1
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Hirose A, Nakamura G, Nikaido M, Fujise Y, Kato H, Kishida T. Localized Expression of Olfactory Receptor Genes in the Olfactory Organ of Common Minke Whales. Int J Mol Sci 2024; 25:3855. [PMID: 38612665 PMCID: PMC11012115 DOI: 10.3390/ijms25073855] [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: 02/21/2024] [Revised: 03/13/2024] [Accepted: 03/20/2024] [Indexed: 04/14/2024] Open
Abstract
Baleen whales (Mysticeti) possess the necessary anatomical structures and genetic elements for olfaction. Nevertheless, the olfactory receptor gene (OR) repertoire has undergone substantial degeneration in the cetacean lineage following the divergence of the Artiodactyla and Cetacea. The functionality of highly degenerated mysticete ORs within their olfactory epithelium remains unknown. In this study, we extracted total RNA from the nasal mucosae of common minke whales (Balaenoptera acutorostrata) to investigate ORs' localized expression. All three sections of the mucosae examined in the nasal chamber displayed comparable histological structure. However, the posterior portion of the frontoturbinal region exhibited notably high OR expression. Neither the olfactory bulb nor the external skin exhibited the expression of these genes. Although this species possesses four intact non-class-2 ORs, all the ORs expressed in the nasal mucosae belong to class-2, implying the loss of aversion to specific odorants. These anatomical and genomic analyses suggest that ORs are still responsible for olfaction within the nasal region of baleen whales, enabling them to detect desirable scents such as prey and potential mating partners.
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Affiliation(s)
- Ayumi Hirose
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo 152-8550, Japan;
- Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Tokyo 108-8477, Japan
| | - Gen Nakamura
- Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Tokyo 108-8477, Japan
| | - Masato Nikaido
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo 152-8550, Japan;
| | | | - Hidehiro Kato
- Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Tokyo 108-8477, Japan
- The Institute of Cetacean Research, Tokyo 104-0055, Japan
| | - Takushi Kishida
- Museum of Natural and Environmental History, Shizuoka 422-8017, Japan;
- College of Bioresource Sciences, Nihon University, Fujisawa 252-0880, Japan
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2
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Sauer DJ, Radford CA, Mull CG, Yopak KE. Quantitative assessment of inner ear variation in elasmobranchs. Sci Rep 2023; 13:11939. [PMID: 37488259 PMCID: PMC10366120 DOI: 10.1038/s41598-023-39151-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 07/20/2023] [Indexed: 07/26/2023] Open
Abstract
Considerable diversity has been documented in most sensory systems of elasmobranchs (sharks, rays, and skates); however, relatively little is known about morphological variation in the auditory system of these fishes. Using magnetic resonance imaging (MRI), the inner ear structures of 26 elasmobranchs were assessed in situ. The inner ear end organs (saccule, lagena, utricle, and macula neglecta), semi-circular canals (horizontal, anterior, and posterior), and endolymphatic duct were compared using phylogenetically-informed, multivariate analyses. Inner ear variation can be characterised by three primary axes that are influenced by diet and habitat, where piscivorous elasmobranchs have larger inner ears compared to non-piscivorous species, and reef-associated species have larger inner ears than oceanic species. Importantly, this variation may reflect differences in auditory specialisation that could be tied to the functional requirements and environmental soundscapes of different species.
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Affiliation(s)
- Derek J Sauer
- Leigh Marine Laboratory, Institute of Marine Science, University of Auckland, Leigh, New Zealand.
| | - Craig A Radford
- Leigh Marine Laboratory, Institute of Marine Science, University of Auckland, Leigh, New Zealand
| | - Christopher G Mull
- Integrated Fisheries Laboratory, Department of Biology, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Kara E Yopak
- Department of Biology and Marine Biology and the Center for Marine Science, University of North Carolina Wilmington, Wilmington, NC, USA
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3
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Wu Z, Jiang J, Lischka FW, McGrane SJ, Porat-Mesenco Y, Zhao K. Domestic cat nose functions as a highly efficient coiled parallel gas chromatograph. PLoS Comput Biol 2023; 19:e1011119. [PMID: 37384594 PMCID: PMC10309622 DOI: 10.1371/journal.pcbi.1011119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 04/20/2023] [Indexed: 07/01/2023] Open
Abstract
The peripheral structures of mammalian sensory organs often serve to support their functionality, such as alignment of hair cells to the mechanical properties of the inner ear. Here, we examined the structure-function relationship for mammalian olfaction by creating an anatomically accurate computational nasal model for the domestic cat (Felis catus) based on high resolution microCT and sequential histological sections. Our results showed a distinct separation of respiratory and olfactory flow regimes, featuring a high-speed dorsal medial stream that increases odor delivery speed and efficiency to the ethmoid olfactory region without compromising the filtration and conditioning purpose of the nose. These results corroborated previous findings in other mammalian species, which implicates a common theme to deal with the physical size limitation of the head that confines the nasal airway from increasing in length infinitely as a straight tube. We thus hypothesized that these ethmoid olfactory channels function as parallel coiled chromatograph channels, and further showed that the theoretical plate number, a widely-used indicator of gas chromatograph efficiency, is more than 100 times higher in the cat nose than an "amphibian-like" straight channel fitting the similar skull space, at restful breathing state. The parallel feature also reduces airflow speed within each coil, which is critical to achieve the high plate number, while feeding collectively from the high-speed dorsal medial stream so that total odor sampling speed is not sacrificed. The occurrence of ethmoid turbinates is an important step in the evolution of mammalian species that correlates to their expansive olfactory function and brain development. Our findings reveal novel mechanisms on how such structure may facilitate better olfactory performance, furthering our understanding of the successful adaptation of mammalian species, including F. catus, a popular pet, to diverse environments.
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Affiliation(s)
- Zhenxing Wu
- Department of Otolaryngology—Head & Neck Surgery, The Ohio State University, Columbus, Ohio, United States of America
| | - Jianbo Jiang
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, United States of America
| | - Fritz W. Lischka
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, United States of America
| | - Scott J. McGrane
- Waltham Petcare Science Institute, Freeby Lane, Waltham-on-the-Wolds, Melton Mowbray, Leicestershire, United Kingdom
| | - Yael Porat-Mesenco
- MJ Ryan Veterinary Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Kai Zhao
- Department of Otolaryngology—Head & Neck Surgery, The Ohio State University, Columbus, Ohio, United States of America
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4
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Martinez Q, Courcelle M, Douzery E, Fabre PH. When morphology does not fit the genomes: the case of rodent olfaction. Biol Lett 2023; 19:20230080. [PMID: 37042683 PMCID: PMC10092080 DOI: 10.1098/rsbl.2023.0080] [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: 09/20/2022] [Accepted: 03/24/2023] [Indexed: 04/13/2023] Open
Abstract
Linking genes to phenotypes has been a major question in evolutionary biology for the last decades. In the genomic era, few studies attempted to link olfactory-related genes to different anatomical proxies. However, they found very inconsistent results. This study is the first to investigate a potential relation between olfactory turbinals and olfactory receptor (OR) genes. We demonstrated that despite the use of similar methodology in the acquisition of data, OR genes do not correlate with the relative and the absolute surface area of olfactory turbinals. These results challenged the interpretations of several studies based on different proxies related to olfaction and their potential relation to olfactory capabilities.
