Precerebellar and vestibular nuclei of the short-beaked echidna (Tachyglossus aculeatus)

Ashwell, Ken W.S.; Paxinos, George; Watson, Charles

doi:10.1007/s00429-007-0139-z

Cited by 9 publications

(7 citation statements)

References 38 publications

(35 reference statements)

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“…96) did not appear to be. Similar results were reported for the short-beaked echidna (Ashwell et al, 2007). The data suggest that expression of this protein in vestibular brainstem is well-conserved across mammalian species, with some possible species differences.…”

Section: Discussionsupporting

confidence: 89%

Nonphosphorylated neurofilament protein is expressed by scattered neurons in the vestibular and precerebellar brainstem

Baizer

2009

Brain Research

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Vestibular information is essential for the control of posture, balance, and eye movements. The vestibular nerve projects to the four nuclei of the vestibular nuclear complex (VNC), as well as to several additional brainstem nuclei and the cerebellum. We have found that expression of the calcium-binding proteins calretinin (CR) and calbindin (CB), and the synthetic enzyme for nitric oxide synthase (nNOS) define subdivisions of the medial vestibular nucleus (MVe) and the nucleus prepositus (PrH), in cat, monkey, and human. We have asked if the pattern of expression of nonphosphorylated neurofilament protein (NPNFP) might define additional subdivisions of these or other nuclei that participate in vestibular function. We studied the distribution of cells immunoreactive to NPNFP in the brainstems of 5 cats and one squirrel monkey. Labeled cells were scattered throughout the four nuclei of the VNC, as well as in PrH, the reticular formation (RF) and the external cuneate nucleus. We used double-label immunofluorescence to visualize the distribution of these cells relative to other neurochemically defined subdivisions. NPNFP cells were excluded from the CR and CB regions of the MVe. In PrH, NPNFP and nNOS were not colocalized. Cells in the lateral vestibular nucleus and RF colocalized NPNFP and a marker for glutamatergic neurons. We also found that the cholinergic cells and axons of cranial nerve nuclei 3, 4, 6, 7,10 and 12 colocalize NPNFP. The data suggest that NPNFP is expressed by a subset of glutamatergic projection neurons of the vestibular brainstem. NPNFP may be a marker for those cells that are especially vulnerable to the effects of normal aging, neurological disease or disruption of sensory input.

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Section: Discussionsupporting

confidence: 89%

Nonphosphorylated neurofilament protein is expressed by scattered neurons in the vestibular and precerebellar brainstem

Baizer

2009

Brain Research

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“…The position and cytoarchitecture of mature vestibular nuclei conforms to that observed throughout therians and monotremes [Cowley, 1976;Henkel and Martin, 1977;Rubertone et al, 1995;Buttner-Ennever and Gerrits, 2004;Ashwell et al, 2007]. The LVe, which was continuous caudally with SpVe, appeared to have the , d-f ).…”

Section: Discussionsupporting

confidence: 79%

Development of the Vestibular Apparatus and Central Vestibular Connections in a Wallaby <i>(Macropus eugenii)</i>

McCluskey¹,

Marotte

Ashwell³

2008

Brain Behav Evol

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We have studied the early development of the vestibular apparatus and its central connections in the tammar wallaby (Macropus eugenii) in order to determine whether the vestibular system anatomy is sufficiently mature at birth to assist in climbing to the pouch. Structural development was studied with the aid of hematoxylin and eosin stained sections and immunoreactivity for GAP-43, whereas the development of vestibular system connections was examined by carbocyanine dye tracing. At the time of birth, the otocyst has distinct utricle, saccule and semicircular canals with immature sensory regions receiving innervation by GAP-43 immunoreactive fibers. Vestibular nerve fibers can be traced into the brainstem to the developing vestibular nuclei, which are not yet cytoarchitectonically distinct. The vestibular nuclei do not contribute direct projections to the lower cervical spinal cord at birth; most bulbospinal projections in the newborn appear to be derived bilaterally from the gigantocellular, lateral paragigantocellular reticular and ventral medullary nuclei. A substantial bilateral projection to the vestibular ganglion and apparatus from the region of the gigantocellular and lateral paragigantocellular nuclei was seen at birth, but not in subsequent ages. This is similar to a projection seen in newborn Ameridelphians. By postnatal day (P) 5, the vestibular apparatus had extensive projections to all vestibular nuclei and neurons projecting in the lateral vestibulospinal tract could be identified in the lateral vestibular nucleus. Cytoarchitectonic differentiation of the vestibular nuclei proceeded over the next 3 to 4 weeks with the emergence of discrete parvicellular and magnocellular components of the medial vestibular nucleus by P19. GAP-43 immunoreactivity stayed high in the lateral vestibulospinal tract for several months after birth, suggesting that the development of this tract followed a prolonged timecourse. Our findings indicate that central and peripheral connections of the vestibular ganglion are present at birth, but that there is no direct projection from the vestibular nuclei to the cervical spinal cord until P5. Nevertheless, the possibility remains that an indirect projection between the vestibular nuclei and the medial reticular formation is present at birth and mediates control of the climb.

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“…Their evolutionary history has influenced how monotremes are viewed in the scientific community, particularly as they are generally considered to be the mammals most distantly related to humans (Krubitzer, Manger, Pettigrew, & Calford, 1995). They have historically been referred to as mammals of the "lowliest status" (Elliot Smith, 1902) and "living fossils" (Darwin, 1959), and are still viewed by many scientists as "primitive" (Ashwell, Paxinos, & Watson, 2007;Musser, 2003). This view is compounded by the fact that monotremes, in addition to their mammalian characteristics, display numerous plesiomorphic reptilian traits in their anatomy, physiology, and reproduction, such as laying keratin-covered eggs and having a single cloacal outlet (Augee, Gooden, & Musser, 2006;Griffiths, 1989).…”

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confidence: 99%

Conditional same/different concept learning in the short-beaked echidna (Tachyglossus aculeatus)

Russell

Burke²

2016

Jrnl Exper Analysis Behavior

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Echidnas have evolved separately from other mammalian groups for around 200 million years and incorporate a mixture of reptilian and mammalian features. Because of these attributes, they have historically been considered "primitive" animals. However, they have successfully adapted to a wide variety of ecological niches and their neurophysiology demonstrates a number of unusual and apparently sophisticated characteristics, including a relatively large brain and cerebral cortex and a comparatively massive frontal cortex. Studies of learning in the echidna have thus far been limited to only a handful of experiments which demonstrated relatively basic abilities such as forming a position habit in a T-maze, successive habit-reversal learning, and simple visual and instrumental discrimination. This study aimed to expand on these results and test the "primitive" echidna on what are generally considered more advanced cognitive tasks-same/different and conditional same/different concept learning. The results demonstrated that echidnas are able to discriminate on the basis of a relational same/different concept, using simultaneously presented multi-element stimuli, and transfer that discrimination to novel stimuli. After further training, they were then able to repeat the performance when the correct choice was conditional on the background color of the stimulus panels.

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Precerebellar and vestibular nuclei of the short-beaked echidna (Tachyglossus aculeatus)

Cited by 9 publications

References 38 publications

Nonphosphorylated neurofilament protein is expressed by scattered neurons in the vestibular and precerebellar brainstem

Nonphosphorylated neurofilament protein is expressed by scattered neurons in the vestibular and precerebellar brainstem

Development of the Vestibular Apparatus and Central Vestibular Connections in a Wallaby <i>(Macropus eugenii)</i>

Conditional same/different concept learning in the short-beaked echidna (Tachyglossus aculeatus)

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