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Bhagwandin A, Molnár Z, Bertelsen MF, Karlsson KÆ, Alagaili AN, Bennett NC, Hof PR, Kaswera-Kyamakya C, Gilissen E, Jayakumar J, Manger PR. Where Do Core Thalamocortical Axons Terminate in Mammalian Neocortex When There Is No Cytoarchitecturally Distinct Layer 4? J Comp Neurol 2024; 532:e25652. [PMID: 38962882 DOI: 10.1002/cne.25652] [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: 03/15/2024] [Revised: 05/20/2024] [Accepted: 06/07/2024] [Indexed: 07/05/2024]
Abstract
Although the mammalian cerebral cortex is most often described as a hexalaminar structure, there are cortical areas (primary motor cortex) and species (elephants, cetaceans, and hippopotami), where a cytoarchitecturally indistinct, or absent, layer 4 is noted. Thalamocortical projections from the core, or first order, thalamic system terminate primarily in layers 4/inner 3. We explored the termination sites of core thalamocortical projections in cortical areas and in species where there is no cytoarchitecturally distinct layer 4 using the immunolocalization of vesicular glutamate transporter 2, a known marker of core thalamocortical axon terminals, in 31 mammal species spanning the eutherian radiation. Several variations from the canonical cortical column outline of layer 4 and core thalamocortical inputs were noted. In shrews/microchiropterans, layer 4 was present, but many core thalamocortical projections terminated in layer 1 in addition to layers 4 and inner 3. In primate primary visual cortex, the sublaminated layer 4 was associated with a specialized core thalamocortical projection pattern. In primate primary motor cortex, no cytoarchitecturally distinct layer 4 was evident and the core thalamocortical projections terminated throughout layer 3. In the African elephant, cetaceans, and river hippopotamus, no cytoarchitecturally distinct layer 4 was observed and core thalamocortical projections terminated primarily in inner layer 3 and less densely in outer layer 3. These findings are contextualized in terms of cortical processing, perception, and the evolutionary trajectory leading to an indistinct or absent cortical layer 4.
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Affiliation(s)
- Adhil Bhagwandin
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Zoltán Molnár
- Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK
| | - Mads F Bertelsen
- Centre for Zoo and Wild Animal Health, Copenhagen Zoo, Frederiksberg, Denmark
| | - Karl Æ Karlsson
- Biomedical Engineering, Reykjavik University, Reykjavik, Iceland
| | | | - Nigel C Bennett
- South African Research Chair of Mammal Behavioural Ecology and Physiology, University of Pretoria, Pretoria, South Africa
| | - Patrick R Hof
- Nash Family Department of Neuroscience, Center for Discovery and Innovation, and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | | | - Emmanuel Gilissen
- Department of African Zoology, Royal Museum for Central Africa, Tervuren, Belgium
- Laboratory of Histology and Neuropathology, Université Libre de Bruxelles, Brussels, Belgium
| | - Jaikishan Jayakumar
- Sudha Gopalakrishnan Brain Centre, Indian Institute of Technology Madras, Chennai, India
- Center for Computational Brain Research, Indian Institute of Technology Madras, Chennai, India
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
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Mahon S. Variation and convergence in the morpho-functional properties of the mammalian neocortex. Front Syst Neurosci 2024; 18:1413780. [PMID: 38966330 PMCID: PMC11222651 DOI: 10.3389/fnsys.2024.1413780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Accepted: 06/03/2024] [Indexed: 07/06/2024] Open
Abstract
Man's natural inclination to classify and hierarchize the living world has prompted neurophysiologists to explore possible differences in brain organisation between mammals, with the aim of understanding the diversity of their behavioural repertoires. But what really distinguishes the human brain from that of a platypus, an opossum or a rodent? In this review, we compare the structural and electrical properties of neocortical neurons in the main mammalian radiations and examine their impact on the functioning of the networks they form. We discuss variations in overall brain size, number of neurons, length of their dendritic trees and density of spines, acknowledging their increase in humans as in most large-brained species. Our comparative analysis also highlights a remarkable consistency, particularly pronounced in marsupial and placental mammals, in the cell typology, intrinsic and synaptic electrical properties of pyramidal neuron subtypes, and in their organisation into functional circuits. These shared cellular and network characteristics contribute to the emergence of strikingly similar large-scale physiological and pathological brain dynamics across a wide range of species. These findings support the existence of a core set of neural principles and processes conserved throughout mammalian evolution, from which a number of species-specific adaptations appear, likely allowing distinct functional needs to be met in a variety of environmental contexts.
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Affiliation(s)
- Séverine Mahon
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France
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3
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Zhang N, Zhang Y. Correlation between gyral size, brain size, and head impact risk across mammalian species. Brain Res 2024; 1828:148768. [PMID: 38244756 DOI: 10.1016/j.brainres.2024.148768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 12/12/2023] [Accepted: 01/12/2024] [Indexed: 01/22/2024]
Abstract
A study on primates has established that gyral size is largely independent of overall brain size. Building on this-and other research suggesting that brain gyrification may mitigate the effects of head impacts-our study aims to explore potential correlations between gyral size and the risk of head impact across a diverse range of mammalian species. Our findings corroborate the idea that gyral sizes are largely independent of brain sizes, especially among species with larger brains, thus extending this observation beyond primates. Preliminary evidence also suggests a correlation between an animal's gyral size and its lifestyle, particularly in terms of head-impact risk. For instance, goats, known for their headbutting behaviors, exhibit smaller gyral sizes. In contrast, species such as manatees and dugongs, which typically face lower risks of head impact, have lissencephalic brains. Additionally, we explore mechanisms that may explain how narrower gyral sizes could offer protective advantages against head impact. Finally, we discuss a possible trade-off associated with gyrencephaly.
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Affiliation(s)
- Nianqin Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
| | - Yongjun Zhang
- Science College, Liaoning Technical University, Fuxin 123000, China.
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4
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Kerber L, Roese-Miron L, Bubadué JM, Martinelli AG. Endocranial anatomy of the early prozostrodonts (Eucynodontia: Probainognathia) and the neurosensory evolution in mammal forerunners. Anat Rec (Hoboken) 2024; 307:1442-1473. [PMID: 37017195 DOI: 10.1002/ar.25215] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 03/09/2023] [Accepted: 03/09/2023] [Indexed: 04/06/2023]
Abstract
Prozostrodon brasiliensis and Therioherpeton cargnini are non-mammaliaform cynodonts that lived ~233 million years ago (late Carnian, Late Triassic) in western Gondwana. They represent some of the earliest divergent members of the clade Prozostrodontia, which includes "tritheledontids", tritylodontids, "brasilodontids", and mammaliaforms (including Mammalia as crown group). Here, we studied the endocranial anatomy (cranial endocast, nerves, vessels, ducts, ear region, and nasal cavity) of these two species. Our findings suggest that during the Carnian, early prozostrodonts had a brain with well-developed olfactory bulbs, expanded cerebral hemispheres divided by the interhemispheric sulcus, and absence of an unossified zone and pineal body. The morphology of the maxillary canal represents the necessary condition for the presence of facial vibrissae. A slight decrease in encephalization is observed at the origin of the clade Prozostrodontia. This new anatomical information provides evidence for the evolution of endocranial traits of the first prozotrodonts, a Late Triassic lineage that culminated in the origin of mammals.
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Affiliation(s)
- Leonardo Kerber
- Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
- Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia, Universidade Federal de Santa Maria (CAPPA/UFSM), São João do Polêsine, RS, Brazil
| | - Lívia Roese-Miron
- Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
- Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia, Universidade Federal de Santa Maria (CAPPA/UFSM), São João do Polêsine, RS, Brazil
| | - Jamile M Bubadué
- Laboratorio de Ciências Ambientais, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Brazil
| | - Agustín G Martinelli
- Sección Paleontologia de Vertebrados, Museo Argentino de Ciencias Naturales "Bernardino Rivadavia", Buenos Aires, Argentina
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5
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Gerussi T, Graïc JM, Peruffo A, Behroozi M, Schlaffke L, Huggenberger S, Güntürkün O, Cozzi B. The prefrontal cortex of the bottlenose dolphin (Tursiops truncatus Montagu, 1821): a tractography study and comparison with the human. Brain Struct Funct 2023; 228:1963-1976. [PMID: 37660322 PMCID: PMC10517040 DOI: 10.1007/s00429-023-02699-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 08/21/2023] [Indexed: 09/05/2023]
Abstract
Cetaceans are well known for their remarkable cognitive abilities including self-recognition, sound imitation and decision making. In other mammals, the prefrontal cortex (PFC) takes a key role in such cognitive feats. In cetaceans, however, a PFC could up to now not be discerned based on its usual topography. Classical in vivo methods like tract tracing are legally not possible to perform in Cetacea, leaving diffusion-weighted imaging (DWI) as the most viable alternative. This is the first investigation focussed on the identification of the cetacean PFC homologue. In our study, we applied the constrained spherical deconvolution (CSD) algorithm on 3 T DWI scans of three formalin-fixed brains of bottlenose dolphins (Tursiops truncatus) and compared the obtained results to human brains, using the same methodology. We first identified fibres related to the medio-dorsal thalamic nuclei (MD) and then seeded the obtained putative PFC in the dolphin as well as the known PFC in humans. Our results outlined the dolphin PFC in areas not previously studied, in the cranio-lateral, ectolateral and opercular gyri, and furthermore demonstrated a similar connectivity pattern between the human and dolphin PFC. The antero-lateral rotation of the PFC, like in other areas, might be the result of the telescoping process which occurred in these animals during evolution.
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Affiliation(s)
- Tommaso Gerussi
- Department of Comparative Biomedicine and Food Science (BCA), University of Padua, Legnaro, Italy.
| | - Jean-Marie Graïc
- Department of Comparative Biomedicine and Food Science (BCA), University of Padua, Legnaro, Italy
| | - Antonella Peruffo
- Department of Comparative Biomedicine and Food Science (BCA), University of Padua, Legnaro, Italy
| | - Mehdi Behroozi
- Department of Biopsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr-University Bochum, 44801, Bochum, Germany
| | - Lara Schlaffke
- Department of Neurology, BG-University Hospital Bergmannsheil, Ruhr-University Bochum, Bürkle-de-La-Camp-Platz 1, 44789, Bochum, Germany
| | - Stefan Huggenberger
- Institute of Anatomy and Clinical Morphology, Witten/Herdecke University, Alfred-Herrhausen-Straße 50, 58448, Witten, Germany
| | - Onur Güntürkün
- Department of Biopsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr-University Bochum, 44801, Bochum, Germany
- Research Center One Health Ruhr, Research Alliance Ruhr, Ruhr-University Bochum, Bochum, Germany
| | - Bruno Cozzi
- Department of Comparative Biomedicine and Food Science (BCA), University of Padua, Legnaro, Italy
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de Sousa AA, Beaudet A, Calvey T, Bardo A, Benoit J, Charvet CJ, Dehay C, Gómez-Robles A, Gunz P, Heuer K, van den Heuvel MP, Hurst S, Lauters P, Reed D, Salagnon M, Sherwood CC, Ströckens F, Tawane M, Todorov OS, Toro R, Wei Y. From fossils to mind. Commun Biol 2023; 6:636. [PMID: 37311857 PMCID: PMC10262152 DOI: 10.1038/s42003-023-04803-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 04/04/2023] [Indexed: 06/15/2023] Open
Abstract
Fossil endocasts record features of brains from the past: size, shape, vasculature, and gyrification. These data, alongside experimental and comparative evidence, are needed to resolve questions about brain energetics, cognitive specializations, and developmental plasticity. Through the application of interdisciplinary techniques to the fossil record, paleoneurology has been leading major innovations. Neuroimaging is shedding light on fossil brain organization and behaviors. Inferences about the development and physiology of the brains of extinct species can be experimentally investigated through brain organoids and transgenic models based on ancient DNA. Phylogenetic comparative methods integrate data across species and associate genotypes to phenotypes, and brains to behaviors. Meanwhile, fossil and archeological discoveries continuously contribute new knowledge. Through cooperation, the scientific community can accelerate knowledge acquisition. Sharing digitized museum collections improves the availability of rare fossils and artifacts. Comparative neuroanatomical data are available through online databases, along with tools for their measurement and analysis. In the context of these advances, the paleoneurological record provides ample opportunity for future research. Biomedical and ecological sciences can benefit from paleoneurology's approach to understanding the mind as well as its novel research pipelines that establish connections between neuroanatomy, genes and behavior.
