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Hoeksema N, Verga L, Mengede J, van Roessel C, Villanueva S, Salazar-Casals A, Rubio-Garcia A, Ćurčić-Blake B, Vernes SC, Ravignani A. Neuroanatomy of the grey seal brain: bringing pinnipeds into the neurobiological study of vocal learning. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200252. [PMID: 34482729 DOI: 10.1098/rstb.2020.0252] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Comparative animal studies of complex behavioural traits, and their neurobiological underpinnings, can increase our understanding of their evolution, including in humans. Vocal learning, a potential precursor to human speech, is one such trait. Mammalian vocal learning is under-studied: most research has either focused on vocal learning in songbirds or its absence in non-human primates. Here, we focus on a highly promising model species for the neurobiology of vocal learning: grey seals (Halichoerus grypus). We provide a neuroanatomical atlas (based on dissected brain slices and magnetic resonance images), a labelled MRI template, a three-dimensional model with volumetric measurements of brain regions, and histological cortical stainings. Four main features of the grey seal brain stand out: (i) it is relatively big and highly convoluted; (ii) it hosts a relatively large temporal lobe and cerebellum; (iii) the cortex is similar to that of humans in thickness and shows the expected six-layered mammalian structure; (iv) there is expression of FoxP2 present in deeper layers of the cortex; FoxP2 is a gene involved in motor learning, vocal learning, and spoken language. Our results could facilitate future studies targeting the neural and genetic underpinnings of mammalian vocal learning, thus bridging the research gap from songbirds to humans and non-human primates. Our findings are relevant not only to vocal learning research but also to the study of mammalian neurobiology and cognition more in general. This article is part of the theme issue 'Vocal learning in animals and humans'.
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Affiliation(s)
- Nienke Hoeksema
- Neurogenetics of Vocal Communication Group, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands.,Neurobiology of Language Department, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
| | - Laura Verga
- Comparative Bioacoustics Group, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands.,Faculty of Psychology and Neuroscience, Department NP&PP, Maastricht University, Maastricht, The Netherlands
| | - Janine Mengede
- Neurogenetics of Vocal Communication Group, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
| | - Corné van Roessel
- Neurogenetics of Vocal Communication Group, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
| | - Stella Villanueva
- Research Department, Sealcentre Pieterburen, Pieterburen, The Netherlands
| | | | - Ana Rubio-Garcia
- Research Department, Sealcentre Pieterburen, Pieterburen, The Netherlands
| | - Branislava Ćurčić-Blake
- Cognitive Neuroscience Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Sonja C Vernes
- Neurogenetics of Vocal Communication Group, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,School of Biology, University of St Andrews, St Andrews, UK
| | - Andrea Ravignani
- Comparative Bioacoustics Group, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands.,Research Department, Sealcentre Pieterburen, Pieterburen, The Netherlands
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2
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Jacobs B, Rally H, Doyle C, O'Brien L, Tennison M, Marino L. Putative neural consequences of captivity for elephants and cetaceans. Rev Neurosci 2021; 33:439-465. [PMID: 34534428 DOI: 10.1515/revneuro-2021-0100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/02/2021] [Indexed: 12/20/2022]
Abstract
The present review assesses the potential neural impact of impoverished, captive environments on large-brained mammals, with a focus on elephants and cetaceans. These species share several characteristics, including being large, wide-ranging, long-lived, cognitively sophisticated, highly social, and large-brained mammals. Although the impact of the captive environment on physical and behavioral health has been well-documented, relatively little attention has been paid to the brain itself. Here, we explore the potential neural consequences of living in captive environments, with a focus on three levels: (1) The effects of environmental impoverishment/enrichment on the brain, emphasizing the negative neural consequences of the captive/impoverished environment; (2) the neural consequences of stress on the brain, with an emphasis on corticolimbic structures; and (3) the neural underpinnings of stereotypies, often observed in captive animals, underscoring dysregulation of the basal ganglia and associated circuitry. To this end, we provide a substantive hypothesis about the negative impact of captivity on the brains of large mammals (e.g., cetaceans and elephants) and how these neural consequences are related to documented evidence for compromised physical and psychological well-being.
