Structural organization of the limbic cortex in dolphins

Kesarev, V. S.

doi:10.1007/bf01124284

Cited by 8 publications

(10 citation statements)

References 6 publications

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“…The putative motor cortex of the pygmy hippopotamus was very similar to that recognized both electrophysiologically and cytoarchitecturally as the motor cortex in cetaceans (Kojima, ; Lende, 1968; Kesarev and Malofeeva, ; Ladygina and Supin, ; Hof and Van der Gucht, ). It is interesting to note that in cetaceans, the belt of motor cortex in the frontal convexity extends rostro‐caudally and is separated laterally from the somatosensory cortex by the cruciate sulcus (Kesarev and Malofeeva, ; Lende and Welker, ; Sokolov et al, ; Ladygina and Supin, ; Glezer, ). However, although the cruciate sulcus develops in a rostrocaudal direction in cetaceans, possibly as a consequence of the rostroventral rotation that the cetacean brain undergoes during development, the cruciate sulcus develops laterally in the pygmy hippopotamus, reaching the most dorsal aspect of the anterior Sylvian cortex.…”

Section: Discussionsupporting

confidence: 55%

The Cerebral Cortex of the Pygmy Hippopotamus, Hexaprotodon liberiensis (Cetartiodactyla, Hippopotamidae): MRI, Cytoarchitecture, and Neuronal Morphology

Butti

Fordyce

Raghanti

et al. 2014

The Anatomical Record

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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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Section: Discussionsupporting

confidence: 55%

The Cerebral Cortex of the Pygmy Hippopotamus, Hexaprotodon liberiensis (Cetartiodactyla, Hippopotamidae): MRI, Cytoarchitecture, and Neuronal Morphology

Butti

Fordyce

Raghanti

et al. 2014

The Anatomical Record

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“…The earliest mention of gigantopyramidal neurons in these orders was in sheep by Lewis (), who found that these neurons were arranged in “nests” similar to what had been observed by Betz () in dogs, but that they also tended to be smaller than those found in humans or the domestic cat. Large layer V pyramidal neurons have been observed in the putative motor cortices in several cetacean species (Hof, Chanis, & Marino, ; Hof & Van der Gucht, ; Kesarev & Malofeeva, ), with potential morphological similarities to gigantopyramidal neurons documented in the humpback whale (Butti et al, ), but it remains unclear if these actually constitute gigantopyramidal motor neurons. In the present morphological analysis, gigantopyramidal neuron soma size in artiodactyls and perissodactyls was relatively small, perhaps because the corticospinal tract in ungulates does not project farther than the cervical level of the spinal cord (Badlangana et al, ; Nieuwenhuys, ten Donkelaar, & Nicholson, ).…”

Section: Discussionmentioning

confidence: 99%

Comparative morphology of gigantopyramidal neurons in primary motor cortex across mammals

Jacobs

Garcia

Shea‐Shumsky

et al. 2017

J of Comparative Neurology

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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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“…The regional organization of the cerebral cortex in cetaceans remains poorly understood, most of our knowledge of it stemming from studies of the bottlenose dolphin (Kesarev, 1969;Kesarev and Malofeeva, 1969;Jacobs et al, 1971Jacobs et al, , 1979Jacobs et al, , 1984Kesarev et al, 1977;Morgane et al, 1982Morgane et al, , 1988Garey et al, 1985;Manger et al, 1998). In general, the dolphin neocortex is thin and agranular, harbors a very prominent thick layer I that is far more cellular than in terrestrial species, has large inverted neurons in the cell-dense layer II, and very large pyramidal neurons frequently forming clusters at the border between layers III and V. Layers III and VI vary considerably in thickness and cellular density across regions (Hof et al, 2005).…”

