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Zhang N, Zhang Y. Correlation between gyral size, brain size, and head impact risk across mammalian species. Brain Res 2024; 1828:148768. [PMID: 38244756 DOI: 10.1016/j.brainres.2024.148768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 12/12/2023] [Accepted: 01/12/2024] [Indexed: 01/22/2024]
Abstract
A study on primates has established that gyral size is largely independent of overall brain size. Building on this-and other research suggesting that brain gyrification may mitigate the effects of head impacts-our study aims to explore potential correlations between gyral size and the risk of head impact across a diverse range of mammalian species. Our findings corroborate the idea that gyral sizes are largely independent of brain sizes, especially among species with larger brains, thus extending this observation beyond primates. Preliminary evidence also suggests a correlation between an animal's gyral size and its lifestyle, particularly in terms of head-impact risk. For instance, goats, known for their headbutting behaviors, exhibit smaller gyral sizes. In contrast, species such as manatees and dugongs, which typically face lower risks of head impact, have lissencephalic brains. Additionally, we explore mechanisms that may explain how narrower gyral sizes could offer protective advantages against head impact. Finally, we discuss a possible trade-off associated with gyrencephaly.
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Affiliation(s)
- Nianqin Zhang
- Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
| | - Yongjun Zhang
- Science College, Liaoning Technical University, Fuxin 123000, China.
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2
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Galakhova AA, Hunt S, Wilbers R, Heyer DB, de Kock CPJ, Mansvelder HD, Goriounova NA. Evolution of cortical neurons supporting human cognition. Trends Cogn Sci 2022; 26:909-922. [PMID: 36117080 PMCID: PMC9561064 DOI: 10.1016/j.tics.2022.08.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 08/18/2022] [Accepted: 08/24/2022] [Indexed: 01/12/2023]
Abstract
Human cognitive abilities are generally thought to arise from cortical expansion over the course of human brain evolution. In addition to increased neuron numbers, this cortical expansion might be driven by adaptations in the properties of single neurons and their local circuits. We review recent findings on the distinct structural, functional, and transcriptomic features of human cortical neurons and their organization in cortical microstructure. We focus on the supragranular cortical layers, which showed the most prominent expansion during human brain evolution, and the properties of their principal cells: pyramidal neurons. We argue that the evolutionary adaptations in neuronal features that accompany the expansion of the human cortex partially underlie interindividual variability in human cognitive abilities.
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Affiliation(s)
- A A Galakhova
- Department of Integrative Neurophysiology, Amsterdam Neuroscience, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, The Netherlands
| | - S Hunt
- Department of Integrative Neurophysiology, Amsterdam Neuroscience, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, The Netherlands
| | - R Wilbers
- Department of Integrative Neurophysiology, Amsterdam Neuroscience, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, The Netherlands
| | - D B Heyer
- Department of Integrative Neurophysiology, Amsterdam Neuroscience, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, The Netherlands
| | - C P J de Kock
- Department of Integrative Neurophysiology, Amsterdam Neuroscience, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, The Netherlands
| | - H D Mansvelder
- Department of Integrative Neurophysiology, Amsterdam Neuroscience, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, The Netherlands
| | - N A Goriounova
- Department of Integrative Neurophysiology, Amsterdam Neuroscience, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, The Netherlands.
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3
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The primary visual cortex of Cetartiodactyls: organization, cytoarchitectonics and comparison with perissodactyls and primates. Brain Struct Funct 2021; 227:1195-1225. [PMID: 34604923 PMCID: PMC9046356 DOI: 10.1007/s00429-021-02392-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 09/19/2021] [Indexed: 12/24/2022]
Abstract
Cetartiodactyls include terrestrial and marine species, all generally endowed with a comparatively lateral position of their eyes and a relatively limited binocular field of vision. To this day, our understanding of the visual system in mammals beyond the few studied animal models remains limited. In the present study, we examined the primary visual cortex of Cetartiodactyls that live on land (sheep, Père David deer, giraffe); in the sea (bottlenose dolphin, Risso’s dolphin, long-finned pilot whale, Cuvier’s beaked whale, sperm whale and fin whale); or in an amphibious environment (hippopotamus). We also sampled and studied the visual cortex of the horse (a closely related perissodactyl) and two primates (chimpanzee and pig-tailed macaque) for comparison. Our histochemical and immunohistochemical results indicate that the visual cortex of Cetartiodactyls is characterized by a peculiar organization, structure, and complexity of the cortical column. We noted a general lesser lamination compared to simians, with diminished density, and an apparent simplification of the intra- and extra-columnar connections. The presence and distribution of calcium-binding proteins indicated a notable absence of parvalbumin in water species and a strong reduction of layer 4, usually enlarged in the striated cortex, seemingly replaced by a more diffuse distribution in neighboring layers. Consequently, thalamo-cortical inputs are apparently directed to the higher layers of the column. Computer analyses and statistical evaluation of the data confirmed the results and indicated a substantial correlation between eye placement and cortical structure, with a markedly segregated pattern in cetaceans compared to other mammals. Furthermore, cetacean species showed several types of cortical lamination which may reflect differences in function, possibly related to depth of foraging and consequent progressive disappearance of light, and increased importance of echolocation.