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Affiliation(s)
- Bob Jacobs
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Colorado College, Colorado Springs, CO, 80903, USA
| | - Heather Rally
- Foundation to Support Animal Protection, Norfolk, VA, 23510, USA
| | - Catherine Doyle
- Performing Animal Welfare Society, P.O. Box 849, Galt, CA, 95632, USA
| | - Lester O'Brien
- Palladium Elephant Consulting Inc., 2408 Pinewood Dr. SE, Calgary, AB, T2B1S4, Canada
| | - Mackenzie Tennison
- Department of Psychology, University of Washington, Seattle, WA, 98195, USA
| | - Lori Marino
- Whale Sanctuary Project, Kanab, UT, 84741, USA
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3
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Herculano-Houzel S, da Cunha FB, Reed JL, Kaswera-Kyamakya C, Gillissen E, Manger PR. Microchiropterans have a diminutive cerebral cortex, not an enlarged cerebellum, compared to megachiropterans and other mammals. J Comp Neurol 2020; 528:2978-2993. [PMID: 32656795 DOI: 10.1002/cne.24985] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 06/14/2020] [Accepted: 06/16/2020] [Indexed: 11/11/2022]
Abstract
Small echolocating bats are set apart from most other mammals by their relatively large cerebellum, a feature that has been associated to echolocation, as it is presumed to indicate a relatively enlarged number of neurons in the cerebellum in comparison to other brain structures. Here we quantify the neuronal composition of the cerebral cortex, cerebellum and remaining brain structures of seven species of large Pteropodid bats (formerly classified as megachiropterans), one of which echolocates, and six species of small bats (formerly classified as microchiropterans), all of which echolocate. This chiropteran data is compared to 60 mammalian species in our dataset to determine whether the relatively large cerebellum of the small echolocating bats, and possibly that of the echolocating Pteropodid, contains a relatively enlarged number of neurons. We find no evidence that the distribution of neurons differs between microchiropterans and megachiropterans, but our data indicate that microchiropterans, like the smallest shrew in our dataset, have diminutive cerebral cortices, which makes the cerebellum appear relatively large. We propose that, in agreement with the diminutive brain size of the earliest fossil mammals, this is a plesiomorphic, not a derived, feature of microchiropteran brains. The results of this study also reveal important neural characteristics related to the phylogenetic affinities and relationships of the chiropterans.
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Affiliation(s)
- Suzana Herculano-Houzel
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, USA.,Department Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA
| | - Felipe Barros da Cunha
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,University of Lethbridge, Lethbridge, Canada
| | - Jamie L Reed
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, USA
| | | | - Emmanuel Gillissen
- Department of African Zoology, Royal Museum for Central Africa, Tervuren, Belgium.,Laboratory of Histology and Neuropathology, Université Libre de Bruxelles, Brussels, Belgium.,Department of Anthropology, University of Arkansas, Fayetteville, Arkansas, USA
| | - Paul R Manger
- School of Anatomical Sciences, University of the Witwatersrand, South Africa
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4
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Sadeghinezhad J, Aghabalazadeh Asl M, Saeidi A, De Silva M. Morphometrical study of the cat cerebellum using unbiased design‐based stereology. Anat Histol Embryol 2020; 49:788-797. [DOI: 10.1111/ahe.12583] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/08/2020] [Accepted: 05/20/2020] [Indexed: 12/11/2022]
Affiliation(s)
- Javad Sadeghinezhad
- Department of Basic Sciences Faculty of Veterinary Medicine University of Tehran Tehran Iran
| | - Mahdi Aghabalazadeh Asl
- Department of Basic Sciences Faculty of Veterinary Medicine University of Tehran Tehran Iran
| | - Ava Saeidi
- Department of Basic Sciences Faculty of Veterinary Medicine University of Tehran Tehran Iran
| | - Margherita De Silva
- Department of Veterinary Medical Sciences (UNI EN ISO 9001:2008) University of Bologna Bologna Italy
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5
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Panneton WM, Gan Q. The Mammalian Diving Response: Inroads to Its Neural Control. Front Neurosci 2020; 14:524. [PMID: 32581683 PMCID: PMC7290049 DOI: 10.3389/fnins.2020.00524] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 04/27/2020] [Indexed: 01/03/2023] Open
Abstract
The mammalian diving response (DR) is a remarkable behavior that was first formally studied by Laurence Irving and Per Scholander in the late 1930s. The DR is called such because it is most prominent in marine mammals such as seals, whales, and dolphins, but nevertheless is found in all mammals studied. It consists generally of breathing cessation (apnea), a dramatic slowing of heart rate (bradycardia), and an increase in peripheral vasoconstriction. The DR is thought to conserve vital oxygen stores and thus maintain life by directing perfusion to the two organs most essential for life-the heart and the brain. The DR is important, not only for its dramatic power over autonomic function, but also because it alters normal homeostatic reflexes such as the baroreceptor reflex and respiratory chemoreceptor reflex. The neurons driving the reflex circuits for the DR are contained within the medulla and spinal cord since the response remains after the brainstem transection at the pontomedullary junction. Neuroanatomical and physiological data suggesting brainstem areas important for the apnea, bradycardia, and peripheral vasoconstriction induced by underwater submersion are reviewed. Defining the brainstem circuit for the DR may open broad avenues for understanding the mechanisms of suprabulbar control of autonomic function in general, as well as implicate its role in some clinical states. Knowledge of the proposed diving circuit should facilitate studies on elite human divers performing breath-holding dives as well as investigations on sudden infant death syndrome (SIDS), stroke, migraine headache, and arrhythmias. We have speculated that the DR is the most powerful autonomic reflex known.
