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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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2
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York AR, Sherwood CC, Manger PR, Kaas JH, Mota B, Herculano-Houzel S. Folding of the cerebellar cortex is clade-specific in form but universal in degree. J Comp Neurol 2024; 532:e25616. [PMID: 38634526 DOI: 10.1002/cne.25616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 02/01/2024] [Accepted: 03/26/2024] [Indexed: 04/19/2024]
Abstract
Like the cerebralcortex, the surface of the cerebellum is repeatedly folded. Unlike the cerebralcortex, however, cerebellar folds are much thinner and more numerous; repeatthemselves largely along a single direction, forming accordion-like folds transverseto the mid-sagittal plane; and occur in all but the smallest cerebella. We haveshown previously that while the location of folds in mammalian cerebral cortex isclade-specific, the overall degree of folding strictly follows a universalpower law relating cortical thickness and the exposed and total surface areas predictedfrom the minimization of the effective free energy of an expanding, self-avoidingsurface of a certain thickness. Here we show that this scaling law extends tothe folding of the mid-sagittal sections of the cerebellum of 53 speciesbelonging to six mammalian clades. Simultaneously, we show that each clade hasa previously unsuspected distinctive spatial pattern of folding evident at themid-sagittal surface of the cerebellum. We note, however, that the mammaliancerebellum folds as a multi-fractal object, because of the difference betweenthe outside-in development of the cerebellar cortex around a preexisting coreof already connected white matter, compared to the inside-out development ofthe cerebral cortex with a white matter volume that develops as the cerebralcortex itself gains neurons. We conclude that repeated folding, one of the mostrecognizable features of biology, can arise simply from the interplay betweenthe universal applicability of the physics of self-organization and biological,phylogenetical clade-specific contingency, without the need for invokingselective pressures in evolution.
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Affiliation(s)
- Annaleigh R York
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, USA
| | - Chet C Sherwood
- Department of Anthropology, The George Washington University, Washington, District of Columbia, USA
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witswatersrand, Johannesburg, South Africa
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA
| | - Bruno Mota
- Institute of Physics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Suzana Herculano-Houzel
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA
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3
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Akula SK, Exposito-Alonso D, Walsh CA. Shaping the brain: The emergence of cortical structure and folding. Dev Cell 2023; 58:2836-2849. [PMID: 38113850 PMCID: PMC10793202 DOI: 10.1016/j.devcel.2023.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 04/08/2023] [Accepted: 11/10/2023] [Indexed: 12/21/2023]
Abstract
The cerebral cortex-the brain's covering and largest region-has increased in size and complexity in humans and supports higher cognitive functions such as language and abstract thinking. There is a growing understanding of the human cerebral cortex, including the diversity and number of cell types that it contains, as well as of the developmental mechanisms that shape cortical structure and organization. In this review, we discuss recent progress in our understanding of molecular and cellular processes, as well as mechanical forces, that regulate the folding of the cerebral cortex. Advances in human genetics, coupled with experimental modeling in gyrencephalic species, have provided insights into the central role of cortical progenitors in the gyrification and evolutionary expansion of the cerebral cortex. These studies are essential for understanding the emergence of structural and functional organization during cortical development and the pathogenesis of neurodevelopmental disorders associated with cortical malformations.
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Affiliation(s)
- Shyam K Akula
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA; Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA, USA; Allen Discovery Center for Human Brain Evolution, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA; Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
| | - David Exposito-Alonso
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA; Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA, USA; Allen Discovery Center for Human Brain Evolution, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA; Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
| | - Christopher A Walsh
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA; Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA, USA; Allen Discovery Center for Human Brain Evolution, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA; Howard Hughes Medical Institute, Chevy Chase, Maryland, USA.
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4
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Sacco JC, Starr E, Weaver A, Dietz R, Spocter MA. Resequencing of the TMF-1 (TATA Element Modulatory Factor) regulated protein (TRNP1) gene in domestic and wild canids. Canine Med Genet 2023; 10:10. [PMID: 37968761 PMCID: PMC10647097 DOI: 10.1186/s40575-023-00133-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 10/27/2023] [Indexed: 11/17/2023] Open
Abstract
BACKGROUND Cortical folding is related to the functional organization of the brain. The TMF-1 regulated protein (TRNP1) regulates the expansion and folding of the mammalian cerebral cortex, a process that may have been accelerated by the domestication of dogs. The objectives of this study were to sequence the TRNP1 gene in dogs and related canid species, provide evidence of its expression in dog brain and compare the genetic variation within dogs and across the Canidae. The gene was located in silico to dog chromosome 2. The sequence was experimentally confirmed by amplifying and sequencing the TRNP1 exonic and promoter regions in 72 canids (36 purebred dogs, 20 Gy wolves and wolf-dog hybrids, 10 coyotes, 5 red foxes and 1 Gy fox). RESULTS A partial TRNP1 transcript was isolated from several regions in the dog brain. Thirty genetic polymorphisms were found in the Canis sp. with 17 common to both dogs and wolves, and only one unique to dogs. Seven polymorphisms were observed only in coyotes. An additional 9 variants were seen in red foxes. Dogs were the least genetically diverse. Several polymorphisms in the promoter and 3'untranslated region were predicted to alter TRNP1 function by interfering with the binding of transcriptional repressors and miRNAs expressed in neural precursors. A c.259_264 deletion variant that encodes a polyalanine expansion was polymorphic in all species studied except for dogs. A stretch of 15 nucleotides that is found in other mammalian sequences (corresponding to 5 amino acids located between Pro58 and Ala59 in the putative dog protein) was absent from the TRNP1 sequences of all 5 canid species sequenced. Both of these aforementioned coding sequence variations were predicted to affect the formation of alpha helices in the disordered region of the TRNP1 protein. CONCLUSIONS Potentially functionally important polymorphisms in the TRNP1 gene are found within and across various Canis species as well as the red fox, and unique differences in protein structure have evolved and been conserved in the Canidae compared to all other mammalian species.