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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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5
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Jacob J, Kent M, Benson-Amram S, Herculano-Houzel S, Raghanti MA, Ploppert E, Drake J, Hindi B, Natale NR, Daniels S, Fanelli R, Miller A, Landis T, Gilbert A, Johnson S, Lai A, Hyer M, Rzucidlo A, Anchor C, Gehrt S, Lambert K. Cytoarchitectural characteristics associated with cognitive flexibility in raccoons. J Comp Neurol 2021; 529:3375-3388. [PMID: 34076254 DOI: 10.1002/cne.25197] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 05/26/2021] [Accepted: 05/27/2021] [Indexed: 02/01/2023]
Abstract
With rates of psychiatric illnesses such as depression continuing to rise, additional preclinical models are needed to facilitate translational neuroscience research. In the current study, the raccoon (Procyon lotor) was investigated due to its similarities with primate brains, including comparable proportional neuronal densities, cortical magnification of the forepaw area, and cortical gyrification. Specifically, we report on the cytoarchitectural characteristics of raccoons profiled as high, intermediate, or low solvers in a multiaccess problem-solving task. Isotropic fractionation indicated that high-solvers had significantly more cells in the hippocampus (HC) than the other solving groups; further, a nonsignificant trend suggested that this increase in cell profile density was due to increased nonneuronal (e.g., glial) cells. Group differences were not observed in the cellular density of the somatosensory cortex. Thionin-based staining confirmed the presence of von Economo neurons (VENs) in the frontoinsular cortex, although no impact of solving ability on VEN cell profile density levels was observed. Elongated fusiform cells were quantified in the HC dentate gyrus where high-solvers were observed to have higher levels of this cell type than the other solving groups. In sum, the current findings suggest that varying cytoarchitectural phenotypes contribute to cognitive flexibility. Additional research is necessary to determine the translational value of cytoarchitectural distribution patterns on adaptive behavioral outcomes associated with cognitive performance and mental health.
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Affiliation(s)
- Joanna Jacob
- Department of Psychology, University of Richmond, Richmond, Virginia, USA
| | - Molly Kent
- Department of Biology, Virginia Military Institute, Lexington, Virginia, USA
| | - Sarah Benson-Amram
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Zoology and Biodiversity Research Center, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Mary Ann Raghanti
- Department of Anthropology, School of Biomedical Sciences, and Brain Health Research Institute, Kent State University, Kent, Ohio, USA
| | - Emily Ploppert
- Department of Psychology, University of Richmond, Richmond, Virginia, USA
| | - Jack Drake
- Department of Psychology, University of Richmond, Richmond, Virginia, USA
| | - Bilal Hindi
- Department of Psychology, University of Richmond, Richmond, Virginia, USA
| | - Nick R Natale
- Department of Psychology, University of Richmond, Richmond, Virginia, USA
| | - Sarah Daniels
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA
| | - Rachel Fanelli
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA
| | - Anderson Miller
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, USA
| | - Tim Landis
- Department of Psychology, Randolph-Macon College, Ashland, Virginia, USA
| | - Amy Gilbert
- USDA-APHIS-WS National Wildlife Research Center, Fort Collins, Colorado, USA
| | - Shylo Johnson
- USDA-APHIS-WS National Wildlife Research Center, Fort Collins, Colorado, USA
| | - Annie Lai
- Department of Psychology, University of Richmond, Richmond, Virginia, USA
| | - Molly Hyer
- Department of Psychology, Randolph-Macon College, Ashland, Virginia, USA
| | - Amanda Rzucidlo
- Forest Preserve District of Cook County, River Forest, Illinois, USA
| | - Chris Anchor
- Forest Preserve District of Cook County, River Forest, Illinois, USA
| | - Stan Gehrt
- School of Environment and Natural Resources, Ohio State University, Columbus, Ohio, USA
| | - Kelly Lambert
- Department of Psychology, University of Richmond, Richmond, Virginia, USA
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6
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Warling A, Uchida R, Shin H, Dodelson C, Garcia ME, Shea-Shumsky NB, Svirsky S, Pothast M, Kelley H, Schumann CM, Brzezinski C, Bauman MD, Alexander A, McKee AC, Stein TD, Schall M, Jacobs B. Putative dendritic correlates of chronic traumatic encephalopathy: A preliminary quantitative Golgi exploration. J Comp Neurol 2020; 529:1308-1326. [PMID: 32869318 DOI: 10.1002/cne.25022] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/24/2020] [Accepted: 08/25/2020] [Indexed: 12/14/2022]
Abstract
Chronic traumatic encephalopathy (CTE) is a neurodegenerative disorder that is associated with repetitive head impacts. Neuropathologically, it is defined by the presence of perivascular hyperphosphorylated tau aggregates in cortical tissue (McKee et al., 2016, Acta Neuropathologica, 131, 75-86). Although many pathological and assumed clinical correlates of CTE have been well characterized, its effects on cortical dendritic arbors are still unknown. Here, we quantified dendrites and dendritic spines of supragranular pyramidal neurons in tissue from human frontal and occipital lobes, in 11 cases with (Mage = 79 ± 7 years) and 5 cases without (Mage = 76 ± 11 years) CTE. Tissue was stained with a modified rapid Golgi technique. Dendritic systems of 20 neurons per region in each brain (N = 640 neurons) were quantified using computer-assisted morphometry. One key finding was that CTE neurons exhibited increased variability and distributional changes across six of the eight dendritic system measures, presumably due to ongoing degeneration and compensatory reorganization of dendritic systems. However, despite heightened variation among CTE neurons, CTE cases exhibited lower mean values than Control cases in seven of the eight dendritic system measures. These dendritic alterations may represent a new pathological marker of CTE, and further examination of dendritic changes could contribute to both mechanistic and functional understandings of the disease.