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Affiliation(s)
- W. Michael Panneton
- Department of Pharmacological and Physiological Science, School of Medicine, Saint Louis University, St. Louis, MO, United States
| | - Qi Gan
- Department of Pharmacological and Physiological Science, School of Medicine, Saint Louis University, St. Louis, MO, United States
- Department of Pediatrics, School of Medicine, Saint Louis University, St. Louis, MO, United States
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6
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Ridgway SH, Brownson RH, Van Alstyne KR, Hauser RA. Higher neuron densities in the cerebral cortex and larger cerebellums may limit dive times of delphinids compared to deep-diving toothed whales. PLoS One 2019; 14:e0226206. [PMID: 31841529 PMCID: PMC6914331 DOI: 10.1371/journal.pone.0226206] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 11/21/2019] [Indexed: 12/17/2022] Open
Abstract
Since the work of Tower in the 1950s, we have come to expect lower neuron density in the cerebral cortex of larger brains. We studied dolphin brains varying from 783 to 6215g. As expected, average neuron density in four areas of cortex decreased from the smallest to the largest brain. Despite having a lower neuron density than smaller dolphins, the killer whale has more gray matter and more cortical neurons than any mammal, including humans. To begin a study of non-dolphin toothed whales, we measured a 596g brain of a pygmy sperm whale and a 2004g brain of a Cuvier's beaked whale. We compared neuron density of Nissl stained cortex of these two brains with those of the dolphins. Non-dolphin brains had lower neuron densities compared to all of the dolphins, even the 6215g brain. The beaked whale and pygmy sperm whale we studied dive deeper and for much longer periods than the dolphins. For example, the beaked whale may dive for more than an hour, and the pygmy sperm whale more than a half hour. In contrast, the dolphins we studied limit dives to five or 10 minutes. Brain metabolism may be one feature limiting dolphin dives. The brain consumes an oversized share of oxygen available to the body. The most oxygen is used by the cortex and cerebellar gray matter. The dolphins have larger brains, larger cerebellums, and greater numbers of cortex neurons than would be expected given their body size. Smaller brains, smaller cerebellums and fewer cortical neurons potentially allow the beaked whale and pygmy sperm whale to dive longer and deeper than the dolphins. Although more gray matter, more neurons, and a larger cerebellum may limit dolphins to shorter, shallower dives, these features must give them some advantage. For example, they may be able to catch more elusive individual high-calorie prey in the upper ocean.
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Affiliation(s)
- Sam H. Ridgway
- National Marine Mammal Foundation, San Diego, California, United States of America
- Department of Pathology, School of Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Robert H. Brownson
- Department of Cell Biology and Human Anatomy, School of Medicine, University of California, Davis, Davis, California, United States of America
| | | | - Robert A. Hauser
- Department of Neurology, University of South Florida, Tampa, Florida, United States of America
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Muller AS, Montgomery SH. Co-evolution of cerebral and cerebellar expansion in cetaceans. J Evol Biol 2019; 32:1418-1431. [PMID: 31507000 PMCID: PMC6916408 DOI: 10.1111/jeb.13539] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 08/27/2019] [Indexed: 12/23/2022]
Abstract
Cetaceans possess brains that rank among the largest to have ever evolved, either in terms of absolute mass or relative to body size. Cetaceans have evolved these huge brains under relatively unique environmental conditions, making them a fascinating case study to investigate the constraints and selection pressures that shape how brains evolve. Indeed, cetaceans have some unusual neuroanatomical features, including a thin but highly folded cerebrum with low cortical neuron density, as well as many structural adaptations associated with acoustic communication. Previous reports also suggest that at least some cetaceans have an expanded cerebellum, a brain structure with wide‐ranging functions in adaptive filtering of sensory information, the control of motor actions, and cognition. Here, we report that, relative to the size of the rest of the brain, both the cerebrum and cerebellum are dramatically enlarged in cetaceans and show evidence of co‐evolution, a pattern of brain evolution that is convergent with primates. However, we also highlight several branches where cortico‐cerebellar co‐evolution may be partially decoupled, suggesting these structures can respond to independent selection pressures. Across cetaceans, we find no evidence of a simple linear relationship between either cerebrum and cerebellum size and the complexity of social ecology or acoustic communication, but do find evidence that their expansion may be associated with dietary breadth. In addition, our results suggest that major increases in both cerebrum and cerebellum size occurred early in cetacean evolution, prior to the origin of the major extant clades, and predate the evolution of echolocation.
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Affiliation(s)
| | - Stephen Hugh Montgomery
- Department of Zoology, University of Cambridge, Cambridge, UK.,School of Biological Sciences, University of Bristol, Bristol, UK
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8
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Parolisi R, Cozzi B, Bonfanti L. Non-neurogenic SVZ-like niche in dolphins, mammals devoid of olfaction. Brain Struct Funct 2017; 222:2625-2639. [PMID: 28238073 DOI: 10.1007/s00429-016-1361-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 12/22/2016] [Indexed: 11/29/2022]
Abstract
Adult neurogenesis has been implicated in brain plasticity and brain repair. In mammals, it is mostly restricted to specific brain regions and specific physiological functions. The function and evolutionary history of mammalian adult neurogenesis has been elusive so far. The largest neurogenic site in mammals (subventricular zone, SVZ) generates neurons destined to populate the olfactory bulb. The SVZ neurogenic activity appears to be related to the dependence of the species on olfaction since it occurs at high rates throughout life in animals strongly dependent on this function for their survival. Indeed, it dramatically decreases in humans, who do not depend so much on it. This study investigates whether the SVZ neurogenic site exists in mammals devoid of olfaction and olfactory brain structures, such as dolphins. Our results demonstate that a small SVZ-like region persists in these aquatic mammals. However, this region seems to have lost its neurogenic capabilities since neonatal stages. In addition, instead of the typical newly generated neuroblasts, some mature neurons were observed in the dolphin SVZ. Since cetaceans evolved from terrestrial ancestors, non-neurogenic SVZ may indicate extinction of adult neurogenesis in the absence of olfactory function, with the retention of an SVZ-like anatomical region either vestigial or of still unknown role.
