Muscle Architecture of the Elongated Nose in the Asian Elephant(Elephas maximus).

Endo, Hideki; Hayashi, Yoshihiro; Komiya, Teruyuki; Narushima, Etsuo; Sasaki, Motoki

doi:10.1292/jvms.63.533

Cited by 19 publications

(18 citation statements)

References 3 publications

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“…An example of this phenomenon is the snake, which typically flicks its chemoreceptor-laden organ to sense its prey (de Groot et al, 2004). The fibers of the elephant trunk, on the other hand, are organized in a spiral fashion about the central longitudinal axis, thereby maximizing the ability of the organ to perform the twisting needed for grasping arboreal vegetation (Endo et al, 2001). The tentacle of the squid, which is most structurally similar to the mammalian tongue, has a core region of transverse fibers surrounded by a longitudinal sheath (Friel and Wainwright, 1998).…”

Section: Discussionmentioning

confidence: 99%

Three‐dimensional myoarchitecture of the bovine tongue demonstrated by diffusion spectrum magnetic resonance imaging with tractography

et al. 2006

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The anatomy of the mammalian tongue consists of an intricate array of variably aligned and extensively interwoven muscle fibers. As a result, it is particularly difficult to resolve the relationship between the tongue's microscopic anatomy and tissue-scale mechanical function. In order to address this question, we employed a method, diffusion spectrum imaging (DSI) with tractography, for displaying the macroscopic orientational properties of the tissue's constituting myofibers. DSI measures spatially variant proton displacement for a given 3D imaging segment (voxel), reflecting the principal orientation(s) of its myofibers. Tractography uses the angular similarity displayed by the principal fiber populations of multiple adjacent voxels to generate tract-like structures. DSI with tractography thus defines a unique set of tracts based on the net orientational behavior of the myofiber populations at different positions in the tissue. By this approach, we demonstrate a novel myoarchitectural pattern for the bovine tongue, consisting of short and orthogonally aligned crossing fiber tracts in the intrinsic core region, and longer, parallel-aligned fiber tracts on the tissue margins and in the regions of extrinsic fiber insertion. The identification of locally aligned myofiber populations by DSI with tractography allows us to reconsider lingual anatomy, not in conventional microscopic terms, but as a set of heterogeneously aligned and macroscopically resolved myofiber tracts. We postulate that the properties associated with these myofiber tracts predict the mechanical behavior of the tissue and thus constitute a method to relate structure and function for anatomically complex muscular tissues.

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Section: Discussionmentioning

confidence: 99%

Three‐dimensional myoarchitecture of the bovine tongue demonstrated by diffusion spectrum magnetic resonance imaging with tractography

et al. 2006

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“…Pioli et al, 2008], through its projection upon the dorsal striatopallidal complex [Dahlström and Fuxe, 1964]. While we cannot definitively state that the specialized organization of the pars compacta of the substantia nigra in the African elephant will enhance fine motor control, it would appear that this is a likely scenario given the need for fine control of the extensive musculature of the trunk [Endo et al, 2001]. It is possible to speculate that each of the pars compacta islands receives a specific subset of sensory afferents, for example related to trunk flexion, thereby enhancing distinct and discrete trunk movements through a topographically organized striatal dopaminergic projection.…”

Section: Motor System Specializations Of the African Elephant Brainstemmentioning

confidence: 92%

“…Klemm and Vertes, 1990;Jones, 2007], along with tissue that can be processed with modern neuroanatomical techniques, permits a detailed re-examination of the structure of these regions of the elephant brain. Given the important role these regions of the brain will play in the life history of the elephant, for example in control of the musculature of the trunk or the muscles controlling the production of infrasound [Endo et al, 2001;Herbst et al, 2012], a better understanding of the anatomy of the elephant diencephalon and brainstem may lead to greater insights into these enigmatic mammals. The…”