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Affiliation(s)
- James C Sacco
- Ellis Pharmacogenomics Laboratory, College of Pharmacy and Health Sciences, Drake University, 50311, Des Moines, IA, USA.
| | - Emma Starr
- Ellis Pharmacogenomics Laboratory, College of Pharmacy and Health Sciences, Drake University, 50311, Des Moines, IA, USA
| | - Alyssa Weaver
- Ellis Pharmacogenomics Laboratory, College of Pharmacy and Health Sciences, Drake University, 50311, Des Moines, IA, USA
| | - Rachel Dietz
- Ellis Pharmacogenomics Laboratory, College of Pharmacy and Health Sciences, Drake University, 50311, Des Moines, IA, USA
| | - Muhammad A Spocter
- Department of Anatomy, Des Moines University, 50266, Des Moines, IA, USA
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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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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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Numerical Analysis of the Cerebral Cortex in Diprotodontids (Marsupialia; Australidelphia) and Comparison with Eutherian Brains. ZOOLOGY 2020; 143:125845. [DOI: 10.1016/j.zool.2020.125845] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 09/09/2020] [Accepted: 09/11/2020] [Indexed: 11/22/2022]
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8
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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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9
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Grewal JS, Gloe T, Hegedus J, Bitterman K, Billings BK, Chengetanai S, Bentil S, Wang VX, Ng JC, Tang CY, Geletta S, Wicinski B, Bertelson M, Tendler BC, Mars RB, Aguirre GK, Rusbridge C, Hof PR, Sherwood CC, Manger PR, Spocter MA. Brain gyrification in wild and domestic canids: Has domestication changed the gyrification index in domestic dogs? J Comp Neurol 2020; 528:3209-3228. [PMID: 32592407 DOI: 10.1002/cne.24972] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 01/09/2023]
Abstract
Over the last 15 years, research on canid cognition has revealed that domestic dogs possess a surprising array of complex sociocognitive skills pointing to the possibility that the domestication process might have uniquely altered their brains; however, we know very little about how evolutionary processes (natural or artificial) might have modified underlying neural structure to support species-specific behaviors. Evaluating the degree of cortical folding (i.e., gyrification) within canids may prove useful, as this parameter is linked to functional variation of the cerebral cortex. Using quantitative magnetic resonance imaging to investigate the impact of domestication on the canine cortical surface, we compared the gyrification index (GI) in 19 carnivore species, including six wild canid and 13 domestic dog individuals. We also explored correlations between global and local GI with brain mass, cortical thickness, white and gray matter volume and surface area. Our results indicated that GI values for domestic dogs are largely consistent with what would be expected for a canid of their given brain mass, although more variable than that observed in wild canids. We also found that GI in canids is positively correlated with cortical surface area, cortical thickness and total cortical gray matter volumes. While we found no evidence of global differences in GI between domestic and wild canids, certain regional differences in gyrification were observed.
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Affiliation(s)
- Jagmeet S Grewal
- Department of Anatomy, Des Moines University, Des Moines, Iowa, USA
| | - Tyler Gloe
- Department of Anatomy, Des Moines University, Des Moines, Iowa, USA
| | - Joseph Hegedus
- Department of Anatomy, Des Moines University, Des Moines, Iowa, USA
| | | | - Brendon K Billings
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Samson Chengetanai
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Sarah Bentil
- Department of Mechanical Engineering, Iowa State University, Ames, Iowa, USA
| | - Victoria X Wang
- Departments of Radiology and Psychiatry,and BioMedical and Engineering Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Johnny C Ng
- Departments of Radiology and Psychiatry,and BioMedical and Engineering Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Cheuk Y Tang
- Departments of Radiology and Psychiatry,and BioMedical and Engineering Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Simon Geletta
- Department of Public Health, Des Moines University, Des Moines, Iowa, USA
| | - Bridget Wicinski
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Mads Bertelson
- Center for Zoo and Wild Animal Health, Copenhagen Zoo, Fredericksberg, Denmark
| | - Benjamin C Tendler
- Wellcome Centre for Intergrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Rogier B Mars
- Wellcome Centre for Intergrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.,Donders Institute for Brain, Cognition and Behavior, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Geoffrey K Aguirre
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania Philadelphia, Philadelphia, Pennsylvania, USA
| | - Clare Rusbridge
- Fitzpatrick Referrals Orthopedics and Neurology, Fitzpatrick Referrals Ltd, Godalming, UK.,School of Veterinary Medicine, University of Surrey, Guildford, Surrey, UK
| | - 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
| | - Chet C Sherwood
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, District of Columbia, USA
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Muhammad A Spocter
- Department of Anatomy, Des Moines University, Des Moines, Iowa, USA.,School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa.,College of Veterinary Medicine, Department of Biomedical Sciences, Iowa State University, Ames, Iowa, USA
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10
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Jaakkola K, Bruck JN, Connor RC, Montgomery SH, King SL. Bias and Misrepresentation of Science Undermines Productive Discourse on Animal Welfare Policy: A Case Study. Animals (Basel) 2020; 10:ani10071118. [PMID: 32610674 PMCID: PMC7401611 DOI: 10.3390/ani10071118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 06/25/2020] [Accepted: 06/26/2020] [Indexed: 11/25/2022] Open
Abstract
Simple Summary Creating good animal welfare-related laws, regulations, and policies depends on accurate knowledge. To that end, scientific reviews that explain and contextualize the relevant research can be powerful tools for informing decision-makers, assuming these reviews represent the state of the scientific knowledge accurately and objectively. In this commentary, we examine the major flaws, biases, and misrepresentations of the scientific literature in one such recent review regarding the welfare and care of captive killer whales. Such pervasive problems, in this or any review, make it impossible to determine the true state of knowledge of the relevant issues, and can ultimately result in misinformed, arbitrary, or even harmful decisions about animals and their care. Abstract Reliable scientific knowledge is crucial for informing legislative, regulatory, and policy decisions in a variety of areas. To that end, scientific reviews of topical issues can be invaluable tools for informing productive discourse and decision-making, assuming these reviews represent the target body of scientific knowledge as completely, accurately, and objectively as possible. Unfortunately, not all reviews live up to this standard. As a case in point, Marino et al.’s review regarding the welfare of killer whales in captivity contains methodological flaws and misrepresentations of the scientific literature, including problematic referencing, overinterpretation of the data, misleading word choice, and biased argumentation. These errors and misrepresentations undermine the authors’ conclusions and make it impossible to determine the true state of knowledge of the relevant issues. To achieve the goal of properly informing public discourse and policy on this and other issues, it is imperative that scientists and science communicators strive for higher standards of analysis, argumentation, and objectivity, in order to clearly communicate what is known, what is not known, what conclusions are supported by the data, and where we are lacking the data necessary to draw reliable conclusions.
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Affiliation(s)
- Kelly Jaakkola
- Dolphin Research Center, Grassy Key, FL 33050, USA
- Correspondence:
| | - Jason N. Bruck
- Department of Biology, Stephen F. Austin State University, Nacogdoches, TX 75962-3003, USA;
| | - Richard C. Connor
- Biology Department, University of Massachusetts Dartmouth, North Dartmouth, MA 02747, USA;
| | - Stephen H. Montgomery
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK; (S.H.M.); (S.L.K.)
| | - Stephanie L. King
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK; (S.H.M.); (S.L.K.)