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Affiliation(s)
- Roberta Parolisi
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy.,Department of Veterinary Sciences, University of Turin, Via Leonardo da Vinci, 44, 10095, Grugliasco, TO, Italy
| | - Bruno Cozzi
- Department of Comparative Biomedicine and Food Science, University of Padua, Legnaro, Italy
| | - Luca Bonfanti
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy. .,Department of Veterinary Sciences, University of Turin, Via Leonardo da Vinci, 44, 10095, Grugliasco, TO, Italy.
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9
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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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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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11
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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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12
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Huckabee ML, Lamvik K, Jones R. Pharyngeal mis-sequencing in dysphagia: characteristics, rehabilitative response, and etiological speculation. J Neurol Sci 2014; 343:153-8. [PMID: 24954087 DOI: 10.1016/j.jns.2014.05.064] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 05/26/2014] [Accepted: 05/28/2014] [Indexed: 12/27/2022]
Abstract
OBJECTIVE Clinical data are submitted as documentation of a pathophysiologic feature of dysphagia termed pharyngeal mis-sequencing and to encourage clinicians and researchers to adopt more critical approaches to diagnosis and treatment planning. BACKGROUND Recent clinical experience has identified a cohort of patients who present with an atypical dysphagia not specifically described in the literature: mis-sequenced constriction of the pharynx when swallowing. As a result, they are unable to coordinate streamlined bolus transfer from the pharynx into the esophagus. This mis-sequencing contributes to nasal redirection, aspiration, and, for some, the inability to safely tolerate an oral diet. METHOD Sixteen patients (8 females, 8 males), with a mean age of 44 years (range=25-78), had an average time post-onset of 23 months (range=2-72) at initiation of intensive rehabilitation. A 3-channel manometric catheter was used to measure pharyngeal pressure. RESULTS The average peak-to-peak latency between nadir pressures at sensor-1 and sensor-2 was 15 ms (95% CI, -2 to 33 ms), compared to normative mean latency of 239 ms (95% CI, 215 to 263 ms). Rehabilitative responses are summarized, along with a single detailed case report. CONCLUSION It is unclear from these data if pharyngeal mis-sequencing is (i) a pathological feature of impaired motor planning from brainstem damage or (ii) a maladaptive compensation developed in response to chronic dysphagia. Future investigation is needed to provide a full report of pharyngeal mis-sequencing, and the implications on our understanding of underlying neural control of swallowing.
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Affiliation(s)
- Maggie-Lee Huckabee
- Department of Communication Disorders, University of Canterbury, Christchurch, New Zealand; New Zealand Brain Research Institute, Christchurch, New Zealand.
| | - Kristin Lamvik
- Department of Communication Disorders, University of Canterbury, Christchurch, New Zealand; New Zealand Brain Research Institute, Christchurch, New Zealand
| | - Richard Jones
- Department of Communication Disorders, University of Canterbury, Christchurch, New Zealand; New Zealand Brain Research Institute, Christchurch, New Zealand; Department of Medical Physics & Bioengineering, Christchurch Hospital, New Zealand; Department of Medicine, University of Otago, Christchurch, New Zealand
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13
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Ridgway SH, Hanson AC. Sperm Whales and Killer Whales with the Largest Brains of All Toothed Whales Show Extreme Differences in Cerebellum. BRAIN, BEHAVIOR AND EVOLUTION 2014; 83:266-74. [DOI: 10.1159/000360519] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 09/16/2013] [Indexed: 11/19/2022]
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Jacobs B, Johnson NL, Wahl D, Schall M, Maseko BC, Lewandowski A, Raghanti MA, Wicinski B, Butti C, Hopkins WD, Bertelsen MF, Walsh T, Roberts JR, Reep RL, Hof PR, Sherwood CC, Manger PR. Comparative neuronal morphology of the cerebellar cortex in afrotherians, carnivores, cetartiodactyls, and primates. Front Neuroanat 2014; 8:24. [PMID: 24795574 PMCID: PMC4005950 DOI: 10.3389/fnana.2014.00024] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 04/01/2014] [Indexed: 11/13/2022] Open
Abstract
Although the basic morphological characteristics of neurons in the cerebellar cortex have been documented in several species, virtually nothing is known about the quantitative morphological characteristics of these neurons across different taxa. To that end, the present study investigated cerebellar neuronal morphology among eight different, large-brained mammalian species comprising a broad phylogenetic range: afrotherians (African elephant, Florida manatee), carnivores (Siberian tiger, clouded leopard), cetartiodactyls (humpback whale, giraffe) and primates (human, common chimpanzee). Specifically, several neuron types (e.g., stellate, basket, Lugaro, Golgi, and granule neurons; N = 317) of the cerebellar cortex were stained with a modified rapid Golgi technique and quantified on a computer-assisted microscopy system. There was a 64-fold variation in brain mass across species in our sample (from clouded leopard to the elephant) and a 103-fold variation in cerebellar volume. Most dendritic measures tended to increase with cerebellar volume. The cerebellar cortex in these species exhibited the trilaminate pattern common to all mammals. Morphologically, neuron types in the cerebellar cortex were generally consistent with those described in primates (Fox et al., 1967) and rodents (Palay and Chan-Palay, 1974), although there was substantial quantitative variation across species. In particular, Lugaro neurons in the elephant appeared to be disproportionately larger than those in other species. To explore potential quantitative differences in dendritic measures across species, MARSplines analyses were used to evaluate whether species could be differentiated from each other based on dendritic characteristics alone. Results of these analyses indicated that there were significant differences among all species in dendritic measures.