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Affiliation(s)
| | - Amélie Beaudet
- Laboratoire de Paléontologie, Évolution, Paléoécosystèmes et Paléoprimatologie (PALEVOPRIM), UMR 7262 CNRS & Université de Poitiers, Poitiers, France.
- University of Cambridge, Cambridge, UK.
| | - Tanya Calvey
- Division of Clinical Anatomy and Biological Anthropology, University of Cape Town, Cape Town, South Africa.
| | - Ameline Bardo
- UMR 7194, CNRS-MNHN, Département Homme et Environnement, Musée de l'Homme, Paris, France
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Julien Benoit
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Christine J Charvet
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL, USA
| | - Colette Dehay
- University of Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, F-69500, Bron, France
| | | | - Philipp Gunz
- Department of Human Origins, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, D-04103, Leipzig, Germany
| | - Katja Heuer
- Institut Pasteur, Université Paris Cité, Unité de Neuroanatomie Appliquée et Théorique, F-75015, Paris, France
| | | | - Shawn Hurst
- University of Indianapolis, Indianapolis, IN, USA
| | - Pascaline Lauters
- Institut royal des Sciences naturelles, Direction Opérationnelle Terre et Histoire de la Vie, Brussels, Belgium
| | - Denné Reed
- Department of Anthropology, University of Texas at Austin, Austin, TX, USA
| | - Mathilde Salagnon
- CNRS, CEA, IMN, GIN, UMR 5293, Université Bordeaux, Bordeaux, France
- PACEA UMR 5199, CNRS, Université Bordeaux, Pessac, France
| | - Chet C Sherwood
- Department of Anthropology, The George Washington University, Washington, DC, USA
| | - Felix Ströckens
- C. & O. Vogt Institute for Brain Research, University Hospital Düsseldorf, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Mirriam Tawane
- Ditsong National Museum of Natural History, Pretoria, South Africa
| | - Orlin S Todorov
- School of Natural Sciences, Macquarie University, Sydney, NSW, Australia
| | - Roberto Toro
- Institut Pasteur, Université Paris Cité, Unité de Neuroanatomie Appliquée et Théorique, F-75015, Paris, France
| | - Yongbin Wei
- Beijing University of Posts and Telecommunications, Beijing, China
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At the root of the mammalian mind: The sensory organs, brain and behavior of pre-mammalian synapsids. PROGRESS IN BRAIN RESEARCH 2023; 275:25-72. [PMID: 36841570 DOI: 10.1016/bs.pbr.2022.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
All modern mammals are descendants of the paraphyletic non-mammaliaform Synapsida, colloquially referred to as the "mammal-like reptiles." It has long been assumed that these mammalian ancestors were essentially reptile-like in their morphology, biology, and behavior, i.e., they had a small brain, displayed simple behavior, and their sensory organs were unrefined compared to those of modern mammals. Recent works have, however, revealed that neurological, sensory, and behavioral traits previously considered typically mammalian, such as whiskers, enhanced olfaction, nocturnality, parental care, and complex social interactions evolved before the origin of Mammaliaformes, among the early-diverging "mammal-like reptiles." In contrast, an enlarged brain did not evolve immediately after the origin of mammaliaforms. As such, in terms of paleoneurology, the last "mammal-like reptiles" were not significantly different from the earliest mammaliaforms. The abundant data and literature published in the last 10 years no longer supports the "three pulses" scenario of synapsid brain evolution proposed by Rowe and colleagues in 2011, but supports the new "outside-in" model of Rodrigues and colleagues proposed in 2018, instead. As Mesozoic reptiles were becoming the dominant taxa within terrestrial ecosystems, synapsids gradually adapted to smaller body sizes and nocturnality. This resulted in a sensory revolution in synapsids as olfaction, audition, and somatosensation compensated for the loss of visual cues. This altered sensory input is aligned with changes in the brain, the most significant of which was an increase in relative brain size.
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8
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Ecomorphology of toothed whales (Cetacea, Odontoceti) as revealed by 3D skull geometry. J MAMM EVOL 2023. [DOI: 10.1007/s10914-022-09642-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
AbstractExtant odontocetes (toothed whales) exhibit differences in body size and brain mass, biosonar mode, feeding strategies, and diving and habitat adaptations. Strong selective pressures associated with these factors have likely contributed to the morphological diversification of their skull. Here, we used 3D landmark geometric morphometric data from the skulls of 60 out of ~ 72 extant odontocete species and a well-supported phylogenetic tree to test whether size and shape variation are associated with ecological adaptations at an interspecific scale. Odontocete skull morphology exhibited a significant phylogenetic signal, with skull size showing stronger signal than shape. After accounting for phylogeny, significant associations were detected between skull size and biosonar mode, body length, brain and body mass, maximum and minimum prey size, and maximum peak frequency. Brain mass was also strongly correlated with skull shape together with surface temperature and average and minimum prey size. When asymmetric and symmetric components of shape were analysed separately, a significant correlation was detected between sea surface temperature and both symmetric and asymmetric components of skull shape, and between diving ecology and the asymmetric component. Skull shape variation of odontocetes was strongly influenced by evolutionary allometry but most of the associations with ecological variables were not supported after phylogenetic correction. This suggests that ecomorphological feeding adaptations vary more between, rather than within, odontocete families, and functional anatomical patterns across odontocete clades are canalised by size constraints.
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Shilovsky GA, Putyatina TS, Markov AV. Evolution of Longevity as a Species-Specific Trait in Mammals. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:1579-1599. [PMID: 36717448 DOI: 10.1134/s0006297922120148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
From the evolutionary point of view, the priority problem for an individual is not longevity, but adaptation to the environment associated with the need for survival, food supply, and reproduction. We see two main vectors in the evolution of mammals. One is a short lifespan and numerous offspring ensuring reproductive success (r-strategy). The other one is development of valuable skills in order compete successfully (K-strategy). Species with the K-strategy should develop and enhance specific systems (anti-aging programs) aimed at increasing the reliability and adaptability, including lifespan. These systems are signaling cascades that provide cell repair and antioxidant defense. Hence, any arbitrarily selected long-living species should be characterized by manifestation to a different extent of the longevity-favoring traits (e.g., body size, brain development, sociality, activity of body repair and antioxidant defense systems, resistance to xenobiotics and tumor formation, presence of neotenic traits). Hereafter, we will call a set of such traits as the gerontological success of a species. Longevity is not equivalent to the evolutionary or reproductive success. This difference between these phenomena reaches its peak in mammals due to the development of endothermy and cephalization associated with the cerebral cortex expansion, which leads to the upregulated production of oxidative radicals by the mitochondria (and, consequently, accelerated aging), increase in the number of non-dividing differentiated cells, accumulation of the age-related damage in these cells, and development of neurodegenerative diseases. The article presents mathematical indicators used to assess the predisposition to longevity in different species (including the standard mortality rate and basal metabolic rate, as well as their derivatives). The properties of the evolution of mammals (including the differences between modern mammals and their ancestral forms) are also discussed.
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Affiliation(s)
- Gregory A Shilovsky
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia. .,Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, 127051, Russia
| | - Tatyana S Putyatina
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Alexander V Markov
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
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Espinós A, Fernández‐Ortuño E, Negri E, Borrell V. Evolution of genetic mechanisms regulating cortical neurogenesis. Dev Neurobiol 2022; 82:428-453. [PMID: 35670518 PMCID: PMC9543202 DOI: 10.1002/dneu.22891] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/26/2022] [Accepted: 05/24/2022] [Indexed: 11/20/2022]
Abstract
The size of the cerebral cortex increases dramatically across amniotes, from reptiles to great apes. This is primarily due to different numbers of neurons and glial cells produced during embryonic development. The evolutionary expansion of cortical neurogenesis was linked to changes in neural stem and progenitor cells, which acquired increased capacity of self‐amplification and neuron production. Evolution works via changes in the genome, and recent studies have identified a small number of new genes that emerged in the recent human and primate lineages, promoting cortical progenitor proliferation and increased neurogenesis. However, most of the mammalian genome corresponds to noncoding DNA that contains gene‐regulatory elements, and recent evidence precisely points at changes in expression levels of conserved genes as key in the evolution of cortical neurogenesis. Here, we provide an overview of basic cellular mechanisms involved in cortical neurogenesis across amniotes, and discuss recent progress on genetic mechanisms that may have changed during evolution, including gene expression regulation, leading to the expansion of the cerebral cortex.
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Affiliation(s)
- Alexandre Espinós
- Instituto de Neurociencias CSIC ‐ UMH, 03550 Sant Joan d'Alacant Spain
| | | | - Enrico Negri
- Instituto de Neurociencias CSIC ‐ UMH, 03550 Sant Joan d'Alacant Spain
| | - Víctor Borrell
- Instituto de Neurociencias CSIC ‐ UMH, 03550 Sant Joan d'Alacant Spain
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11
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Imam A, Bhagwandin A, Ajao MS, Manger PR. The brain of the tree pangolin (Manis tricuspis). IX. The pallial telencephalon. J Comp Neurol 2022; 530:2645-2691. [PMID: 35621013 PMCID: PMC9546464 DOI: 10.1002/cne.25349] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 04/13/2022] [Accepted: 05/04/2022] [Indexed: 11/25/2022]
Abstract
A cyto‐, myelo‐, and chemoarchitectonic analysis of the pallial telencephalon of the tree pangolin is provided. As certain portions of the pallial telencephalon have been described previously (olfactory pallium, hippocampal formation, and amygdaloid complex), we focus on the claustrum and endopiriform nuclear complex, the white matter and white matter interstitial cells, and the areal organization of the cerebral cortex. Our analysis indicates that the organization of the pallial telencephalon of the tree pangolin is similar to that observed in many other mammals, and specifically quite similar to the closely related carnivores. The claustrum of the tree pangolin exhibits a combination of insular and laminar architecture, while the endopiriform nuclear complex contains three nuclei, both reminiscent of observations made in other mammals. The population of white matter interstitial cells resembles that observed in other mammals, while a distinct laminated organization of the intracortical white matter was revealed with parvalbumin immunostaining. The cerebral cortex of the tree pangolin presented with indistinct laminar boundaries as well as pyramidalization of the neurons in both layers 2 and 4. All cortical regions typically found in mammals were present, with the cortical areas within these regions often corresponding to what has been reported in carnivores. Given the similarity of the organization of the pallial telencephalon of the tree pangolin to that observed in other mammals, especially carnivores, it would be reasonable to assume that the neural processing afforded the tree pangolin by these structures does not differ dramatically to that of other mammals.
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Affiliation(s)
- Aminu Imam
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa.,Department of Anatomy, Faculty of Basic Medical Sciences, College of Health Sciences, University of Ilorin, Ilorin, Nigeria
| | - Adhil Bhagwandin
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Moyosore S Ajao
- Department of Anatomy, Faculty of Basic Medical Sciences, College of Health Sciences, University of Ilorin, Ilorin, Nigeria
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
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12
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Bisconti M, Daniello R, Damarco P, Tartarelli G, Pavia M, Carnevale G. High Encephalization in a Fossil Rorqual Illuminates Baleen Whale Brain Evolution. BRAIN, BEHAVIOR AND EVOLUTION 2021; 96:78-90. [PMID: 34758463 DOI: 10.1159/000519852] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 09/22/2021] [Indexed: 11/19/2022]
Abstract
Baleen whales are considered underencephalized mammals due to their reduced brain size with respect to their body size (encephalization quotient [EQ] << 1). Despite their low EQ, mysticetes exhibit complex behavioral patterns in terms of motor abilities, vocal repertoire, and cultural learning. Very scarce information is available about the morphological evolution of the brain in this group; this makes it difficult to investigate the historical changes in brain shape and size in order to relate the origin of the complex mysticete behavioral repertoire to the evolution of specific neural substrates. Here, the first description of the virtual endocast of a fossil balaenopterid species, Marzanoptera tersillae from the Italian Pliocene, reveals an EQ of around 3, which is exceptional for baleen whales. The endocast showed a morphologically different organization of the brain in this fossil whale as the cerebral hemispheres are anteroposteriorly shortened, the cerebellum lacks the posteromedial expansion of the cerebellar hemispheres, and the cerebellar vermis is unusually reduced. The comparative reductions of the cerebral and cerebellar hemispheres suggest that the motor behavior of M. tersillae probably was less sophisticated than that exhibited by the extant rorqual and humpback species. The presence of an EQ value in this fossil species that is around 10 times higher than that of extant mysticetes opens new questions about brain evolution and provides new, invaluable information about the evolutionary path of morphological and size change in the brain of baleen whales.
