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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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Through the looking glass: how do marked dolphins use mirrors and what does it mean? Anim Cogn 2022; 25:1151-1160. [PMID: 36125644 PMCID: PMC9617816 DOI: 10.1007/s10071-022-01680-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 08/10/2022] [Accepted: 08/16/2022] [Indexed: 11/22/2022]
Abstract
Mirror-guided self-inspection is seen as a cognitive hallmark purportedly indicating the existence of self-recognition. Only a few species of great apes have been reported to pass a standard mark test for mirror self-recognition in which animals attempt to touch a mark. In addition, evidence for passing the mark test was also reported for Asian elephants, two species of corvids, and a species of cleaner fish. Mirror self-recognition has also been claimed for bottlenose dolphins, using exposure of marked areas to a mirror as evidence. However, what counts as self-directed behaviour to see the mark and what does not has been debated. To avoid this problem, we marked the areas around both eyes of the animals at the same time, one with visible and the other with transparent dye to control for haptic cues. This allowed the animal to see the mark easily and us to investigate what side was exposed to the mirror as an indicator for mark observation. We found that the animals actively chose to inspect their visibly marked side while they did not show an increased interest in a marked conspecific in the pool. These results demonstrate that dolphins use the mirror to inspect their marks and, therefore, likely recognise a distinction between self and others.
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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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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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5
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Schubiger MN, Fichtel C, Burkart JM. Validity of Cognitive Tests for Non-human Animals: Pitfalls and Prospects. Front Psychol 2020; 11:1835. [PMID: 32982822 PMCID: PMC7488350 DOI: 10.3389/fpsyg.2020.01835] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/03/2020] [Indexed: 01/04/2023] Open
Abstract
Comparative psychology assesses cognitive abilities and capacities of non-human animals and humans. Based on performance differences and similarities in various species in cognitive tests, it is inferred how their minds work and reconstructed how cognition might have evolved. Critically, such species comparisons are only valid and meaningful if the tasks truly capture individual and inter-specific variation in cognitive abilities rather than contextual variables that might affect task performance. Unlike in human test psychology, however, cognitive tasks for non-human primates (and most other animals) have been rarely evaluated regarding their measurement validity. We review recent studies that address how non-cognitive factors affect performance in a set of commonly used cognitive tasks, and if cognitive tests truly measure individual variation in cognitive abilities. We find that individual differences in emotional and motivational factors primarily affect performance via attention. Hence, it is crucial to systematically control for attention during cognitive tasks to obtain valid and reliable results. Aspects of test design, however, can also have a substantial effect on cognitive performance. We conclude that non-cognitive factors are a minor source of measurement error if acknowledged and properly controlled for. It is essential, however, to validate and eventually re-design several primate cognition tasks in order to ascertain that they capture the cognitive abilities they were designed to measure. This will provide a more solid base for future cognitive comparisons within primates but also across a wider range of non-human animal species.
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Affiliation(s)
- Michèle N. Schubiger
- Evolutionary Cognition Group, Department of Anthropology, University of Zurich, Zurich, Switzerland
- World Ape Fund, London, United Kingdom
| | - Claudia Fichtel
- Behavioural Ecology and Sociobiology Unit, German Primate Center, Göttingen, Germany
- Leibniz ScienceCampus “Primate Cognition”, Göttingen, Germany
| | - Judith M. Burkart
- Evolutionary Cognition Group, Department of Anthropology, University of Zurich, Zurich, Switzerland
