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De Vreese S, Orekhova K, Morell M, Gerussi T, Graïc JM. Neuroanatomy of the Cetacean Sensory Systems. Animals (Basel) 2023; 14:66. [PMID: 38200796 PMCID: PMC10778493 DOI: 10.3390/ani14010066] [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: 09/28/2023] [Revised: 11/10/2023] [Accepted: 12/21/2023] [Indexed: 01/12/2024] Open
Abstract
Cetaceans have undergone profound sensory adaptations in response to their aquatic environment during evolution. These adaptations are characterised by anatomo-functional changes in the classically defined sensory systems, shaping their neuroanatomy accordingly. This review offers a concise and up-to-date overview of our current understanding of the neuroanatomy associated with cetacean sensory systems. It encompasses a wide spectrum, ranging from the peripheral sensory cells responsible for detecting environmental cues, to the intricate structures within the central nervous system that process and interpret sensory information. Despite considerable progress in this field, numerous knowledge gaps persist, impeding a comprehensive and integrated understanding of their sensory adaptations, and through them, of their sensory perspective. By synthesising recent advances in neuroanatomical research, this review aims to shed light on the intricate sensory alterations that differentiate cetaceans from other mammals and allow them to thrive in the marine environment. Furthermore, it highlights pertinent knowledge gaps and invites future investigations to deepen our understanding of the complex processes in cetacean sensory ecology and anatomy, physiology and pathology in the scope of conservation biology.
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Affiliation(s)
- Steffen De Vreese
- Laboratory of Applied Bioacoustics (LAB), Universitat Politècnica de Catalunya-BarcelonaTech (UPC), 08800 Vilanova i la Geltrú, Spain
| | - Ksenia Orekhova
- Department of Comparative Biomedicine and Food Science (BCA), University of Padova, 35020 Legnaro, Italy; (K.O.); (T.G.); (J.-M.G.)
| | - Maria Morell
- Institute for Terrestrial and Aquatic Wildlife Research (ITAW), University of Veterinary Medicine Hannover, Foundation, 25761 Büsum, Germany;
| | - Tommaso Gerussi
- Department of Comparative Biomedicine and Food Science (BCA), University of Padova, 35020 Legnaro, Italy; (K.O.); (T.G.); (J.-M.G.)
| | - Jean-Marie Graïc
- Department of Comparative Biomedicine and Food Science (BCA), University of Padova, 35020 Legnaro, Italy; (K.O.); (T.G.); (J.-M.G.)
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2
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Orekhova K, Selmanovic E, De Gasperi R, Gama Sosa MA, Wicinski B, Maloney B, Seifert A, Alipour A, Balchandani P, Gerussi T, Graïc JM, Centelleghe C, Di Guardo G, Mazzariol S, Hof PR. Multimodal Assessment of Bottlenose Dolphin Auditory Nuclei Using 7-Tesla MRI, Immunohistochemistry and Stereology. Vet Sci 2022; 9:vetsci9120692. [PMID: 36548853 PMCID: PMC9781543 DOI: 10.3390/vetsci9120692] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/05/2022] [Accepted: 12/09/2022] [Indexed: 12/14/2022] Open
Abstract
The importance of assessing neurochemical processes in the cetacean brain as a tool for monitoring their cognitive health and to indirectly model human neurodegenerative conditions is increasingly evident, although available data are largely semiquantitative. High-resolution MRI for post-mortem brains and stereology allow for quantitative assessments of the cetacean brain. In this study, we scanned two brains of bottlenose dolphins in a 7-Tesla (7T) MR scanner and assessed the connectivity of the inferior colliculi and ventral cochlear nuclei using diffusion tensor imaging (DTI). Serial thick sections were investigated stereologically in one of the dolphins to generate rigorous quantitative estimates of identifiable cell types according to their morphology and expression of molecular markers, yielding reliable cell counts with most coefficients of error <10%. Fibronectin immunoreactivity in the dolphin resembled the pattern in a human chronic traumatic encephalopathy brain, suggesting that neurochemical compensation for insults such as hypoxia may constitute a noxious response in humans, while being physiological in dolphins. These data contribute to a growing body of knowledge on the morphological and neurochemical properties of the dolphin brain and highlight a stereological and neuroimaging workflow that may enable quantitative and translational assessment of pathological processes in the dolphin brain in the future.