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Affiliation(s)
- Bob Jacobs
- Laboratory of Quantitative Neuromorphology, Psychology, Colorado CollegeColorado Springs, CO, USA
| | - Nicholas L. Johnson
- Laboratory of Quantitative Neuromorphology, Psychology, Colorado CollegeColorado Springs, CO, USA
| | - Devin Wahl
- Laboratory of Quantitative Neuromorphology, Psychology, Colorado CollegeColorado Springs, CO, USA
| | - Matthew Schall
- Laboratory of Quantitative Neuromorphology, Psychology, Colorado CollegeColorado Springs, CO, USA
| | - Busisiwe C. Maseko
- Faculty of Health Sciences, School of Anatomical Sciences, University of the WitwatersrandJohannesburg, South Africa
| | | | | | - Bridget Wicinski
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount SinaiNew York, NY, USA
| | - Camilla Butti
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount SinaiNew York, NY, USA
| | - William D. Hopkins
- Division of Developmental and Cognitive Neuroscience, Yerkes National Primate Research CenterAtlanta, GA, USA
| | - Mads F. Bertelsen
- Center for Zoo and Wild Animal Health, Copenhagen ZooFrederiksberg, Denmark
| | - Timothy Walsh
- Smithsonian National Zoological ParkWashington, DC, USA
| | | | - Roger L. Reep
- Department of Physiological Sciences, University of FloridaGainesville, FL, USA
| | - Patrick R. Hof
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount SinaiNew York, NY, USA
| | - Chet C. Sherwood
- Department of Anthropology, The George Washington UniversityWashington, DC, USA
| | - Paul R. Manger
- Faculty of Health Sciences, School of Anatomical Sciences, University of the WitwatersrandJohannesburg, South Africa
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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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16
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Panneton WM. The mammalian diving response: an enigmatic reflex to preserve life? Physiology (Bethesda) 2014; 28:284-97. [PMID: 23997188 DOI: 10.1152/physiol.00020.2013] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mammalian diving response is a remarkable behavior that overrides basic homeostatic reflexes. It is most studied in large aquatic mammals but is seen in all vertebrates. Pelagic mammals have developed several physiological adaptations to conserve intrinsic oxygen stores, but the apnea, bradycardia, and vasoconstriction is shared with those terrestrial and is neurally mediated. The adaptations of aquatic mammals are reviewed here as well as the neural control of cardiorespiratory physiology during diving in rodents.
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Affiliation(s)
- W Michael Panneton
- Department of Pharmacological and Physiological Science, St. Louis University School of Medicine, St. Louis, MO, USA.
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17
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Hanson A, Grisham W, Sheh C, Annese J, Ridgway S. Quantitative examination of the bottlenose dolphin cerebellum. Anat Rec (Hoboken) 2013; 296:1215-28. [PMID: 23775830 DOI: 10.1002/ar.22726] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 03/05/2013] [Accepted: 04/10/2013] [Indexed: 11/09/2022]
Abstract
Neuroanatomical research into the brain of the bottlenose dolphin (Tursiops truncatus) has revealed striking similarities with the human brain in terms of size and complexity. However, the dolphin brain also contains unique allometric relationships. When compared to the human brain, the dolphin cerebellum is noticeably larger. Upon closer examination, the lobule composition of the cerebellum is distinct between the two species. In this study, we used magnetic resonance imaging to analyze cerebellar anatomy in the bottlenose dolphin and measure the volume of the separate cerebellar lobules in the bottlenose dolphin and human. Lobule identification was assisted by three-dimensional modeling. We find that lobules VI, VIIb, VIII, and IX are the largest lobules of the bottlenose dolphin cerebellum, while the anterior lobe (I-V), crus I, crus II, and the flocculonodular lobe are smaller. Different lobule sizes may have functional implications. Auditory-associated lobules VIIb, VIII, IX are likely large in the bottlenose dolphin due to echolocation abilities. Our study provides quantitative information on cerebellar anatomy that substantiates previous reports based on gross observation and subjective analysis. This study is part of a continuing effort toward providing explicit descriptions of cetacean neuroanatomy to support the interpretation of behavioral studies on cetacean cognition.