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Saniotis A, Grantham JP, Kumaratilake J, Henneberg M. Neuro-hormonal Regulation Is a Better Indicator of Human Cognitive Abilities Than Brain Anatomy: The Need for a New Paradigm. Front Neuroanat 2020; 13:101. [PMID: 31998082 PMCID: PMC6962128 DOI: 10.3389/fnana.2019.00101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 12/04/2019] [Indexed: 12/31/2022] Open
Affiliation(s)
- Arthur Saniotis
- Department of Medical Laboratory Science, Knowledge University, Erbil, Iraq
- Biological Anthropology and Comparative Anatomy Research Unit (BACARU), Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
- *Correspondence: Arthur Saniotis
| | - James P. Grantham
- Biological Anthropology and Comparative Anatomy Research Unit (BACARU), Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
- Institute of Evolutionary Medicine, Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Jaliya Kumaratilake
- Biological Anthropology and Comparative Anatomy Research Unit (BACARU), Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
| | - Maciej Henneberg
- Biological Anthropology and Comparative Anatomy Research Unit (BACARU), Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
- Institute of Evolutionary Medicine, Faculty of Medicine, University of Zurich, Zurich, Switzerland
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Serio C, Castiglione S, Tesone G, Piccolo M, Melchionna M, Mondanaro A, Di Febbraro M, Raia P. Macroevolution of Toothed Whales Exceptional Relative Brain Size. Evol Biol 2019. [DOI: 10.1007/s11692-019-09485-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Benoit J, Legendre LJ, Tabuce R, Obada T, Mararescul V, Manger P. Brain evolution in Proboscidea (Mammalia, Afrotheria) across the Cenozoic. Sci Rep 2019; 9:9323. [PMID: 31249366 PMCID: PMC6597534 DOI: 10.1038/s41598-019-45888-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 06/07/2019] [Indexed: 12/12/2022] Open
Abstract
As the largest and among the most behaviourally complex extant terrestrial mammals, proboscideans (elephants and their extinct relatives) are iconic representatives of the modern megafauna. The timing of the evolution of large brain size and above average encephalization quotient remains poorly understood due to the paucity of described endocranial casts. Here we created the most complete dataset on proboscidean endocranial capacity and analysed it using phylogenetic comparative methods and ancestral character states reconstruction using maximum likelihood. Our analyses support that, in general, brain size and body mass co-evolved in proboscideans across the Cenozoic; however, this pattern appears disrupted by two instances of specific increases in relative brain size in the late Oligocene and early Miocene. These increases in encephalization quotients seem to correspond to intervals of important climatic, environmental and faunal changes in Africa that may have positively selected for larger brain size or body mass.
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Affiliation(s)
- Julien Benoit
- Evolutionary Studies Institute (ESI), University of the Witwatersrand, Braamfontein, 2050, Johannesburg, South Africa.
| | - Lucas J Legendre
- Jackson School of Geosciences, The University of Texas at Austin, 2275 Speedway Stop C9000, Austin, TX, United States
| | - Rodolphe Tabuce
- Institut des Sciences de L'Evolution de Montpellier, Université Montpellier 2, Place Eugène Batillon, F-34095 Montpellier, cedex 05, Montpellier, France
| | - Theodor Obada
- Academy of Sciences of Moldova, Institute of Zoology, Chişinău, Moldova
| | | | - Paul Manger
- School of Anatomical Sciences, University of the Witwatersrand, 7 York Road, Parktown, 2193, Johannesburg, South Africa
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Abstract
We investigate which of the higher cognitive abilities or types of intelligence characteristic of humans are found, even in preliminary form, in non-human animals, predominantly primates, or whether qualitatively different ("unique") human abilities exist. This concerns (1) tool use and fabrication, (2) problem solving, (3) gaze following, (4) mirror self-recognition, (5) imitation, (6) metacognition, (7) theory of mind, (8) consciousness, (9) prosociality, and (10) language. We found that none of these abilities can be regarded as unique to humans without precursors in non-human primates. The observed differences in cognitive functions, underlying brain mechanisms and resulting behaviors correlate best with differences in the information processing capacity as an equivalent of general intelligence based on the number of cortical neurons, packing density and axonal conduction velocity plus long-range cortical fascicles. The biggest quantitative change appears to concern the origin of syntactical language, but this was preceded by an increased mental ability to manipulate sequential events within working memory.