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11
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Marino L, Rose NA, Visser IN, Rally H, Ferdowsian H, Slootsky V. The harmful effects of captivity and chronic stress on the well-being of orcas (Orcinus orca). J Vet Behav 2020. [DOI: 10.1016/j.jveb.2019.05.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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12
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Malungo IB, Gravett N, Bhagwandin A, Davimes JG, Manger PR. A Preliminary Description of the Sleep-Related Neural Systems in the Brain of the Blue Wildebeest, Connochaetes taurinus. Anat Rec (Hoboken) 2019; 303:1977-1997. [PMID: 31513360 DOI: 10.1002/ar.24265] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 06/12/2019] [Accepted: 07/16/2019] [Indexed: 12/18/2022]
Abstract
The current study provides a detailed qualitative description of the organization of the cholinergic, catecholaminergic, serotonergic, orexinergic, and GABAergic sleep-related systems in the brain of the blue wildebeest (Connocheates taurinus), along with a quantitative analysis of the pontine cholinergic and noradrenergic neurons, and the hypothalamic orexinergic neurons. The aim of this study was to compare the nuclear organization of these systems to other mammalian species and specifically that reported for other Cetartiodactyla. In the brain of the blue wildebeest, from the basal forebrain to the pons, the nuclear organization of the cholinergic, catecholaminergic, serotonergic, and orexinergic systems, for the most part, showed a corresponding nuclear organization to that reported in other mammals and more specifically the Cetartiodactyla. Furthermore, the description and distribution of the GABAergic system, which was examined through immunostaining for the calcium binding proteins calbindin, calretinin, and parvalbumin, was also similar to that seen in other mammals. These findings indicate that sleep in the blue wildebeest is likely to show typically mammalian features in terms of the global brain activity of the generally recognized sleep states of mammals, but Cetartiodactyl-specific features of the orexinergic system may act to lower overall daily total sleep time in relation to similar sized non-Cetartiodactyl mammals. Anat Rec, 2019. © 2019 American Association for Anatomy Anat Rec, 303:1977-1997, 2020. © 2019 American Association for Anatomy.
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Affiliation(s)
- Illke B Malungo
- School of Anatomical Sciences, Faulty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Nadine Gravett
- School of Anatomical Sciences, Faulty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Adhil Bhagwandin
- School of Anatomical Sciences, Faulty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Joshua G Davimes
- School of Anatomical Sciences, Faulty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Paul R Manger
- School of Anatomical Sciences, Faulty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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13
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McBride SD, Morton AJ. Indices of comparative cognition: assessing animal models of human brain function. Exp Brain Res 2018; 236:3379-3390. [PMID: 30267138 PMCID: PMC6267686 DOI: 10.1007/s00221-018-5370-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 08/29/2018] [Indexed: 11/27/2022]
Abstract
Understanding the cognitive capacities of animals is important, because (a) several animal models of human neurodegenerative disease are considered poor representatives of the human equivalent and (b) cognitive capacities may provide insight into alternative animal models. We used a three-stage process of cognitive and neuroanatomical comparison (using sheep as an example) to assess the appropriateness of a species to model human brain function. First, a cognitive task was defined via a reinforcement-learning algorithm where values/constants in the algorithm were taken as indirect measures of neurophysiological attributes. Second, cognitive data (values/constants) were generated for the example species (sheep) and compared to other species. Third, cognitive data were compared with neuroanatomical metrics for each species (endocranial volume, gyrification index, encephalisation quotient, and number of cortical neurons). Four breeds of sheep (n = 15/sheep) were tested using the two-choice discrimination-reversal task. The 'reversal index' was used as a measure of constants within the learning algorithm. Reversal index data ranked sheep as third in a table of species that included primates, dogs, and pigs. Across all species, number of cortical neurons correlated strongest against the reversal index (r2 = 0.66, p = 0.0075) followed by encephalization quotient (r2 = 0.42, p = 0.03), endocranial volume (r2 = 0.30, p = 0.08), and gyrification index (r2 = 0.16, p = 0.23). Sheep have a high predicted level of cognitive capacity and are thus a valid alternative model for neurodegenerative research. Using learning algorithms within cognitive tasks increases the resolution of methods of comparative cognition and can help to identify the most relevant species to model human brain function and dysfunction.
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Affiliation(s)
- Sebastian D McBride
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Penglais, Aberystwyth, Ceredigion, SY23 3FG, UK.
| | - A Jennifer Morton
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, UK
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14
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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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15
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Jebb D, Hiller M. Recurrent loss of HMGCS2 shows that ketogenesis is not essential for the evolution of large mammalian brains. eLife 2018; 7:38906. [PMID: 30322448 PMCID: PMC6191284 DOI: 10.7554/elife.38906] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 09/09/2018] [Indexed: 12/04/2022] Open
Abstract
Apart from glucose, fatty acid-derived ketone bodies provide metabolic energy for the brain during fasting and neonatal development. We investigated the evolution of HMGCS2, the key enzyme required for ketone body biosynthesis (ketogenesis). Unexpectedly, we found that three mammalian lineages, comprising cetaceans (dolphins and whales), elephants and mastodons, and Old World fruit bats have lost this gene. Remarkably, many of these species have exceptionally large brains and signs of intelligent behavior. While fruit bats are sensitive to starvation, cetaceans and elephants can still withstand periods of fasting. This suggests that alternative strategies to fuel large brains during fasting evolved repeatedly and reveals flexibility in mammalian energy metabolism. Furthermore, we show that HMGCS2 loss preceded brain size expansion in toothed whales and elephants. Thus, while ketogenesis was likely important for brain size expansion in modern humans, ketogenesis is not a universal precondition for the evolution of large mammalian brains. Our brain requires a lot of energy to work properly. Sugars are usually the main type of fuel for the body, but when they run low – for example during a food shortage – fat, in the form of fatty acids, can be used instead. However, the brain cannot directly process these molecules; instead, fatty acids need to go through ketogenesis, a process that turns fat into ketone bodies, which the organ can then burn. Scientists believe that the ability to create ketone bodies was essential for us to evolve large brains. Yet, it is still unclear if all mammals can transform fatty acids into ketone bodies. One way to look into this question is to track whether other species have HMGCS2, the main enzyme that drives ketogenesis. Jebb and Hiller examined the genomes of 70 different species of mammals for the gene that codes for HMGCS2. The comparisons revealed that cetaceans (whales, dolphins and porpoises), Old World fruit bats and the African savanna elephant have all independently lost their working version of HMGCS2. Yet, many members of these three groups have evolved brains that are large for their body size. The genetic analyses showed that dolphins and elephants developed big brains after the enzyme became inactive, challenging the idea that HMGCS2 – and by extension ketogenesis – is always required for the evolution of large brains. These results may also be useful for conservation efforts. Many fruit bats across the world are severely threatened, and their lack of ketogenesis could explain why these animals are highly sensitive to starvation and quickly die when food becomes scarce.