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Affiliation(s)
- Allysa Warling
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Department of Psychology, Colorado College, Colorado Springs, Colorado, USA
| | - Riri Uchida
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Department of Psychology, Colorado College, Colorado Springs, Colorado, USA
| | - Hyunsoo Shin
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Department of Psychology, Colorado College, Colorado Springs, Colorado, USA
| | - Coby Dodelson
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Department of Psychology, Colorado College, Colorado Springs, Colorado, USA
| | - Madeleine E Garcia
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Department of Psychology, Colorado College, Colorado Springs, Colorado, USA
| | - N Beckett Shea-Shumsky
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Department of Psychology, Colorado College, Colorado Springs, Colorado, USA
| | - Sarah Svirsky
- Department of Neurology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Morgan Pothast
- Department of Neurology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Hunter Kelley
- Department of Neurology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Cynthia M Schumann
- Department of Psychiatry and Behavioral Sciences, University of California, Sacramento, California, USA
| | - Christine Brzezinski
- Department of Neurosurgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Melissa D Bauman
- Department of Psychiatry and Behavioral Sciences, University of California, Sacramento, California, USA
| | - Allyson Alexander
- Department of Neurosurgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Ann C McKee
- Department of Neurology, Boston University School of Medicine, Boston, Massachusetts, USA.,Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts, USA.,Boston University Alzheimer's Disease and CTE Center, Boston University School of Medicine, Boston, Massachusetts, USA.,VA Boston Healthcare System, Boston, Massachusetts, USA.,Department of Veterans Affairs Medical Center, Bedford, Massachusetts, USA
| | - Thor D Stein
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts, USA.,Boston University Alzheimer's Disease and CTE Center, Boston University School of Medicine, Boston, Massachusetts, USA.,VA Boston Healthcare System, Boston, Massachusetts, USA.,Department of Veterans Affairs Medical Center, Bedford, Massachusetts, USA
| | - Matthew Schall
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Department of Psychology, Colorado College, Colorado Springs, Colorado, USA
| | - Bob Jacobs
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Department of Psychology, Colorado College, Colorado Springs, Colorado, USA
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7
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Nguyen VT, Uchida R, Warling A, Sloan LJ, Saviano MS, Wicinski B, Hård T, Bertelsen MF, Stimpson CD, Bitterman K, Schall M, Hof PR, Sherwood CC, Manger PR, Spocter MA, Jacobs B. Comparative neocortical neuromorphology in felids: African lion, African leopard, and cheetah. J Comp Neurol 2020; 528:1392-1422. [DOI: 10.1002/cne.24823] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 11/18/2019] [Accepted: 11/18/2019] [Indexed: 02/03/2023]
Affiliation(s)
- Vivian T. Nguyen
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Department of PsychologyColorado College Colorado Springs Colorado
| | - Riri Uchida
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Department of PsychologyColorado College Colorado Springs Colorado
| | - Allysa Warling
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Department of PsychologyColorado College Colorado Springs Colorado
| | - Lucy J. Sloan
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Department of PsychologyColorado College Colorado Springs Colorado
| | - Mark S. Saviano
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Department of PsychologyColorado College Colorado Springs Colorado
| | - Bridget Wicinski
- Nash Family Department of Neuroscience and Friedman Brain InstituteIcahn School of Medicine at Mount Sinai New York New York
| | | | - Mads F. Bertelsen
- Center for Zoo and Wild Animal HealthCopenhagen Zoo Frederiksberg Denmark
| | - Cheryl D. Stimpson
- Department of Anthropology and Center for the Advanced Study of Human PaleobiologyThe George Washington University Washington District of Columbia
| | - Kathleen Bitterman
- School of Anatomical Sciences, Faculty of Health SciencesUniversity of the Witwatersrand Johannesburg South Africa
| | - Matthew Schall
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Department of PsychologyColorado College Colorado Springs Colorado
| | - Patrick R. Hof
- Nash Family Department of Neuroscience and Friedman Brain InstituteIcahn School of Medicine at Mount Sinai New York New York
| | - Chet C. Sherwood
- Department of Anthropology and Center for the Advanced Study of Human PaleobiologyThe George Washington University Washington District of Columbia
| | - Paul R. Manger
- School of Anatomical Sciences, Faculty of Health SciencesUniversity of the Witwatersrand Johannesburg South Africa
| | - Muhammad A. Spocter
- School of Anatomical Sciences, Faculty of Health SciencesUniversity of the Witwatersrand Johannesburg South Africa
- Department of AnatomyDes Moines University Des Moines Iowa
| | - Bob Jacobs
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Department of PsychologyColorado College Colorado Springs Colorado