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Affiliation(s)
- Michelangelo Bisconti
- Dipartimento di Scienze della Terra, Università degli Studi di Torino, Torino, Italy.,Paleontology Department, Natural History Museum of San Diego, San Diego, California, USA
| | - Riccardo Daniello
- Dipartimento di Scienze della Terra, Università degli Studi di Torino, Torino, Italy
| | - Piero Damarco
- Museo Paleontologico Territoriale dell'Astigiano, Ente di Gestione del Parco Paleontologico Astigiano, Asti, Italy
| | | | - Marco Pavia
- Dipartimento di Scienze della Terra, Università degli Studi di Torino, Torino, Italy
| | - Giorgio Carnevale
- Dipartimento di Scienze della Terra, Università degli Studi di Torino, Torino, Italy
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13
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Waugh DA, Thewissen JGM. The pattern of brain-size change in the early evolution of cetaceans. PLoS One 2021; 16:e0257803. [PMID: 34582492 PMCID: PMC8478358 DOI: 10.1371/journal.pone.0257803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 09/10/2021] [Indexed: 11/17/2022] Open
Abstract
Most authors have identified two rapid increases in relative brain size (encephalization quotient, EQ) in cetacean evolution: first at the origin of the modern suborders (odontocetes and mysticetes) around the Eocene-Oligocene transition, and a second at the origin of the delphinoid odontocetes during the middle Miocene. We explore how methods used to estimate brain and body mass alter this perceived timing and rate of cetacean EQ evolution. We provide new data on modern mammals (mysticetes, odontocetes, and terrestrial artiodactyls) and show that brain mass and endocranial volume scale allometrically, and that endocranial volume is not a direct proxy for brain mass. We demonstrate that inconsistencies in the methods used to estimate body size across the Eocene-Oligocene boundary have caused a spurious pattern in earlier relative brain size studies. Instead, we employ a single method, using occipital condyle width as a skeletal proxy for body mass using a new dataset of extant cetaceans, to clarify this pattern. We suggest that cetacean relative brain size is most accurately portrayed using EQs based on the scaling coefficients as observed in the closely related terrestrial artiodactyls. Finally, we include additional data for an Eocene whale, raising the sample size of Eocene archaeocetes to seven. Our analysis of fossil cetacean EQ is different from previous works which had shown that a sudden increase in EQ coincided with the origin of odontocetes at the Eocene-Oligocene boundary. Instead, our data show that brain size increased at the origin of basilosaurids, 5 million years before the Eocene-Oligocene transition, and we do not observe a significant increase in relative brain size at the origin of odontocetes.
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Affiliation(s)
- David A. Waugh
- Department of Anatomy and Neurobiology, Northeast Ohio
Medical University, Rootstown, Ohio, United States of America
| | - J. G. M. Thewissen
- Department of Anatomy and Neurobiology, Northeast Ohio
Medical University, Rootstown, Ohio, United States of America
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14
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Jacobs B, Rally H, Doyle C, O'Brien L, Tennison M, Marino L. Putative neural consequences of captivity for elephants and cetaceans. Rev Neurosci 2021; 33:439-465. [PMID: 34534428 DOI: 10.1515/revneuro-2021-0100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/02/2021] [Indexed: 12/20/2022]
Abstract
The present review assesses the potential neural impact of impoverished, captive environments on large-brained mammals, with a focus on elephants and cetaceans. These species share several characteristics, including being large, wide-ranging, long-lived, cognitively sophisticated, highly social, and large-brained mammals. Although the impact of the captive environment on physical and behavioral health has been well-documented, relatively little attention has been paid to the brain itself. Here, we explore the potential neural consequences of living in captive environments, with a focus on three levels: (1) The effects of environmental impoverishment/enrichment on the brain, emphasizing the negative neural consequences of the captive/impoverished environment; (2) the neural consequences of stress on the brain, with an emphasis on corticolimbic structures; and (3) the neural underpinnings of stereotypies, often observed in captive animals, underscoring dysregulation of the basal ganglia and associated circuitry. To this end, we provide a substantive hypothesis about the negative impact of captivity on the brains of large mammals (e.g., cetaceans and elephants) and how these neural consequences are related to documented evidence for compromised physical and psychological well-being.
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Affiliation(s)
- Bob Jacobs
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Colorado College, Colorado Springs, CO, 80903, USA
| | - Heather Rally
- Foundation to Support Animal Protection, Norfolk, VA, 23510, USA
| | - Catherine Doyle
- Performing Animal Welfare Society, P.O. Box 849, Galt, CA, 95632, USA
| | - Lester O'Brien
- Palladium Elephant Consulting Inc., 2408 Pinewood Dr. SE, Calgary, AB, T2B1S4, Canada
| | - Mackenzie Tennison
- Department of Psychology, University of Washington, Seattle, WA, 98195, USA
| | - Lori Marino
- Whale Sanctuary Project, Kanab, UT, 84741, USA
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15
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Endocranial Morphology of a Middle Miocene South American Dugongid and the Neurosensorial Evolution of Sirenians. J MAMM EVOL 2021. [DOI: 10.1007/s10914-021-09555-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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16
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Mccurry MR, Marx FG, Evans AR, Park T, Pyenson ND, Kohno N, Castiglione S, Fitzgerald EMG. Brain size evolution in whales and dolphins: new data from fossil mysticetes. Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab054] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Cetaceans (whales and dolphins) have some of the largest and most complex brains in the animal kingdom. When and why this trait evolved remains controversial, with proposed drivers ranging from echolocation to foraging complexity and high-level sociality. This uncertainty partially reflects a lack of data on extinct baleen whales (mysticetes), which has obscured deep-time patterns of brain size evolution in non-echolocating cetaceans. Building on new measurements from mysticete fossils, we show that the evolution of large brains preceded that of echolocation, and subsequently followed a complex trajectory involving several independent increases (e.g. in rorquals and oceanic dolphins) and decreases (e.g. in right whales and ‘river dolphins’). Echolocating whales show a greater tendency towards large brain size, thus reaffirming cognitive demands associated with sound processing as a plausible driver of cetacean encephalization. Nevertheless, our results suggest that other factors such as sociality were also important.
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Affiliation(s)
- Matthew R Mccurry
- Australian Museum Research Institute, 1 William Street, Sydney, New South Wales 2010, Australia
- Earth and Sustainability Science Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Kensington, New South Wales 2052, Australia
- Paleobiology, NMNH, Smithsonian Institution, Washington, DC, USA
| | - Felix G Marx
- Museum of New Zealand Te Papa Tongarewa, Wellington, 6011, New Zealand
- Department of Geology, University of Otago, Dunedin, 3054, New Zealand
| | - Alistair R Evans
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
- Geosciences, Museums Victoria, Melbourne, Victoria, Australia
| | - Travis Park
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, UK
| | - Nicholas D Pyenson
- Paleobiology, NMNH, Smithsonian Institution, Washington, DC, USA
- Department of Paleontology and Geology, Burke Museum of Natural History and Culture, University of Washington, Seattle, WA, USA
| | - Naoki Kohno
- Department of Geology and Palaeontology, National Museum of Nature and Science, Tsukuba, Japan
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Silvia Castiglione
- Department of Earth Sciences, Environment and Resources, University of Naples Federico II, 80138 Napoli,Italy
| | - Erich M G Fitzgerald
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
- Geosciences, Museums Victoria, Melbourne, Victoria, Australia
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, UK
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17
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Smaers JB, Rothman RS, Hudson DR, Balanoff AM, Beatty B, Dechmann DKN, de Vries D, Dunn JC, Fleagle JG, Gilbert CC, Goswami A, Iwaniuk AN, Jungers WL, Kerney M, Ksepka DT, Manger PR, Mongle CS, Rohlf FJ, Smith NA, Soligo C, Weisbecker V, Safi K. The evolution of mammalian brain size. SCIENCE ADVANCES 2021; 7:7/18/eabe2101. [PMID: 33910907 PMCID: PMC8081360 DOI: 10.1126/sciadv.abe2101] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 03/10/2021] [Indexed: 05/08/2023]
Abstract
Relative brain size has long been considered a reflection of cognitive capacities and has played a fundamental role in developing core theories in the life sciences. Yet, the notion that relative brain size validly represents selection on brain size relies on the untested assumptions that brain-body allometry is restrained to a stable scaling relationship across species and that any deviation from this slope is due to selection on brain size. Using the largest fossil and extant dataset yet assembled, we find that shifts in allometric slope underpin major transitions in mammalian evolution and are often primarily characterized by marked changes in body size. Our results reveal that the largest-brained mammals achieved large relative brain sizes by highly divergent paths. These findings prompt a reevaluation of the traditional paradigm of relative brain size and open new opportunities to improve our understanding of the genetic and developmental mechanisms that influence brain size.
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Affiliation(s)
- J B Smaers
- Department of Anthropology, Stony Brook University, Stony Brook, NY 11794, USA.
- Division of Anthropology, American Museum of Natural History, New York, NY 10024, USA
| | - R S Rothman
- Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
| | - D R Hudson
- Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
| | - A M Balanoff
- Department of Psychological and Brain Sciences Johns Hopkins University, Baltimore, MD 21218, USA
- Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
| | - B Beatty
- NYIT College of Osteopathic Medicine, Old Westbury, NY 11568, USA
- United States National Museum, Smithsonian Institution, Washington, DC 20560, USA
| | - D K N Dechmann
- Department of Migration, Max-Planck Institute of Animal Behavior, 78315 Radolfzell, Germany
- Department of Biology, University of Konstanz, 78464 Konstanz, Germany
| | - D de Vries
- Ecosystems and Environment Research Centre, School of Science, Engineering and Environment, University of Salford, Manchester M5 4WX, UK
| | - J C Dunn
- Division of Biological Anthropology, University of Cambridge, Cambridge CB2 3QG, UK
- Behavioral Ecology Research Group, Anglia Ruskin University, Cambridge CB1 1PT, UK
- Department of Cognitive Biology, University of Vienna, Vienna 1090, Austria
| | - J G Fleagle
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794, USA
| | - C C Gilbert
- NYIT College of Osteopathic Medicine, Old Westbury, NY 11568, USA
- Department of Anthropology, Hunter College, New York, NY 10065, USA
- PhD Program in Anthropology, Graduate Center of the City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
- New York Consortium in Evolutionary Primatology, New York, NY 10065, USA
| | - A Goswami
- Department of Life Sciences, Natural History Museum, London SW7 5BD, UK
| | - A N Iwaniuk
- Department of Neuroscience, University of Lethbridge, Lethbridge, AB T1K-3M4, Canada
| | - W L Jungers
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794, USA
- Association Vahatra, BP 3972, Antananarivo 101, Madagascar
| | - M Kerney
- Behavioral Ecology Research Group, Anglia Ruskin University, Cambridge CB1 1PT, UK
| | - D T Ksepka
- Bruce Museum, Greenwich, CT 06830, USA
- Department of Ornithology, American Museum of Natural History, New York, NY 10024, USA
- Division of Science and Education, Field Museum of Natural History, Chicago, IL 60605, USA
- Department of Paleobiology, Smithsonian Institution, Washington, DC 20013, USA
| | - P R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - C S Mongle
- Division of Anthropology, American Museum of Natural History, New York, NY 10024, USA
- Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
- Turkana Basin Institute, Stony Brook University, Stony Brook, NY 11794, USA
| | - F J Rohlf
- Department of Anthropology, Stony Brook University, Stony Brook, NY 11794, USA
| | - N A Smith
- Division of Science and Education, Field Museum of Natural History, Chicago, IL 60605, USA
- Campbell Geology Museum, Clemson University, Clemson, SC 29634, USA
| | - C Soligo
- Department of Anthropology, University College London, London WC1H 0BW, UK
| | - V Weisbecker
- College of Science and Engineering, Flinders University, Bedford Park, SA 5042, Australia
| | - K Safi
- Department of Migration, Max-Planck Institute of Animal Behavior, 78315 Radolfzell, Germany
- Department of Biology, University of Konstanz, 78464 Konstanz, Germany
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18
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Kerber L, Ferreira JD, Fonseca PHM, Franco A, Martinelli AG, Soares MB, Ribeiro AM. An additional brain endocast of the ictidosaur Riograndia guaibensis (Eucynodontia: Probainognathia): intraspecific variation of endocranial traits. AN ACAD BRAS CIENC 2021; 93:e20200084. [PMID: 33681891 DOI: 10.1590/0001-3765202120200084] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 07/08/2020] [Indexed: 11/22/2022] Open
Abstract
Recently, the morphology and encephalization of the brain endocast of the Triassic non-mammaliaform probainognathian cynodont Riograndia guaibensis were studied. Here, we analyzed the brain endocast of an additional specimen of this species. The new endocast shows well-defined olfactory bulbs and a median sulcus dividing the hemispheres, traits that were not clearly observed in the first studied specimen. Encephalization quotients were also calculated, revealing similar values to other non-mammaliaform cynodonts and lower than those of the first analyzed specimen. The analyzed cranium is slightly larger than the first studied one and may represent an advanced ontogenetic stage. Hence, these differences may be related to the intraspecific variation of this cynodont or alternatively, to the preservation of each specimen.