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Affiliation(s)
- David Jebb
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Max Planck Institute for the Physics of Complex Systems, Dresden, Germany.,Center for Systems Biology Dresden, Dresden, Germany
| | - Michael Hiller
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Max Planck Institute for the Physics of Complex Systems, Dresden, Germany.,Center for Systems Biology Dresden, Dresden, Germany
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16
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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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17
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Triarhou LC. The Comparative Neurology of Neocortical Gyration and the Quest for Functional Specialization. Front Syst Neurosci 2017; 11:96. [PMID: 29311858 PMCID: PMC5744476 DOI: 10.3389/fnsys.2017.00096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 12/07/2017] [Indexed: 12/31/2022] Open
Affiliation(s)
- Lazaros C Triarhou
- Laboratory of Theoretical and Applied Neuroscience and Graduate Program in Neuroscience and Education, University of Macedonia, Thessalonica, Greece
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18
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Jardim-Messeder D, Lambert K, Noctor S, Pestana FM, de Castro Leal ME, Bertelsen MF, Alagaili AN, Mohammad OB, Manger PR, Herculano-Houzel S. Dogs Have the Most Neurons, Though Not the Largest Brain: Trade-Off between Body Mass and Number of Neurons in the Cerebral Cortex of Large Carnivoran Species. Front Neuroanat 2017; 11:118. [PMID: 29311850 PMCID: PMC5733047 DOI: 10.3389/fnana.2017.00118] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 11/27/2017] [Indexed: 12/27/2022] Open
Abstract
Carnivorans are a diverse group of mammals that includes carnivorous, omnivorous and herbivorous, domesticated and wild species, with a large range of brain sizes. Carnivory is one of several factors expected to be cognitively demanding for carnivorans due to a requirement to outsmart larger prey. On the other hand, large carnivoran species have high hunting costs and unreliable feeding patterns, which, given the high metabolic cost of brain neurons, might put them at risk of metabolic constraints regarding how many brain neurons they can afford, especially in the cerebral cortex. For a given cortical size, do carnivoran species have more cortical neurons than the herbivorous species they prey upon? We find they do not; carnivorans (cat, mongoose, dog, hyena, lion) share with non-primates, including artiodactyls (the typical prey of large carnivorans), roughly the same relationship between cortical mass and number of neurons, which suggests that carnivorans are subject to the same evolutionary scaling rules as other non-primate clades. However, there are a few important exceptions. Carnivorans stand out in that the usual relationship between larger body, larger cortical mass and larger number of cortical neurons only applies to small and medium-sized species, and not beyond dogs: we find that the golden retriever dog has more cortical neurons than the striped hyena, African lion and even brown bear, even though the latter species have up to three times larger cortices than dogs. Remarkably, the brown bear cerebral cortex, the largest examined, only has as many neurons as the ten times smaller cat cerebral cortex, although it does have the expected ten times as many non-neuronal cells in the cerebral cortex compared to the cat. We also find that raccoons have dog-like numbers of neurons in their cat-sized brain, which makes them comparable to primates in neuronal density. Comparison of domestic and wild species suggests that the neuronal composition of carnivoran brains is not affected by domestication. Instead, large carnivorans appear to be particularly vulnerable to metabolic constraints that impose a trade-off between body size and number of cortical neurons.
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Affiliation(s)
- Débora Jardim-Messeder
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Kelly Lambert
- Department of Psychology, University of Richmond, Richmond, VA, United States
| | - Stephen Noctor
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Fernanda M Pestana
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - 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
| | - Osama B Mohammad
- KSU Mammals Research Chair, Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Suzana Herculano-Houzel
- Department of Psychology, Vanderbilt University, Nashville, TN, United States.,Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, United States
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19
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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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20
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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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21
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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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22
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Minervini S, Accogli G, Pirone A, Graïc JM, Cozzi B, Desantis S. Brain Mass and Encephalization Quotients in the Domestic Industrial Pig (Sus scrofa). PLoS One 2016; 11:e0157378. [PMID: 27351807 PMCID: PMC4924858 DOI: 10.1371/journal.pone.0157378] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 05/28/2016] [Indexed: 12/31/2022] Open
Abstract
In the present study we examined the brain of fetal, newborn, and adult pigs raised for meat production. The fresh and formalin-fixed weights of the brain have been recorded and used, together with body weight, to calculate the Encephalization Quotient (EQ). The weight of the cerebellum has been used to calculate the Cerebellar Quotient (CQ). The results have been discussed together with analogue data obtained in other terrestrial Cetartiodactyla (including the domestic bovine, sheep, goat, and camel), domesticated Carnivora, Proboscidata, and Primates. Our study, based on a relatively large experimental series, corrects former observations present in the literature based on smaller samples, and emphasizes that the domestic pig has a small brain relative to its body size (EQ = 0.38 for adults), possibly due to factors linked to the necessity of meat production and improved body weight. Comparison with other terrestrial Cetartiodactyla indicates a similar trend for all domesticated species.
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Affiliation(s)
- Serena Minervini
- Section of Veterinary Clinics and Animal Productions, Department of Emergency and Organ Transplantation (DETO), University of Bari Aldo Moro, Valenzano (Ba), Italy
| | - Gianluca Accogli
- Section of Veterinary Clinics and Animal Productions, Department of Emergency and Organ Transplantation (DETO), University of Bari Aldo Moro, Valenzano (Ba), Italy
| | - Andrea Pirone
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy
| | - Jean-Marie Graïc
- Department of Comparative Biomedicine and Food Science, University of Padova, Padova, Italy
| | - Bruno Cozzi
- Department of Comparative Biomedicine and Food Science, University of Padova, Padova, Italy
| | - Salvatore Desantis
- Section of Veterinary Clinics and Animal Productions, Department of Emergency and Organ Transplantation (DETO), University of Bari Aldo Moro, Valenzano (Ba), Italy
- * E-mail:
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23
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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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24
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Dell LA, Patzke N, Spocter MA, Bertelsen MF, Siegel JM, Manger PR. Organization of the sleep-related neural systems in the brain of the river hippopotamus (Hippopotamus amphibius): A most unusual cetartiodactyl species. J Comp Neurol 2016; 524:2036-58. [PMID: 26588600 DOI: 10.1002/cne.23930] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 11/13/2015] [Accepted: 11/16/2015] [Indexed: 11/09/2022]
Abstract