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Affiliation(s)
- Alicia Hanson
- National Marine Mammal Foundation, San Diego, California, USA
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18
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Maseko BC, Spocter MA, Haagensen M, Manger PR. Elephants have relatively the largest cerebellum size of mammals. Anat Rec (Hoboken) 2012; 295:661-72. [PMID: 22282440 DOI: 10.1002/ar.22425] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 11/17/2011] [Accepted: 11/23/2011] [Indexed: 11/07/2022]
Abstract
The current study used MR imaging to determine the volume of the cerebellum and its component parts in the brain of three adult male African elephants (Loxodonta africana) and compared this with published data from Asian elephants and other mammalian species including odontocete cetaceans, primates, chiropterans, insectivores, carnivores, and artiodactyls. The cerebellum of the adult elephant has a volume of ∼925 mL (average of both African and Asian species). Allometric analysis indicates that the elephant has the largest relative cerebellum size of all mammals studied to date. In addition, both odontocete cetaceans and microchiropterans appear to have large relative cerebellar sizes. The vermal and hemispheric components of the African elephant cerebellum are both large relative to other mammals of similar brain size, however, for odontocete cetaceans the vermal component is small and the hemispheric component is large. These volumetric observations are related to life-histories and anatomies of the species investigated. The current study provides context for one aspect of the elephant brain in the broader picture of mammalian brain evolution.
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Affiliation(s)
- Busisiwe C Maseko
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg, Republic of South Africa
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Houser DS, Moore PW, Johnson S, Lutmerding B, Branstetter B, Ridgway SH, Trickey J, Finneran JJ, Jensen E, Hoh C. Relationship of blood flow and metabolism to acoustic processing centers of the dolphin brain. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2010; 128:1460-1466. [PMID: 20815480 DOI: 10.1121/1.3442572] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Odontocete brain tissues associated with auditory processing are hypertrophied and modified relative to their terrestrial counterparts. The relationship between the functional demand on these tissues and metabolic substrate requirements is unknown. Using positron emission tomography (PET), relative cerebral blood flow was measured in a bottlenose dolphin. Approximately 60 mCi (13)NH(3) was administered to the dolphin via a catheter inserted into the hepatic vein and threaded proximate to the vena cava. Radiolabel initially appeared as distributed focal points in the cerebellum. Increasing scan time resulted in an increase in the number of focal regions and in the diffusivity of label activity throughout the brain. The time course and spatial distribution of radiolabel was consistent with a cerebral blood supply dominated by the spinal meningeal arteries. Blood flow was predominantly observed in the cerebellum and neocortex, particularly the auditory and visual cortex. Differential brain glucose uptake, previously measured in a separate dolphin, showed good agreement with the differential supply of blood to brain tissues. Rates of blood supply and glucose uptake in the auditory cortex, inferior colliculus, and cerebellum are consistent with a high metabolic demand of tissues which are important to the integration of auditory and other sensory inputs.
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Affiliation(s)
- Dorian S Houser
- National Marine Mammal Foundation, 2240 Shelter Island Drive, San Diego, California 92106, USA.
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20
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Parsons LM, Petacchi A, Schmahmann JD, Bower JM. Pitch discrimination in cerebellar patients: Evidence for a sensory deficit. Brain Res 2009; 1303:84-96. [DOI: 10.1016/j.brainres.2009.09.052] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2009] [Revised: 09/11/2009] [Accepted: 09/12/2009] [Indexed: 01/08/2023]
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21
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Montie EW, Schneider G, Ketten DR, Marino L, Touhey KE, Hahn ME. Volumetric Neuroimaging of the Atlantic White-Sided Dolphin (Lagenorhynchus acutus) Brain from in situ Magnetic Resonance Images. Anat Rec (Hoboken) 2008; 291:263-82. [DOI: 10.1002/ar.20654] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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22
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Oelschläger HHA. The dolphin brain--a challenge for synthetic neurobiology. Brain Res Bull 2007; 75:450-9. [PMID: 18331914 DOI: 10.1016/j.brainresbull.2007.10.051] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2007] [Accepted: 10/17/2007] [Indexed: 11/17/2022]
Abstract
Toothed whales (odontocetes) are a promising paradigm for neurobiology and evolutionary biology. The ecophysiological implications and structural adaptations of their brain seem to reflect the necessity of effective underwater hearing for echolocation (sonar), navigation, and communication. However, not all components of the auditory system are equally well developed. Other sensory systems are more or less strongly reduced such as the olfactory system and, as an exception among vertebrates, the vestibular system (the semicircular canals and vestibular nuclei). Additional outstanding features are: (1) the hypertrophy of the neocortex, pons, cerebellum (particularly the paraflocculus), the elliptic nucleus, the facial motor nucleus and the medial accessory inferior olive and (2) the reduction of the hippocampus. The screening of brain structures with respect to shared circuitry and shared size correlations resulted in central loops also known from other mammals which overlap in the cerebellum and serve in the integration and processing of sensory input. It is highly probable that for dolphin navigation the ascending auditory pathway, including the inferior colliculus and the medial geniculate body, is of utmost importance. The extended auditory neocortical fields project to the midbrain and rhombencephalon and may influence premotor and motor areas in such a way as to allow the smooth regulation of sound-induced and sound-controlled locomotor activity as well as sophisticated phonation. This sonar-guided acousticomotor system for navigation and vocalization in the aquatic environment may have been a major factor if not the key feature in the relative size increase seen in dolphin brains.