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Affiliation(s)
- Ksenia Orekhova
- Department of Comparative Biomedicine and Food Science, University of Padova AGRIPOLIS, Viale dell’Università 16, 35020 Legnaro, Italy
- Correspondence:
| | - Enna Selmanovic
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Rita De Gasperi
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, Bronx, New York, NY 10468, USA
| | - Miguel A. Gama Sosa
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- General Medical Research Service, James J. Peters Department of Veterans Affairs Medical Center, Bronx, New York, NY 10468, USA
| | - Bridget Wicinski
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Brigid Maloney
- Laboratory of Neurogenetics of Vocal Learning, Rockefeller University, New York, NY 10065, USA
| | - Alan Seifert
- Department of Radiology, BioMedical Engineering and Imaging Institute (BMEII), Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Akbar Alipour
- Department of Radiology, BioMedical Engineering and Imaging Institute (BMEII), Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Priti Balchandani
- Department of Radiology, BioMedical Engineering and Imaging Institute (BMEII), Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Tommaso Gerussi
- Department of Comparative Biomedicine and Food Science, University of Padova AGRIPOLIS, Viale dell’Università 16, 35020 Legnaro, Italy
| | - Jean-Marie Graïc
- Department of Comparative Biomedicine and Food Science, University of Padova AGRIPOLIS, Viale dell’Università 16, 35020 Legnaro, Italy
| | - Cinzia Centelleghe
- Department of Comparative Biomedicine and Food Science, University of Padova AGRIPOLIS, Viale dell’Università 16, 35020 Legnaro, Italy
| | - Giovanni Di Guardo
- Faculty of Veterinary Medicine, University of Teramo, 64100 Teramo, Italy
| | - Sandro Mazzariol
- Department of Comparative Biomedicine and Food Science, University of Padova AGRIPOLIS, Viale dell’Università 16, 35020 Legnaro, Italy
| | - Patrick R. Hof
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
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Orekhova K, Centelleghe C, Di Guardo G, Graïc JM, Cozzi B, Trez D, Verin R, Mazzariol S. Systematic validation and assessment of immunohistochemical markers for central nervous system pathology in cetaceans, with emphasis on auditory pathways. PLoS One 2022; 17:e0269090. [PMID: 35648776 PMCID: PMC9159615 DOI: 10.1371/journal.pone.0269090] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 05/14/2022] [Indexed: 12/23/2022] Open
Abstract
Cetacean neuropathology is a developing field that aims to assess structural and neurochemical changes involved in neurodegenerative, infectious and traumatic processes, however markers used previously in cetaceans have rarely undergone systematic validation. This is a prerequisite to investigating the potential damage inflicted on the cetacean auditory system by anthropogenic noise. In order to assess apoptotic, neuroinflammatory and structural aberrations on a protein level, the baseline expression of biomarker proteins has to be characterized, implementing a systematic approach to validate the use of anti-human and anti-laboratory animal antibodies in dolphin tissues. This approach was taken to study 12 different antibodies associated with hypoxic-ischemic, inflammatory, plastic and excitatory-inhibitory changes implicated in acoustic trauma within the ventral cochlear nuclei and inferior colliculi of 20 bottlenose dolphins (Tursiops truncatus). Out of the 12 tested antibodies, pro-apoptotic protease factor 1 (Apaf-1), diacylglycerolkinase-ζ (DGK-ζ), B-cell lymphoma related protein 2 (Bcl-2), amyloid-β peptide (Aβ) and neurofilament 200 (NF200) were validated employing Western blot analyses and immunohistochemistry (IHC). The results of the validation process indicate specific patterns of immunoreactivity that are comparable to those reported in other mammals, thus suggesting a key panel of IHC biomarkers of pathological processes in the cetacean brain. As a consequence, the antibodies tested in this study may constitute a valid tool for supporting existing diagnostic methods in neurological diseases. The approach of systematic validation of IHC markers in cetaceans is proposed as a standard practice, in order for results to be transparent, reliable and comparable.