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Affiliation(s)
- Leonardo Kerber
- Universidade Federal de Santa Maria, Centro de Apoio à Pesquisa Paleontológica, Rua Maximiliano Vizzotto, 598, 97230-000 São João do Polêsine, RS, Brazil.,Museu Paraense Emílio Goeldi, Coordenação de Ciências da Terra e Ecologia, Av. Perimetral, 1901, 66077-830 Belém, PA, Brazil.,Universidade Federal de Santa Maria, Programa de Pós-Graduação em Biodiversidade Animal, Av. Roraima 1000, 97105-900 Santa Maria, RS, Brazil
| | - JosÉ Darival Ferreira
- Universidade Federal de Santa Maria, Programa de Pós-Graduação em Biodiversidade Animal, Av. Roraima 1000, 97105-900 Santa Maria, RS, Brazil
| | - Pedro Henrique M Fonseca
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Geociências, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Arymatheia Franco
- Universidade Federal de Santa Maria, Programa de Pós-Graduação em Biodiversidade Animal, Av. Roraima 1000, 97105-900 Santa Maria, RS, Brazil
| | - AgustÍn G Martinelli
- Museo Argentino de Ciencias Naturales 'Bernardino Rivadavia', CONICET-Sección Paleontología de Vertebrados, Av. Ángel Gallardo, 470, C1405 DJR, Buenos Aires, Argentina
| | - Marina Bento Soares
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Geociências, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil.,Universidade Federal do Rio de Janeiro, Museu Nacional, Departamento de Geologia e Paleontologia, Quinta da Boa Vista, São Cristóvão, 20940-040 Rio de Janeiro, RJ, Brazil
| | - Ana Maria Ribeiro
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Geociências, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil.,Secretaria do Meio Ambiente e Infraestrutura, Museu de Ciências Naturais, Seção de Paleontologia, Av. Salvador França, 1427, 90690-000 Porto Alegre, RS, Brazil
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19
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Manger PR, Patzke N, Spocter MA, Bhagwandin A, Karlsson KÆ, Bertelsen MF, Alagaili AN, Bennett NC, Mohammed OB, Herculano-Houzel S, Hof PR, Fuxe K. Amplification of potential thermogenetic mechanisms in cetacean brains compared to artiodactyl brains. Sci Rep 2021; 11:5486. [PMID: 33750832 PMCID: PMC7970898 DOI: 10.1038/s41598-021-84762-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 02/19/2021] [Indexed: 01/25/2023] Open
Abstract
To elucidate factors underlying the evolution of large brains in cetaceans, we examined 16 brains from 14 cetartiodactyl species, with immunohistochemical techniques, for evidence of non-shivering thermogenesis. We show that, in comparison to the 11 artiodactyl brains studied (from 11 species), the 5 cetacean brains (from 3 species), exhibit an expanded expression of uncoupling protein 1 (UCP1, UCPs being mitochondrial inner membrane proteins that dissipate the proton gradient to generate heat) in cortical neurons, immunolocalization of UCP4 within a substantial proportion of glia throughout the brain, and an increased density of noradrenergic axonal boutons (noradrenaline functioning to control concentrations of and activate UCPs). Thus, cetacean brains studied possess multiple characteristics indicative of intensified thermogenetic functionality that can be related to their current and historical obligatory aquatic niche. These findings necessitate reassessment of our concepts regarding the reasons for large brain evolution and associated functional capacities in cetaceans.
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Affiliation(s)
- Paul R Manger
- School of Anatomical Sciences, University of the Witwatersrand, Johannesburg, South Africa.
| | - Nina Patzke
- School of Anatomical Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Institute for the Advancement of Higher Education, Hokkaido University, Sapporo, Japan
| | - Muhammad A Spocter
- School of Anatomical Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Anatomy, Des Moines University, Des Moines, IA, USA
| | - Adhil Bhagwandin
- School of Anatomical Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Division of Clinical Anatomy and Biological Anthropology, Department of Human Biology, University of Cape Town, Cape Town, South Africa
| | - Karl Æ Karlsson
- Biomedical Engineering, Reykjavik University, Reykjavik, Iceland
| | - Mads F Bertelsen
- Centre for Zoo and Wild Animal Health, Copenhagen Zoo, Frederiksberg, Denmark
| | - Abdulaziz N Alagaili
- KSU Mammals Research Chair, Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Nigel C Bennett
- KSU Mammals Research Chair, Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia.,Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Osama B Mohammed
- KSU Mammals Research Chair, Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Suzana Herculano-Houzel
- Department of Psychology, Department of Biological Sciences, Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
| | - Patrick R Hof
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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20
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Bauer GB, Cook PF, Harley HE. The Relevance of Ecological Transitions to Intelligence in Marine Mammals. Front Psychol 2020; 11:2053. [PMID: 33013519 PMCID: PMC7505747 DOI: 10.3389/fpsyg.2020.02053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/24/2020] [Indexed: 12/26/2022] Open
Abstract
Macphail's comparative approach to intelligence focused on associative processes, an orientation inconsistent with more multifaceted lay and scientific understandings of the term. His ultimate emphasis on associative processes indicated few differences in intelligence among vertebrates. We explore options more attuned to common definitions by considering intelligence in terms of richness of representations of the world, the interconnectivity of those representations, the ability to flexibly change those connections, and knowledge. We focus on marine mammals, represented by the amphibious pinnipeds and the aquatic cetaceans and sirenians, as animals that transitioned from a terrestrial existence to an aquatic one, experiencing major changes in ecological pressures. They adapted with morphological transformations related to streamlining the body, physiological changes in respiration and thermoregulation, and sensory/perceptual changes, including echolocation capabilities and diminished olfaction in many cetaceans, both in-air and underwater visual focus, and enhanced senses of touch in pinnipeds and sirenians. Having a terrestrial foundation on which aquatic capacities were overlaid likely affected their cognitive abilities, especially as a new reliance on sound and touch, and the need to surface to breath changed their interactions with the world. Vocal and behavioral observational learning capabilities in the wild and in laboratory experiments suggest versatility in group coordination. Empirical reports on aspects of intelligent behavior like problem-solving, spatial learning, and concept learning by various species of cetaceans and pinnipeds suggest rich cognitive abilities. The high energy demands of the brain suggest that brain-intelligence relationships might be fruitful areas for study when specific hypotheses are considered, e.g., brain mapping indicates hypertrophy of specific sensory areas in marine mammals. Modern neuroimaging techniques provide ways to study neural connectivity, and the patterns of connections between sensory, motor, and other cortical regions provide a biological framework for exploring how animals represent and flexibly use information in navigating and learning about their environment. At this stage of marine mammal research, it would still be prudent to follow Macphail's caution that it is premature to make strong comparative statements without more empirical evidence, but an approach that includes learning more about how animals flexibly link information across multiple representations could be a productive way of comparing species by allowing them to use their specific strengths within comparative tasks.
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Affiliation(s)
- Gordon B. Bauer
- Division of Social Sciences, New College of Florida, Sarasota, FL, United States
- Mote Marine Laboratory, Sarasota, FL, United States
| | - Peter F. Cook
- Division of Social Sciences, New College of Florida, Sarasota, FL, United States
- Mote Marine Laboratory, Sarasota, FL, United States
| | - Heidi E. Harley
- Division of Social Sciences, New College of Florida, Sarasota, FL, United States
- Mote Marine Laboratory, Sarasota, FL, United States
- The Seas, Epcot, Walt Disney World Resorts, Lake Buena Vista, FL, United States
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21
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Chengetanai S, Tenley JD, Bertelsen MF, Hård T, Bhagwandin A, Haagensen M, Tang CY, Wang VX, Wicinski B, Hof PR, Manger PR, Spocter MA. Brain of the African wild dog. I. Anatomy, architecture, and volumetrics. J Comp Neurol 2020; 528:3245-3261. [PMID: 32720707 DOI: 10.1002/cne.24999] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 07/17/2020] [Accepted: 07/22/2020] [Indexed: 02/05/2023]
Abstract
The African wild dog is endemic to sub-Saharan Africa and belongs to the family Canidae which includes domestic dogs and their closest relatives (i.e., wolves, coyotes, jackals, dingoes, and foxes). The African wild dog is known for its highly social behavior, co-ordinated pack predation, and striking vocal repertoire, but little is known about its brain and whether it differs in any significant way from that of other canids. We employed gross anatomical observation, magnetic resonance imaging, and classical neuroanatomical staining to provide a broad overview of the structure of the African wild dog brain. Our results reveal a mean brain mass of 154.08 g, with an encephalization quotient of 1.73, indicating that the African wild dog has a relatively large brain size. Analysis of the various structures that comprise their brains and their topological inter-relationships, as well as the areas and volumes of the corpus callosum, ventricular system, hippocampus, amygdala, cerebellum and the gyrification index, all reveal that the African wild dog brain is, in general, similar to that of other mammals, and very similar to that of other carnivorans. While at this level of analysis we do not find any striking specializations within the brain of the African wild dog, apart from a relatively large brain size, the observations made indicate that more detailed analyses of specific neural systems, particularly those involved in sensorimotor processing, sociality or cognition, may reveal features that are either unique to this species or shared among the Canidae to the exclusion of other Carnivora.
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Affiliation(s)
- Samson Chengetanai
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | | | - Mads F Bertelsen
- Center for Zoo and Wild Animal Health, Copenhagen Zoo, Fredericksberg, Denmark
| | | | - Adhil Bhagwandin
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Mark Haagensen
- Department of Radiology, University of Witwatersrand-Donald Gordon Medical Centre, Johannesburg, South Africa
| | - Cheuk Y Tang
- Department of Psychiatry, and BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Victoria X Wang
- Department of Psychiatry, and BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Bridget Wicinski
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Patrick R Hof
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,New York Consortium in Evolutionary Primatology, New York, New York, USA
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Muhammad A Spocter
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Anatomy, Des Moines University, Des Moines, Iowa, USA.,College of Veterinary Medicine, Department of Biomedical Sciences, Iowa State University, Ames, Iowa, USA
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22
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Ridgway SH, Brownson RH, Van Alstyne KR, Hauser RA. Higher neuron densities in the cerebral cortex and larger cerebellums may limit dive times of delphinids compared to deep-diving toothed whales. PLoS One 2019; 14:e0226206. [PMID: 31841529 PMCID: PMC6914331 DOI: 10.1371/journal.pone.0226206] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 11/21/2019] [Indexed: 12/17/2022] Open
Abstract
Since the work of Tower in the 1950s, we have come to expect lower neuron density in the cerebral cortex of larger brains. We studied dolphin brains varying from 783 to 6215g. As expected, average neuron density in four areas of cortex decreased from the smallest to the largest brain. Despite having a lower neuron density than smaller dolphins, the killer whale has more gray matter and more cortical neurons than any mammal, including humans. To begin a study of non-dolphin toothed whales, we measured a 596g brain of a pygmy sperm whale and a 2004g brain of a Cuvier's beaked whale. We compared neuron density of Nissl stained cortex of these two brains with those of the dolphins. Non-dolphin brains had lower neuron densities compared to all of the dolphins, even the 6215g brain. The beaked whale and pygmy sperm whale we studied dive deeper and for much longer periods than the dolphins. For example, the beaked whale may dive for more than an hour, and the pygmy sperm whale more than a half hour. In contrast, the dolphins we studied limit dives to five or 10 minutes. Brain metabolism may be one feature limiting dolphin dives. The brain consumes an oversized share of oxygen available to the body. The most oxygen is used by the cortex and cerebellar gray matter. The dolphins have larger brains, larger cerebellums, and greater numbers of cortex neurons than would be expected given their body size. Smaller brains, smaller cerebellums and fewer cortical neurons potentially allow the beaked whale and pygmy sperm whale to dive longer and deeper than the dolphins. Although more gray matter, more neurons, and a larger cerebellum may limit dolphins to shorter, shallower dives, these features must give them some advantage. For example, they may be able to catch more elusive individual high-calorie prey in the upper ocean.