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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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9
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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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10
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Pirone A, Miragliotta V, Cozzi B, Granato A. The Claustrum of the Pig: An Immunohistochemical and a Quantitative Golgi Study. Anat Rec (Hoboken) 2019; 302:1638-1646. [DOI: 10.1002/ar.24073] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 08/03/2018] [Accepted: 09/25/2018] [Indexed: 12/12/2022]
Affiliation(s)
- Andrea Pirone
- Department of Veterinary SciencesUniversity of Pisa Pisa Italy
| | | | - Bruno Cozzi
- Department of Comparative Biomedicine and Food ScienceUniversity of Padova Legnaro Italy
| | - Alberto Granato
- Department of PsychologyCatholic University of the Sacred Heart Milan Italy
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11
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Raghanti MA, Wicinski B, Meierovich R, Warda T, Dickstein DL, Reidenberg JS, Tang CY, George JC, Hans Thewissen JGM, Butti C, Hof PR. A Comparison of the Cortical Structure of the Bowhead Whale (Balaena mysticetus), a Basal Mysticete, with Other Cetaceans. Anat Rec (Hoboken) 2018; 302:745-760. [PMID: 30332717 DOI: 10.1002/ar.23991] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 09/12/2017] [Accepted: 10/16/2017] [Indexed: 12/13/2022]
Abstract
Few studies exist of the bowhead whale brain and virtually nothing is known about its cortical cytoarchitecture or how it compares to other cetaceans. Bowhead whales are one of the least encephalized cetaceans and occupy a basal phylogenetic position among mysticetes. Therefore, the bowhead whale is an important specimen for understanding the evolutionary specializations of cetacean brains. Here, we present an overview of the structure and cytoarchitecture of the bowhead whale cerebral cortex gleaned from Nissl-stained sections and magnetic resonance imaging (MRI) in comparison with other mysticetes and odontocetes. In general, the cytoarchitecture of cetacean cortex is consistent in displaying a thin cortex, a thick, prominent layer I, and absence of a granular layer IV. Cell density, composition, and width of layers III, V, and VI vary among cortical regions, and cetacean cortex is cell-sparse relative to that of terrestrial mammals. Notably, all regions of the bowhead cortex possess high numbers of von Economo neurons and fork neurons, with the highest numbers observed at the apex of gyri. The bowhead whale is also distinctive in having a significantly reduced hippocampus that occupies a space below the corpus callosum within the lateral ventricle. Consistent with other balaenids, bowhead whales possess what appears to be a blunted temporal lobe, which is in contrast to the expansive temporal lobes that characterize most odontocetes. The present report demonstrates that many morphological and cytoarchitectural characteristics are conserved among cetaceans, while other features, such as a reduced temporal lobe, may characterize balaenids among mysticetes. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc. Anat Rec, 302:745-760, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Mary Ann Raghanti
- Department of Anthropology and School of Biomedical Sciences, Kent State University, Kent, Ohio
| | - Bridget Wicinski
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Rachel Meierovich
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York.,Convent of the Sacred Heart School, New York, New York
| | - Tahia Warda
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Dara L Dickstein
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York.,Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Joy S Reidenberg
- Center for Anatomy and Functional Morphology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Cheuk Y Tang
- Department of Radiology and Translational Medicine Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - John C George
- Department of Wildlife Management, North Slope Borough, Barrow, Alaska
| | - J G M Hans Thewissen
- Department of Anatomy and Neurobiology, Northeastern Ohio Medical University, Rootstown, Ohio
| | - Camilla Butti
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Patrick R Hof
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York
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12
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Cortical Gradients and Laminar Projections in Mammals. Trends Neurosci 2018; 41:775-788. [DOI: 10.1016/j.tins.2018.06.003] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 06/10/2018] [Accepted: 06/11/2018] [Indexed: 12/30/2022]
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13
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Jacobs B, Garcia ME, Shea-Shumsky NB, Tennison ME, Schall M, Saviano MS, Tummino TA, Bull AJ, Driscoll LL, Raghanti MA, Lewandowski AH, Wicinski B, Ki Chui H, Bertelsen MF, Walsh T, Bhagwandin A, Spocter MA, Hof PR, Sherwood CC, Manger PR. Comparative morphology of gigantopyramidal neurons in primary motor cortex across mammals. J Comp Neurol 2017; 526:496-536. [PMID: 29088505 DOI: 10.1002/cne.24349] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 10/19/2017] [Accepted: 10/24/2017] [Indexed: 12/11/2022]
Abstract