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Affiliation(s)
- Helmut H A Oelschläger
- Institute of Anatomy III (Dr. Senckenbergische Anatomie), University of Frankfurt am Main, Germany.
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Oelschläger H, Haas-Rioth M, Fung C, Ridgway S, Knauth M. Morphology and Evolutionary Biology of the Dolphin ( Delphinus sp.) Brain – MR Imaging and Conventional Histology. BRAIN, BEHAVIOR AND EVOLUTION 2007; 71:68-86. [DOI: 10.1159/000110495] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Accepted: 07/05/2007] [Indexed: 11/19/2022]
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Abstract
Changes in neocortex size were a prominent feature of mammalian brain evolution, but the implications for cortical structure, and consequently for the functional significance of such changes in overall cortical size, are poorly understood. A basic question is whether functionally differentiated cortical areas evolved independently of one another (adaptive specialization) or were allometrically constrained to co-vary tightly with the size of the whole. Here, I provide comparative evidence for adaptive specialization of cortical structure. First, the sizes of individual areas differ significantly between taxa after controlling for overall cortical size. Second, an analysis of separate visual cortical areas reveals that these exhibit statistically correlated evolution, independent of variation in nonvisual areas. Third, visual cortex size exhibits correlated evolution with peripheral visual adaptations (eye morphology and optic nerve size) and with photic niche. Thus, the evolution of mammalian cortical structure was closely associated with specialization for different sensory niches.
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Affiliation(s)
- R A Barton
- Evolutionary Anthropology Research Group, Department of Anthropology, Durham University, Durham, UK.
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26
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Weaver AH. Reciprocal evolution of the cerebellum and neocortex in fossil humans. Proc Natl Acad Sci U S A 2005; 102:3576-80. [PMID: 15731345 PMCID: PMC553338 DOI: 10.1073/pnas.0500692102] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2004] [Indexed: 11/18/2022] Open
Abstract
Human brain evolution involved both neurological reorganization and an increase in overall brain volume relative to body mass. It is generally difficult to draw functional inferences about the timing and nature of brain reorganization, given that superficial brain morphology recorded on fossil endocasts is functionally ambiguous. However, the cerebellum, housed in the clearly delineated posterior cranial fossa, is functionally and ontologically discrete. The cerebellum is reciprocally connected to each of 14 neocortical regions important to human cognitive evolution. Cerebellar volume varies significantly relative to overall brain volume among mammalian orders, as well as within the primate order. There is also significant diachronic variation among fossil human taxa. In the australopithecines and early members of the genus Homo, the cerebral hemispheres were large in proportion to the cerebellum, compared with other hominoids. This trend continued in Middle and Late Pleistocene humans, including Neandertals and Cro-Magnon 1, who have the largest cerebral hemispheres relative to cerebellum volume of any primates, including earlier and Holocene humans. In recent humans, however, the pattern is reversed; the cerebellum is larger with respect to the rest of the brain (and, conversely, the cerebral hemispheres are smaller with respect to the cerebellum) than in Late Pleistocene humans. The cerebellum and cerebral hemispheres appear to have evolved reciprocally. Cerebellar development in Holocene humans may have provided greater computational efficiency for coping with an increasingly complex cultural and conceptual environment.
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Affiliation(s)
- Anne H Weaver
- Department of Arts and Sciences, Santa Fe Community College, 6401 Richards Avenue, Santa Fe, NM 87508, USA.
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Marino L, Sudheimer K, McLellan WA, Johnson JI. Neuroanatomical structure of the spinner dolphin (Stenella longirostris orientalis) brain from magnetic resonance images. ACTA ACUST UNITED AC 2004; 279:601-10. [PMID: 15224402 DOI: 10.1002/ar.a.20047] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
High-resolution magnetic resonance (MR) images of the brain of an adult spinner dolphin (Stenella longirostris orientalis) were acquired in the coronal plane at 55 antero-posterior levels. From these scans a computer-generated set of resectioned virtual images in the two remaining orthogonal planes was constructed with the use of the VoxelView and VoxelMath (Vital Images, Inc.) programs. Neuroanatomical structures were labeled in all three planes, providing the first labeled anatomical description of the spinner dolphin brain.
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Affiliation(s)
- Lori Marino
- Neuroscience and Behavioral Biology Program, Emory University, Atlanta, Georgia 30322, USA.