This study provides the first systematic analysis of the nuclear organization of the neural systems related to sleep and wake in the basal forebrain, diencephalon, midbrain, and pons of the river hippopotamus, one of the closest extant terrestrial relatives of the cetaceans. All nuclei involved in sleep regulation and control found in other mammals, including cetaceans, were present in the river hippopotamus, with no specific nuclei being absent, but novel features of the cholinergic system, including novel nuclei, were present. This qualitative similarity relates to the cholinergic, noradrenergic, serotonergic, and orexinergic systems and is extended to the γ-aminobutyric acid (GABA)ergic elements of these nuclei. Quantitative analysis reveals that the numbers of pontine cholinergic (259,578) and noradrenergic (127,752) neurons, and hypothalamic orexinergic neurons (68,398) are markedly higher than in other large-brained mammals. These features, along with novel cholinergic nuclei in the intralaminar nuclei of the dorsal thalamus and the ventral tegmental area of the midbrain, as well as a major expansion of the hypothalamic cholinergic nuclei and a large laterodorsal tegmental nucleus of the pons that has both parvocellular and magnocellular cholinergic neurons, indicates an unusual sleep phenomenology for the hippopotamus. Our observations indicate that the hippopotamus is likely to be a bihemispheric sleeper that expresses REM sleep. The novel features of the cholinergic system suggest the presence of an undescribed sleep state in the hippopotamus, as well as the possibility that this animal could, more rapidly than other mammals, switch cortical electroencephalographic activity from one state to another. J. Comp. Neurol. 524:2036-2058, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Leigh-Anne Dell
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Parktown 2193, Johannesburg, Republic of South Africa
| | - Nina Patzke
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Parktown 2193, Johannesburg, Republic of South Africa
| | - Muhammad A Spocter
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Parktown 2193, Johannesburg, Republic of South Africa.,Department of Anatomy, Des Moines University, Des Moines, Iowa, 50312
| | - Mads F Bertelsen
- Center for Zoo and Wild Animal Health, Copenhagen Zoo, 2000, Fredericksberg, Denmark
| | - Jerome M Siegel
- Department of Psychiatry, University of California, Los Angeles, Neurobiology Research 151A3, Veterans Administration Sepulveda Ambulatory Medical Center, North Hills, California, 91343
| | - 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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Dell LA, Karlsson KA, Patzke N, Spocter MA, Siegel JM, Manger PR. Organization of the sleep-related neural systems in the brain of the minke whale (Balaenoptera acutorostrata). J Comp Neurol 2015; 524:2018-35. [PMID: 26588800 DOI: 10.1002/cne.23931] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 11/13/2015] [Accepted: 11/16/2015] [Indexed: 12/12/2022]
Abstract
The current study analyzed the nuclear organization of the neural systems related to the control and regulation of sleep and wake in the basal forebrain, diencephalon, midbrain, and pons of the minke whale, a mysticete cetacean. While odontocete cetaceans sleep in an unusual manner, with unihemispheric slow wave sleep (USWS) and suppressed REM sleep, it is unclear whether the mysticete whales show a similar sleep pattern. Previously, we detailed a range of features in the odontocete brain that appear to be related to odontocete-type sleep, and here present our analysis of these features in the minke whale brain. All neural elements involved in sleep regulation and control found in bihemispheric sleeping mammals and the harbor porpoise were present in the minke whale, with no specific nuclei being absent, and no novel nuclei being present. This qualitative similarity relates to the cholinergic, noradrenergic, serotonergic and orexinergic systems, and the GABAergic elements of these nuclei. Quantitative analysis revealed that the numbers of pontine cholinergic (274,242) and noradrenergic (203,686) neurons, and hypothalamic orexinergic neurons (277,604), are markedly higher than other large-brained bihemispheric sleeping mammals. Small telencephalic commissures (anterior, corpus callosum, and hippocampal), an enlarged posterior commissure, supernumerary pontine cholinergic and noradrenergic cells, and an enlarged peripheral division of the dorsal raphe nuclear complex of the minke whale, all indicate that the suite of neural characteristics thought to be involved in the control of USWS and the suppression of REM in the odontocete cetaceans are present in the minke whale. J. Comp. Neurol. 524:2018-2035, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Leigh-Anne Dell
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Karl Ae Karlsson
- Biomedical Engineering, Reykjavik University, Reykjavik, Iceland
| | - Nina Patzke
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Muhammad A Spocter
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa.,Department of Anatomy, Des Moines University, Des Moines, Iowa, USA
| | - Jerome M Siegel
- Department of Psychiatry, University of California, Los Angeles, Neurobiology Research 151A3, Sepulveda VAMC, North Hills, California, USA
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
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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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Dell LA, Spocter MA, Patzke N, Karlson KÆ, Alagaili AN, Bennett NC, Muhammed OB, Bertelsen MF, Siegel JM, Manger PR. Orexinergic bouton density is lower in the cerebral cortex of cetaceans compared to artiodactyls. J Chem Neuroanat 2015; 68:61-76. [DOI: 10.1016/j.jchemneu.2015.07.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 06/29/2015] [Accepted: 07/22/2015] [Indexed: 12/25/2022]
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Affiliation(s)
| | - Shyam Srinivasan
- The Salk Institute for Biological Sciences, La Jolla, California 92037;
- Kavli Institute for Brain and Mind, University of California, San Diego, La Jolla, California 92037
| | - Edwin S. Monuki
- Department of Pathology and Laboratory Medicine, University of California, Irvine, California 92697; ,
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Affiliation(s)
- Georg F. Striedter
- Department of Neurobiology & Behavior, University of California, Irvine, CA 92697, USA
| | - Shyam Srinivasan
- Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA, and Kavli Institute for Brain and Mind, University of California, San Diego, La Jolla, CA 92037, USA
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Mortensen HS, Pakkenberg B, Dam M, Dietz R, Sonne C, Mikkelsen B, Eriksen N. Quantitative relationships in delphinid neocortex. Front Neuroanat 2014; 8:132. [PMID: 25505387 PMCID: PMC4244864 DOI: 10.3389/fnana.2014.00132] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 10/29/2014] [Indexed: 12/04/2022] Open
Abstract
Possessing large brains and complex behavioral patterns, cetaceans are believed to be highly intelligent. Their brains, which are the largest in the Animal Kingdom and have enormous gyrification compared with terrestrial mammals, have long been of scientific interest. Few studies, however, report total number of brain cells in cetaceans, and even fewer have used unbiased counting methods. In this study, using stereological methods, we estimated the total number of cells in the neocortex of the long-finned pilot whale (Globicephala melas) brain. For the first time, we show that a species of dolphin has more neocortical neurons than any mammal studied to date including humans. These cell numbers are compared across various mammals with different brain sizes, and the function of possessing many neurons is discussed. We found that the long-finned pilot whale neocortex has approximately 37.2 × 109 neurons, which is almost twice as many as humans, and 127 × 109 glial cells. Thus, the absolute number of neurons in the human neocortex is not correlated with the superior cognitive abilities of humans (at least compared to cetaceans) as has previously been hypothesized. However, as neuron density in long-finned pilot whales is lower than that in humans, their higher cell number appears to be due to their larger brain. Accordingly, our findings make an important contribution to the ongoing debate over quantitative relationships in the mammalian brain.