Section: ;mentioning

confidence: 99%

“…Recent evidence indicates that the cetacean neocortical structure is in fact quite complex, with a degree of regional parcellation comparable to that of many terrestrial mammals (Hof et al, 2005). However, while there has been a few detailed analyses of the archicortex, paleocortex, insular, and cingulate cortex of dolphins (Jacobs et al, 1971(Jacobs et al, , 1979(Jacobs et al, , 1984Morgane et al, 1982), most studies focused on rather restricted domains of cortex (Kojima, 1951;Pilleri et al, 1968;Kesarev, 1969;Kesarev and Malofeeva, 1969;Jacobs et al, 1971Jacobs et al, , 1979Jacobs et al, , 1984Kesarev et al, 1977;Zworykin, 1977;Morgane et al, 1982Morgane et al, , 1988Garey et al, 1985;Garey and Leuba, 1986;Ferrer and Perera, 1988;Glezer and Morgane, 1990;Glezer et al, 1992Glezer et al, , 1993Hof et al, 1992;Manger et al, 1998). The structure of the cerebral cortex in mysticetes has barely been studied (Kraus and Pilleri, 1969;Jacobs et al, 1979;Morgane et al, 1982).…”

Section: General Morphology and Histologymentioning

confidence: 99%

Structure of the cerebral cortex of the humpback whale,Megaptera novaeangliae (Cetacea, Mysticeti, Balaenopteridae)

Hof¹,

Gucht²

2006

Anat. Rec.

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Cetaceans diverged from terrestrial mammals between 50 and 60 million years ago and acquired, during their adaptation to a fully aquatic milieu, many derived features, including echolocation (in odontocetes), remarkable auditory and communicative abilities, as well as a complex social organization. Whereas brain structure has been documented in detail in some odontocetes, few reports exist on its organization in mysticetes. We studied the cerebral cortex of the humpback whale (Megaptera novaeangliae) in comparison to another balaenopterid, the fin whale, and representative odontocetes. We observed several differences between Megaptera and odontocetes, such as a highly clustered organization of layer II over the occipital and inferotemporal neocortex, whereas such pattern is restricted to the ventral insula in odontocetes. A striking observation in Megaptera was the presence in layer V of the anterior cingulate, anterior insular, and frontopolar cortices of large spindle cells, similar in morphology and distribution to those described in hominids, suggesting a case of parallel evolution. They were also observed in the fin whale and the largest odontocetes, but not in species with smaller brains or body size. The hippocampal formation, unremarkable in odontocetes, is further diminutive in Megaptera, contrasting with terrestrial mammals. As in odontocetes, clear cytoarchitectural patterns exist in the neocortex of Megaptera, making it possible to define many cortical domains. These observations demonstrate that Megaptera differs from Odontoceti in certain aspects of cortical cytoarchitecture and may provide a neuromorphologic basis for functional and behavioral differences between the suborders as well as a reflection of their divergent evolution. Anat Rec, 290:1-31, 2007. 2006 Wiley-Liss, Inc.Key words: balaenopterids; cetaceans; cytoarchitecture; dolphins; mysticete; neocortex; odontoceteThe order Cetacea comprises highly diversified species distributed into two suborders, the Mysticeti (baleen whales) and the Odontoceti (toothed whales). The suborder Mysticeti includes 13 species (the so-called right whales, the pygmy right whale, the gray whale, and the rorquals), while Odontoceti contains 72 species of toothed whales, dolphins, and porpoises, distributed into four superfamilies (Mann et al., 2000). Morphological features and molecular phylogenetics suggest that cetaceans are directly related to artiodactyls (even-toed ungulates) (Gingerich et al., 2001;

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Structural organization of the limbic cortex in dolphins

Cited by 8 publications

References 6 publications

The Cerebral Cortex of the Pygmy Hippopotamus, Hexaprotodon liberiensis (Cetartiodactyla, Hippopotamidae): MRI, Cytoarchitecture, and Neuronal Morphology

The Cerebral Cortex of the Pygmy Hippopotamus, Hexaprotodon liberiensis (Cetartiodactyla, Hippopotamidae): MRI, Cytoarchitecture, and Neuronal Morphology

Comparative morphology of gigantopyramidal neurons in primary motor cortex across mammals

Structure of the cerebral cortex of the humpback whale,Megaptera novaeangliae (Cetacea, Mysticeti, Balaenopteridae)

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