymph-filled semicircular ducts of the inner ear, which monitor head rotations and are essential for motor coordination, navigation and spatial awareness18-22. Increased body temperatures during the ectotherm-endotherm transition of mammal ancestors would decrease endolymph viscosity, negatively affecting semicircular duct biomechanics23,24, while simultaneously increasing behavioural activity25,26 probably required improved performance27. Morphological changes to the membranous ducts and enclosing bony canals would have been necessary to maintain optimal functionality during this transition. To track these morphofunctional changes in 56 extinct synapsid species, we developed the thermo-motility index, a proxy based on bony canal morphology. The results suggest that endothermy evolved abruptly during the Late Triassic period in Mammaliamorpha, correlated with a sharp increase in body temperature (5-9 °C) and an expansion of aerobic and anaerobic capacities. Contrary to previous suggestions3-14, all stem mammaliamorphs were most probably ectotherms. Endothermy, as a crucial physiological characteristic, joins other distinctive mammalian features that arose during this period of climatic instability28.
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Affiliation(s)
- Ricardo Araújo
- Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal. .,Institut des Sciences de L'Évolution de Montpellier, Université de Montpellier, Montpellier, France.
| | - Romain David
- Natural History Museum, London, UK. .,Max Plank Institute for Evolutionary Anthropology, Leipzig, Germany.
| | - Julien Benoit
- Evolutionary Studies Institute, University of Witwatersrand, Johannesburg, South Africa
| | - Jacqueline K Lungmus
- Department of Paleobiology, National Museum of Natural History, Washington DC, USA
| | - Alexander Stoessel
- Max Plank Institute for Evolutionary Anthropology, Leipzig, Germany.,Institute of Zoology and Evolutionary Research, Friedrich Schiller University Jena, Jena, Germany
| | | | - Jessica A Maisano
- Jackson School of Geosciences, University of Texas at Austin, Austin, TX, USA
| | - Eric Ekdale
- Department of Biology, San Diego State University, San Diego, CA, USA.,Department of Paleontology, San Diego Natural History Museum, San Diego, CA, USA
| | - Maëva Orliac
- Institut des Sciences de L'Évolution de Montpellier, Université de Montpellier, Montpellier, France
| | - Zhe-Xi Luo
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, USA
| | - Agustín G Martinelli
- Museo Argentino de Ciencias Naturales 'Bernardino Rivadavia', Buenos Aires, Argentina
| | - Eva A Hoffman
- Division of Paleontology, American Museum of Natural History, New York, NY, USA
| | - Christian A Sidor
- Burke Museum and Department of Biology, University of Washington, Seattle, WA, USA
| | - Rui M S Martins
- Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - Fred Spoor
- Natural History Museum, London, UK.,Max Plank Institute for Evolutionary Anthropology, Leipzig, Germany.,Department of Anthropology, University College London, London, UK
| | - Kenneth D Angielczyk
- Neguanee Integrative Research Center, Field Museum of Natural History, Chicago, IL, USA.
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de Vincenzi G, Micarelli P, Viola S, Buffa G, Sciacca V, Maccarrone V, Corrias V, Reinero FR, Giacoma C, Filiciotto F. Biological Sound vs. Anthropogenic Noise: Assessment of Behavioural Changes in Scyliorhinus canicula Exposed to Boats Noise. Animals (Basel) 2021; 11:ani11010174. [PMID: 33451005 PMCID: PMC7828510 DOI: 10.3390/ani11010174] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 11/16/2022] Open
Abstract
Despite the growing interest in human-made noise effects on marine wildlife, few studies have investigated the potential role of underwater noise on elasmobranch species. In this study, twelve specimens of small-spotted catshark (Scyliorhinus canicula) were exposed to biological and anthropogenic sounds in order to assess their behavioural changes in response to prey acoustic stimuli and to different amplitude levels of shipping noise. The sharks, individually held in aquariums, were exposed to four experimental acoustic conditions characterized by different spectral (Hz) components and amplitude (dB re 1 µPa) levels. The swimming behaviour and spatial distribution of sharks were observed. The results highlighted significant differences in swimming time and in the spatial use of the aquarium among the experimental conditions. When the amplitude levels of biological sources were higher than those of anthropogenic sources, the sharks' swimming behaviour was concentrated in the bottom sections of the aquarium; when the amplitude levels of anthropogenic sources were higher than biological ones, the specimens increased the time spent swimming. Moreover, their spatial distribution highlighted a tendency to occupy the least noisy sections of the aquarium. In conclusion, this study highlighted that anthropogenic noise is able to affect behaviour of catshark specimens and the impact depends on acoustic amplitude levels.