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Affiliation(s)
- Quentin Martinez
- Institut des Sciences de l'Évolution (ISEM, UMR 5554 CNRS-IRD-UM-EPHE), Université de Montpellier, Place E. Bataillon - CC 064 - 34095, Montpellier Cedex 5, France
- Staatliches Museum für Naturkunde Stuttgart DE-70191, Stuttgart, Germany
| | - Maxime Courcelle
- Institut des Sciences de l'Évolution (ISEM, UMR 5554 CNRS-IRD-UM-EPHE), Université de Montpellier, Place E. Bataillon - CC 064 - 34095, Montpellier Cedex 5, France
| | - Emmanuel Douzery
- Institut des Sciences de l'Évolution (ISEM, UMR 5554 CNRS-IRD-UM-EPHE), Université de Montpellier, Place E. Bataillon - CC 064 - 34095, Montpellier Cedex 5, France
| | - Pierre-Henri Fabre
- Institut des Sciences de l'Évolution (ISEM, UMR 5554 CNRS-IRD-UM-EPHE), Université de Montpellier, Place E. Bataillon - CC 064 - 34095, Montpellier Cedex 5, France
- Mammal Section, Department of Life Sciences, The Natural History Museum, London SW7 5DB, UK
- Institut Universitaire de France (IUF), Paris, France
- Division of Vertebrate Zoology (Mammalogy), American Museum of Natural History, Central Park West, 79th St., New York, NY 10024-5192, USA
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5
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Zdun M, Ruszkowski JJ, Hetman M, Melnyk OO, Frąckowiak H. Strategies of vascularization of the ethmoid labyrinth in selected even-toed ungulates (Artiodactyla) and carnivores (Carnivora). J Anat 2023; 242:1067-1077. [PMID: 36688531 PMCID: PMC10184540 DOI: 10.1111/joa.13829] [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: 10/07/2022] [Revised: 12/23/2022] [Accepted: 01/09/2023] [Indexed: 01/24/2023] Open
Abstract
The anatomy of the nasal cavity and its structures, as well as other elements building a scaffold for olfactory organs, differs significantly among various groups of mammals. Understanding anatomical conditions of quality of olfaction are being studied worldwide and is a complex problem. Among many studies regarding bone and epithelial structures of turbinates and connected anatomical structures, few studies describe the vascularization of turbinates. Ethmoid turbinates are above all covered in olfactory epithelium containing branched axons that receive olfactory stimuli and as olfactory nerves penetrate the cribriform lamina of the ethmoid bone conveying information from smell receptors to the brain. Differences in vascularization of the cribriform plate and turbinates may add crucial information complementing studies regarding the olfactory organ's bone and soft tissue structures. In the study, we describe the vascularization of the cribriform plate of the ethmoid bone of 54 Artiodactyla and Carnivora.
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Affiliation(s)
- Maciej Zdun
- Department of Animal Anatomy, Poznan University of Life Sciences, Poznań, Poland.,Department of Basic and Preclinical Sciences, Nicolaus Copernicus University in Torun, Torun, Poland
| | - Jakub J Ruszkowski
- Department of Animal Anatomy, Poznan University of Life Sciences, Poznań, Poland
| | - Mateusz Hetman
- Department of Animal Anatomy, Poznan University of Life Sciences, Poznań, Poland
| | - Oleksii O Melnyk
- Department of Animal Anatomy, Histology and Pathomorphology, National University of Nature and Environmental Sciences of Ukraine, Kyiv, Ukraine
| | - Hieronim Frąckowiak
- Department of Basic and Preclinical Sciences, Nicolaus Copernicus University in Torun, Torun, Poland
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6
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Shepherd GM, Rowe TB, Greer CA. An Evolutionary Microcircuit Approach to the Neural Basis of High Dimensional Sensory Processing in Olfaction. Front Cell Neurosci 2021; 15:658480. [PMID: 33994949 PMCID: PMC8120314 DOI: 10.3389/fncel.2021.658480] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 03/30/2021] [Indexed: 11/16/2022] Open
Abstract
Odor stimuli consist of thousands of possible molecules, each molecule with many different properties, each property a dimension of the stimulus. Processing these high dimensional stimuli would appear to require many stages in the brain to reach odor perception, yet, in mammals, after the sensory receptors this is accomplished through only two regions, the olfactory bulb and olfactory cortex. We take a first step toward a fundamental understanding by identifying the sequence of local operations carried out by microcircuits in the pathway. Parallel research provided strong evidence that processed odor information is spatial representations of odor molecules that constitute odor images in the olfactory bulb and odor objects in olfactory cortex. Paleontology provides a unique advantage with evolutionary insights providing evidence that the basic architecture of the olfactory pathway almost from the start ∼330 million years ago (mya) has included an overwhelming input from olfactory sensory neurons combined with a large olfactory bulb and olfactory cortex to process that input, driven by olfactory receptor gene duplications. We identify a sequence of over 20 microcircuits that are involved, and expand on results of research on several microcircuits that give the best insights thus far into the nature of the high dimensional processing.
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Affiliation(s)
- Gordon M. Shepherd
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
| | - Timothy B. Rowe
- Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, United States
| | - Charles A. Greer
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
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7
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Abstract
Amniotes originated on land, but aquatic/amphibious groups emerged multiple times independently in amniotes. On becoming aquatic, species with different phylogenetic backgrounds and body plans have to adapt themselves to handle similar problems inflicted by their new environment, and this makes aquatic adaptation of amniotes one of the greatest natural experiments. Particularly, evolution of the sense of smell upon aquatic adaptation is of great interest because receptors required for underwater olfaction differ remarkably from those for terrestrial olfaction. Here, I review the olfactory capabilities of aquatic/amphibious amniotes, especially those of cetaceans and sea snakes. Most aquatic/amphibious amniotes show reduced olfactory organs, receptor gene repertoires, and olfactory capabilities. Remarkably, cetaceans and sea snakes show extreme examples: cetaceans have lost the vomeronasal system, and furthermore, toothed whales have lost all of their olfactory nervous systems. Baleen whales can smell in the air, but their olfactory capability is limited. Fully aquatic sea snakes have lost the main olfactory system but they retain the vomeronasal system for sensing underwater. Amphibious species show an intermediate status between terrestrial and aquatic species, implying their importance on understanding the process of aquatic adaptation. The olfactory capabilities of aquatic amniotes are diverse, reflecting their diverse phylogenetic backgrounds and ecology.
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8
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Bird DJ, Jacquemetton C, Buelow SA, Evans AW, Van Valkenburgh B. Domesticating olfaction: Dog breeds, including scent hounds, have reduced cribriform plate morphology relative to wolves. Anat Rec (Hoboken) 2020; 304:139-153. [PMID: 33205623 DOI: 10.1002/ar.24518] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 05/26/2020] [Accepted: 06/12/2020] [Indexed: 11/08/2022]
Abstract
The domestic dog is assumed by nearly everyone to be the consummate smeller. Within the species Canis familiaris individual breeds, such as the bloodhound or beagle, are known as olfactory stars. These are "scent breeds," a grouping variably defined as a genetic clade or breed class commonly used for scent detection tasks. Previous work suggests that the dog has a more robust olfactory anatomy than many mammal species. Now we undertake a closer investigation of the dog's olfactory system, both in relationship to its closest wild relatives, the wolf and coyote, and across individual breeds. First, we seek to resolve whether the dog has lost olfactory capacity through its domestication from the wolf lineage. Second, we test the inertial lore that among dogs, "scent breeds," have a superior olfactory facility. As a measure of relative olfactory capacity, we look to the cribriform plate (CP), a bony cup in the posterior nasal cavity perforated by passageways for all olfactory nerve bundles streaming from the periphery to the brain. Using high-resolution computed tomography (CT) scans and digital quantification, we compare relative CP size in 46 dog breeds, the coyote and gray wolf. Results show the dog has a reduced CP surface area relative to the wolf and coyote. Moreover, we found no significant differences between CP size of "scent" and "non-scent" breeds. Our study suggests that the dog lost olfactory capacity as a result of domestication and this loss was not recovered in particular breed groupings through directed artificial selection for increased olfactory facility.