Gigantopyramidal neurons, referred to as Betz cells in primates, are characterized by large somata and extensive basilar dendrites. Although there have been morphological descriptions and drawings of gigantopyramidal neurons in a limited number of species, quantitative investigations have typically been limited to measures of soma size. The current study thus employed two separate analytical approaches: a morphological investigation using the Golgi technique to provide qualitative and quantitative somatodendritic measures of gigantopyramidal neurons across 19 mammalian species from 7 orders; and unbiased stereology to compare the soma volume of layer V pyramidal and gigantopyramidal neurons in primary motor cortex between 11 carnivore and 9 primate species. Of the 617 neurons traced in the morphological analysis, 181 were gigantopyramidal neurons, with deep (primarily layer V) pyramidal (n = 203) and superficial (primarily layer III) pyramidal (n = 233) neurons quantified for comparative purposes. Qualitatively, dendritic morphology varied considerably across species, with some (sub)orders (e.g., artiodactyls, perissodactyls, feliforms) exhibiting bifurcating, V-shaped apical dendrites. Basilar dendrites exhibited idiosyncratic geometry across and within taxonomic groups. Quantitatively, most dendritic measures were significantly greater in gigantopyramidal neurons than in superficial and deep pyramidal neurons. Cluster analyses revealed that most taxonomic groups could be discriminated based on somatodendritic morphology for both superficial and gigantopyramidal neurons. Finally, in agreement with Brodmann, gigantopyramidal neurons in both the morphological and stereological analyses were larger in feliforms (especially in the Panthera species) than in other (sub)orders, possibly due to specializations in muscle fiber composition and musculoskeletal systems.
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Affiliation(s)
- Bob Jacobs
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Colorado College, Colorado Springs, Colorado
| | - Madeleine E Garcia
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Colorado College, Colorado Springs, Colorado
| | - Noah B Shea-Shumsky
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Colorado College, Colorado Springs, Colorado
| | - Mackenzie E Tennison
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Colorado College, Colorado Springs, Colorado
| | - Matthew Schall
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Colorado College, Colorado Springs, Colorado
| | - Mark S Saviano
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Colorado College, Colorado Springs, Colorado
| | - Tia A Tummino
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Colorado College, Colorado Springs, Colorado
| | - Anthony J Bull
- Human Biology and Kinesiology, Colorado College, Colorado Springs, Colorado
| | - Lori L Driscoll
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Colorado College, Colorado Springs, Colorado
| | - Mary Ann Raghanti
- Department of Anthropology and School of Biomedical Sciences, Kent State University, Kent, Ohio
| | | | - Bridget Wicinski
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Hong Ki Chui
- Laboratory of Quantitative Neuromorphology, Neuroscience Program, Colorado College, Colorado Springs, Colorado
| | - Mads F Bertelsen
- Center for Zoo and Wild Animal Health, Copenhagen Zoo, Fredericksberg, Denmark
| | - Timothy Walsh
- Smithsonian National Zoological Park, Washington, District of Columbia
| | - Adhil Bhagwandin
- 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.,Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| | - Patrick R Hof
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Chet C Sherwood
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, District of Columbia
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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14
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Fox KCR, Muthukrishna M, Shultz S. The social and cultural roots of whale and dolphin brains. Nat Ecol Evol 2017; 1:1699-1705. [PMID: 29038481 DOI: 10.1038/s41559-017-0336-y] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 09/01/2017] [Indexed: 02/04/2023]
Abstract
Encephalization, or brain expansion, underpins humans' sophisticated social cognition, including language, joint attention, shared goals, teaching, consensus decision-making and empathy. These abilities promote and stabilize cooperative social interactions, and have allowed us to create a 'cognitive' or 'cultural' niche and colonize almost every terrestrial ecosystem. Cetaceans (whales and dolphins) also have exceptionally large and anatomically sophisticated brains. Here, by evaluating a comprehensive database of brain size, social structures and cultural behaviours across cetacean species, we ask whether cetacean brains are similarly associated with a marine cultural niche. We show that cetacean encephalization is predicted by both social structure and by a quadratic relationship with group size. Moreover, brain size predicts the breadth of social and cultural behaviours, as well as ecological factors (diversity of prey types and to a lesser extent latitudinal range). The apparent coevolution of brains, social structure and behavioural richness of marine mammals provides a unique and striking parallel to the large brains and hyper-sociality of humans and other primates. Our results suggest that cetacean social cognition might similarly have arisen to provide the capacity to learn and use a diverse set of behavioural strategies in response to the challenges of social living.