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Affiliation(s)
- Giovanni de Vincenzi
- Consiglio Nazionale delle Ricerche—Istituto per le Risorse Biologiche e le Biotecnologie Marine, Messina (IRBIM-CNR)—Spianata S. Raineri, 86, 98122 Messina (ME), Italy; (V.S.); (F.F.)
- Dipartimento di Scienze della Vita e Biologia dei Sistemi, Università degli Studi di Torino, 10123 Torino (TO), Italy;
- eConscience—Art of Soundscape, No-Profit Organization, via Provinciale 610, 90046 Monreale (PA), Italy
- Correspondence: ; Tel.: +39-339-328-5855
| | - Primo Micarelli
- Centro Studi Squali—Istituto Scientifico presso Aquarium Mondo Marino—Loc. Valpiana, 58024 Massa Marittima (GR), Italy;
| | - Salvatore Viola
- Istituto Nazionale di Fisica Nucleare (INFN)—Laboratori Nazionali del Sud, 95100 Catania (CT), Italy;
| | - Gaspare Buffa
- Consiglio Nazionale delle Ricerche—Istituto per lo studio degli impatti Antropici e Sostenibilità in ambiente marino, Capo Granitola (IAS-CNR)—Via del Mare, 3, 91021 T.G. Campobello di Mazara (TP), Italy; (G.B.); (V.M.)
| | - Virginia Sciacca
- Consiglio Nazionale delle Ricerche—Istituto per le Risorse Biologiche e le Biotecnologie Marine, Messina (IRBIM-CNR)—Spianata S. Raineri, 86, 98122 Messina (ME), Italy; (V.S.); (F.F.)
- eConscience—Art of Soundscape, No-Profit Organization, via Provinciale 610, 90046 Monreale (PA), Italy
| | - Vincenzo Maccarrone
- Consiglio Nazionale delle Ricerche—Istituto per lo studio degli impatti Antropici e Sostenibilità in ambiente marino, Capo Granitola (IAS-CNR)—Via del Mare, 3, 91021 T.G. Campobello di Mazara (TP), Italy; (G.B.); (V.M.)
| | - Valentina Corrias
- Dipartimento di Scienze Marine, Ecologia e Biologia—Università degli Studi della Tuscia—Largo delle Università, 01100 Viterbo (VT), Italy;
| | | | - Cristina Giacoma
- Dipartimento di Scienze della Vita e Biologia dei Sistemi, Università degli Studi di Torino, 10123 Torino (TO), Italy;
| | - Francesco Filiciotto
- Consiglio Nazionale delle Ricerche—Istituto per le Risorse Biologiche e le Biotecnologie Marine, Messina (IRBIM-CNR)—Spianata S. Raineri, 86, 98122 Messina (ME), Italy; (V.S.); (F.F.)