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Affiliation(s)
- Gerhard Roth
- Faculty of Biology and Chemistry, Brain Research Institute, University of Bremen, Bremen, Germany.
| | - Ursula Dicke
- Faculty of Biology and Chemistry, Brain Research Institute, University of Bremen, Bremen, Germany
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10
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11
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Lind J. What can associative learning do for planning? ROYAL SOCIETY OPEN SCIENCE 2018; 5:180778. [PMID: 30564390 PMCID: PMC6281940 DOI: 10.1098/rsos.180778] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 10/29/2018] [Indexed: 05/31/2023]
Abstract
There is a new associative learning paradox. The power of associative learning for producing flexible behaviour in non-human animals is downplayed or ignored by researchers in animal cognition, whereas artificial intelligence research shows that associative learning models can beat humans in chess. One phenomenon in which associative learning often is ruled out as an explanation for animal behaviour is flexible planning. However, planning studies have been criticized and questions have been raised regarding both methodological validity and interpretations of results. Due to the power of associative learning and the uncertainty of what causes planning behaviour in non-human animals, I explored what associative learning can do for planning. A previously published sequence learning model which combines Pavlovian and instrumental conditioning was used to simulate two planning studies, namely Mulcahy & Call 2006 'Apes save tools for future use.' Science 312, 1038-1040 and Kabadayi & Osvath 2017 'Ravens parallel great apes in flexible planning for tool-use and bartering.' Science 357, 202-204. Simulations show that behaviour matching current definitions of flexible planning can emerge through associative learning. Through conditioned reinforcement, the learning model gives rise to planning behaviour by learning that a behaviour towards a current stimulus will produce high value food at a later stage; it can make decisions about future states not within current sensory scope. The simulations tracked key patterns both between and within studies. It is concluded that one cannot rule out that these studies of flexible planning in apes and corvids can be completely accounted for by associative learning. Future empirical studies of flexible planning in non-human animals can benefit from theoretical developments within artificial intelligence and animal learning.
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Affiliation(s)
- Johan Lind
- Centre for Cultural Evolution, Stockholm University, Stockholm, Sweden
- Department of Zoology, Stockholm University, Stockholm, Sweden
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12
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Lyamin OI, Kosenko PO, Korneva SM, Vyssotski AL, Mukhametov LM, Siegel JM. Fur Seals Suppress REM Sleep for Very Long Periods without Subsequent Rebound. Curr Biol 2018; 28:2000-2005.e2. [PMID: 29887309 DOI: 10.1016/j.cub.2018.05.022] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 02/26/2018] [Accepted: 05/08/2018] [Indexed: 11/17/2022]
Abstract
Virtually all land mammals and birds have two sleep states: slow-wave sleep (SWS) and rapid eye movement (REM) sleep [1, 2]. After deprivation of REM sleep by repeated awakenings, mammals increase REM sleep time [3], supporting the idea that REM sleep is homeostatically regulated. Some evidence suggests that periods of REM sleep deprivation for a week or more cause physiological dysfunction and eventual death [4, 5]. However, separating the effects of REM sleep loss from the stress of repeated awakening is difficult [2, 6]. The northern fur seal (Callorhinus ursinus) is a semiaquatic mammal [7]. It can sleep on land and in seawater. The fur seal is unique in showing both the bilateral SWS seen in most mammals and the asymmetric sleep previously reported in cetaceans [8]. Here we show that when the fur seal stays in seawater, where it spends most of its life [7], it goes without or greatly reduces REM sleep for days or weeks. After this nearly complete elimination of REM, it displays minimal or no REM rebound upon returning to baseline conditions. Our data are consistent with the hypothesis that REM sleep may serve to reverse the reduced brain temperature and metabolism effects of bilateral nonREM sleep, a state that is greatly reduced when the fur seal is in the seawater, rather than REM sleep being directly homeostatically regulated. This can explain the absence of REM sleep in the dolphin and other cetaceans and its increasing proportion as the end of the sleep period approaches in humans and other mammals.
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Affiliation(s)
- Oleg I Lyamin
- Department of Psychiatry and Biobehavioral Sciences and Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, USA; A.N. Severtsov Institute of Ecology and Evolution, RAS, Moscow, Russia; Utrish Dolphinarium, Moscow, Russia.
| | | | | | - Alexei L Vyssotski
- Institute of Neuroinformatics, University of Zurich and Swiss Federal Institute of Technology (ETH), Zurich, Switzerland
| | - Lev M Mukhametov
- A.N. Severtsov Institute of Ecology and Evolution, RAS, Moscow, Russia; Utrish Dolphinarium, Moscow, Russia
| | - Jerome M Siegel
- Department of Psychiatry and Biobehavioral Sciences and Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, USA.