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Affiliation(s)
- Deborah J Bird
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California, USA
| | - Christiane Jacquemetton
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California, USA
| | - Sophie A Buelow
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California, USA
| | - Andrew W Evans
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California, USA
| | - Blaire Van Valkenburgh
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California, USA
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9
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Ruiz–Monachesi MR, Cruz FB, Valdecantos S, Labra A. Unravelling associations among chemosensory system components in
Liolaemus
lizards. J Zool (1987) 2020. [DOI: 10.1111/jzo.12819] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- M. R. Ruiz–Monachesi
- CONICET‐ Instituto de Bio y Geo Ciencias del NOA (IBIGEO) Facultad de Ciencias Naturales Universidad Nacional de Salta Rosario de Lerma Argentina
| | - F. B. Cruz
- INIBIOMA (CONICET – UNCOMA) Centro Regional Universitario Bariloche Universidad Nacional del Comahue (CRUB)‐Bariloche Río Negro Argentina
| | - S. Valdecantos
- CONICET‐ Instituto de Bio y Geo Ciencias del NOA (IBIGEO) Facultad de Ciencias Naturales Universidad Nacional de Salta Rosario de Lerma Argentina
| | - A. Labra
- Center for Ecological and Evolutionary Synthesis Department of Biosciences University of Oslo Oslo Norway
- ONG Vida Nativa Santiago Chile
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10
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Bird DJ, Hamid I, Fox‐Rosales L, Van Valkenburgh B. Olfaction at depth: Cribriform plate size declines with dive depth and duration in aquatic arctoid carnivorans. Ecol Evol 2020; 10:6929-6953. [PMID: 32760503 PMCID: PMC7391337 DOI: 10.1002/ece3.6343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 03/31/2020] [Accepted: 04/06/2020] [Indexed: 12/05/2022] Open
Abstract
It is widely accepted that obligate aquatic mammals, specifically toothed whales, rely relatively little on olfaction. There is less agreement about the importance of smell among aquatic mammals with residual ties to land, such as pinnipeds and sea otters. Field observations of marine carnivorans stress their keen use of smell while on land or pack ice. Yet, one dimension of olfactory ecology is often overlooked: while underwater, aquatic carnivorans forage "noseblind," diving with nares closed, removed from airborne chemical cues. For this reason, we predicted marine carnivorans would have reduced olfactory anatomy relative to closely related terrestrial carnivorans. Moreover, because species that dive deeper and longer forage farther removed from surface scent cues, we predicted further reductions in their olfactory anatomy. To test these hypotheses, we looked to the cribriform plate (CP), a perforated bone in the posterior nasal chamber of mammals that serves as the only passageway for olfactory nerves crossing from the periphery to the olfactory bulb and thus covaries in size with relative olfactory innervation. Using CT scans and digital quantification, we compared CP morphology across Arctoidea, a clade at the interface of terrestrial and aquatic ecologies. We found that aquatic carnivoran species from two lineages that independently reinvaded marine environments (Pinnipedia and Mustelidae), have significantly reduced relative CP than terrestrial species. Furthermore, within these aquatic lineages, diving depth and duration were strongly correlated with CP loss, and the most extreme divers, elephant seals, displayed the greatest reductions. These observations suggest that CP reduction in carnivorans is an adaptive response to shifting selection pressures during secondary invasion of marine environments, particularly to foraging at great depths. Because the CP is fairly well preserved in the fossil record, using methods presented here to quantify CP morphology in extinct species could further clarify evolutionary patterns of olfactory loss across aquatic mammal lineages that have independently committed to life in water.
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Affiliation(s)
- Deborah J. Bird
- Department of Ecology and Evolutionary BiologyUniversity of California Los AngelesLos AngelesCAUSA
| | - Iman Hamid
- Department of Ecology and Evolutionary BiologyUniversity of California Los AngelesLos AngelesCAUSA
| | - Lester Fox‐Rosales
- Department of Ecology and Evolutionary BiologyUniversity of California Los AngelesLos AngelesCAUSA
| | - Blaire Van Valkenburgh
- Department of Ecology and Evolutionary BiologyUniversity of California Los AngelesLos AngelesCAUSA
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11
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Convergent evolution of olfactory and thermoregulatory capacities in small amphibious mammals. Proc Natl Acad Sci U S A 2020; 117:8958-8965. [PMID: 32253313 DOI: 10.1073/pnas.1917836117] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Olfaction and thermoregulation are key functions for mammals. The former is critical to feeding, mating, and predator avoidance behaviors, while the latter is essential for homeothermy. Aquatic and amphibious mammals face olfactory and thermoregulatory challenges not generally encountered by terrestrial species. In mammals, the nasal cavity houses a bony system supporting soft tissues and sensory organs implicated in either olfactory or thermoregulatory functions. It is hypothesized that to cope with aquatic environments, amphibious mammals have expanded their thermoregulatory capacity at the expense of their olfactory system. We investigated the evolutionary history of this potential trade-off using a comparative dataset of three-dimensional (3D) CT scans of 189 skulls, capturing 17 independent transitions from a strictly terrestrial to an amphibious lifestyle across small mammals (Afrosoricida, Eulipotyphla, and Rodentia). We identified rapid and repeated loss of olfactory capacities synchronously associated with gains in thermoregulatory capacity in amphibious taxa sampled from across mammalian phylogenetic diversity. Evolutionary models further reveal that these convergences result from faster rates of turbinal bone evolution and release of selective constraints on the thermoregulatory-olfaction trade-off in amphibious species. Lastly, we demonstrated that traits related to vital functions evolved faster to the optimum compared to traits that are not related to vital functions.
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12
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Norwood JN, Zhang Q, Card D, Craine A, Ryan TM, Drew PJ. Anatomical basis and physiological role of cerebrospinal fluid transport through the murine cribriform plate. eLife 2019; 8:44278. [PMID: 31063132 PMCID: PMC6524970 DOI: 10.7554/elife.44278] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 05/06/2019] [Indexed: 12/25/2022] Open
Abstract
Cerebrospinal fluid (CSF) flows through the brain, transporting chemical signals and removing waste. CSF production in the brain is balanced by a constant outflow of CSF, the anatomical basis of which is poorly understood. Here, we characterized the anatomy and physiological function of the CSF outflow pathway along the olfactory sensory nerves through the cribriform plate, and into the nasal epithelia. Chemical ablation of olfactory sensory nerves greatly reduced outflow of CSF through the cribriform plate. The reduction in CSF outflow did not cause an increase in intracranial pressure (ICP), consistent with an alteration in the pattern of CSF drainage or production. Our results suggest that damage to olfactory sensory neurons (such as from air pollution) could contribute to altered CSF turnover and flow, providing a potential mechanism for neurological diseases.
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Affiliation(s)
- Jordan N Norwood
- Cellular and Developmental Biology Graduate Program, Pennsylvania State University, University Park, United States
| | - Qingguang Zhang
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, United States
| | - David Card
- Department of Physics, Pennsylvania State University, University Park, United States
| | - Amanda Craine
- Department of Biomedical Engineering, Pennsylvania State University, University Park, United States
| | - Timothy M Ryan
- Department of Anthropology, Pennsylvania State University, University Park, United States
| | - Patrick J Drew
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, United States.,Department of Biomedical Engineering, Pennsylvania State University, University Park, United States.,Department of Neurosurgery, Pennsylvania State University, University Park, United States
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13
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Niimura Y, Matsui A, Touhara K. Acceleration of Olfactory Receptor Gene Loss in Primate Evolution: Possible Link to Anatomical Change in Sensory Systems and Dietary Transition. Mol Biol Evol 2019; 35:1437-1450. [PMID: 29659972 DOI: 10.1093/molbev/msy042] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Primates have traditionally been regarded as vision-oriented animals with low olfactory ability, though this "microsmatic primates" view has been challenged recently. To clarify when and how degeneration of the olfactory system occurred and to specify the relevant factors during primate evolution, we here examined the olfactory receptor (OR) genes from 24 phylogenetically and ecologically diverse primate species. The results revealed that strepsirrhines with curved noses had functional OR gene repertoires that were nearly twice as large as those for haplorhines with simple noses. Neither activity pattern (nocturnal/diurnal) nor color vision system showed significant correlation with the number of functional OR genes while phylogeny and nose structure (haplorhine/strepsirrhine) are statistically controlled, but extent of folivory did. We traced the evolutionary fates of individual OR genes by identifying orthologous gene groups, demonstrating that the rates of OR gene losses were accelerated at the ancestral branch of haplorhines, which coincided with the acquisition of acute vision. The highest rate of OR gene loss was observed at the ancestral branch of leaf-eating colobines; this reduction is possibly linked with the dietary transition from frugivory to folivory because odor information is essential for fruit foraging but less so for leaf foraging. Intriguingly, we found accelerations of OR gene losses in an external branch to every hominoid species examined. These findings suggest that the current OR gene repertoire in each species has been shaped by a complex interplay of phylogeny, anatomy, and habitat; therefore, multiple factors may contribute to the olfactory degeneration in primates.