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Affiliation(s)
- Ksenia Orekhova
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Padova, Italy
- * E-mail:
| | - Cinzia Centelleghe
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Padova, Italy
| | - Giovanni Di Guardo
- Faculty of Veterinary Medicine, University of Teramo, Località Piano d’Accio, Teramo, Italy
| | - Jean-Marie Graïc
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Padova, Italy
| | - Bruno Cozzi
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Padova, Italy
| | - Davide Trez
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Padova, Italy
| | - Ranieri Verin
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Padova, Italy
| | - Sandro Mazzariol
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Padova, Italy
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Siebert U, Stürznickel J, Schaffeld T, Oheim R, Rolvien T, Prenger-Berninghoff E, Wohlsein P, Lakemeyer J, Rohner S, Aroha Schick L, Gross S, Nachtsheim D, Ewers C, Becher P, Amling M, Morell M. Blast injury on harbour porpoises (Phocoena phocoena) from the Baltic Sea after explosions of deposits of World War II ammunition. ENVIRONMENT INTERNATIONAL 2022; 159:107014. [PMID: 34883460 DOI: 10.1016/j.envint.2021.107014] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 11/26/2021] [Accepted: 11/29/2021] [Indexed: 05/21/2023]
Abstract
Harbour porpoises are under pressure from increasing human activities. This includes the detonation of ammunition that was dumped in large amounts into the sea during and after World War II. In this context, forty-two British ground mines from World War II were cleared by means of blasting in the period from 28 to 31 August 2019 by a NATO unit in the German Exclusive Economic Zone within the marine protected area of Fehmarn Belt in the Baltic Sea, Germany. Between September and November 2019, 24 harbour porpoises were found dead in the period after those clearing events along the coastline of the federal state of Schleswig-Holstein and were investigated for direct and indirect effects of blast injury. Health evaluations were conducted including examinations of the brain, the air-filled (lungs and gastrointestinal tract) and acoustic organs (melon, acoustic fat in the lower jaw, ears and their surrounding tissues). The bone structure of the tympano-periotic complexes was examined using high-resolution peripheral quantitative computed tomography (HR-pQCT). In 8/24 harbour porpoises, microfractures of the malleus, dislocation of middle ear bones, bleeding, and haemorrhages in the melon, lower jaw and peribullar acoustic fat were detected, suggesting blast injury. In addition, one bycaught animal and another porpoise with signs of blunt force trauma also showed evidence of blast injury. The cause of death of the other 14 animals varied and remained unclear in two individuals. Due to the vulnerability and the conservation status of harbour porpoise populations in the Baltic Sea, noise mitigation measures must be improved to prevent any risk of injury. The data presented here highlight the importance of systematic investigations into the acute and chronic effects of blast and acoustic trauma in harbour porpoises, improving the understanding of underwater noise effects and herewith develop effective measures to protect the population level.
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Affiliation(s)
- Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstr. 6, 25761 Büsum, Germany.