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Affiliation(s)
- Kieran C R Fox
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, 94305, USA
| | - Michael Muthukrishna
- Department of Psychological and Behavioural Science, London School of Economics and Political Science, London, WC2A 2AE, UK.,Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Susanne Shultz
- School of Earth and Environmental Sciences, University of Manchester, Manchester, M13 9PL, UK.
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15
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Jacobs B. Arnold Bernard Scheibel, M.D. (1923-2017). J Comp Neurol 2017; 525:2459-2464. [DOI: 10.1002/cne.24231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 04/20/2017] [Accepted: 04/21/2017] [Indexed: 11/08/2022]
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16
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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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17
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Johnson CB, Schall M, Tennison ME, Garcia ME, Shea-Shumsky NB, Raghanti MA, Lewandowski AH, Bertelsen MF, Waller LC, Walsh T, Roberts JF, Hof PR, Sherwood CC, Manger PR, Jacobs B. Neocortical neuronal morphology in the Siberian Tiger (Panthera tigris altaica) and the clouded leopard (Neofelis nebulosa). J Comp Neurol 2016; 524:3641-3665. [DOI: 10.1002/cne.24022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 04/18/2016] [Accepted: 04/19/2016] [Indexed: 12/13/2022]
Affiliation(s)
- Cameron B. Johnson
- Laboratory of Quantitative Neuromorphology, Neuroscience Program; Colorado College; Colorado Springs Colorado 80903
| | - Matthew Schall
- Laboratory of Quantitative Neuromorphology, Neuroscience Program; Colorado College; Colorado Springs Colorado 80903
| | - Mackenzie E. Tennison
- Laboratory of Quantitative Neuromorphology, Neuroscience Program; Colorado College; Colorado Springs Colorado 80903
| | - Madeleine E. Garcia
- Laboratory of Quantitative Neuromorphology, Neuroscience Program; Colorado College; Colorado Springs Colorado 80903
| | - Noah B. Shea-Shumsky
- Laboratory of Quantitative Neuromorphology, Neuroscience Program; Colorado College; Colorado Springs Colorado 80903
| | - Mary Ann Raghanti
- Department of Anthropology and School of Biomedical Sciences; Kent State University; Kent Ohio 44242
| | | | - Mads F. Bertelsen
- Center for Zoo and Wild Animal Health; Copenhagen Zoo; 2000 Fredericksberg Denmark
| | - Leona C. Waller
- Laboratory of Quantitative Neuromorphology, Neuroscience Program; Colorado College; Colorado Springs Colorado 80903
| | - Timothy Walsh
- Smithsonian National Zoological Park; Washington DC 20008
| | - John F. Roberts
- Thompson Bishop Sparks State Diagnostic Laboratory, Alabama Department of Agriculture and Industries; Auburn Alabama 36849
| | - Patrick R. Hof
- Fishberg Department of Neuroscience and Friedman Brain Institute; Icahn School of Medicine at Mount Sinai; New York New York 10029
| | - Chet C. Sherwood
- Department of Anthropology; The George Washington University; Washington DC 20052
| | - Paul R. Manger
- School of Anatomical Sciences, Faculty of Health Sciences; University of the Witwatersrand; Johannesburg 2000 South Africa
| | - Bob Jacobs
- Laboratory of Quantitative Neuromorphology, Neuroscience Program; Colorado College; Colorado Springs Colorado 80903
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18
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Reyes LD, Harland T, Reep RL, Sherwood CC, Jacobs B. Golgi Analysis of Neuron Morphology in the Presumptive Somatosensory Cortex and Visual Cortex of the Florida Manatee (Trichechus manatus latirostris). BRAIN, BEHAVIOR AND EVOLUTION 2016; 87:105-16. [PMID: 27166161 DOI: 10.1159/000445495] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 03/15/2016] [Indexed: 11/19/2022]
Abstract
The current study investigates neuron morphology in presumptive primary somatosensory (S1) and primary visual (V1) cortices of the Florida manatee (Trichechus manatus latirostris) as revealed by Golgi impregnation. Sirenians, including manatees, have an aquatic lifestyle, a large body size, and a relatively large lissencephalic brain. The present study examines neuron morphology in 3 cortical areas: in S1, dorsolateral cortex area 1 (DL1) and cluster cortex area 2 (CL2) and in V1, dorsolateral cortex area 4 (DL4). Neurons exhibited a variety of morphological types, with pyramidal neurons being the most common. The large variety of neuron types present in the manatee cortex was comparable to that seen in other eutherian mammals, except for rodents and primates, where pyramid-shaped neurons predominate. A comparison between pyramidal neurons in S1 and V1 indicated relatively greater dendritic branching in S1. Across all 3 areas, the dendritic arborization pattern of pyramidal neurons was also similar to that observed previously in the afrotherian rock hyrax, cetartiodactyls, opossums, and echidnas but did not resemble the widely bifurcated dendrites seen in the large-brained African elephant. Despite adaptations for an aquatic environment, manatees did not share specific neuron types such as tritufted and star-like neurons that have been found in cetaceans. Manatees exhibit an evolutionarily primitive pattern of cortical neuron morphology shared with most other mammals and do not appear to have neuronal specializations for an aquatic niche.