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Affiliation(s)
- Yoshihito Niimura
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.,ERATO Touhara Chemosensory Signal Project, JST, The University of Tokyo, Tokyo, Japan.,Lead Contact
| | - Atsushi Matsui
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.,ERATO Touhara Chemosensory Signal Project, JST, The University of Tokyo, Tokyo, Japan
| | - Kazushige Touhara
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.,ERATO Touhara Chemosensory Signal Project, JST, The University of Tokyo, Tokyo, Japan
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14
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Bird DJ, Murphy WJ, Fox-Rosales L, Hamid I, Eagle RA, Van Valkenburgh B. Olfaction written in bone: cribriform plate size parallels olfactory receptor gene repertoires in Mammalia. Proc Biol Sci 2019. [PMID: 29540522 DOI: 10.1098/rspb.2018.0100] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The evolution of mammalian olfaction is manifested in a remarkable diversity of gene repertoires, neuroanatomy and skull morphology across living species. Olfactory receptor genes (ORGs), which initiate the conversion of odorant molecules into odour perceptions and help an animal resolve the olfactory world, range in number from a mere handful to several thousand genes across species. Within the snout, each of these ORGs is exclusively expressed by a discrete population of olfactory sensory neurons (OSNs), suggesting that newly evolved ORGs may be coupled with new OSN populations in the nasal epithelium. Because OSN axon bundles leave high-fidelity perforations (foramina) in the bone as they traverse the cribriform plate (CP) to reach the brain, we predicted that taxa with larger ORG repertoires would have proportionately expanded footprints in the CP foramina. Previous work found a correlation between ORG number and absolute CP size that disappeared after accounting for body size. Using updated, digital measurement data from high-resolution CT scans and re-examining the relationship between CP and body size, we report a striking linear correlation between relative CP area and number of functional ORGs across species from all mammalian superorders. This correlation suggests strong developmental links in the olfactory pathway between genes, neurons and skull morphology. Furthermore, because ORG number is linked to olfactory discriminatory function, this correlation supports relative CP size as a viable metric for inferring olfactory capacity across modern and extinct species. By quantifying CP area from a fossil sabertooth cat (Smilodon fatalis), we predicted a likely ORG repertoire for this extinct felid.
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Affiliation(s)
- Deborah J Bird
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, 610 Charles E. Young Drive South, Los Angeles, CA 90095-8347, USA
| | - William J Murphy
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX 77843-4458, USA
| | - Lester Fox-Rosales
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, 610 Charles E. Young Drive South, Los Angeles, CA 90095-8347, USA
| | - Iman Hamid
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, 610 Charles E. Young Drive South, Los Angeles, CA 90095-8347, USA
| | - Robert A Eagle
- Department of Atmospheric and Oceanic Sciences, Institute of the Environment and Sustainability, University of California Los Angeles, 520 Portola Plaza, Math Sciences Building 7127, Los Angeles, CA 90095, USA
| | - Blaire Van Valkenburgh
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, 610 Charles E. Young Drive South, Los Angeles, CA 90095-8347, USA
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15
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Teşileanu T, Cocco S, Monasson R, Balasubramanian V. Adaptation of olfactory receptor abundances for efficient coding. eLife 2019; 8:39279. [PMID: 30806351 PMCID: PMC6398974 DOI: 10.7554/elife.39279] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 02/13/2019] [Indexed: 01/27/2023] Open
Abstract
Olfactory receptor usage is highly heterogeneous, with some receptor types being orders of magnitude more abundant than others. We propose an explanation for this striking fact: the receptor distribution is tuned to maximally represent information about the olfactory environment in a regime of efficient coding that is sensitive to the global context of correlated sensor responses. This model predicts that in mammals, where olfactory sensory neurons are replaced regularly, receptor abundances should continuously adapt to odor statistics. Experimentally, increased exposure to odorants leads variously, but reproducibly, to increased, decreased, or unchanged abundances of different activated receptors. We demonstrate that this diversity of effects is required for efficient coding when sensors are broadly correlated, and provide an algorithm for predicting which olfactory receptors should increase or decrease in abundance following specific environmental changes. Finally, we give simple dynamical rules for neural birth and death processes that might underlie this adaptation.
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Affiliation(s)
- Tiberiu Teşileanu
- Center for Computational BiologyFlatiron InstituteNew YorkUnited States,Initiative for the Theoretical Sciences, The Graduate CenterCity University of New YorkNew YorkUnited States,David Rittenhouse LaboratoriesUniversity of PennsylvaniaPhiladelphiaUnited States
| | - Simona Cocco
- Laboratoire de Physique StatistiqueÉcole Normale Supérieure and CNRS UMR 8550, PSL Research, UPMC Sorbonne UniversitéParisFrance
| | - Rémi Monasson
- Laboratoire de Physique ThéoriqueÉcole Normale Supérieure and CNRS UMR 8550, PSL Research, UPMC Sorbonne UniversitéParisFrance
| | - Vijay Balasubramanian
- Initiative for the Theoretical Sciences, The Graduate CenterCity University of New YorkNew YorkUnited States,David Rittenhouse LaboratoriesUniversity of PennsylvaniaPhiladelphiaUnited States
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16
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Márquez S, Pagano AS, Mongle CS, Albertine KH, Laitman JT. The Nasal Complex of a Semiaquatic Artiodactyl, the Moose (Alces alces): Is it a Good Evolutionary Model for the Ancestors of Cetaceans? Anat Rec (Hoboken) 2018; 302:667-692. [DOI: 10.1002/ar.24022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 09/17/2018] [Accepted: 09/23/2018] [Indexed: 12/26/2022]
Affiliation(s)
- Samuel Márquez
- Departments of Cell Biology and OtolaryngologySUNY Downstate Medical Center Brooklyn New York
| | - Anthony S. Pagano
- Department of Medical SciencesHackensack‐Meridian School of Medicine at Seton Hall University Nutley New Jersey
| | - Carrie S. Mongle
- Interdepartmental Program in Anthropological SciencesStony Brook University Stony Brook New York
| | - Kurt H. Albertine
- Department of PediatricsUniversity of Utah School of Medicine Salt Lake City Utah
| | - Jeffrey T. Laitman
- Departments of Medical Education and Otolaryngology, Icahn School of Medicine at Mount SinaiCenter for Anatomy & Functional Morphology New York New York
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17
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Rygg AD, Van Valkenburgh B, Craven BA. The Influence of Sniffing on Airflow and Odorant Deposition in the Canine Nasal Cavity. Chem Senses 2018; 42:683-698. [PMID: 28981825 DOI: 10.1093/chemse/bjx053] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Nasal airflow plays a critical role in olfaction by transporting odorant from the environment to the olfactory epithelium, where chemical detection occurs. Most studies of olfaction neglect the unsteadiness of sniffing and assume that nasal airflow and odorant transport are "quasi-steady," wherein reality most mammals "sniff." Here, we perform computational fluid dynamics simulations of airflow and odorant deposition in an anatomically accurate model of the coyote (Canis latrans) nasal cavity during quiet breathing, a notional quasi-steady sniff, and unsteady sniffing to: quantify the influence of unsteady sniffing, assess the validity of the quasi-steady assumption, and investigate the functional advantages of sniffing compared to breathing. Our results reveal that flow unsteadiness during sniffing does not appreciably influence qualitative (gross airflow and odorant deposition patterns) or quantitative (time-averaged olfactory flow rate and odorant uptake) measures of olfactory function. A quasi-steady approximation is, therefore, justified for simulating time-averaged olfactory function in the canine nose. Simulations of sniffing versus quiet breathing demonstrate that sniffing delivers about 2.5 times more air to the olfactory recess and results in 2.5-3 times more uptake of highly- and moderately-soluble odorants in the sensory region per unit time, suggesting one reason why dogs actively sniff. Simulations also reveal significantly different deposition patterns in the olfactory region during inspiration for different odorants, and that during expiration there is little retronasal odorant deposition in the sensory region. These results significantly improve our understanding of canine olfaction, and have several practical implications regarding computer simulation of olfactory function.