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Affiliation(s)
- Sam H. Ridgway
- National Marine Mammal Foundation, San Diego, California, United States of America
- Department of Pathology, School of Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Robert H. Brownson
- Department of Cell Biology and Human Anatomy, School of Medicine, University of California, Davis, Davis, California, United States of America
| | | | - Robert A. Hauser
- Department of Neurology, University of South Florida, Tampa, Florida, United States of America
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23
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de Simão-Oliveira D, Kerber L, L Pinheiro F. Endocranial morphology of the Brazilian Permian dicynodont Rastodon procurvidens (Therapsida: Anomodontia). J Anat 2019; 236:384-397. [PMID: 31670465 DOI: 10.1111/joa.13107] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2019] [Indexed: 12/18/2022] Open
Abstract
Dicynodontia is a major clade of terrestrial tetrapods that greatly diversified during the Permian and Triassic periods, reaching a worldwide distribution. In this study, the endocranial cavity of the Brazilian Permian dicynodont Rastodon procurvidens is described based on a digital endocast obtained using digital imaging (X-ray computed tomography) and 3D modeling. It was possible to reconstruct the brain, olfactory bulbs, inner ear, some neurovascular canals, cranial nerves, the nasal cavity, and the maxillary recesses. The endocast of R. procurvidens preserves a typical plesiomorphic morphology of non-mammaliaform therapsids, being predominantly tubular and displaying a relatively short and robust hindbrain. Encephalization quotients (EQs) were calculated for R. procurvidens, resulting in EQs of 0.09 ± 0.03 and 0.13 ± 0.05 (Jerison's EQ and Manger's EQ, respectively). Finally, some biological implications of the endocast morphology were inferred for R. procurvidens. Its inner ear is especially small, and its orientation implies a slightly downturned head posture in life. Furthermore, the presence of uncompressed maxillary recesses in R. procurvidens indicates a correlation between the enlargement of the recesses and the reduction of the tusks, also seen in other dicynodonts with reduced tusks.
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Affiliation(s)
- Daniel de Simão-Oliveira
- Laboratório de Paleobiologia, Programa de Pós-Graduação em Ciências Biológicas, Universidade Federal do Pampa (Unipampa), São Gabriel, Rio Grande do Sul, Brazil.,Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia (CAPPA), Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria (UFSM), São João do Polêsine, Rio Grande do Sul, Brazil
| | - Leonardo Kerber
- Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia (CAPPA), Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria (UFSM), São João do Polêsine, Rio Grande do Sul, Brazil
| | - Felipe L Pinheiro
- Laboratório de Paleobiologia, Programa de Pós-Graduação em Ciências Biológicas, Universidade Federal do Pampa (Unipampa), São Gabriel, Rio Grande do Sul, Brazil
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24
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Serio C, Castiglione S, Tesone G, Piccolo M, Melchionna M, Mondanaro A, Di Febbraro M, Raia P. Macroevolution of Toothed Whales Exceptional Relative Brain Size. Evol Biol 2019. [DOI: 10.1007/s11692-019-09485-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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25
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Pavanatto AEB, Kerber L, Dias-da-Silva S. Virtual reconstruction of cranial endocasts of traversodontid cynodonts (Eucynodontia: Gomphodontia) from the upper Triassic of Southern Brazil. J Morphol 2019; 280:1267-1281. [PMID: 31241801 DOI: 10.1002/jmor.21029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 06/03/2019] [Accepted: 06/10/2019] [Indexed: 12/12/2022]
Abstract
The brain endocasts of the late Triassic (Carnian) traversodontids (Eucynodontia: Gomphodontia) Siriusgnathus niemeyerorum and Exaeretodon riograndensis from southern Brazil are described based on virtual models generated using computed tomography scan data. Their skull anatomy resembles that of other non-mammaliaform cynodonts, showing an endocranial cavity that is not fully ossified. A "V-shaped" orbitosphenoid, neither fully developed nor ossified is present in E. riograndensis. The nasal cavity is confluent with the encephalic cavity. Thus, the anterior limit of the olfactory bulbs is not definite. The brain endocast is elongated, being narrow anteriorly and wide posteriorly, with the maximum width at the parafloccular cast. The olfactory bulbs do not present a clear division between their counterparts, due to the absence of a longitudinal sulcus. A longitudinal sulcus in the forebrain delimiting the cerebral hemispheres, the pineal tube, and the parietal foramen are absent in both taxa. The large and well-developed unossified zone is partially separated from the remaining endocast by a notch formed by the supraoccipital. The encephalization quotients, as well as the endocranial volume/body mass relationships of S. niemeyerorum and E. riograndensis are within the range expected for non-mammaliaform Therapsida.
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Affiliation(s)
- Ane E B Pavanatto
- Programa de Pós-Graduação em Biodiversidade Animal, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Brazil
| | - Leonardo Kerber
- Programa de Pós-Graduação em Biodiversidade Animal, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Brazil.,Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, São João do Polêsine, Brazil
| | - Sérgio Dias-da-Silva
- Programa de Pós-Graduação em Biodiversidade Animal, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Brazil.,Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, São João do Polêsine, Brazil
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26
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Benoit J, Legendre LJ, Tabuce R, Obada T, Mararescul V, Manger P. Brain evolution in Proboscidea (Mammalia, Afrotheria) across the Cenozoic. Sci Rep 2019; 9:9323. [PMID: 31249366 PMCID: PMC6597534 DOI: 10.1038/s41598-019-45888-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 06/07/2019] [Indexed: 12/12/2022] Open
Abstract
As the largest and among the most behaviourally complex extant terrestrial mammals, proboscideans (elephants and their extinct relatives) are iconic representatives of the modern megafauna. The timing of the evolution of large brain size and above average encephalization quotient remains poorly understood due to the paucity of described endocranial casts. Here we created the most complete dataset on proboscidean endocranial capacity and analysed it using phylogenetic comparative methods and ancestral character states reconstruction using maximum likelihood. Our analyses support that, in general, brain size and body mass co-evolved in proboscideans across the Cenozoic; however, this pattern appears disrupted by two instances of specific increases in relative brain size in the late Oligocene and early Miocene. These increases in encephalization quotients seem to correspond to intervals of important climatic, environmental and faunal changes in Africa that may have positively selected for larger brain size or body mass.
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Affiliation(s)
- Julien Benoit
- Evolutionary Studies Institute (ESI), University of the Witwatersrand, Braamfontein, 2050, Johannesburg, South Africa.
| | - Lucas J Legendre
- Jackson School of Geosciences, The University of Texas at Austin, 2275 Speedway Stop C9000, Austin, TX, United States
| | - Rodolphe Tabuce
- Institut des Sciences de L'Evolution de Montpellier, Université Montpellier 2, Place Eugène Batillon, F-34095 Montpellier, cedex 05, Montpellier, France
| | - Theodor Obada
- Academy of Sciences of Moldova, Institute of Zoology, Chişinău, Moldova
| | | | - Paul Manger
- School of Anatomical Sciences, University of the Witwatersrand, 7 York Road, Parktown, 2193, Johannesburg, South Africa
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27
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Lyras GA. Brain Changes during Phyletic Dwarfing in Elephants and Hippos. BRAIN, BEHAVIOR AND EVOLUTION 2019; 92:167-181. [PMID: 30943507 DOI: 10.1159/000497268] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 01/27/2019] [Indexed: 11/19/2022]
Abstract
Of all known insular mammals, hippos and elephants present the extremes of body size decrease, reducing to 4 and a mere 2% of their ancestral mainland size, respectively. Despite the numerous studies on these taxa, what happens to their relative brain size during phyletic dwarfing is not well known, and results are sometimes conflicting. For example, relative brain size increase has been noted in the Sicilian dwarf elephant, Palaeoloxodon falconeri, whereas relative brain size decrease has been postulated for Malagasy dwarf hippos. Here, I perform an analysis of brain, skull, and body size of 3 insular elephants (Palaeoloxodon "mnaidriensis," P. tiliensis, and P. falconeri) and 3 insular hippos (Hippopotamus madagascariensis, H. lemerlei, and H. minor) to address this issue and to test whether relative brain size in phyletic dwarf species can be predicted. The results presented here show that the encephalization of all insular elephants and hippos is higher than that of their continental relatives. P. falconeri in particular has an enormous encephalization increase, which has so far not been reported in any other insular mammal. Insular brain size cannot be reliably predicted using either static allometric or ontogenetic scaling models. The results of this study indicate that insular dwarf species follow brain-body allometric relationships different from the expected patterns seen for their mainland relatives.