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Martínez-Cerdeño V, García-Moreno F, Tosches MA, Csillag A, Manger PR, Molnár Z. Update on forebrain evolution: From neurogenesis to thermogenesis. Semin Cell Dev Biol 2017; 76:15-22. [PMID: 28964836 DOI: 10.1016/j.semcdb.2017.09.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 09/22/2017] [Accepted: 09/26/2017] [Indexed: 01/25/2023]
Abstract
Comparative developmental studies provide growing understanding of vertebrate forebrain evolution. This short review directs the spotlight to some newly emerging aspects, including the evolutionary origin of the proliferative region known as the subventricular zone (SVZ) and of intermediate progenitor cells (IPCs) that populate the SVZ, neural circuits that originated within homologous regions across all amniotes, and the role of thermogenesis in the acquisition of an increased brain size. These data were presented at the 8th European Conference on Comparative Neurobiology.
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Affiliation(s)
- Verónica Martínez-Cerdeño
- Department of Pathology and Laboratory Medicine, UC Davis, USA; Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children Northern California, USA; MIND Institute, UC Davis School of Medicine, CA, USA.
| | - Fernando García-Moreno
- Achucarro Basque Center for Neuroscience, Parque Científico UPV/EHU Edif. Sede, E-48940 Leioa, Spain
| | | | - András Csillag
- Department of Anatomy, Histology and Embryology, Semmelweis University, Faculty of Medicine, Budapest, Hungary
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of Witwatersrand, South Africa
| | - Zoltán Molnár
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK.
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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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15
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Dicke U, Roth G. Neuronal factors determining high intelligence. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150180. [PMID: 26598734 DOI: 10.1098/rstb.2015.0180] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Many attempts have been made to correlate degrees of both animal and human intelligence with brain properties. With respect to mammals, a much-discussed trait concerns absolute and relative brain size, either uncorrected or corrected for body size. However, the correlation of both with degrees of intelligence yields large inconsistencies, because although they are regarded as the most intelligent mammals, monkeys and apes, including humans, have neither the absolutely nor the relatively largest brains. The best fit between brain traits and degrees of intelligence among mammals is reached by a combination of the number of cortical neurons, neuron packing density, interneuronal distance and axonal conduction velocity--factors that determine general information processing capacity (IPC), as reflected by general intelligence. The highest IPC is found in humans, followed by the great apes, Old World and New World monkeys. The IPC of cetaceans and elephants is much lower because of a thin cortex, low neuron packing density and low axonal conduction velocity. By contrast, corvid and psittacid birds have very small and densely packed pallial neurons and relatively many neurons, which, despite very small brain volumes, might explain their high intelligence. The evolution of a syntactical and grammatical language in humans most probably has served as an additional intelligence amplifier, which may have happened in songbirds and psittacids in a convergent manner.
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Affiliation(s)
- Ursula Dicke
- Brain Research Institute, University of Bremen, 28334 Bremen, Germany
| | - Gerhard Roth
- Brain Research Institute, University of Bremen, 28334 Bremen, Germany
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Roth G. Convergent evolution of complex brains and high intelligence. Philos Trans R Soc Lond B Biol Sci 2016; 370:rstb.2015.0049. [PMID: 26554042 DOI: 10.1098/rstb.2015.0049] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Within the animal kingdom, complex brains and high intelligence have evolved several to many times independently, e.g. among ecdysozoans in some groups of insects (e.g. blattoid, dipteran, hymenopteran taxa), among lophotrochozoans in octopodid molluscs, among vertebrates in teleosts (e.g. cichlids), corvid and psittacid birds, and cetaceans, elephants and primates. High levels of intelligence are invariantly bound to multimodal centres such as the mushroom bodies in insects, the vertical lobe in octopodids, the pallium in birds and the cerebral cortex in primates, all of which contain highly ordered associative neuronal networks. The driving forces for high intelligence may vary among the mentioned taxa, e.g. needs for spatial learning and foraging strategies in insects and cephalopods, for social learning in cichlids, instrumental learning and spatial orientation in birds and social as well as instrumental learning in primates.