| | - Julian Stürznickel
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 59, 22529 Hamburg, Germany; Department of Trauma and Orthopaedic Surgery, Division of Orthopaedics, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Tobias Schaffeld
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstr. 6, 25761 Büsum, Germany
| | - Ralf Oheim
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 59, 22529 Hamburg, Germany
| | - Tim Rolvien
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 59, 22529 Hamburg, Germany; Department of Trauma and Orthopaedic Surgery, Division of Orthopaedics, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Ellen Prenger-Berninghoff
- Institute for Hygiene and Infectious Diseases of Animals, Justus Liebig University Giessen, Frankfurter Str. 85-87, 35392 Giessen, Germany
| | - Peter Wohlsein
- Department of Pathology, University of Veterinary Medicine Hannover, Foundation, Bünteweg 17, 30559 Hannover, Germany
| | - Jan Lakemeyer
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstr. 6, 25761 Büsum, Germany
| | - Simon Rohner
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstr. 6, 25761 Büsum, Germany
| | - Luca Aroha Schick
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstr. 6, 25761 Büsum, Germany
| | - Stephanie Gross
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstr. 6, 25761 Büsum, Germany
| | - Dominik Nachtsheim
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstr. 6, 25761 Büsum, Germany
| | - Christa Ewers
- Institute for Hygiene and Infectious Diseases of Animals, Justus Liebig University Giessen, Frankfurter Str. 85-87, 35392 Giessen, Germany
| | - Paul Becher
- Institute of Virology, University of Veterinary Medicine Hannover, Foundation, Bünteweg 17, 30559 Hannover, Germany
| | - Michael Amling
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 59, 22529 Hamburg, Germany
| | - Maria Morell
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstr. 6, 25761 Büsum, Germany
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Morell M, Rojas L, Haulena M, Busse B, Siebert U, Shadwick RE, Raverty SA. Selective Inner Hair Cell Loss in a Neonate Harbor Seal (Phoca vitulina). Animals (Basel) 2022; 12:ani12020180. [PMID: 35049802 PMCID: PMC8772928 DOI: 10.3390/ani12020180] [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: 12/22/2021] [Revised: 01/06/2022] [Accepted: 01/07/2022] [Indexed: 01/19/2023] Open
Abstract
Simple Summary Congenital hearing loss (i.e., hearing impairment present at birth) is recognized in humans and other terrestrial species, but there is a lack of information on congenital malformations and associated hearing loss in pinnipeds (seals, sea lions, and walruses). Baseline knowledge on marine mammal inner ear malformations is essential to differentiate between congenital and acquired abnormalities, which may be caused by infectious agents, age, or anthropogenic interactions, such as noise exposure. Analysis of the cochlea of a neonate harbor seal (Phoca vitulina) revealed bilateral loss of inner hair cells (sensory cells responsible for transducing the auditory signal) while the outer hair cells (sensory cells responsible for sound amplification and frequency selectivity and sensitivity) were intact. The selective inner hair cell loss (up to 84.6% of loss) was more severe in the basal turn, where the high frequencies are encoded. Potential causes and consequences are discussed. This is the first report of a case of selective inner hair cell loss in a marine mammal neonate, likely congenital. Abstract Congenital hearing loss is recognized in humans and other terrestrial species. However, there is a lack of information on its prevalence or pathophysiology in pinnipeds. It is important to have baseline knowledge on marine mammal malformations in the inner ear, to differentiate between congenital and acquired abnormalities, which may be caused by infectious pathogens, age, or anthropogenic interactions, such as noise exposure. Ultrastructural evaluation of the cochlea of a neonate harbor seal (Phoca vitulina) by scanning electron microscopy revealed bilateral loss of inner hair cells with intact outer hair cells. The selective inner hair cell loss was more severe in the basal turn, where high-frequency sounds are encoded. The loss of inner hair cells started around 40% away from the apex or tip of the spiral, reaching a maximum loss of 84.6% of hair cells at 80–85% of the length from the apex. Potential etiologies and consequences are discussed. This is believed to be the first case report of selective inner hair cell loss in a marine mammal neonate, likely congenital.