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Affiliation(s)
- George A Lyras
- Department of Geology and Geoenvironment, National and Kapodistrian University of Athens, Athens, Greece,
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28
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Raghanti MA, Wicinski B, Meierovich R, Warda T, Dickstein DL, Reidenberg JS, Tang CY, George JC, Hans Thewissen JGM, Butti C, Hof PR. A Comparison of the Cortical Structure of the Bowhead Whale (Balaena mysticetus), a Basal Mysticete, with Other Cetaceans. Anat Rec (Hoboken) 2018; 302:745-760. [PMID: 30332717 DOI: 10.1002/ar.23991] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 09/12/2017] [Accepted: 10/16/2017] [Indexed: 12/13/2022]
Abstract
Few studies exist of the bowhead whale brain and virtually nothing is known about its cortical cytoarchitecture or how it compares to other cetaceans. Bowhead whales are one of the least encephalized cetaceans and occupy a basal phylogenetic position among mysticetes. Therefore, the bowhead whale is an important specimen for understanding the evolutionary specializations of cetacean brains. Here, we present an overview of the structure and cytoarchitecture of the bowhead whale cerebral cortex gleaned from Nissl-stained sections and magnetic resonance imaging (MRI) in comparison with other mysticetes and odontocetes. In general, the cytoarchitecture of cetacean cortex is consistent in displaying a thin cortex, a thick, prominent layer I, and absence of a granular layer IV. Cell density, composition, and width of layers III, V, and VI vary among cortical regions, and cetacean cortex is cell-sparse relative to that of terrestrial mammals. Notably, all regions of the bowhead cortex possess high numbers of von Economo neurons and fork neurons, with the highest numbers observed at the apex of gyri. The bowhead whale is also distinctive in having a significantly reduced hippocampus that occupies a space below the corpus callosum within the lateral ventricle. Consistent with other balaenids, bowhead whales possess what appears to be a blunted temporal lobe, which is in contrast to the expansive temporal lobes that characterize most odontocetes. The present report demonstrates that many morphological and cytoarchitectural characteristics are conserved among cetaceans, while other features, such as a reduced temporal lobe, may characterize balaenids among mysticetes. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc. Anat Rec, 302:745-760, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Mary Ann Raghanti
- Department of Anthropology and School of Biomedical Sciences, Kent State University, Kent, Ohio
| | - Bridget Wicinski
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Rachel Meierovich
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York.,Convent of the Sacred Heart School, New York, New York
| | - Tahia Warda
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Dara L Dickstein
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York.,Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Joy S Reidenberg
- Center for Anatomy and Functional Morphology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Cheuk Y Tang
- Department of Radiology and Translational Medicine Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - John C George
- Department of Wildlife Management, North Slope Borough, Barrow, Alaska
| | - J G M Hans Thewissen
- Department of Anatomy and Neurobiology, Northeastern Ohio Medical University, Rootstown, Ohio
| | - Camilla Butti
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Patrick R Hof
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York
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29
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Spocter MA, Fairbanks J, Locey L, Nguyen A, Bitterman K, Dunn R, Sherwood CC, Geletta S, Dell LA, Patzke N, Manger PR. Neuropil Distribution in the Anterior Cingulate and Occipital Cortex of Artiodactyls. Anat Rec (Hoboken) 2018; 301:1871-1881. [DOI: 10.1002/ar.23905] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 02/14/2018] [Accepted: 02/26/2018] [Indexed: 01/18/2023]
Affiliation(s)
- Muhammad A. Spocter
- Department of Anatomy; Des Moines University; Des Moines Iowa
- College of Veterinary Medicine, Biomedical Sciences; Iowa State University; Ames Iowa
- School of Anatomical Sciences; University of the Witwatersrand; Johannesburg Republic of South Africa
| | | | - Lisa Locey
- Department of Anatomy; Des Moines University; Des Moines Iowa
| | - Amy Nguyen
- College of Pharmacy and Health Sciences, Drake University; Des Moines Iowa
| | | | - Rachel Dunn
- Department of Anatomy; Des Moines University; Des Moines Iowa
| | - Chet C. Sherwood
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology; The George Washington University; Washington Washington, DC
| | - Simon Geletta
- Department of Public Health; Des Moines University; Des Moines Iowa
| | - Leigh-Anne Dell
- School of Anatomical Sciences; University of the Witwatersrand; Johannesburg Republic of South Africa
- Institute of Computational Neuroscience; University Medical Center Hamburg-Eppendorf; Hamburg Germany
| | - Nina Patzke
- School of Anatomical Sciences; University of the Witwatersrand; Johannesburg Republic of South Africa
- Department of Biology; Hokkaido University; Hokkaido Japan
| | - Paul R. Manger
- School of Anatomical Sciences; University of the Witwatersrand; Johannesburg Republic of South Africa
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30
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Ridgway SH, Dibble DS, Kennemer JA. Timing and context of dolphin clicks during and after mine simulator detection and marking in the open ocean. Biol Open 2018; 7:7/2/bio031625. [PMID: 29463515 PMCID: PMC5861363 DOI: 10.1242/bio.031625] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Two dolphins carrying cameras swam in the ocean as they searched for and marked mine simulators – buried, proud or moored. As the animals swam ahead of a boat they searched the ocean. Cameras on their harness recorded continuous sound and video. Once a target was detected, the dolphins received a marker to take to the simulator's location. During search and detection, dolphins made almost continuous trains of varying interval clicks. During the marking phase, shorter click trains were interrupted by periods of silence. As the dolphins marked simulators, they often produced victory squeals – pulse bursts that vary in duration, peak frequency and amplitude. Victory squeals were produced on 72% of marks. Sometimes after marking, or at other times during their long swims, the dolphins produced click packets. Packets typically consisted of two to 10 clicks with inter-click intervals of 7-117 ms followed by a silence of 223-983 ms. Click packets appeared unrelated with searching or marking. We suggest that the packets were used to improve signal to noise ratios for locating a boat or other distant object. Victory squeals produced when marking the targets suggest to us that the dolphins know when they have succeeded in this multipart task. Summary: Dolphins wore cameras so we could hear them and watch them mark mine simulators. We observed rhythmic click trains, victory squeals, and click packets with their behavioral context.
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Affiliation(s)
- Sam H Ridgway
- Neurobiology Group, National Marine Mammal Foundation, 2240 Shelter Island Drive #200, San Diego, CA 92106, USA .,Department of Pathology, School of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Dianna S Dibble
- Neurobiology Group, National Marine Mammal Foundation, 2240 Shelter Island Drive #200, San Diego, CA 92106, USA
| | - Jaime A Kennemer
- U.S. Navy Marine Mammal Program, Space and Naval Warfare Systems Center San Diego 53560 Hull Street, San Diego, CA 92152 , USA
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31
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Martínez-Cerdeño V, García-Moreno F, Tosches MA, Csillag A, Manger PR, Molnár Z. Update on forebrain evolution: From neurogenesis to thermogenesis. Semin Cell Dev Biol 2017; 76:15-22. [PMID: 28964836 DOI: 10.1016/j.semcdb.2017.09.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 09/22/2017] [Accepted: 09/26/2017] [Indexed: 01/25/2023]
Abstract
Comparative developmental studies provide growing understanding of vertebrate forebrain evolution. This short review directs the spotlight to some newly emerging aspects, including the evolutionary origin of the proliferative region known as the subventricular zone (SVZ) and of intermediate progenitor cells (IPCs) that populate the SVZ, neural circuits that originated within homologous regions across all amniotes, and the role of thermogenesis in the acquisition of an increased brain size. These data were presented at the 8th European Conference on Comparative Neurobiology.
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Affiliation(s)
- Verónica Martínez-Cerdeño
- Department of Pathology and Laboratory Medicine, UC Davis, USA; Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children Northern California, USA; MIND Institute, UC Davis School of Medicine, CA, USA.
| | - Fernando García-Moreno
- Achucarro Basque Center for Neuroscience, Parque Científico UPV/EHU Edif. Sede, E-48940 Leioa, Spain
| | | | - András Csillag
- Department of Anatomy, Histology and Embryology, Semmelweis University, Faculty of Medicine, Budapest, Hungary
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of Witwatersrand, South Africa
| | - Zoltán Molnár
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK.
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32
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Fox KCR, Muthukrishna M, Shultz S. The social and cultural roots of whale and dolphin brains. Nat Ecol Evol 2017; 1:1699-1705. [PMID: 29038481 DOI: 10.1038/s41559-017-0336-y] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 09/01/2017] [Indexed: 02/04/2023]
Abstract
Encephalization, or brain expansion, underpins humans' sophisticated social cognition, including language, joint attention, shared goals, teaching, consensus decision-making and empathy. These abilities promote and stabilize cooperative social interactions, and have allowed us to create a 'cognitive' or 'cultural' niche and colonize almost every terrestrial ecosystem. Cetaceans (whales and dolphins) also have exceptionally large and anatomically sophisticated brains. Here, by evaluating a comprehensive database of brain size, social structures and cultural behaviours across cetacean species, we ask whether cetacean brains are similarly associated with a marine cultural niche. We show that cetacean encephalization is predicted by both social structure and by a quadratic relationship with group size. Moreover, brain size predicts the breadth of social and cultural behaviours, as well as ecological factors (diversity of prey types and to a lesser extent latitudinal range). The apparent coevolution of brains, social structure and behavioural richness of marine mammals provides a unique and striking parallel to the large brains and hyper-sociality of humans and other primates. Our results suggest that cetacean social cognition might similarly have arisen to provide the capacity to learn and use a diverse set of behavioural strategies in response to the challenges of social living.
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Affiliation(s)
- Kieran C R Fox
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, 94305, USA
| | - Michael Muthukrishna
- Department of Psychological and Behavioural Science, London School of Economics and Political Science, London, WC2A 2AE, UK.,Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Susanne Shultz
- School of Earth and Environmental Sciences, University of Manchester, Manchester, M13 9PL, UK.
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33
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Bhagwandin A, Haagensen M, Manger PR. The Brain of the Black ( Diceros bicornis) and White ( Ceratotherium simum) African Rhinoceroses: Morphology and Volumetrics from Magnetic Resonance Imaging. Front Neuroanat 2017; 11:74. [PMID: 28912691 PMCID: PMC5583206 DOI: 10.3389/fnana.2017.00074] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 08/15/2017] [Indexed: 12/22/2022] Open
Abstract
The morphology and volumetrics of the understudied brains of two iconic large terrestrial African mammals: the black (Diceros bicornis) and white (Ceratotherium simum) rhinoceroses are described. The black rhinoceros is typically solitary whereas the white rhinoceros is social, and both are members of the Perissodactyl order. Here, we provide descriptions of the surface of the brain of each rhinoceros. For both species, we use magnetic resonance images (MRI) to develop a description of the internal anatomy of the rhinoceros brain and to calculate the volume of the amygdala, cerebellum, corpus callosum, hippocampus, and ventricular system as well as to determine the gyrencephalic index. The morphology of both black and white rhinoceros brains is very similar to each other, although certain minor differences, seemingly related to diet, were noted, and both brains evince the general anatomy of the mammalian brain. The rhinoceros brains display no obvious neuroanatomical specializations in comparison to other mammals previously studied. In addition, the volumetric analyses indicate that the size of the various regions of the rhinoceros brain measured, as well as the extent of gyrification, are what would be predicted for a mammal with their brain mass when compared allometrically to previously published data. We conclude that the brains of the black and white rhinoceros exhibit a typically mammalian organization at a superficial level, but histological studies may reveal specializations of interest in relation to rhinoceros behavior.
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Affiliation(s)
- Adhil Bhagwandin
- School of Anatomical Sciences, Faculty of Health Sciences, University of the WitwatersrandJohannesburg, South Africa
| | - Mark Haagensen
- Department of Radiology, Wits Donald Gordon Medical Centre, University of the WitwatersrandJohannesburg, South Africa
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the WitwatersrandJohannesburg, South Africa
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34
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Nuclear organisation of cholinergic, catecholaminergic, serotonergic and orexinergic neurons in two relatively large-brained rodent species-The springhare (Pedetes capensis) and Beecroft's scaly-tailed squirrel (Anomalurus beecrofti). J Chem Neuroanat 2017; 86:78-91. [PMID: 28916505 DOI: 10.1016/j.jchemneu.2017.09.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/12/2017] [Accepted: 09/12/2017] [Indexed: 01/18/2023]
Abstract
The present study describes the nuclear organization of the cholinergic, catecholaminergic, serotonergic and orexinergic systems in the brains of the springhare and Beecroft's scaly-tailed squirrel following immunohistochemical labelling. We aimed to investigate any differences in the nuclear organization of these neural systems when compared to previous data on other species of rodents, as these two rodent species have relatively large brains - 1.2 to 1.4 times larger than would be expected for mammals of their body mass and 1.7-1.9 times larger than would be expected for rodents of their body mass. A series of coronal sections were taken through two brains of each species and immunohistochemically labelled with antibodies against choline acetyltransferase, tyrosine hydroxylase, serotonin and orexin-A. Generally, the nuclear complement of these systems revealed extensive similarities between both species and to previously studied rodents. While no differences were observed in the nuclear complement of the serotonergic and orexinergic systems, some differences were observed in the nuclear complement of the cholinergic and catecholaminergic systems. These include the presence of cholinergic neurons in the cerebral cortex and nucleus of the trapezoid body in the springhare; while the Beecroft's scaly-tailed squirrel exhibited cholinergic neurons in the pretectal area of the midbrain. For the catecholaminergic system it was observed that Beecroft's scaly-tailed squirrel possessed immunoreactive neurons in the accessory olfactory bulb. Despite these four differences, most not previously observed in rodents, the remaining complement of cholinergic and catecholaminergic nuclei were identical to that observed in other rodents, including the presence of the rodent specific catecholaminergic rostral dorsal midline medullary (C3) nucleus in the medulla oblongata. Thus, even with a significant increase in relative brain size, the overall complement of nuclei forming these systems shows minimal changes in complexity within a specific mammalian order.
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Benoit J, Manger PR, Norton L, Fernandez V, Rubidge BS. Synchrotron scanning reveals the palaeoneurology of the head-butting Moschops capensis (Therapsida, Dinocephalia). PeerJ 2017; 5:e3496. [PMID: 28828230 PMCID: PMC5554600 DOI: 10.7717/peerj.3496] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 06/02/2017] [Indexed: 12/17/2022] Open
Abstract
Dinocephalian therapsids are renowned for their massive, pachyostotic and ornamented skulls adapted for head-to-head fighting during intraspecific combat. Synchrotron scanning of the tapinocephalid Moschops capensis reveals, for the first time, numerous anatomical adaptations of the central nervous system related to this combative behaviour. Many neural structures (such as the brain, inner ear and ophthalmic branch of the trigeminal nerve) were completely enclosed and protected by bones, which is unusual for non-mammaliaform therapsids. The nearly complete ossification of the braincase enables precise determination of the brain cavity volume and encephalization quotient, which appears greater than expected for such a large and early herbivore. The practice of head butting is often associated with complex social behaviours and gregariousness in extant species, which are known to influence brain size evolution. Additionally, the plane of the lateral (horizontal) semicircular canal of the bony labyrinth is oriented nearly vertically if the skull is held horizontally, which suggests that the natural position of the head was inclined about 60–65°to the horizontal. This is consistent with the fighting position inferred from osteology, as well as ground-level browsing. Finally, the unusually large parietal tube may have been filled with thick conjunctive tissue to protect the delicate pineal eye from injury sustained during head butting.