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Affiliation(s)
- Alex D Rygg
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, California 90095, USA
| | - Blaire Van Valkenburgh
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, California 90095, USA
| | - Brent A Craven
- Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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18
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Dawley EM. Comparative Morphology of Plethodontid Olfactory and Vomeronasal Organs: How Snouts Are Packed. HERPETOLOGICAL MONOGRAPHS 2017. [DOI: 10.1655/herpmonographs-d-15-00008.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Ellen M. Dawley
- Department of Biology, Ursinus College, Collegeville, PA 19426, USA
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19
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Aland RC, Gosden E, Bradley AJ. Seasonal morphometry of the vomeronasal organ in the marsupial mouse, Antechinus subtropicus. J Morphol 2016; 277:1517-1530. [PMID: 27641160 PMCID: PMC5095805 DOI: 10.1002/jmor.20593] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 07/19/2016] [Accepted: 08/15/2016] [Indexed: 11/24/2022]
Abstract
The vomeronasal system consists of a peripheral organ and the connected central neuronal networks. The central connections are sexually dimorphic in rodents, and in some species, parameters of the vomeronasal organ (VNO) vary with sex, hormonal exposure, body size and seasonality. The VNO of the dasyurid marsupial mouse, Antechinus subtropicus is presumed to be functional. The unusual life history (male semelparity) is marked by distinct seasonality with differences in hormonal environments both between males and females, and in males at different time points. Body size parameters (e.g., length, weight) display sexual dimorphism and, in males, a pronounced weight gain before breeding is followed by a rapid decline during the single, short reproductive season. VNO morphometry was investigated in male and female A. subtropicus to identify possible life cycle associated activity. The overall length of the VNO is positively correlated with the size of the animal. The amount of sensory epithelium exhibits a negative correlation, decreasing with increasing size of the animal. The effects of sex and breeding condition are not obvious, although they do suggest that sensory vomeronasal epithelium mass declines in the breeding period. The VNO may be more important in A. subtropicus before breeding when it may participate in synchronising reproduction and in the development of the male stress response. J. Morphol. 277:1517–1530, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Rachel Claire Aland
- School of Rural Medicine, University of New England, Armidale, NSW, Australia. .,School of Biomedical Sciences, Faculty of Medicine and Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia.
| | - Edward Gosden
- Research Methods Group, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia
| | - Adrian J Bradley
- School of Biomedical Sciences, Faculty of Medicine and Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
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20
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Kremers D, Célérier A, Schaal B, Campagna S, Trabalon M, Böye M, Hausberger M, Lemasson A. Sensory Perception in Cetaceans: Part I—Current Knowledge about Dolphin Senses As a Representative Species. Front Ecol Evol 2016. [DOI: 10.3389/fevo.2016.00049] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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21
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Pang B, Yee KK, Lischka FW, Rawson NE, Haskins ME, Wysocki CJ, Craven BA, Van Valkenburgh B. The influence of nasal airflow on respiratory and olfactory epithelial distribution in felids. ACTA ACUST UNITED AC 2016; 219:1866-74. [PMID: 27045093 DOI: 10.1242/jeb.131482] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 03/26/2016] [Indexed: 11/20/2022]
Abstract
The surface area of the maxilloturbinals and fronto-ethmoturbinals is commonly used as an osteological proxy for the respiratory and the olfactory epithelium, respectively. However, this assumption does not fully account for animals with short snouts in which these two turbinal structures significantly overlap, potentially placing fronto-ethmoturbinals in the path of respiratory airflow. In these species, it is possible that anterior fronto-ethmoturbinals are covered with non-sensory (respiratory) epithelium instead of olfactory epithelium. In this study, we analyzed the distribution of olfactory and non-sensory, respiratory epithelia on the turbinals of two domestic cats (Felis catus) and a bobcat (Lynx rufus). We also conducted a computational fluid dynamics simulation of nasal airflow in the bobcat to explore the relationship between epithelial distribution and airflow patterns. The results showed that a substantial amount of respiratory airflow passes over the anterior fronto-ethmoturbinals, and that contrary to what has been observed in caniform carnivorans, much of the anterior ethmoturbinals are covered by non-sensory epithelium. This confirms that in short-snouted felids, portions of the fronto-ethmoturbinals have been recruited for respiration, and that estimates of olfactory epithelial coverage based purely on fronto-ethmoturbinal surface area will be exaggerated. The correlation between the shape of the anterior fronto-ethmoturbinals and the direction of respiratory airflow suggests that in short-snouted species, CT data alone are useful in assessing airflow patterns and epithelium distribution on the turbinals.
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Affiliation(s)
- Benison Pang
- Department of Ecology and Evolutionary Biology, University of California at Los Angeles, 610 Charles Young Drive E, Los Angeles, CA 90095-7239, USA
| | - Karen K Yee
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA
| | - Fritz W Lischka
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA
| | - Nancy E Rawson
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA
| | - Mark E Haskins
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Charles J Wysocki
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Brent A Craven
- Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Blaire Van Valkenburgh
- Department of Ecology and Evolutionary Biology, University of California at Los Angeles, 610 Charles Young Drive E, Los Angeles, CA 90095-7239, USA
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22
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Van Valkenburgh B, Smith TD, Craven BA. Tour of a labyrinth: exploring the vertebrate nose. Anat Rec (Hoboken) 2015; 297:1975-84. [PMID: 25312359 DOI: 10.1002/ar.23021] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 06/25/2014] [Indexed: 01/18/2023]
Abstract
This special issue of The Anatomical Record is the outcome of a symposium entitled "Inside the Vertebrate Nose: Evolution, Structure and Function." The skeletal framework of the nasal cavity is a complicated structure that often houses sinuses and comprises an internal skeleton of bone or cartilage that can vary greatly in architecture among species. The nose serves multiple functions, including olfaction and respiratory air-conditioning, and its morphology is constrained by evolution, development, and conflicting demands on cranial space, such as enlarged orbits. The nasal cavity of vertebrates has received much more attention in the last decade due to the emergence of nondestructive methods that allow improved visualization of the internal anatomy of the skull, such as high-resolution x-ray computed tomography and magnetic resonance imaging. The 17 articles included here represent a broad range of investigators, from paleontologists to engineers, who approach the nose from different perspectives. Key topics include the evolution and development of the nose, its comparative anatomy and function, and airflow through the nasal cavity of individual species. In addition, this special issue includes review articles on anatomical reduction of the olfactory apparatus in both cetaceans and primates (the vomeronasal system), as well as the molecular biology of olfaction in vertebrates. Together these articles provide an expansive summary of our current understanding of vertebrate nasal anatomy and function. In this introduction, we provide background information and an overview of each of the three primary topics, and place each article within the context of previous research and the major challenges that lie ahead.
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23
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van Valkenburgh B, Pang B, Bird D, Curtis A, Yee K, Wysocki C, Craven BA. Respiratory and olfactory turbinals in feliform and caniform carnivorans: the influence of snout length. Anat Rec (Hoboken) 2015; 297:2065-79. [PMID: 25312365 DOI: 10.1002/ar.23026] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 06/25/2014] [Indexed: 11/10/2022]
Abstract
To enhance bite force at the canines, feliform carnivorans have short rostra relative to caniform carnivorans. Rostral reduction in feliforms results in less rostrocaudal space for the maxilloturbinals, the complex set of bones involved in conditioning inspired air and conserving water. It is unknown whether the maxilloturbinals might show adaptations to adjust for this loss, such as greater complexity than what is observed in longer snouted caniforms. To understand the impact of rostral shortening on turbinals in feliforms, we used high resolution CT scans to quantify turbinal surface areas (SA) in 16 feliforms and compared them with published data on 20 caniforms. Results indicate that feliforms have reduced maxilloturbinal SA for their body mass relative to caniforms, but comparable fronto-ethmoturbinal SA. However, anterior portions of the ethmoturbinals in feliforms extend forward into the snout and are positioned within the respiratory pathway. When the SA of these anterior ethmoturbinals is added to maxilloturbinal SA to produce an estimated respiratory SA, feliforms and caniforms are similar in respiratory SA. This transfer of ethmoturbinal SA to respiratory function results in feliforms having less estimated olfactory SA relative to caniforms. Previous work on canids found a positive association between olfactory surface area and diet, but this was not found for felids. Results are consistent with feliforms having somewhat reduced olfactory ability relative to caniforms. If confirmed by behavioral data, the relative reduction in olfactory SA in many feliforms may reflect a greater reliance on vision in foraging relative to caniforms.