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Affiliation(s)
- Laura D Reyes
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, D.C., USA
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19
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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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20
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Reyes LD, Stimpson CD, Gupta K, Raghanti MA, Hof PR, Reep RL, Sherwood CC. Neuron Types in the Presumptive Primary Somatosensory Cortex of the Florida Manatee (Trichechus manatus latirostris). BRAIN, BEHAVIOR AND EVOLUTION 2015; 86:210-31. [PMID: 26613530 DOI: 10.1159/000441964] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 10/25/2015] [Indexed: 11/19/2022]
Abstract
Within afrotherians, sirenians are unusual due to their aquatic lifestyle, large body size and relatively large lissencephalic brain. However, little is known about the neuron type distributions of the cerebral cortex in sirenians within the context of other afrotherians and aquatic mammals. The present study investigated two cortical regions, dorsolateral cortex area 1 (DL1) and cluster cortex area 2 (CL2), in the presumptive primary somatosensory cortex (S1) in Florida manatees (Trichechus manatus latirostris) to characterize cyto- and chemoarchitecture. The mean neuron density for both cortical regions was 35,617 neurons/mm(3) and fell within the 95% prediction intervals relative to brain mass based on a reference group of afrotherians and xenarthrans. Densities of inhibitory interneuron subtypes labeled against calcium-binding proteins and neuropeptide Y were relatively low compared to afrotherians and xenarthrans and also formed a small percentage of the overall population of inhibitory interneurons as revealed by GAD67 immunoreactivity. Nonphosphorylated neurofilament protein-immunoreactive (NPNFP-ir) neurons comprised a mean of 60% of neurons in layer V across DL1 and CL2. DL1 contained a higher percentage of NPNFP-ir neurons than CL2, although CL2 had a higher variety of morphological types. The mean percentage of NPNFP-ir neurons in the two regions of the presumptive S1 were low compared to other afrotherians and xenarthrans but were within the 95% prediction intervals relative to brain mass, and their morphologies were comparable to those found in other afrotherians and xenarthrans. Although this specific pattern of neuron types and densities sets the manatee apart from other afrotherians and xenarthrans, the manatee isocortex does not appear to be explicitly adapted for an aquatic habitat. Many of the features that are shared between manatees and cetaceans are also shared with a diverse array of terrestrial mammals and likely represent highly conserved neural features. A comparative study across manatees and dugongs is necessary to determine whether these traits are specific to one or more of the manatee species, or can be generalized to all sirenians.
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Affiliation(s)
- Laura D Reyes
- Department of Anthropology and Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, D.C., USA
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21
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Parolisi R, Peruffo A, Messina S, Panin M, Montelli S, Giurisato M, Cozzi B, Bonfanti L. Forebrain neuroanatomy of the neonatal and juvenile dolphin (T. truncatus and S. coeruloalba). Front Neuroanat 2015; 9:140. [PMID: 26594155 PMCID: PMC4635206 DOI: 10.3389/fnana.2015.00140] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 10/16/2015] [Indexed: 12/16/2022] Open
Abstract
Knowledge of dolphin functional neuroanatomy mostly derives from post-mortem studies and non-invasive approaches (i.e., magnetic resonance imaging), due to limitations in experimentation on cetaceans. As a consequence the availability of well-preserved tissues for histology is scarce, and detailed histological analyses are referred mainly to adults. Here we studied the neonatal/juvenile brain in two species of dolphins, the bottlenose dolphin (Tursiops truncatus) and the striped dolphin (Stenella coeruleoalba), with special reference to forebrain regions. We analyzed cell density in subcortical nuclei, white/gray matter ratio, and myelination in selected regions at different anterior–posterior levels of the whole dolphin brain at different ages, to better define forebrain neuroanatomy and the developmental stage of the dolphin brain around birth. The analyses were extended to the periventricular germinal layer and the cerebellum, whose delayed genesis of the granule cell layer is a hallmark of postnatal development in the mammalian nervous system. Our results establish an atlas of the young dolphin forebrain and, on the basis of occurrence/absence of delayed neurogenic layers, confirm the stage of advanced brain maturation in these animals with respect to most terrestrial mammals.