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Affiliation(s)
- Maria Morell
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, 25761 Büsum, Germany;
- Zoology Department, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada;
- Correspondence:
| | - Laura Rojas
- Faculty of Veterinary Medicine and Zootechnics, National Autonomous University of Mexico, Av. Universidad 3000, Delegación Coyoacán, Mexico City 04510, Mexico;
| | - Martin Haulena
- Vancouver Aquarium Marine Science Center, Vancouver, BC V6G 3E2, Canada;
| | - Björn Busse
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 22529 Hamburg, Germany;
| | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, 25761 Büsum, Germany;
| | - Robert E. Shadwick
- Zoology Department, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada;
| | - Stephen A. Raverty
- Zoology Department, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada;
- Animal Health Center, Ministry of Agriculture, Abbotsford, BC V3G 2M3, Canada;
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Morell M, IJsseldijk LL, Berends AJ, Gröne A, Siebert U, Raverty SA, Shadwick RE, Kik MJL. Evidence of Hearing Loss and Unrelated Toxoplasmosis in a Free-Ranging Harbour Porpoise ( Phocoena phocoena). Animals (Basel) 2021; 11:ani11113058. [PMID: 34827790 PMCID: PMC8614470 DOI: 10.3390/ani11113058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 10/20/2021] [Indexed: 01/09/2023] Open
Abstract
Simple Summary Evidence of hearing impairment was identified in a female harbour porpoise (Phocoena phocoena) on the basis of inner ear analysis. The animal live stranded on the Dutch coast at Domburg in 2016 and died a few hours later. Ultrastructural examination of the inner ear revealed evidence of sensory cell loss, which is compatible with noise exposure. In addition, histopathology also revealed multifocal necrotising protozoal encephalitis. A diagnosis of toxoplasmosis was confirmed by positive staining of tissue with anti-Toxoplasma gondii antibodies; however, T. gondii tachyzoites were not observed histologically in any of the examined tissues. This is the first case of presumptive noise-induced hearing loss and demonstration of T. gondii cysts in the brain of a free-ranging harbour porpoise from the North Sea. Abstract Evidence of hearing impairment was identified in a harbour porpoise (Phocoena phocoena) on the basis of scanning electron microscopy. In addition, based on histopathology and immunohistochemistry, there were signs of unrelated cerebral toxoplasmosis. The six-year old individual live stranded on the Dutch coast at Domburg in 2016 and died a few hours later. The most significant gross lesion was multifocal necrosis and haemorrhage of the cerebrum. Histopathology of the brain revealed extensive necrosis and haemorrhage in the cerebrum with multifocal accumulations of degenerated neutrophils, lymphocytes and macrophages, and perivascular lymphocytic cuffing. The diagnosis of cerebral toxoplasmosis was confirmed by positive staining of protozoa with anti-Toxoplasma gondii antibodies. Tachyzoites were not observed histologically in any of the examined tissues. Ultrastructural evaluation of the inner ear revealed evidence of scattered loss of outer hair cells in a 290 µm long segment of the apical turn of the cochlea, and in a focal region of ~ 1.5 mm from the apex of the cochlea, which was compatible with noise-induced hearing loss. This is the first case of concurrent presumptive noise-induced hearing loss and toxoplasmosis in a free-ranging harbour porpoise from the North Sea.
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Affiliation(s)
- Maria Morell
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, 25761 Büsum, Germany;
- Zoology Department, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (S.A.R.); (R.E.S.)
- Correspondence: (M.M.); (L.L.I.)
| | - Lonneke L. IJsseldijk
- Department of Biomolecular Health Sciences, Division of Pathology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands; (A.J.B.); (A.G.); (M.J.L.K.)
- Correspondence: (M.M.); (L.L.I.)
| | - Alinda J. Berends
- Department of Biomolecular Health Sciences, Division of Pathology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands; (A.J.B.); (A.G.); (M.J.L.K.)
| | - Andrea Gröne
- Department of Biomolecular Health Sciences, Division of Pathology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands; (A.J.B.); (A.G.); (M.J.L.K.)
| | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, 25761 Büsum, Germany;
| | - Stephen A. Raverty
- Zoology Department, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (S.A.R.); (R.E.S.)
- Animal Health Center, Ministry of Agriculture, Abbotsford, BC V3G 2M3, Canada
| | - Robert E. Shadwick
- Zoology Department, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (S.A.R.); (R.E.S.)
| | - Marja J. L. Kik
- Department of Biomolecular Health Sciences, Division of Pathology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands; (A.J.B.); (A.G.); (M.J.L.K.)
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Racicot R. Evolution of whale sensory ecology: Frontiers in nondestructive anatomical investigations. Anat Rec (Hoboken) 2021; 305:736-752. [PMID: 34546007 DOI: 10.1002/ar.24761] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 06/09/2021] [Accepted: 07/14/2021] [Indexed: 12/18/2022]
Abstract
Studies surrounding the evolution of sensory system anatomy in cetaceans over the last ~100 years have shed light on aspects of the early evolution of hearing sensitivities, the small relative size of the organ of balance (semicircular canals and vestibule), brain (endocast) shape and relative volume changes, and ontogenetic development of sensory-related structures. Here, I review advances in our knowledge of sensory system anatomy as informed by the use of nondestructive imaging techniques, with a focus on applied methods in computed tomography (CT and μCT), and identify the key questions that remain to be addressed. Of these, the most important are: Is lower frequency hearing sensitivity the ancestral condition for whales? Did echolocation evolve more than once in odontocetes; and if so, when and why? How has the structure of the cetacean brain changed, through the evolution of whales, and does this correspond to changes in hearing sensitivities? Finally, what are the general pathways of ontogenetic development of sensory systems in odontocetes and mysticetes? Answering these questions will allow us to understand important macroevolutionary patterns in a fully aquatic mammalian group and provides baseline data on species for which we have limited biological information because of logistical limitations.