Section: Introductionmentioning

confidence: 99%

Architectural Organization of the African Elephant Diencephalon and Brainstem

Maseko

Patzke²,

Fuxé³

et al. 2013

Brain Behav Evol

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The current study examined the organization of the diencephalon and brainstem of the African elephant (Loxodonta africana) - a region of the elephant brain that has not been examined for at least 50 years. The current description, employing material amenable for use with modern neuroanatomical methods, shows that, for the most part, the elephant diencephalon and brainstem are what could be considered typically mammalian, with subtle differences in proportions and topology. The variations from these previous descriptions, where they occurred, were related to four specific aspects of neural information processing: (1) the motor systems, (2) the auditory and vocalization systems, (3) the orexinergic satiety/wakefulness centre of the hypothalamus and the locus coeruleus, and (4) the potential neurogenic lining of the brainstem. For the motor systems, three specific structures exhibited interesting differences in organization - the pars compacta of the substantia nigra, the facial motor nerve nucleus, and the inferior olivary nuclear complex, all related to the timing and learning of movements and likely related to the control of the trunk. The dopaminergic neurons of the substantia nigra appear to form distinct islands separated from each other by large fibre pathways, an appearance unique to the elephant. Each island may send topologically organized projections to the striatum forming a dopaminergic innervation mosaic that may relate to trunk movements. At least five regions of the combined vocalization production and auditory/seismic reception system were specialized, including the large and distinct nucleus ellipticus of the periaqueductal grey matter, the enlarged lateral superior olivary nucleus, the novel transverse infrageniculate nucleus of the dorsal thalamus, the enlarged dorsal column nuclei and the ventral posterior inferior nucleus of the dorsal thalamus. These specializations, related to production and reception of infrasound, allow the proposal of a novel concept regarding the reception and localization of infrasonic sources. The orexinergic system of the hypothalamus displayed a medial hypothalamic parvocellular cluster of neurons in addition to the magnocellular clusters typical of mammals located in the lateral hypothalamus, and a novel medial division of the locus coeruleus was observed in the pons. These systems are related to appetitive drive and promotion of wakefulness, two aspects of elephant behaviour that appear to be inextricably linked. Lastly, we observed an extensive potential neurogenic lining of the ventricles throughout the brainstem that is present in even quite old elephants, although the function of these cells remains elusive. These observations combined demonstrate that, while much of the elephant brainstem is typically mammalian, certain aspects of the anatomy related to specialized behaviour of elephants are present and instructive in understanding elephant behaviour.

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“…Although the method of food acquisition varies among mammals, herbivores and many omnivores possess elaborated facial and perioral musculature that is used to grasp and manipulate plant material in a prehensile manner for ingestion [e.g., Getty, 1975;Hofmann, 1989;Hofmann, 1996, 1997;Clifford and Witmer, 2004]. Such musculature has been greatly modified in some taxa, particularly in elephants [Boas and Paulli, 1908;Endo et al, 2001], suoids [Herring, 1972], tapirs [Witmer et al, 1999], and sirenians [Marshall et al, 1998a[Marshall et al, , b, 2003. Extreme facial muscle elaboration is perhaps best exemplified by elephants (Elephas maximus) .…”

Section: Introductionmentioning

confidence: 99%

“…Elephant trunks are characterized by a lack of skeletal elements and they contain muscles that attach solely to soft tissue. Their trunk muscles are organized into radial, longitudinal, transverse and circular complexes [Boas and Paulli, 1908;Endo et al, 2001], and are capable of highly controlled, detailed and varied movements. Such structures are known as 'muscular hydrostats' [Kier and Smith, 1985].…”

Section: Introductionmentioning

confidence: 99%

Topographical Organization of the Facial Motor Nucleus in Florida Manatees <i>(Trichechus manatus latirostris)</i>

Marshall

Vaughn²,

Sarko³

et al. 2007

Brain Behav Evol

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Florida manatees (Trichechus manatus latirostris) possess modified vibrissae that are used in conjunction with specialized perioral musculature to manipulate vegetation for ingestion, and aid in the tactile exploration of their environment. Therefore it is expected that manatees possess a large facial motor nucleus that exhibits a complex organization relative to other taxa. The topographical organization of the facial motor nucleus of five adult Florida manatees was analyzed using neuroanatomical methods. Cresyl violet and hematoxylin staining were used to localize the rostrocaudal extent of the facial motor nucleus as well as the organization and location of subdivisions within this nucleus. Differences in size, length, and organization of the facial motor nucleus among mammals correspond to the functional importance of the superficial facial muscles, including perioral musculature involved in the movement of mystacial vibrissae. The facial motor nucleus of Florida manatees was divided into seven subnuclei. The mean rostrocaudal length, width, and height of the entire Florida manatee facial motor nucleus was 6.6 mm (SD 8 0.51; range: 6.2–7.5 mm), 4.7 mm (SD 8 0.65; range: 4.0–5.6 mm), and 3.9 mm (SD 8 0.26; range: 3.5–4.2 mm), respectively. It is speculated that manatees could possess direct descending corticomotorneuron projections to the facial motornucleus. This conjecture is based on recent data for rodents, similiarities in the rodent and sirenian muscular-vibrissal complex, and the analogous nature of the sirenian cortical Rindenkerne system with the rodent barrel system.

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Muscle Architecture of the Elongated Nose in the Asian Elephant(Elephas maximus).

Cited by 19 publications

References 3 publications

Three‐dimensional myoarchitecture of the bovine tongue demonstrated by diffusion spectrum magnetic resonance imaging with tractography

Three‐dimensional myoarchitecture of the bovine tongue demonstrated by diffusion spectrum magnetic resonance imaging with tractography

Architectural Organization of the African Elephant Diencephalon and Brainstem

Topographical Organization of the Facial Motor Nucleus in Florida Manatees <i>(Trichechus manatus latirostris)</i>

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