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Schnetz L, Pfaff C, Libowitzky E, Johanson Z, Stepanek R, Kriwet J. Morphology and evolutionary significance of phosphatic otoliths within the inner ears of cartilaginous fishes (Chondrichthyes). BMC Evol Biol 2019; 19:238. [PMID: 31888446 PMCID: PMC6937729 DOI: 10.1186/s12862-019-1568-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 12/17/2019] [Indexed: 12/02/2022] Open
Abstract
Background Chondrichthyans represent a monophyletic group of crown group gnathostomes and are central to our understanding of vertebrate evolution. Like all vertebrates, cartilaginous fishes evolved concretions of material within their inner ears to aid with equilibrium and balance detection. Up to now, these materials have been identified as calcium carbonate-bearing otoconia, which are small bio-crystals consisting of an inorganic mineral and a protein, or otoconial masses (aggregations of otoconia bound by an organic matrix), being significantly different in morphology compared to the singular, polycrystalline otolith structures of bony fishes, which are solidified bio-crystals forming stony masses. Reinvestigation of the morphological and chemical properties of these chondrichthyan otoconia revises our understanding of otolith composition and has implications on the evolution of these characters in both the gnathostome crown group, and cartilaginous fishes in particular. Results Dissections of Amblyraja radiata, Potamotrygon leopoldi, and Scyliorhinus canicula revealed three pairs of singular polycrystalline otolith structures with a well-defined morphology within their inner ears, as observed in bony fishes. IR spectroscopy identified the material to be composed of carbonate/collagen-bearing apatite in all taxa. These findings contradict previous hypotheses suggesting these otoconial structures were composed of calcium carbonate in chondrichthyans. A phylogenetic mapping using 37 chondrichthyan taxa further showed that the acquisition of phosphatic otolith structures might be widespread within cartilaginous fishes. Conclusions Differences in the size and shape of otoliths between taxa indicate a taxonomic signal within elasmobranchs. Otoliths made of carbonate/collagen-bearing apatite are reported for the first time in chondrichthyans. The intrinsic pathways to form singular, polycrystalline otoliths may represent the plesiomorphic condition for vertebrates but needs further testing. Likewise, the phosphatic composition of otoliths in early vertebrates such as cyclostomes and elasmobranchs is probably closely related to the lack of bony tissue in these groups, supporting a close relationship between skeletal tissue mineralization patterns and chemical otolith composition, underlined by physiological constraints.
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Affiliation(s)
- Lisa Schnetz
- University of Birmingham, School of Geography, Earth and Environmental Sciences, Birmingham, B15 2TT, UK.
| | - Cathrin Pfaff
- University of Vienna, Faculty of Earth Sciences, Geography and Astronomy, Institute of Palaeontology, Geozentrum, Althanstraße 14, 1090, Vienna, Austria
| | - Eugen Libowitzky
- University of Vienna, Faculty of Earth Sciences, Geography and Astronomy, Institute of Mineralogy and Crystallography, Geozentrum, Althanstraße 14, 1090, Vienna, Austria
| | - Zerina Johanson
- Department of Earth Sciences, Natural History Museum, London, SW7 5BD, UK
| | - Rica Stepanek
- University of Vienna, Faculty of Earth Sciences, Geography and Astronomy, Institute of Palaeontology, Geozentrum, Althanstraße 14, 1090, Vienna, Austria
| | - Jürgen Kriwet
- University of Vienna, Faculty of Earth Sciences, Geography and Astronomy, Institute of Palaeontology, Geozentrum, Althanstraße 14, 1090, Vienna, Austria.
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Comparative Brain Morphology of the Greenland and Pacific Sleeper Sharks and its Functional Implications. Sci Rep 2019; 9:10022. [PMID: 31296954 PMCID: PMC6624305 DOI: 10.1038/s41598-019-46225-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 06/17/2019] [Indexed: 11/23/2022] Open
Abstract
In cartilaginous fishes, variability in the size of the brain and its major regions is often associated with primary habitat and/or specific behavior patterns, which may allow for predictions on the relative importance of different sensory modalities. The Greenland (Somniosus microcephalus) and Pacific sleeper (S. pacificus) sharks are the only non-lamnid shark species found in the Arctic and are among the longest living vertebrates ever described. Despite a presumed visual impairment caused by the regular presence of parasitic ocular lesions, coupled with the fact that locomotory muscle power is often depressed at cold temperatures, these sharks remain capable of capturing active prey, including pinnipeds. Using magnetic resonance imaging (MRI), brain organization of S. microcephalus and S. pacificus was assessed in the context of up to 117 other cartilaginous fish species, using phylogenetic comparative techniques. Notably, the region of the brain responsible for motor control (cerebellum) is small and lacking foliation, a characteristic not yet described for any other large-bodied (>3 m) shark. Further, the development of the optic tectum is relatively reduced, while olfactory brain regions are among the largest of any shark species described to date, suggestive of an olfactory-mediated rather than a visually-mediated lifestyle.