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Affiliation(s)
- Roberta Parolisi
- Neuroscience Institute Cavalieri Ottolenghi, University of Turin Orbassano, Italy ; Department of Veterinary Sciences, University of Turin Torino, Italy
| | - Antonella Peruffo
- Department of Comparative Biomedicine and Food Science, University of Padova Legnaro, Italy
| | - Silvia Messina
- Neuroscience Institute Cavalieri Ottolenghi, University of Turin Orbassano, Italy
| | - Mattia Panin
- Department of Comparative Biomedicine and Food Science, University of Padova Legnaro, Italy
| | - Stefano Montelli
- Department of Comparative Biomedicine and Food Science, University of Padova Legnaro, Italy
| | - Maristella Giurisato
- Department of Comparative Biomedicine and Food Science, University of Padova Legnaro, Italy
| | - Bruno Cozzi
- Department of Comparative Biomedicine and Food Science, University of Padova Legnaro, Italy
| | - Luca Bonfanti
- Neuroscience Institute Cavalieri Ottolenghi, University of Turin Orbassano, Italy ; Department of Veterinary Sciences, University of Turin Torino, Italy
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Jacobs B, Lee L, Schall M, Raghanti MA, Lewandowski AH, Kottwitz JJ, Roberts JF, Hof PR, Sherwood CC. Neocortical neuronal morphology in the newborn giraffe (Giraffa camelopardalis tippelskirchi) and African elephant (Loxodonta africana). J Comp Neurol 2015; 524:257-87. [DOI: 10.1002/cne.23841] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 06/19/2015] [Accepted: 06/22/2015] [Indexed: 12/20/2022]
Affiliation(s)
- Bob Jacobs
- Laboratory of Quantitative Neuromorphology Department of Psychology, Colorado College; Colorado Springs Colorado 80903
| | - Laura Lee
- Laboratory of Quantitative Neuromorphology Department of Psychology, Colorado College; Colorado Springs Colorado 80903
| | - Matthew Schall
- Laboratory of Quantitative Neuromorphology Department of Psychology, Colorado College; Colorado Springs Colorado 80903
| | | | | | - Jack J. Kottwitz
- Department of Anatomy, Physiology, and Pharmacology, College of Veterinary Medicine; Auburn University; Auburn Alabama 36849
| | - John F. Roberts
- Thompson Bishop Sparks State Diagnostic Laboratory Alabama Department of Agriculture and Industries; Auburn Alabama 36849
| | - Patrick R. Hof
- Fishberg Department of Neuroscience and Friedman Brain Institute; Icahn School of Medicine at Mount Sinai; New York New York 10029
| | - Chet C. Sherwood
- Department of Anthropology; The George Washington University; Washington DC 20052
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The neocortex of cetartiodactyls. II. Neuronal morphology of the visual and motor cortices in the giraffe (Giraffa camelopardalis). Brain Struct Funct 2014; 220:2851-72. [PMID: 25048683 DOI: 10.1007/s00429-014-0830-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Accepted: 06/21/2014] [Indexed: 12/24/2022]
Abstract
The present quantitative study extends our investigation of cetartiodactyls by exploring the neuronal morphology in the giraffe (Giraffa camelopardalis) neocortex. Here, we investigate giraffe primary visual and motor cortices from perfusion-fixed brains of three subadults stained with a modified rapid Golgi technique. Neurons (n = 244) were quantified on a computer-assisted microscopy system. Qualitatively, the giraffe neocortex contained an array of complex spiny neurons that included both "typical" pyramidal neuron morphology and "atypical" spiny neurons in terms of morphology and/or orientation. In general, the neocortex exhibited a vertical columnar organization of apical dendrites. Although there was no significant quantitative difference in dendritic complexity for pyramidal neurons between primary visual (n = 78) and motor cortices (n = 65), there was a significant difference in dendritic spine density (motor cortex > visual cortex). The morphology of aspiny neurons in giraffes appeared to be similar to that of other eutherian mammals. For cross-species comparison of neuron morphology, giraffe pyramidal neurons were compared to those quantified with the same methodology in African elephants and some cetaceans (e.g., bottlenose dolphin, minke whale, humpback whale). Across species, the giraffe (and cetaceans) exhibited less widely bifurcating apical dendrites compared to elephants. Quantitative dendritic measures revealed that the elephant and humpback whale had more extensive dendrites than giraffes, whereas the minke whale and bottlenose dolphin had less extensive dendritic arbors. Spine measures were highest in the giraffe, perhaps due to the high quality, perfusion fixation. The neuronal morphology in giraffe neocortex is thus generally consistent with what is known about other cetartiodactyls.
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