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Affiliation(s)
- Gerhard Roth
- Brain Research Institute, University of Bremen, 28334 Bremen, Germany
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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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The Evolution of Brains and Cognitive Abilities. Evol Biol 2016. [DOI: 10.1007/978-3-319-41324-2_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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20
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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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21
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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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Krützen M, Kreicker S, MacLeod CD, Learmonth J, Kopps AM, Walsham P, Allen SJ. Cultural transmission of tool use by Indo-Pacific bottlenose dolphins (Tursiops sp.) provides access to a novel foraging niche. Proc Biol Sci 2014; 281:20140374. [PMID: 24759862 DOI: 10.1098/rspb.2014.0374] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Culturally transmitted tool use has important ecological and evolutionary consequences and has been proposed as a significant driver of human evolution. Such evidence is still scarce in other animals. In cetaceans, tool use has been inferred using indirect evidence in one population of Indo-Pacific bottlenose dolphins (Tursiops sp.), where particular dolphins ('spongers') use marine sponges during foraging. To date, evidence of whether this foraging tactic actually provides access to novel food items is lacking. We used fatty acid (FA) signature analysis to identify dietary differences between spongers and non-spongers, analysing data from 11 spongers and 27 non-spongers from two different study sites. Both univariate and multivariate analyses revealed significant differences in FA profiles between spongers and non-spongers between and within study sites. Moreover, FA profiles differed significantly between spongers and non-spongers foraging within the same deep channel habitat, whereas the profiles of non-spongers from deep channel and shallow habitats at this site could not be distinguished. Our results indicate that sponge use by bottlenose dolphins is linked to significant differences in diet. It appears that cultural transmission of tool use in dolphins, as in humans, allows the exploitation of an otherwise unused niche.
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Affiliation(s)
- Michael Krützen
- Evolutionary Genetics Group, Anthropological Institute and Museum, University of Zurich, , Winterthurerstrasse 190, Zurich 8057, Switzerland, Institute of Biological and Environmental Sciences, University of Aberdeen, , Aberdeen, UK, Evolution and Ecology Research Centre, School of Biological, Earth, and Environmental Sciences, University of New South Wales, , Sydney, New South Wales 2052, Australia, Marine Scotland Science, Marine Laboratory, , PO Box 101, 375 Victoria Road, Aberdeen AB11 9DB, UK, Murdoch University Cetacean Research Unit, School of Veterinary and Life Sciences, Murdoch University, , Murdoch, Western Australia 6150, Australia, School of Veterinary and Life Sciences, Murdoch University, , Murdoch, Western Australia 6150, Australia
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Avarguès-Weber A, d’Amaro D, Metzler M, Dyer AG. Conceptualization of relative size by honeybees. Front Behav Neurosci 2014; 8:80. [PMID: 24672444 PMCID: PMC3953954 DOI: 10.3389/fnbeh.2014.00080] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 02/24/2014] [Indexed: 11/13/2022] Open
Abstract
The ability to process visual information using relational rules allows for decisions independent of the specific physical attributes of individual stimuli. Until recently, the manipulation of relational concepts was considered as a prerogative of large mammalian brains. Here we show that individual free flying honeybees can learn to use size relationship rules to choose either the larger or smaller stimulus as the correct solution in a given context, and subsequently apply the learnt rule to novel colors and shapes providing that there is sufficient input to the long wavelength (green) photoreceptor channel. Our results add a novel, size-based conceptual rule to the set of relational concepts that honeybees have been shown to master and underline the value of bees as an animal model for studying the emergence of conceptualization abilities.
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Affiliation(s)
- Aurore Avarguès-Weber
- Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University LondonLondon, UK
| | - Daniele d’Amaro
- Institut für Zoologie III (Neurobiologie), Johannes Gutenberg-UniversitätMainz, Germany
| | - Marita Metzler
- Institut für Zoologie III (Neurobiologie), Johannes Gutenberg-UniversitätMainz, Germany
| | - Adrian G. Dyer
- Department of Physiology, Monash UniversityClayton, VIC, Australia
- School of Media and Communication, Royal Melbourne Institute of TechnologyMelbourne, VIC, Australia
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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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