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Iversen MM, Rabbitt RD. Wave Mechanics of the Vestibular Semicircular Canals. Biophys J 2017; 113:1133-1149. [PMID: 28877495 DOI: 10.1016/j.bpj.2017.08.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 07/14/2017] [Accepted: 08/02/2017] [Indexed: 01/08/2023] Open
Abstract
The semicircular canals are biomechanical sensors responsible for detecting and encoding angular motion of the head in 3D space. Canal afferent neurons provide essential inputs to neural circuits responsible for representation of self-position/orientation in space, and to compensatory circuits including the vestibulo-ocular and vestibulo-collic reflex arcs. In this work we derive, to our knowledge, a new 1D mathematical model quantifying canal biomechanics based on the morphology, dynamics of the inner ear fluids, and membranous labyrinth deformability. The model takes the form of a dispersive wave equation and predicts canal responses to angular motion, sound, and mechanical stimulation. Numerical simulations were carried out for the morphology of the human lateral canal using known physical properties of the endolymph and perilymph in three diverse conditions: surgical plugging, rotation, and mechanical indentation. The model reproduces frequency-dependent attenuation and phase shift in cases of canal plugging. During rotation, duct deformability extends the frequency bandwidth and enhances the high frequency gain. Mechanical indentation of the membranous duct at high frequencies evokes traveling waves that move away from the location of indentation and at low frequencies compels endolymph displacement along the canal. These results demonstrate the importance of the conformal perilymph-filled bony labyrinth to pressure changes and to high frequency sound and vibration.
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Affiliation(s)
- Marta M Iversen
- Department of Bioengineering, University of Utah, Salt Lake City, Utah.
| | - Richard D Rabbitt
- Department of Bioengineering, University of Utah, Salt Lake City, Utah; Department of Otolaryngology, University of Utah, Salt Lake City, Utah; Marine Biological Laboratory, Woods Hole, Massachusetts
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10
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Ladich F, Schulz-Mirbach T. Diversity in Fish Auditory Systems: One of the Riddles of Sensory Biology. Front Ecol Evol 2016. [DOI: 10.3389/fevo.2016.00028] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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11
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Schulz-Mirbach T, Heß M, Metscher BD. Sensory epithelia of the fish inner ear in 3D: studied with high-resolution contrast enhanced microCT. Front Zool 2013; 10:63. [PMID: 24160754 PMCID: PMC4177137 DOI: 10.1186/1742-9994-10-63] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 10/21/2013] [Indexed: 11/10/2022] Open
Abstract
Introduction While a number of studies have illustrated and analyzed 3D models of inner ears in higher vertebrates, inner ears in fishes have rarely been investigated in 3D, especially with regard to the sensory epithelia of the end organs, the maculae. It has been suggested that the 3D curvature of these maculae may also play an important role in hearing abilities in fishes. We therefore set out to develop a fast and reliable approach for detailed 3D visualization of whole inner ears as well as maculae. Results High-resolution microCT imaging of black mollies Poecilia sp. (Poeciliidae, Teleostei) and Steatocranus tinanti (Cichlidae, Teleostei) stained with phosphotungstic acid (PTA) resulted in good tissue contrast, enabling us to perform a reliable 3D reconstruction of all three sensory maculae of the inner ears. Comparison with maculae that have been 3D reconstructed based on histological serial sections and phalloidin-stained maculae showed high congruence in overall shape of the maculae studied here. Conclusions PTA staining and subsequent high-resolution contrast enhanced microCT imaging is a powerful method to obtain 3D models of fish inner ears and maculae in a fast and more reliable manner. Future studies investigating functional morphology, phylogenetic potential of inner ear features, or evolution of hearing and inner ear specialization in fishes may benefit from the use of 3D models of inner ears and maculae.
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Affiliation(s)
- Tanja Schulz-Mirbach
- Department of Biology II, Zoology, Ludwig-Maximilians-University, Martinsried, Germany.
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