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Affiliation(s)
- Julien Benoit
- Evolutionary Institute, School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa.,School of Anatomical Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Paul R Manger
- School of Anatomical Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Luke Norton
- Evolutionary Institute, School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Vincent Fernandez
- Beamline ID19, European Synchrotron Radiation Facility, Grenoble, France
| | - Bruce S Rubidge
- Evolutionary Institute, School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
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Imam A, Ajao MS, Bhagwandin A, Ihunwo AO, Manger PR. The brain of the tree pangolin (Manis tricuspis
). I. General appearance of the central nervous system. J Comp Neurol 2017; 525:2571-2582. [DOI: 10.1002/cne.24222] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 04/03/2017] [Accepted: 04/04/2017] [Indexed: 11/12/2022]
Affiliation(s)
- Aminu Imam
- School of Anatomical Sciences; Faculty of Health Sciences, University of the Witwatersrand; Johannesburg Republic of South Africa
- Department of Anatomy; Faculty of Basic Medical Sciences, College of Health Sciences, University of Ilorin; Ilorin Nigeria
| | - Moyosore S. Ajao
- Department of Anatomy; Faculty of Basic Medical Sciences, College of Health Sciences, University of Ilorin; Ilorin Nigeria
| | - Adhil Bhagwandin
- School of Anatomical Sciences; Faculty of Health Sciences, University of the Witwatersrand; Johannesburg Republic of South Africa
| | - Amadi O. Ihunwo
- School of Anatomical Sciences; Faculty of Health Sciences, University of the Witwatersrand; Johannesburg Republic of South Africa
| | - Paul R. Manger
- School of Anatomical Sciences; Faculty of Health Sciences, University of the Witwatersrand; Johannesburg Republic of South Africa
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Graïc JM, Peruffo A, Ballarin C, Cozzi B. The Brain of the Giraffe (Giraffa Camelopardalis): Surface Configuration, Encephalization Quotient, and Analysis of the Existing Literature. Anat Rec (Hoboken) 2017; 300:1502-1511. [DOI: 10.1002/ar.23593] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 12/20/2016] [Accepted: 01/05/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Jean-Marie Graïc
- Department of Comparative Biomedicine and Food Science; University of Padova, viale dell'Università 16; Legnaro (PD) 35020 Italy
| | - Antonella Peruffo
- Department of Comparative Biomedicine and Food Science; University of Padova, viale dell'Università 16; Legnaro (PD) 35020 Italy
| | - Cristina Ballarin
- Department of Comparative Biomedicine and Food Science; University of Padova, viale dell'Università 16; Legnaro (PD) 35020 Italy
| | - Bruno Cozzi
- Department of Comparative Biomedicine and Food Science; University of Padova, viale dell'Università 16; Legnaro (PD) 35020 Italy
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Primate brain size is predicted by diet but not sociality. Nat Ecol Evol 2017; 1:112. [DOI: 10.1038/s41559-017-0112] [Citation(s) in RCA: 236] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 02/07/2017] [Indexed: 01/24/2023]
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Ridgway SH, Carlin KP, Van Alstyne KR, Hanson AC, Tarpley RJ. Comparison of Dolphins' Body and Brain Measurements with Four Other Groups of Cetaceans Reveals Great Diversity. BRAIN, BEHAVIOR AND EVOLUTION 2017; 88:235-257. [PMID: 28122370 DOI: 10.1159/000454797] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 11/28/2016] [Indexed: 01/06/2023]
Abstract
We compared mature dolphins with 4 other groupings of mature cetaceans. With a large data set, we found great brain diversity among 5 different taxonomic groupings. The dolphins in our data set ranged in body mass from about 40 to 6,750 kg and in brain mass from 0.4 to 9.3 kg. Dolphin body length ranged from 1.3 to 7.6 m. In our combined data set from the 4 other groups of cetaceans, body mass ranged from about 20 to 120,000 kg and brain mass from about 0.2 to 9.2 kg, while body length varied from 1.21 to 26.8 m. Not all cetaceans have large brains relative to their body size. A few dolphins near human body size have human-sized brains. On the other hand, the absolute brain mass of some other cetaceans is only one-sixth as large. We found that brain volume relative to body mass decreases from Delphinidae to a group of Phocoenidae and Monodontidae, to a group of other odontocetes, to Balaenopteroidea, and finally to Balaenidae. We also found the same general trend when we compared brain volume relative to body length, except that the Delphinidae and Phocoenidae-Monodontidae groups do not differ significantly. The Balaenidae have the smallest relative brain mass and the lowest cerebral cortex surface area. Brain parts also vary. Relative to body mass and to body length, dolphins also have the largest cerebellums. Cortex surface area is isometric with brain size when we exclude the Balaenidae. Our data show that the brains of Balaenidae are less convoluted than those of the other cetaceans measured. Large vascular networks inside the cranial vault may help to maintain brain temperature, and these nonbrain tissues increase in volume with body mass and with body length ranging from 8 to 65% of the endocranial volume. Because endocranial vascular networks and other adnexa, such as the tentorium cerebelli, vary so much in different species, brain size measures from endocasts of some extinct cetaceans may be overestimates. Our regression of body length on endocranial adnexa might be used for better estimates of brain volume from endocasts or from endocranial volume of living species or extinct cetaceans.
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Affiliation(s)
- Sam H Ridgway
- National Marine Mammal Foundation, San Diego, CA, USA
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Knopf JP, Hof PR, Oelschläger HHA. The Neocortex of Indian River Dolphins (Genus Platanista): Comparative, Qualitative and Quantitative Analysis. BRAIN, BEHAVIOR AND EVOLUTION 2016; 88:93-110. [PMID: 27732977 DOI: 10.1159/000448274] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 07/06/2016] [Indexed: 11/19/2022]
Abstract
We investigated the morphology of four primary neocortical projection areas (somatomotor, somatosensory, auditory, visual) qualitatively and quantitatively in the Indian river dolphins (Platanista gangetica gangetica, P. gangetica minor) with histological and stereological methods. For comparison, we included brains of other toothed whale species. Design-based stereology was applied to the primary neocortical areas (M1, S1, A1, V1) of the Indian river dolphins and compared to those of the bottlenose dolphin with respect to layers III and V. These neocortical fields were identified using existing electrophysiological and morphological data from marine dolphins as to their topography and histological structure, including the characteristics of the neuron populations concerned. In contrast to other toothed whales, the visual area (V1) of the 'blind' river dolphins seems to be rather small. M1 is displaced laterally and the auditory area (A1) is larger than in marine species with respect to total brain size. The layering is similar in the cortices of all the toothed whale brains investigated; a layer IV could not be identified. Cell density in layer III is always higher than in layer V. The maximal neuron density in P. gangetica gangetica is found in layer III of A1, followed by layers III in V1, S1, and M1. The cell density in layer V is at a similar level in all primary areas. There are, however, some differences in neuron density between the two subspecies of Indian river dolphins. Taken as a whole, it appears that the neocortex of platanistids exhibits a considerable expansion of the auditory field. Even more than other toothed whales, they seem to depend on their biosonar abilities for navigation, hunting, and communication in their riverine habitat.
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Affiliation(s)
- Julian P Knopf
- Institute of Anatomy III (Dr. Senckenbergische Anatomie), Johann Wolfgang Goethe University, Frankfurt am Main, Germany
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Steinhausen C, Zehl L, Haas-Rioth M, Morcinek K, Walkowiak W, Huggenberger S. Multivariate Meta-Analysis of Brain-Mass Correlations in Eutherian Mammals. Front Neuroanat 2016; 10:91. [PMID: 27746724 PMCID: PMC5043137 DOI: 10.3389/fnana.2016.00091] [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: 03/15/2016] [Accepted: 09/13/2016] [Indexed: 11/26/2022] Open
Abstract
The general assumption that brain size differences are an adequate proxy for subtler differences in brain organization turned neurobiologists toward the question why some groups of mammals such as primates, elephants, and whales have such remarkably large brains. In this meta-analysis, an extensive sample of eutherian mammals (115 species distributed in 14 orders) provided data about several different biological traits and measures of brain size such as absolute brain mass (AB), relative brain mass (RB; quotient from AB and body mass), and encephalization quotient (EQ). These data were analyzed by established multivariate statistics without taking specific phylogenetic information into account. Species with high AB tend to (1) feed on protein-rich nutrition, (2) have a long lifespan, (3) delayed sexual maturity, and (4) long and rare pregnancies with small litter sizes. Animals with high RB usually have (1) a short life span, (2) reach sexual maturity early, and (3) have short and frequent gestations. Moreover, males of species with high RB also have few potential sexual partners. In contrast, animals with high EQs have (1) a high number of potential sexual partners, (2) delayed sexual maturity, and (3) rare gestations with small litter sizes. Based on these correlations, we conclude that Eutheria with either high AB or high EQ occupy positions at the top of the network of food chains (high trophic levels). Eutheria of low trophic levels can develop a high RB only if they have small body masses.
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Affiliation(s)
- Charlene Steinhausen
- Department II of Anatomy, University of CologneCologne, Germany
- Biocenter, University of CologneCologne, Germany
| | - Lyuba Zehl
- Biocenter, University of CologneCologne, Germany
- Jülich Research Centre, Institute of Neuroscience and Medicine (INM-6) and Institute for Advanced Simulation (IAS-6) and JARA BRAIN Institute IJülich, Germany
| | - Michaela Haas-Rioth
- Department of Anatomy III (Dr. Senckenbergische Anatomie), Goethe University of Frankfurt am MainFrankfurt am Main, Germany
| | | | | | - Stefan Huggenberger
- Department II of Anatomy, University of CologneCologne, Germany
- Biocenter, University of CologneCologne, Germany
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Fabrizius A, Hoff MLM, Engler G, Folkow LP, Burmester T. When the brain goes diving: transcriptome analysis reveals a reduced aerobic energy metabolism and increased stress proteins in the seal brain. BMC Genomics 2016; 17:583. [PMID: 27507242 PMCID: PMC4979143 DOI: 10.1186/s12864-016-2892-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Accepted: 07/06/2016] [Indexed: 12/19/2022] Open
Abstract
Background During long dives, the brain of whales and seals experiences a reduced supply of oxygen (hypoxia). The brain neurons of the hooded seal (Cystophora cristata) are more tolerant towards low-oxygen conditions than those of mice, and also better survive other hypoxia-related stress conditions like a reduction in glucose supply and high concentrations of lactate. Little is known about the molecular mechanisms that support the hypoxia tolerance of the diving brain. Results Here we employed RNA-seq to approach the molecular basis of the unusual stress tolerance of the seal brain. An Illumina-generated transcriptome of the visual cortex of the hooded seal was compared with that of the ferret (Mustela putorius furo), which served as a terrestrial relative. Gene ontology analyses showed a significant enrichment of transcripts related to translation and aerobic energy production in the ferret but not in the seal brain. Clusterin, an extracellular chaperone, is the most highly expressed gene in the seal brain and fourfold higher than in the ferret or any other mammalian brain transcriptome. The largest difference was found for S100B, a calcium-binding stress protein with pleiotropic function, which was 38-fold enriched in the seal brain. Notably, significant enrichment of S100B mRNA was also found in the transcriptomes of whale brains, but not in the brains of terrestrial mammals. Conclusion Comparative transcriptomics indicates a lower aerobic capacity of the seal brain, which may be interpreted as a general energy saving strategy. Elevated expression of stress-related genes, such as clusterin and S100B, possibly contributes to the remarkable hypoxia tolerance of the brain of the hooded seal. Moreover, high levels of S100B that possibly protect the brain appear to be the result of the convergent adaptation of diving mammals. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2892-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Andrej Fabrizius
- Institute of Zoology, Biocenter Grindel, University of Hamburg, Martin-Luther-King-Platz 3, D-20146, Hamburg, Germany
| | - Mariana Leivas Müller Hoff
- Institute of Zoology, Biocenter Grindel, University of Hamburg, Martin-Luther-King-Platz 3, D-20146, Hamburg, Germany
| | - Gerhard Engler
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Lars P Folkow
- Department of Arctic and Marine Biology, University of Tromsø - The Arctic University of Norway, NO-9037, Tromsø, Norway
| | - Thorsten Burmester
- Institute of Zoology, Biocenter Grindel, University of Hamburg, Martin-Luther-King-Platz 3, D-20146, Hamburg, Germany.