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Manger PR, Fuxe K, Ridgway SH, Siegel JM. The distribution and morphological characteristics of catecholaminergic cells in the diencephalon and midbrain of the bottlenose dolphin (Tursiops truncatus). BRAIN, BEHAVIOR AND EVOLUTION 2004; 64:42-60. [PMID: 15051966 PMCID: PMC8770345 DOI: 10.1159/000077542] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2003] [Accepted: 12/16/2003] [Indexed: 11/19/2022]
Abstract
The present study describes the distribution and cellular morphology of catecholaminergic neurons in the diencephalon and midbrain of the bottlenose dolphin (Tursiops truncatus). Tyrosine hydroxylase immunohistochemistry was used to visualize these putatively dopaminergic neurons. The standard A1-A17, C1-C3, nomenclature is used for expediency; however, the neuroanatomical names of the various nuclei have also been given. Dolphins exhibit certain tyrosine hydroxylase immunoreactive (TH-ir) catecholaminergic neuronal groups in the midbrain (A8, A9, A10) and diencephalon (A11, A12, A14), however, no neuronal clusters clearly corresponding to the A13 and A15 groups could be identified. The subdivisions of these neuronal groups are in general agreement with those of other mammals, but there is a high degree of species specificity. First, three TH-ir neuronal groups not identified in other species were found: in the ventral lateral peri-aqueductal gray matter, posterior dorsal hypothalamus, and rostral mesencephalic raphe. Second, the normal components of the substantia nigra (A9 or pars compacta, A9 lateral or pars lateralis, A9 ventral or pars reticulata) were extremely cell sparse, but there was a substantial expansion of the A9 medial and A10 lateral subdivisions forming an impressive 'ventral wing' in the posterior substantia nigra. The findings of this and previous studies suggest a distinct evolutionary trend occurring in the neuromodulatory systems in mammals. The results are discussed in relation to motor control, thermoregulation, unihemispheric sleep, and dolphin cognition.
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Affiliation(s)
- Paul R Manger
- School of Anatomical Sciences, Faculty of Health Science, University of the Witwatersrand, Johannesburg, Republic of South Africa.
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Marino L, Sherwood CC, Delman BN, Tang CY, Naidich TP, Hof PR. Neuroanatomy of the killer whale (Orcinus orca) from magnetic resonance images. ACTA ACUST UNITED AC 2004; 281:1256-63. [PMID: 15486954 DOI: 10.1002/ar.a.20075] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This article presents the first series of MRI-based anatomically labeled sectioned images of the brain of the killer whale (Orcinus orca). Magnetic resonance images of the brain of an adult killer whale were acquired in the coronal and axial planes. The gross morphology of the killer whale brain is comparable in some respects to that of other odontocete brains, including the unusual spatial arrangement of midbrain structures. There are also intriguing differences. Cerebral hemispheres appear extremely convoluted and, in contrast to smaller cetacean species, the killer whale brain possesses an exceptional degree of cortical elaboration in the insular cortex, temporal operculum, and the cortical limbic lobe. The functional and evolutionary implications of these features are discussed.
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Affiliation(s)
- Lori Marino
- Neuroscience and Behavioral Biology Program, Emory University, 1462 Clifton Road, Ste. 304, Atlanta, GA 30322, USA.
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Abstract
A new method of in situ formalin fixation was used on 38 brains from minke whales (Balaenoptera acutorostrata). The method was developed because traditional ways of fixing brains are poorly suited to the collection of whale brains. The whole brain was preserved uncut in its meninges and then excised undamaged from the skull at a later opportunity. There was no handling of the brain in the fresh state. Fixation was started within a couple of hours post mortem. All brains were subjected to gross and light microscopy examination. The results showed that both the gross and microscopic architecture of the brains were adequately preserved, with no massive gross or histological changes due to insufficient fixation apparent. The occurrence of fixation artifacts was low. Microscopic examination showed well-preserved cells and myelin in all parts of the brain. We report the mean fixed weight of the minke whale brain as 2741 g, which is the lowest among the baleen whales. The cerebellum constituted 22% of the total brain weight, which conforms to findings in other baleen whales. This in situ method can probably be used without any particular modifications in other whale species and also in large terrestrial mammals.
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Affiliation(s)
- Siri Kristine Knudsen
- Department of Arctic Veterinary Medicine, The Norwegian School of Veterinary Science, NO-9292, Tromsø, Norway.
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31
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Marino L, Sudheimer KD, Murphy TL, Davis KK, Pabst DA, McLellan WA, Rilling JK, Johnson JI. Anatomy and three-dimensional reconstructions of the brain of a bottlenose dolphin (Tursiops truncatus) from magnetic resonance images. THE ANATOMICAL RECORD 2001; 264:397-414. [PMID: 11745095 DOI: 10.1002/ar.10018] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cetacean (dolphin, whale, and porpoise) brains are among the least studied mammalian brains because of the formidable challenge of collecting and histologically preparing such relatively rare and large specimens. Magnetic resonance imaging offers a means of observing the internal structure of the brain when traditional histological procedures are not practical. Furthermore, internal structures can be analyzed in their precise anatomic positions, which is difficult to accomplish after the spatial distortions often accompanying histological processing. In this study, images of the brain of an adult bottlenose dolphin, Tursiops truncatus, were scanned in the coronal plane at 148 antero-posterior levels. From these scans a computer-generated three-dimensional model was constructed using the programs VoxelView and VoxelMath (Vital Images, Inc.). This model, wherein details of internal and external morphology are represented in three-dimensional space, was then resectioned in orthogonal planes to produce corresponding series of virtual sections in the horizontal and sagittal planes. Sections in all three planes display the sizes and positions of major neuroanatomical features such as the arrangement of cortical lobes and subcortical structures such as the inferior and superior colliculi, and demonstrate the utility of MRI for neuroanatomical investigations of dolphin brains.
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Affiliation(s)
- L Marino
- Neuroscience and Behavioral Biology Program, Emory University, Atlanta, Georgia 30322, USA.
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