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Affiliation(s)
- Heidi S Mortensen
- Research Laboratory for Stereology and Neuroscience, Bispebjerg and Frederiksberg University Hospitals Copenhagen, Denmark ; Research Department, Environment Agency Torshavn, Faroe Islands
| | - Bente Pakkenberg
- Research Laboratory for Stereology and Neuroscience, Bispebjerg and Frederiksberg University Hospitals Copenhagen, Denmark
| | - Maria Dam
- Research Department, Environment Agency Torshavn, Faroe Islands
| | - Rune Dietz
- Department of Bioscience, Institute for Bioscience - Arctic Research Centre, Roskilde, University of Aarhus Roskilde, Denmark
| | - Christian Sonne
- Department of Bioscience, Institute for Bioscience - Arctic Research Centre, Roskilde, University of Aarhus Roskilde, Denmark
| | | | - Nina Eriksen
- Research Laboratory for Stereology and Neuroscience, Bispebjerg and Frederiksberg University Hospitals Copenhagen, Denmark
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Kazu RS, Maldonado J, Mota B, Manger PR, Herculano-Houzel S. Cellular scaling rules for the brain of Artiodactyla include a highly folded cortex with few neurons. Front Neuroanat 2014; 8:128. [PMID: 25429261 PMCID: PMC4228855 DOI: 10.3389/fnana.2014.00128] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 10/20/2014] [Indexed: 11/30/2022] Open
Abstract
Quantitative analysis of the cellular composition of rodent, primate, insectivore, and afrotherian brains has shown that non-neuronal scaling rules are similar across these mammalian orders that diverged about 95 million years ago, and therefore appear to be conserved in evolution, while neuronal scaling rules appear to be free to vary in a clade-specific manner. Here we analyze the cellular scaling rules that apply to the brain of artiodactyls, a group within the order Cetartiodactyla, believed to be a relatively recent radiation from the common Eutherian ancestor. We find that artiodactyls share non-neuronal scaling rules with all groups analyzed previously. Artiodactyls share with afrotherians and rodents, but not with primates, the neuronal scaling rules that apply to the cerebral cortex and cerebellum. The neuronal scaling rules that apply to the remaining brain areas are, however, distinct in artiodactyls. Importantly, we show that the folding index of the cerebral cortex scales with the number of neurons in the cerebral cortex in distinct fashions across artiodactyls, afrotherians, rodents, and primates, such that the artiodactyl cerebral cortex is more convoluted than primate cortices of similar numbers of neurons. Our findings suggest that the scaling rules found to be shared across modern afrotherians, glires, and artiodactyls applied to the common Eutherian ancestor, such as the relationship between the mass of the cerebral cortex as a whole and its number of neurons. In turn, the distribution of neurons along the surface of the cerebral cortex, which is related to its degree of gyrification, appears to be a clade-specific characteristic. If the neuronal scaling rules for artiodactyls extend to all cetartiodactyls, we predict that the large cerebral cortex of cetaceans will still have fewer neurons than the human cerebral cortex.
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Affiliation(s)
- Rodrigo S Kazu
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil ; Instituto Nacional de Neurociência Translacional, CNPq/MCT, São Paulo, Brazil
| | | | - Bruno Mota
- Instituto de Física, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil
| | - Paul R Manger
- School of Anatomical Sciences, University of the Witwatersrand Johannesburg, South Africa
| | - Suzana Herculano-Houzel
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil ; Instituto Nacional de Neurociência Translacional, CNPq/MCT, São Paulo, Brazil
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Stoeger AS, Manger P. Vocal learning in elephants: neural bases and adaptive context. Curr Opin Neurobiol 2014; 28:101-7. [PMID: 25062469 PMCID: PMC4181794 DOI: 10.1016/j.conb.2014.07.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 06/28/2014] [Accepted: 07/01/2014] [Indexed: 10/28/2022]
Abstract
In the last decade clear evidence has accumulated that elephants are capable of vocal production learning. Examples of vocal imitation are documented in African (Loxodonta africana) and Asian (Elephas maximus) elephants, but little is known about the function of vocal learning within the natural communication systems of either species. We are also just starting to identify the neural basis of elephant vocalizations. The African elephant diencephalon and brainstem possess specializations related to aspects of neural information processing in the motor system (affecting the timing and learning of trunk movements) and the auditory and vocalization system. Comparative interdisciplinary (from behavioral to neuroanatomical) studies are strongly warranted to increase our understanding of both vocal learning and vocal behavior in elephants.
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Affiliation(s)
- Angela S Stoeger
- Department of Cognitive Biology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.
| | - Paul Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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Butti C, Janeway CM, Townshend C, Wicinski BA, Reidenberg JS, Ridgway SH, Sherwood CC, Hof PR, Jacobs B. The neocortex of cetartiodactyls: I. A comparative Golgi analysis of neuronal morphology in the bottlenose dolphin (Tursiops truncatus), the minke whale (Balaenoptera acutorostrata), and the humpback whale (Megaptera novaeangliae). Brain Struct Funct 2014; 220:3339-68. [PMID: 25100560 DOI: 10.1007/s00429-014-0860-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 07/25/2014] [Indexed: 12/12/2022]
Abstract
The present study documents the morphology of neurons in several regions of the neocortex from the bottlenose dolphin (Tursiops truncatus), the North Atlantic minke whale (Balaenoptera acutorostrata), and the humpback whale (Megaptera novaeangliae). Golgi-stained neurons (n = 210) were analyzed in the frontal and temporal neocortex as well as in the primary visual and primary motor areas. Qualitatively, all three species exhibited a diversity of neuronal morphologies, with spiny neurons including typical pyramidal types, similar to those observed in primates and rodents, as well as other spiny neuron types that had more variable morphology and/or orientation. Five neuron types, with a vertical apical dendrite, approximated the general pyramidal neuron morphology (i.e., typical pyramidal, extraverted, magnopyramidal, multiapical, and bitufted neurons), with a predominance of typical and extraverted pyramidal neurons. In what may represent a cetacean morphological apomorphy, both typical pyramidal and magnopyramidal neurons frequently exhibited a tri-tufted variant. In the humpback whale, there were also large, star-like neurons with no discernable apical dendrite. Aspiny bipolar and multipolar interneurons were morphologically consistent with those reported previously in other mammals. Quantitative analyses showed that neuronal size and dendritic extent increased in association with body size and brain mass (bottlenose dolphin < minke whale < humpback whale). The present data thus suggest that certain spiny neuron morphologies may be apomorphies in the neocortex of cetaceans as compared to other mammals and that neuronal dendritic extent covaries with brain and body size.
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Affiliation(s)
- Camilla Butti
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, Box 1639, One Gustave L. Levy Place, New York, NY, 10029, USA.