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24
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Smith TD, Eiting TP, Bonar CJ, Craven BA. Nasal morphometry in marmosets: loss and redistribution of olfactory surface area. Anat Rec (Hoboken) 2015; 297:2093-104. [PMID: 25312367 DOI: 10.1002/ar.23029] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 06/25/2014] [Indexed: 11/11/2022]
Abstract
The two major groups of primates differ in internal nasal anatomy. Strepsirrhines (e.g., lemurs) have more numerous turbinals and recesses compared with haplorhines (e.g., monkeys). Since detailed quantitative comparisons of nasal surface area (SA) have not been made, we measured mucosa in serially sectioned monkeys (Callithrix jacchus, Cebuella pygmaea). Data were compared with previously published findings on the mouse lemur, Microcebus murinus. The nasal airways were digitally reconstructed using computed tomography scanned heads of Cebuella and Microcebus. In addition, morphometric and functional analyses were carried out using segmented photographs of the histological sections of Cebuella and Microcebus. The SA of the ethmoturbinal complex is about half as large in marmosets compared with Microcebus, and is covered with less olfactory mucosa (18%-24% in marmosets, compared with ∼ 50% in Microcebus). Whereas the ethmoturbinal complex of Microcebus bears half of the total olfactory mucosa in the nasal airway, most (∼ 80%) olfactory mucosa is distributed on other surfaces in the marmosets (e.g., nasal septum). A comparison to previously published data suggests all primate species have less olfactory surface area (OSA) compared with other similar-sized mammals, but this is especially true of marmosets. Taken together, these findings support the hypothesis that there is a reduced OSA in at least some haplorhines, and this can be linked to diminished posterosuperior dimensions of the nasal fossae. However, haplorhines may have minimized their olfactory loss by redistributing olfactory mucosa on non-turbinal surfaces. Our findings also imply that airflow patterns in the olfactory region differ among primates.
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Affiliation(s)
- Timothy D Smith
- School of Physical Therapy, Slippery Rock University, Slippery Rock, Pennsylvania; Department of Anthropology, University of Pittsburgh, Pittsburgh, Pennsylvania
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25
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Bird DJ, Amirkhanian A, Pang B, Van Valkenburgh B. Quantifying the cribriform plate: influences of allometry, function, and phylogeny in Carnivora. Anat Rec (Hoboken) 2015; 297:2080-92. [PMID: 25312366 DOI: 10.1002/ar.23032] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 06/25/2014] [Indexed: 11/12/2022]
Abstract
The small, perforated bony cup of the anterior cranial fossa called the cribriform plate (CP) is perhaps the best-preserved remnant of olfactory anatomy in fossil mammal skulls. The CP and its myriad foramina record the passage of peripheral olfactory nerves from nasal cavity to olfactory bulb. Previous work has suggested that CP surface area reflects aspects of olfactory capacity (as inferred from habitat and observed behavior) in mammals. To further explore the utility of CP as a proxy for olfactory function, we designed novel, nondestructive digital methods to quantify CP morphology from dry skulls. Using CT scans and 3-D imaging software, we quantified CP features from 42 species of Carnivora, a group that represents a wide spectrum of ecologies and sensory demands. Two metrics, CP surface area (CPSA) and cumulative CP foramina area (FXSA), scaled to skull length with negative allometry, and differed between aquatic and terrestrial species, with the former having reduced areas. Number of foramina (NF) was not correlated with skull length but tended to be greater in caniforms than feliforms. Both CPSA and FXSA are well correlated with ethmoturbinal surface area, a known osteological correlate of olfactory function. This suggests that CPSA and FXSA are useful proxies for olfactory ability, especially when studying fossils or skulls in which turbinals are not preserved. Total area of CP foramina (FXSA), an exacting measure of olfactory nerve endocasts, is tightly correlated with CPSA. Because of this, it may be desirable to use CPSA alone as a proxy given that it is easier to measure than FXSA.
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Affiliation(s)
- Deborah J Bird
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, California
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26
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Eliasson M, Hernandez Salazar LT, Laska M. Spider monkeys (Ateles geoffroyi) are less sensitive to the odor of aliphatic ketones than to the odor of other classes of aliphatic compounds. Neurosci Res 2015; 99:46-54. [PMID: 26055441 DOI: 10.1016/j.neures.2015.05.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 05/10/2015] [Accepted: 05/29/2015] [Indexed: 11/25/2022]
Abstract
Aliphatic ketones are widely present in body-borne and food odors of primates. Therefore, we used an operant conditioning paradigm and determined olfactory detection thresholds in four spider monkeys for a homologous series of aliphatic 2-ketones (2-butanone to 2-nonanone) and two of their isomers (3- and 4-heptanone). We found that, with the exception of the two shortest-chained ketones, all animals detected concentrations <1 ppm (parts per million), and with five odorants individual animals even reached threshold values <0.1 ppm. Further, we found a significant correlation between olfactory sensitivity of the spider monkeys and carbon chain length of the 2-ketones which can best be described as a U-shaped function. In contrast, no significant correlation was found between olfactory sensitivity and position of the functional carbonyl group. Across-odorant and across-species comparisons revealed the following: spider monkeys are significantly less sensitive to the odors of aliphatic ketones than to the odor of other classes of aliphatic compounds (1-alcohols, n-aldehydes, n-acetic esters, and n-carboxylic acids) sharing the same carbon length. Spider monkeys do not differ significantly in their olfactory sensitivity for aliphatic ketones from squirrel monkeys and pigtail macaques, but are significantly less sensitive to these odorants compared to human subjects and mice. These findings support the notion that neuroanatomical and genetic properties do not allow for reliable predictions with regard to a species' olfactory sensitivity. Further, we conclude that the frequency of occurrence of a class of odorants in a species' chemical environment does not allow for reliable predictions of the species' olfactory sensitivity.
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Affiliation(s)
- Moa Eliasson
- IFM Biology, Linköping University, 581 83 Linköping, Sweden
| | | | - Matthias Laska
- IFM Biology, Linköping University, 581 83 Linköping, Sweden.
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27
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Ashwell KWS, Hardman CD, Musser AM. Brain and behaviour of living and extinct echidnas. ZOOLOGY 2014; 117:349-61. [PMID: 25053446 DOI: 10.1016/j.zool.2014.05.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 05/09/2014] [Accepted: 05/12/2014] [Indexed: 11/17/2022]
Abstract
The Tachyglossidae (long- and short-beaked echidnas) are a family of monotremes, confined to Australia and New Guinea, that exhibit striking trigeminal, olfactory and cortical specialisations. Several species of long-beaked echidna (Zaglossus robusta, Zaglossus hacketti, Megalibgwilia ramsayi) were part of the large-bodied (10 kg or more) fauna of Pleistocene Australasia, but only the diminutive (2-7 kg) Tachyglossus aculeatus is widespread today on the Australian mainland. We used high-resolution CT scanning and other osteological techniques to determine whether the remarkable neurological specialisations of modern echidnas were also present in Pleistocene forms or have undergone modification as the Australian climate changed in the transition from the Pleistocene to the Holocene. All the living and extinct echidnas studied have a similar pattern of cortical gyrification that suggests comparable functional topography to the modern short-beaked form. Osteological features related to olfactory, trigeminal, auditory and vestibular specialisation (e.g., foramina and cribriform plate area, osseous labyrinth topography) are also similar in living and extinct species. Our findings indicate that despite differences in diet, habitat and body size, the suite of neurological specialisations in the Tachyglossidae has been remarkably constant: encephalisation, sensory anatomy and specialisation (olfactory, trigeminal, auditory and vestibular), hypoglossal nerve size and cortical topography have all been stable neurological features of the group for at least 300,000 years.