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Ballarin C, Povinelli M, Granato A, Panin M, Corain L, Peruffo A, Cozzi B. The Brain of the Domestic Bos taurus: Weight, Encephalization and Cerebellar Quotients, and Comparison with Other Domestic and Wild Cetartiodactyla. PLoS One 2016; 11:e0154580. [PMID: 27128674 PMCID: PMC4851379 DOI: 10.1371/journal.pone.0154580] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 04/17/2016] [Indexed: 11/18/2022] Open
Abstract
The domestic bovine Bos taurus is raised worldwide for meat and milk production, or even for field work. However the functional anatomy of its central nervous system has received limited attention and most of the reported data in textbooks and reviews are derived from single specimens or relatively old literature. Here we report information on the brain of Bos taurus obtained by sampling 158 individuals, 150 of which at local abattoirs and 8 in the dissecting room, these latter subsequently formalin-fixed. Using body weight and fresh brain weight we calculated the Encephalization Quotient (EQ), and Cerebellar Quotient (CQ). Formalin-fixed brains sampled in the necropsy room were used to calculate the absolute and relative weight of the major components of the brain. The data that we obtained indicate that the domestic bovine Bos taurus possesses a large, convoluted brain, with a slightly lower weight than expected for an animal of its mass. Comparisons with other terrestrial and marine members of the order Cetartiodactyla suggested close similarity with other species with the same feeding adaptations, and with representative baleen whales. On the other hand differences with fish-hunting toothed whales suggest separate evolutionary pathways in brain evolution. Comparison with the other large domestic herbivore Equus caballus (belonging to the order Perissodactyla) indicates that Bos taurus underwent heavier selection of bodily traits, which is also possibly reflected in a comparatively lower EQ than in the horse. The data analyzed suggest that the brain of domestic bovine is potentially interesting for comparative neuroscience studies and may represents an alternative model to investigate neurodegeneration processes.
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Affiliation(s)
- Cristina Ballarin
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell’Università 16, 35020 Legnaro (PD), Italy
| | - Michele Povinelli
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell’Università 16, 35020 Legnaro (PD), Italy
| | - Alberto Granato
- Department of Psychology, Catholic University of Rome, Largo Gemelli 1, 20100 Milan (MI), Italy
| | - Mattia Panin
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell’Università 16, 35020 Legnaro (PD), Italy
| | - Livio Corain
- Department of Management and Engineering, University of Padova, Stradella S. Nicola 3, 36100 Vicenza (VI), Italy
| | - Antonella Peruffo
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell’Università 16, 35020 Legnaro (PD), Italy
| | - Bruno Cozzi
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell’Università 16, 35020 Legnaro (PD), Italy
- * E-mail:
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Gregory MD, Kippenhan JS, Dickinson D, Carrasco J, Mattay VS, Weinberger DR, Berman KF. Regional Variations in Brain Gyrification Are Associated with General Cognitive Ability in Humans. Curr Biol 2016; 26:1301-5. [PMID: 27133866 DOI: 10.1016/j.cub.2016.03.021] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 02/12/2016] [Accepted: 03/07/2016] [Indexed: 11/16/2022]
Abstract
Searching for a neurobiological understanding of human intellectual capabilities has long occupied those very capabilities. Brain gyrification, or folding of the cortex, is as highly evolved and variable a characteristic in humans as is intelligence. Indeed, gyrification scales with brain size, and relationships between brain size and intelligence have been demonstrated in humans [1-3]. However, gyrification shows a large degree of variability that is independent from brain size [4-6], suggesting that the former may independently contribute to cognitive abilities and thus supporting a direct investigation of this parameter in the context of intelligence. Moreover, uncovering the regional pattern of such an association could offer insights into evolutionary and neural mechanisms. We tested for this brain-behavior relationship in two separate, independently collected, large cohorts-440 healthy adults and 662 healthy children-using high-resolution structural neuroimaging and comprehensive neuropsychometric batteries. In both samples, general cognitive ability was significantly associated (pFDR < 0.01) with increasing gyrification in a network of neocortical regions, including large portions of the prefrontal cortex, inferior parietal lobule, and temporoparietal junction, as well as the insula, cingulate cortex, and fusiform gyrus, a regional distribution that was nearly identical in both samples (Dice similarity coefficient = 0.80). This neuroanatomical pattern is consistent with an existing, well-known proposal, the Parieto-Frontal Integration Theory of intelligence [7], and is also consistent with research in comparative evolutionary biology showing rapid neocortical expansion of these regions in humans relative to other species. These data provide a framework for understanding the neurobiology of human cognitive abilities and suggest a potential neurocellular association.
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Affiliation(s)
- Michael D Gregory
- Section on Integrative Neuroimaging, Clinical and Translational Neuroscience Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA.
| | - J Shane Kippenhan
- Section on Integrative Neuroimaging, Clinical and Translational Neuroscience Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Dwight Dickinson
- Psychosis and Cognitive Studies Section, Clinical and Translational Neuroscience Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jessica Carrasco
- Section on Integrative Neuroimaging, Clinical and Translational Neuroscience Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Venkata S Mattay
- Lieber Institute for Brain Development, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Daniel R Weinberger
- Lieber Institute for Brain Development, Baltimore, MD 21205, USA; Departments of Psychiatry and Neuroscience and the McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Karen F Berman
- Section on Integrative Neuroimaging, Clinical and Translational Neuroscience Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA; Psychosis and Cognitive Studies Section, Clinical and Translational Neuroscience Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA.
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Neuroanatomy of the killer whale (Orcinus orca): a magnetic resonance imaging investigation of structure with insights on function and evolution. Brain Struct Funct 2016; 222:417-436. [PMID: 27119362 DOI: 10.1007/s00429-016-1225-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Accepted: 04/07/2016] [Indexed: 12/18/2022]
Abstract
The evolutionary process of adaptation to an obligatory aquatic existence dramatically modified cetacean brain structure and function. The brain of the killer whale (Orcinus orca) may be the largest of all taxa supporting a panoply of cognitive, sensory, and sensorimotor abilities. Despite this, examination of the O. orca brain has been limited in scope resulting in significant deficits in knowledge concerning its structure and function. The present study aims to describe the neural organization and potential function of the O. orca brain while linking these traits to potential evolutionary drivers. Magnetic resonance imaging was used for volumetric analysis and three-dimensional reconstruction of an in situ postmortem O. orca brain. Measurements were determined for cortical gray and cerebral white matter, subcortical nuclei, cerebellar gray and white matter, corpus callosum, hippocampi, superior and inferior colliculi, and neuroendocrine structures. With cerebral volume comprising 81.51 % of the total brain volume, this O. orca brain is one of the most corticalized mammalian brains studied to date. O. orca and other delphinoid cetaceans exhibit isometric scaling of cerebral white matter with increasing brain size, a trait that violates an otherwise evolutionarily conserved cerebral scaling law. Using comparative neurobiology, it is argued that the divergent cerebral morphology of delphinoid cetaceans compared to other mammalian taxa may have evolved in response to the sensorimotor demands of the aquatic environment. Furthermore, selective pressures associated with the evolution of echolocation and unihemispheric sleep are implicated in substructure morphology and function. This neuroanatomical dataset, heretofore absent from the literature, provides important quantitative data to test hypotheses regarding brain structure, function, and evolution within Cetacea and across Mammalia.
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Konadhode RR, Pelluru D, Shiromani PJ. Unihemispheric Sleep: An Enigma for Current Models of Sleep-Wake Regulation. Sleep 2016; 39:491-4. [PMID: 26856898 DOI: 10.5665/sleep.5508] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 01/19/2016] [Indexed: 12/16/2022] Open
Affiliation(s)
- Roda Rani Konadhode
- Departments of Psychiatry & Behavioral Sciences, Medical University of South Carolina
| | - Dheeraj Pelluru
- Departments of Psychiatry & Behavioral Sciences, Medical University of South Carolina
| | - Priyattam J Shiromani
- Departments of Psychiatry & Behavioral Sciences, Medical University of South Carolina.,Ralph H. Johnson VA Medical Center, Charleston, SC
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de Lussanet MHE. Comment on "Cortical folding scales universally with surface area and thickness, not number of neurons". Science 2016; 351:825. [PMID: 26912885 DOI: 10.1126/science.aad0127] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The cerebrum of large mammals is convoluted, whereas that of small mammals is smooth. Mota and Herculano-Houzel (Reports, 3 July 2015, p. 74) inspired a model on an old theory that proposed a fractal geometry. I show that their model reduces to the product of gray-matter proportion times the folding index. This proportional relation describes the available data even better than the fractal model.
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Affiliation(s)
- Marc H E de Lussanet
- Institute of Sports Science, University of Münster, Horstmarer Landweg 62b, D-48149 Münster, Germany
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Naya DE, Naya H, Lessa EP. Brain size and thermoregulation during the evolution of the genus Homo. Comp Biochem Physiol A Mol Integr Physiol 2016; 191:66-73. [DOI: 10.1016/j.cbpa.2015.09.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 08/18/2015] [Accepted: 09/24/2015] [Indexed: 11/16/2022]
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The Evolution of Brains and Cognitive Abilities. Evol Biol 2016. [DOI: 10.1007/978-3-319-41324-2_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Kharlamova AS, Saveliev SV, Protopopov AV, Maseko BC, Bhagwandin A, Manger PR. The mummified brain of a pleistocene woolly mammoth (Mammuthus primigenius) compared with the brain of the extant African elephant (Loxodonta africana). J Comp Neurol 2015; 523:2326-43. [PMID: 26011110 DOI: 10.1002/cne.23817] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 05/14/2015] [Accepted: 05/14/2015] [Indexed: 11/11/2022]
Abstract
This study presents the results of an examination of the mummified brain of a pleistocene woolly mammoth (Mammuthus primigenius) recovered from the Yakutian permafrost in Siberia, Russia. This unique specimen (from 39,440-38,850 years BP) provides the rare opportunity to compare the brain morphology of this extinct species with a related extant species, the African elephant (Loxodonta africana). An anatomical description of the preserved brain of the woolly mammoth is provided, along with a series of quantitative analyses of various brain structures. These descriptions are based on visual inspection of the actual specimen as well as qualitative and quantitative comparison of computed tomography imaging data obtained for the woolly mammoth in comparison with magnetic resonance imaging data from three African elephant brains. In general, the brain of the woolly mammoth specimen examined, estimated to weigh between 4,230 and 4,340 g, showed the typical shape, size, and gross structures observed in extant elephants. Quantitative comparative analyses of various features of the brain, such as the amygdala, corpus callosum, cerebellum, and gyrnecephalic index, all indicate that the brain of the woolly mammoth specimen examined has many similarities with that of modern African elephants. The analysis provided here indicates that a specific brain type representative of the Elephantidae is likely to be a feature of this mammalian family. In addition, the extensive similarities between the woolly mammoth brain and the African elephant brain indicate that the specializations observed in the extant elephant brain are likely to have been present in the woolly mammoth.
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Affiliation(s)
| | | | - Albert V Protopopov
- Academy of Sciences of the Sakha Republic (Yakutia), Yakutsk, Sakha Republic (Yakutia), 677007, Russia
| | - Busisiwe C Maseko
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Parktown, 2193, Johannesburg, Republic of South Africa
| | - Adhil Bhagwandin
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Parktown, 2193, Johannesburg, Republic of South Africa
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Parktown, 2193, Johannesburg, Republic of South Africa
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