| | - Caroline M Janeway
- Laboratory of Quantitative Neuromorphology, Psychology, Colorado College, 14 E. Cache La Poudre, Colorado Springs, CO, 80903, USA
| | - Courtney Townshend
- Laboratory of Quantitative Neuromorphology, Psychology, Colorado College, 14 E. Cache La Poudre, Colorado Springs, CO, 80903, USA
| | - Bridget A Wicinski
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, Box 1639, One Gustave L. Levy Place, New York, NY, 10029, USA
| | - Joy S Reidenberg
- Center for Anatomy and Functional Morphology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
| | - Sam H Ridgway
- National Marine Mammal Foundation, 2240 Shelter Island Drive, San Diego, CA, 92106, USA
| | - Chet C Sherwood
- Department of Anthropology, The George Washington University, 2110 G Street NW, Washington, DC, 20052, USA
| | - Patrick R Hof
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, Box 1639, One Gustave L. Levy Place, New York, NY, 10029, USA
| | - Bob Jacobs
- Laboratory of Quantitative Neuromorphology, Psychology, Colorado College, 14 E. Cache La Poudre, Colorado Springs, CO, 80903, USA
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Raghanti MA, Spurlock LB, Treichler FR, Weigel SE, Stimmelmayr R, Butti C, Thewissen JGMH, Hof PR. An analysis of von Economo neurons in the cerebral cortex of cetaceans, artiodactyls, and perissodactyls. Brain Struct Funct 2014; 220:2303-14. [PMID: 24852852 DOI: 10.1007/s00429-014-0792-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 04/29/2014] [Indexed: 10/25/2022]
Abstract
Von Economo neurons (VENs) are specialized projection neurons with a characteristic spindle-shaped soma and thick basal and apical dendrites. VENs have been described in restricted cortical regions, with their most frequent appearance in layers III and V of the anterior cingulate cortex, anterior insula, and frontopolar cortex of humans, great apes, macaque monkeys, elephants, and some cetaceans. Recently, a ubiquitous distribution of VENs was reported in various cortical areas in the pygmy hippopotamus, one of the closest living relatives of cetaceans. That finding suggested that VENs might not be unique to only a few species that possess enlarged brains. In the present analysis, we assessed the phylogenetic distribution of VENs within species representative of the superordinal clade that includes cetartiodactyls and perissodactyls, as well as afrotherians. In addition, the distribution of fork cells that are often found in close proximity to VENs was also assessed. Nissl-stained sections from the frontal pole, anterior cingulate cortex, anterior insula, and occipital pole of bowhead whale, cow, sheep, deer, horse, pig, rock hyrax, and human were examined using stereologic methods to quantify VENs and fork cells within layer V of all four cortical regions. VENs and fork cells were found in each of the species examined here with species-specific differences in distributions and densities. The present results demonstrated that VENs and fork cells were not restricted to highly encephalized or socially complex species, and their repeated emergence among distantly related species seems to represent convergent evolution of specialized pyramidal neurons. The widespread phylogenetic presence of VENs and fork cells indicates that these neuron morphologies readily emerged in response to selective forces,whose variety and nature are yet to be identified.
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Affiliation(s)
- Mary Ann Raghanti
- Department of Anthropology and School of Biomedical Sciences, Kent State University, 750 Hilltop Drive, 222 Lowry Hall, Kent, OH, 44242, USA,
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Butti C, Ewan Fordyce R, Ann Raghanti M, Gu X, Bonar CJ, Wicinski BA, Wong EW, Roman J, Brake A, Eaves E, Spocter MA, Tang CY, Jacobs B, Sherwood CC, Hof PR. The cerebral cortex of the pygmy hippopotamus, Hexaprotodon liberiensis (Cetartiodactyla, Hippopotamidae): MRI, cytoarchitecture, and neuronal morphology. Anat Rec (Hoboken) 2014; 297:670-700. [PMID: 24474726 DOI: 10.1002/ar.22875] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 11/04/2013] [Indexed: 12/24/2022]
Abstract
The structure of the hippopotamus brain is virtually unknown because few studies have examined more than its external morphology. In view of their semiaquatic lifestyle and phylogenetic relatedness to cetaceans, the brain of hippopotamuses represents a unique opportunity for better understanding the selective pressures that have shaped the organization of the brain during the evolutionary process of adaptation to an aquatic environment. Here we examined the histology of the cerebral cortex of the pygmy hippopotamus (Hexaprotodon liberiensis) by means of Nissl, Golgi, and calretinin (CR) immunostaining, and provide a magnetic resonance imaging (MRI) structural and volumetric dataset of the anatomy of its brain. We calculated the corpus callosum area/brain mass ratio (CCA/BM), the gyrencephalic index (GI), the cerebellar quotient (CQ), and the cerebellar index (CI). Results indicate that the cortex of H. liberiensis shares one feature exclusively with cetaceans (the lack of layer IV across the entire cerebral cortex), other features exclusively with artiodactyls (e.g., the morphologiy of CR-immunoreactive multipolar neurons in deep cortical layers, gyrencephalic index values, hippocampus and cerebellum volumetrics), and others with at least some species of cetartiodactyls (e.g., the presence of a thick layer I, the pattern of distribution of CR-immunoreactive neurons, the presence of von Economo neurons, clustering of layer II in the occipital cortex). The present study thus provides a comprehensive dataset of the neuroanatomy of H. liberiensis that sets the ground for future comparative studies including the larger Hippopotamus amphibius.
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Affiliation(s)
- Camilla Butti
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York
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Cozzi B, Povinelli M, Ballarin C, Granato A. The brain of the horse: weight and cephalization quotients. BRAIN, BEHAVIOR AND EVOLUTION 2013; 83:9-16. [PMID: 24335261 DOI: 10.1159/000356527] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 10/18/2013] [Indexed: 11/19/2022]
Abstract
The horse is a common domestic animal whose anatomy has been studied since the XVI century. However, a modern neuroanatomy of this species does not exist and most of the data utilized in textbooks and reviews derive from single specimens or relatively old literature. Here, we report information on the brain of Equus caballus obtained by sampling 131 horses, including brain weight (as a whole and subdivided into its constituents), encephalization quotient (EQ), and cerebellar quotient (CQ), and comparisons with what is known about other relevant species. The mean weight of the fresh brains in our experimental series was 598.63 g (SEM ± 7.65), with a mean body weight of 514.12 kg (SEM ± 15.42). The EQ was 0.78 and the CQ was 0.841. The data we obtained indicate that the horse possesses a large, convoluted brain, with a weight similar to that of other hoofed species of like mass. However, the shape of the brain, the noteworthy folding of the neocortex, and the peculiar longitudinal distribution of the gyri suggest an evolutionary specificity at least partially separate from that of the Cetartiodactyla (even-toed mammals and cetaceans) with whom Perissodactyla (odd-toed mammals) are often grouped.
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Affiliation(s)
- Bruno Cozzi
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Italy
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In contrast to many other mammals, cetaceans have relatively small hippocampi that appear to lack adult neurogenesis. Brain Struct Funct 2013; 220:361-83. [PMID: 24178679 DOI: 10.1007/s00429-013-0660-1] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 10/15/2013] [Indexed: 12/16/2022]
Abstract
The hippocampus is essential for the formation and retrieval of memories and is a crucial neural structure sub-serving complex cognition. Adult hippocampal neurogenesis, the birth, migration and integration of new neurons, is thought to contribute to hippocampal circuit plasticity to augment function. We evaluated hippocampal volume in relation to brain volume in 375 mammal species and examined 71 mammal species for the presence of adult hippocampal neurogenesis using immunohistochemistry for doublecortin, an endogenous marker of immature neurons that can be used as a proxy marker for the presence of adult neurogenesis. We identified that the hippocampus in cetaceans (whales, dolphins and porpoises) is both absolutely and relatively small for their overall brain size, and found that the mammalian hippocampus scaled as an exponential function in relation to brain volume. In contrast, the amygdala was found to scale as a linear function of brain volume, but again, the relative size of the amygdala in cetaceans was small. The cetacean hippocampus lacks staining for doublecortin in the dentate gyrus and thus shows no clear signs of adult hippocampal neurogenesis. This lack of evidence of adult hippocampal neurogenesis, along with the small hippocampus, questions current assumptions regarding cognitive abilities associated with hippocampal function in the cetaceans. These anatomical features of the cetacean hippocampus may be related to the lack of postnatal sleep, causing a postnatal cessation of hippocampal neurogenesis.