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Affiliation(s)
- Ken W S Ashwell
- Department of Anatomy, School of Medical Sciences, The University of New South Wales, Botany Street, Sydney, NSW 2052, Australia.
| | - Craig D Hardman
- Department of Anatomy, School of Medical Sciences, The University of New South Wales, Botany Street, Sydney, NSW 2052, Australia
| | - Anne M Musser
- The Australian Museum, 6 College Street, Sydney, NSW 2010, Australia
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28
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Garrett EC, Steiper ME. Strong links between genomic and anatomical diversity in both mammalian olfactory chemosensory systems. Proc Biol Sci 2014; 281:20132828. [PMID: 24718758 DOI: 10.1098/rspb.2013.2828] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mammalian olfaction comprises two chemosensory systems: the odorant-detecting main olfactory system (MOS) and the pheromone-detecting vomeronasal system (VNS). Mammals are diverse in their anatomical and genomic emphases on olfactory chemosensation, including the loss or reduction of these systems in some orders. Despite qualitative evidence linking the genomic evolution of the olfactory systems to specific functions and phenotypes, little work has quantitatively tested whether the genomic aspects of the mammalian olfactory chemosensory systems are correlated to anatomical diversity. We show that the genomic and anatomical variation in these systems is tightly linked in both the VNS and the MOS, though the signature of selection is different in each system. Specifically, the MOS appears to vary based on absolute organ and gene family size while the VNS appears to vary according to the relative proportion of functional genes and relative anatomical size and complexity. Furthermore, there is little evidence that these two systems are evolving in a linked fashion. The relationships between genomic and anatomical diversity strongly support a role for natural selection in shaping both the anatomical and genomic evolution of the olfactory chemosensory systems in mammals.
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Affiliation(s)
- Eva C Garrett
- Program in Anthropology, The Graduate Center, City University of New York, , 365 Fifth Avenue, New York, NY 10016-4309, USA, Program in Biology, The Graduate Center, City University of New York, , 365 Fifth Avenue, New York, NY 10016-4309, USA, New York Consortium in Evolutionary Primatology (NYCEP), , New York, NY, USA, Department of Anthropology, Hunter College, City University of New York, , 695 Park Avenue, New York, NY 10065-5024, USA
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29
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Exploring the mammalian sensory space: co-operations and trade-offs among senses. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2013; 199:1077-92. [PMID: 24043357 DOI: 10.1007/s00359-013-0846-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 07/29/2013] [Accepted: 08/03/2013] [Indexed: 10/26/2022]
Abstract
The evolution of a particular sensory organ is often discussed with no consideration of the roles played by other senses. Here, we treat mammalian vision, olfaction and hearing as an interconnected whole, a three-dimensional sensory space, evolving in response to ecological challenges. Until now, there has been no quantitative method for estimating how much a particular animal invests in its different senses. We propose an anatomical measure based on sensory organ sizes. Dimensions of functional importance are defined and measured, and normalized in relation to animal mass. For 119 taxonomically and ecologically diverse species, we can define the position of the species in a three-dimensional sensory space. Thus, we can ask questions related to possible trade-off vs. co-operation among senses. More generally, our method allows morphologists to identify sensory organ combinations that are characteristic of particular ecological niches. After normalization for animal size, we note that arboreal mammals tend to have larger eyes and smaller noses than terrestrial mammals. On the other hand, we observe a strong correlation between eyes and ears, indicating that co-operation between vision and hearing is a general mammalian feature. For some groups of mammals we note a correlation, and possible co-operation between olfaction and whiskers.
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Green PA, Van Valkenburgh B, Pang B, Bird D, Rowe T, Curtis A. Respiratory and olfactory turbinal size in canid and arctoid carnivorans. J Anat 2012; 221:609-21. [PMID: 23035637 DOI: 10.1111/j.1469-7580.2012.01570.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/11/2012] [Indexed: 11/29/2022] Open
Abstract
Within the nasal cavity of mammals is a complex scaffold of paper-thin bones that function in respiration and olfaction. Known as turbinals, the bones greatly enlarge the surface area available for conditioning inspired air, reducing water loss, and improving olfaction. Given their functional significance, the relative development of turbinal bones might be expected to differ among species with distinct olfactory, thermoregulatory and/or water conservation requirements. Here we explore the surface area of olfactory and respiratory turbinals relative to latitude and diet in terrestrial Caniformia, a group that includes the canid and arctoid carnivorans (mustelids, ursids, procyonids, mephitids, ailurids). Using high-resolution computed tomography x-ray scans, we estimated respiratory and olfactory turbinal surface area and nasal chamber volume from three-dimensional virtual models of skulls. Across the Caniformia, respiratory surface area scaled isometrically with estimates of body size and there was no significant association with climate, as estimated by latitude. Nevertheless, one-on-one comparisons of sister taxa suggest that arctic species may have expanded respiratory turbinals. Olfactory surface area scaled isometrically among arctoids, but showed positive allometry in canids, reflecting the fact that larger canids, all of which are carnivorous, had relatively greater olfactory surface areas. In addition, among the arctoids, large carnivorous species such as the polar bear (Ursus maritimus) and wolverine (Gulo gulo) also displayed enlarged olfactory turbinals. More omnivorous caniform species that feed on substantial quantities of non-vertebrate foods had less expansive olfactory turbinals. Because large carnivorous species hunt widely dispersed prey, an expanded olfactory turbinal surface area may improve a carnivore's ability to detect prey over great distances using olfactory cues.
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Affiliation(s)
- Patrick A Green
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA 90095-1606, USA
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Thomas RJ, Davies C, Nunez A, Hibbs S, Eastaugh L, Harding S, Jordan J, Barnes K, Oyston P, Eley S. Particle-size dependent effects in the Balb/c murine model of inhalational melioidosis. Front Cell Infect Microbiol 2012; 2:101. [PMID: 22919690 PMCID: PMC3417579 DOI: 10.3389/fcimb.2012.00101] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 07/03/2012] [Indexed: 11/21/2022] Open
Abstract
Deposition of Burkholderia pseudomallei within either the lungs or nasal passages of the Balb/c murine model resulted in different infection kinetics. The infection resulting from the inhalation of B. pseudomallei within a 12 μm particle aerosol was prolonged compared to a 1 μm particle aerosol with a mean time-to-death (MTD) of 174.7 ± 14.9 h and 73.8 ± 11.3 h, respectively. Inhalation of B. pseudomallei within 1 μm or 12 μm particle aerosols resulted in a median lethal dose (MLD) of 4 and 12 cfu, respectively. The 12 μm particle inhalational infection was characterized by a marked involvement of the nasal mucosa and extension of bacterial colonization and inflammatory lesions from the olfactory epithelium through the olfactory nerves (or tracts) to the olfactory bulb (100%), culminating in abscessation of the brain (33%). Initial involvement of the upper respiratory tract lymphoid tissues (nasal-associated lymphoid tissue (NALT) and cervical lymph nodes) was observed in both the 1 and 12 μm particle inhalational infections (80-85%). Necrotising alveolitis and bronchiolitis were evident in both inhalational infections, however, lung pathology was greater after inhalation of the 1 μm particle aerosol with pronounced involvement of the mediastinal lymph node (50%). Terminal disease was characterized by bacteraemia in both inhalational infections with dissemination to the spleen, liver, kidneys, and thymus. Treatment with co-trimoxazole was more effective than treatment with doxycycline irrespective of the size of the particles inhaled. Doxycycline was more effective against the 12 μm particle inhalational infection as evidenced by increased time to death. However, both treatment regimes exhibited significant relapse when therapy was discontinued with massive enlargement and abscessation of the lungs, spleen, and cervical lymph nodes observed.