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Affiliation(s)
- Rachel Racicot
- Abteilung Messelforschung und Mammalogie, Senckenberg Forschungsinstitut und Naturkundemuseum, Frankfurt am Main, Germany.,Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
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8
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Morell M, IJsseldijk LL, Piscitelli-Doshkov M, Ostertag S, Estrade V, Haulena M, Doshkov P, Bourien J, Raverty SA, Siebert U, Puel JL, Shadwick RE. Cochlear apical morphology in toothed whales: Using the pairing hair cell-Deiters' cell as a marker to detect lesions. Anat Rec (Hoboken) 2021; 305:622-642. [PMID: 34096183 DOI: 10.1002/ar.24680] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 03/17/2021] [Accepted: 04/15/2021] [Indexed: 11/06/2022]
Abstract
The apex or apical region of the cochlear spiral within the inner ear encodes for low-frequency sounds. The disposition of sensory hair cells on the organ of Corti is largely variable in the apical region of mammals, and it does not necessarily follow the typical three-row pattern of outer hair cells (OHCs). As most underwater noise sources contain low-frequency components, we expect to find most lesions in the apical region of the cochlea of toothed whales, in cases of permanent noise-induced hearing loss. To further understand how man-made noise might affect cetacean hearing, there is a need to describe normal morphological features of the apex and document interspecific anatomic variations in cetaceans. However, distinguishing between apical normal variability and hair cell death is challenging. We describe anatomical features of the organ of Corti of the apex in 23 ears from five species of toothed whales (harbor porpoise Phocoena phocoena, spinner dolphin Stenella longirostris, pantropical spotted dolphin Stenella attenuata, pygmy sperm whale Kogia breviceps, and beluga whale Delphinapterus leucas) by scanning electron microscopy and immunofluorescence. Our results showed an initial region where the lowest frequencies are encoded with two or three rows of OHCs, followed by the typical configuration of three OHC rows and three rows of supporting Deiters' cells. Whenever two rows of OHCs were detected, there were usually only two corresponding rows of supporting Deiters' cells, suggesting that the number of rows of Deiters' cells is a good indicator to distinguish between normal and pathological features.
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Affiliation(s)
- Maria Morell
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Büsum, Germany.,Institute for Neurosciences of Montpellier, University of Montpellier, INSERM Unit 1051, Montpellier, France.,Department of Zoology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Lonneke L IJsseldijk
- Division of Pathology, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | | | - Sonja Ostertag
- School of Public Health, University of Waterloo, Waterloo, Ontario, Canada.,Freshwater Institute, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada
| | | | - Martin Haulena
- Vancouver Aquarium Marine Science Center, Vancouver, British Columbia, Canada
| | - Paul Doshkov
- Cape Hatteras National Seashore, Manteo, North Carolina, USA
| | - Jérôme Bourien
- Institute for Neurosciences of Montpellier, University of Montpellier, INSERM Unit 1051, Montpellier, France
| | - Stephen A Raverty
- Department of Zoology, The University of British Columbia, Vancouver, British Columbia, Canada.,Animal Health Center, Animal Health Center, Ministry of Agriculture, Abbotsford, British Columbia, Canada
| | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Büsum, Germany
| | - Jean-Luc Puel
- Institute for Neurosciences of Montpellier, University of Montpellier, INSERM Unit 1051, Montpellier, France
| | - Robert E Shadwick
- Department of Zoology, The University of British Columbia, Vancouver, British Columbia, Canada
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