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Maseko BC, Patzke N, Fuxe K, Manger PR. Architectural Organization of the African Elephant Diencephalon and Brainstem. BRAIN, BEHAVIOR AND EVOLUTION 2013; 82:83-128. [DOI: 10.1159/000352004] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 05/03/2013] [Indexed: 11/19/2022]
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Manger PR, Spocter MA, Patzke N. The evolutions of large brain size in mammals: the 'over-700-gram club quartet'. BRAIN, BEHAVIOR AND EVOLUTION 2013; 82:68-78. [PMID: 23979457 DOI: 10.1159/000352056] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The current paper details our developing understanding of the evolution of large brains in mammals. In order to do this, we first define brains that we consider to be large--those that have passed the apparent 700-gram ceiling on brain mass evolution in the class Mammalia. The over-700-gram club includes certain species within the genus Homo, order Cetacea, order Proboscidea, and suborder Pinnipedia. Our analysis suggests that selection for body size appears to be the most important factor in the evolution of large brain size, but there also appear to be internal morphophysiological constraints on large brain size evolution that need to be overcome in order for brains to break the 700-gram barrier. These two aspects appear to be common themes in the evolution of large brains. This significantly diminishes the explanatory value of selection for greater cognitive capacities as a principal factor in the evolution of enlarged brain sizes above the 700-gram threshold.
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Affiliation(s)
- Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa.
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Lewitus E, Kelava I, Huttner WB. Conical expansion of the outer subventricular zone and the role of neocortical folding in evolution and development. Front Hum Neurosci 2013; 7:424. [PMID: 23914167 PMCID: PMC3729979 DOI: 10.3389/fnhum.2013.00424] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 07/14/2013] [Indexed: 12/01/2022] Open
Abstract
THERE IS A BASIC RULE TO MAMMALIAN NEOCORTICAL EXPANSION as it expands, so does it fold. The degree to which it folds, however, cannot strictly be attributed to its expansion. Across species, cortical volume does not keep pace with cortical surface area, but rather folds appear more rapidly than expected. As a result, larger brains quickly become disproportionately more convoluted than smaller brains. Both the absence (lissencephaly) and presence (gyrencephaly) of cortical folds is observed in all mammalian orders and, while there is likely some phylogenetic signature to the evolutionary appearance of gyri and sulci, there are undoubtedly universal trends to the acquisition of folds in an expanding neocortex. Whether these trends are governed by conical expansion of neocortical germinal zones, the distribution of cortical connectivity, or a combination of growth- and connectivity-driven forces remains an open question. But the importance of cortical folding for evolution of the uniquely mammalian neocortex, as well as for the incidence of neuropathologies in humans, is undisputed. In this hypothesis and theory article, we will summarize the development of cortical folds in the neocortex, consider the relative influence of growth- vs. connectivity-driven forces for the acquisition of cortical folds between and within species, assess the genetic, cell-biological, and mechanistic implications for neocortical expansion, and discuss the significance of these implications for human evolution, development, and disease. We will argue that evolutionary increases in the density of neuron production, achieved via maintenance of a basal proliferative niche in the neocortical germinal zones, drive the conical migration of neurons toward the cortical surface and ultimately lead to the establishment of cortical folds in large-brained mammal species.
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Affiliation(s)
| | | | - Wieland B. Huttner
- Max Planck Institute of Molecular Cell Biology and GeneticsDresden, Germany
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Kelava I, Lewitus E, Huttner WB. The secondary loss of gyrencephaly as an example of evolutionary phenotypical reversal. Front Neuroanat 2013; 7:16. [PMID: 23805079 PMCID: PMC3693069 DOI: 10.3389/fnana.2013.00016] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 05/20/2013] [Indexed: 11/13/2022] Open
Abstract
Gyrencephaly (the folding of the surface of the neocortex) is a mammalian-specific trait present in almost all mammalian orders. Despite the widespread appearance of the trait, little is known about the mechanism of its genesis or its adaptive significance. Still, most of the hypotheses proposed concentrated on the pattern of connectivity of mature neurons as main components of gyri formation. Recent work on embryonic neurogenesis in several species of mammals revealed different progenitor and stem cells and their neurogenic potential as having important roles in the process of gyrification. Studies in the field of comparative neurogenesis revealed that gyrencephaly is an evolutionarily labile trait, and that some species underwent a secondary loss of a convoluted brain surface and thus reverted to a more ancient form, a less folded brain surface (lissencephaly). This phenotypic reversion provides an excellent system for understanding the phenomenon of secondary loss. In this review, we will outline the theory behind secondary loss and, as specific examples, present species that have undergone this transition with respect to neocortical folding. We will also discuss different possible pathways for obtaining (or losing) gyri. Finally, we will explore the potential adaptive consequence of gyrencephaly relative to lissencephaly and vice versa.
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Affiliation(s)
| | | | - Wieland B. Huttner
- Max Planck Institute of Molecular Cell Biology and GeneticsDresden, Germany
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Ventura-Antunes L, Mota B, Herculano-Houzel S. Different scaling of white matter volume, cortical connectivity, and gyrification across rodent and primate brains. Front Neuroanat 2013; 7:3. [PMID: 23576961 PMCID: PMC3620553 DOI: 10.3389/fnana.2013.00003] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 03/20/2013] [Indexed: 11/13/2022] Open
Abstract
Expansion of the cortical gray matter in evolution has been accompanied by an even faster expansion of the subcortical white matter volume and by folding of the gray matter surface, events traditionally considered to occur homogeneously across mammalian species. Here we investigate how white matter expansion and cortical folding scale across species of rodents and primates as the gray matter gains neurons. We find very different scaling rules of white matter expansion across the two orders, favoring volume conservation and smaller propagation times in primates. For a similar number of cortical neurons, primates have a smaller connectivity fraction and less white matter volume than rodents; moreover, as the cortex gains neurons, there is a much faster increase in white matter volume and in its ratio to gray matter volume in rodents than in primates. Order-specific scaling of the white matter can be attributed to different scaling of average fiber caliber and neuronal connectivity in rodents and primates. Finally, cortical folding increases as different functions of the number of cortical neurons in rodents and primates, scaling faster in the latter than in the former. While the neuronal rules that govern gray and white matter scaling are different across rodents and primates, we find that they can be explained by the same unifying model, with order-specific exponents. The different scaling of the white matter has implications for the scaling of propagation time and computational capacity in evolution, and calls for a reappraisal of developmental models of cortical expansion in evolution.
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Affiliation(s)
- Lissa Ventura-Antunes
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro Ilha do Fundão, Brazil ; Instituto Nacional de Neurociência Translacional, Ministério de Ciência de Tecnologia/CNPq Rio de Janeiro, Brazil
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