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Affiliation(s)
- Richard J Thomas
- Department of Biomedical Sciences, Defence Science and Technology Laboratory, Salisbury Wiltshire, UK.
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Macrini TE. Comparative Morphology of the Internal Nasal Skeleton of Adult Marsupials Based on X-ray Computed Tomography. BULLETIN OF THE AMERICAN MUSEUM OF NATURAL HISTORY 2012. [DOI: 10.1206/365.1] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Bastir M, Rosas A, Gunz P, Peña-Melian A, Manzi G, Harvati K, Kruszynski R, Stringer C, Hublin JJ. Evolution of the base of the brain in highly encephalized human species. Nat Commun 2011; 2:588. [PMID: 22158443 DOI: 10.1038/ncomms1593] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 11/14/2011] [Indexed: 01/14/2023] Open
Abstract
The increase of brain size relative to body size-encephalization-is intimately linked with human evolution. However, two genetically different evolutionary lineages, Neanderthals and modern humans, have produced similarly large-brained human species. Thus, understanding human brain evolution should include research into specific cerebral reorganization, possibly reflected by brain shape changes. Here we exploit developmental integration between the brain and its underlying skeletal base to test hypotheses about brain evolution in Homo. Three-dimensional geometric morphometric analyses of endobasicranial shape reveal previously undocumented details of evolutionary changes in Homo sapiens. Larger olfactory bulbs, relatively wider orbitofrontal cortex, relatively increased and forward projecting temporal lobe poles appear unique to modern humans. Such brain reorganization, beside physical consequences for overall skull shape, might have contributed to the evolution of H. sapiens' learning and social capacities, in which higher olfactory functions and its cognitive, neurological behavioral implications could have been hitherto underestimated factors.
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Affiliation(s)
- Markus Bastir
- Paleoanthropology Group, Department of Paleobiology, Museo Nacional de Ciencias Naturales, CSIC. J. G. Abascal 2, 28006 Madrid, Spain.
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Ober HK, Degroote LW, Mcdonough CM, Mizell RF, Mankin RW. Identification of an attractant for the nine-banded armadillo, Dasypus novemcinctus. WILDLIFE SOC B 2011. [DOI: 10.1002/wsb.79] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Van Valkenburgh B, Curtis A, Samuels JX, Bird D, Fulkerson B, Meachen-Samuels J, Slater GJ. Aquatic adaptations in the nose of carnivorans: evidence from the turbinates. J Anat 2011; 218:298-310. [PMID: 21198587 DOI: 10.1111/j.1469-7580.2010.01329.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Inside the mammalian nose lies a labyrinth of bony plates covered in epithelium collectively known as turbinates. Respiratory turbinates lie anteriorly and aid in heat and water conservation, while more posterior olfactory turbinates function in olfaction. Previous observations on a few carnivorans revealed that aquatic species have relatively large, complex respiratory turbinates and greatly reduced olfactory turbinates compared with terrestrial species. Body heat is lost more quickly in water than air and increased respiratory surface area likely evolved to minimize heat loss. At the same time, olfactory surface area probably diminished due to a decreased reliance on olfaction when foraging under water. To explore how widespread these adaptations are, we documented scaling of respiratory and olfactory turbinate surface area with body size in a variety of terrestrial, freshwater, and marine carnivorans, including pinnipeds, mustelids, ursids, and procyonids. Surface areas were estimated from high-resolution CT scans of dry skulls, a novel approach that enabled a greater sampling of taxa than is practical with fresh heads. Total turbinate, respiratory, and olfactory surface areas correlate well with body size (r(2) ≥0.7), and are relatively smaller in larger species. Relative to body mass or skull length, aquatic species have significantly less olfactory surface area than terrestrial species. Furthermore, the ratio of olfactory to respiratory surface area is associated with habitat. Using phylogenetic comparative methods, we found strong support for convergence on 1:3 proportions in aquatic taxa and near the inverse in terrestrial taxa, indicating that aquatic mustelids and pinnipeds independently acquired similar proportions of olfactory to respiratory turbinates. Constraints on turbinate surface area in the nasal chamber may result in a trade-off between respiratory and olfactory function in aquatic mammals.
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Kavoi B, Makanya A, Hassanali J, Carlsson HE, Kiama S. Comparative functional structure of the olfactory mucosa in the domestic dog and sheep. Ann Anat 2010; 192:329-37. [PMID: 20801626 DOI: 10.1016/j.aanat.2010.07.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 07/23/2010] [Accepted: 07/24/2010] [Indexed: 10/19/2022]
Abstract
Olfactory acuity differs among animal species depending on age and dependence on smell. However, the attendant functional anatomy has not been elucidated. We sought to determine the functional structure of the olfactory mucosa in suckling and adult dog and sheep. Mucosal samples harvested from ethmoturbinates were analyzed qualitatively and quantitatively. In both species, the olfactory mucosa comprised olfactory, supporting and basal cells, and a lamina propria containing bundles of olfactory cell axons, Bowman's glands and vascular elements. The olfactory cells terminated apically with an expanded knob, from which cilia projected in a radial fashion from its base and in form of a tuft from its apex in the dog and the sheep respectively. Olfactory cilia per knob were more numerous in the dog (19 ± 3) compared to the sheep (7 ± 2) (p<0.05). In the dog, axonal bundles exhibited one to two centrally located capillaries and the bundles were of greater diameters (73.3 ± 10.3 μm) than those of the sheep (50.6 ± 6.8 μm), which had no capillaries. From suckling to adulthood in the dog, the packing density of the olfactory and supporting cells increased by 22.5% and 12.6% respectively. Surprisingly in the sheep, the density of the olfactory cells decreased by 26.2% while that of the supportive cells showed no change. Overall epithelial thickness reached 72.5 ± 2.9 μm in the dog and 56.8 ± 3.1 μm in the sheep. These observations suggest that the mucosa is better structurally refined during maturation in the dog than in the sheep.
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Affiliation(s)
- Boniface Kavoi
- Department of Veterinary Anatomy & Physiology, University of Nairobi, Riveside Drive, PO Box 30197, Nairobi, Kenya.
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Craven BA, Paterson EG, Settles GS. The fluid dynamics of canine olfaction: unique nasal airflow patterns as an explanation of macrosmia. J R Soc Interface 2009; 7:933-43. [PMID: 20007171 DOI: 10.1098/rsif.2009.0490] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The canine nasal cavity contains hundreds of millions of sensory neurons, located in the olfactory epithelium that lines convoluted nasal turbinates recessed in the rear of the nose. Traditional explanations for canine olfactory acuity, which include large sensory organ size and receptor gene repertoire, overlook the fluid dynamics of odorant transport during sniffing. But odorant transport to the sensory part of the nose is the first critical step in olfaction. Here we report new experimental data on canine sniffing and demonstrate allometric scaling of sniff frequency, inspiratory airflow rate and tidal volume with body mass. Next, a computational fluid dynamics simulation of airflow in an anatomically accurate three-dimensional model of the canine nasal cavity, reconstructed from high-resolution magnetic resonance imaging scans, reveals that, during sniffing, spatially separate odour samples are acquired by each nostril that may be used for bilateral stimulus intensity comparison and odour source localization. Inside the nose, the computation shows that a unique nasal airflow pattern develops during sniffing, which is optimized for odorant transport to the olfactory part of the nose. These results contrast sharply with nasal airflow in the human. We propose that mammalian olfactory function and acuity may largely depend on odorant transport by nasal airflow patterns resulting from either the presence of a highly developed olfactory recess (in macrosmats such as the canine) or the lack of one (in microsmats including humans).
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Affiliation(s)
- Brent A Craven
- Applied Research Laboratory, The Pennsylvania State University, University Park, PA 16802, USA.
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BECK ROBINMD. Was the Oligo-Miocene Australian metatherian Yalkaparidon a ‘mammalian woodpecker’? Biol J Linn Soc Lond 2009. [DOI: 10.1111/j.1095-8312.2009.01171.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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