Early development of the hypothalamus of a wallaby (Macropus eugenii)

Cheng, Gang; Marotte, L.R.; Kurths, Jürgen; Ashwell, Ken W.S.

doi:10.1002/cne.10395

Cited by 13 publications

(15 citation statements)

References 64 publications

(73 reference statements)

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“…Even with filling the entire nasal cavity with DiI, only a handful of axons could be identified entering the basal forebrain. Our previous tracing experiments with this mammal [Cheng et al, 2002] did not find any evidence of forebrain nuclei projecting to the spinal cord at birth and only 2 or 3 neurons projecting from the lateral hypothalamus to the brainstem at the same age. The terminal nerve projection is probably providing an avenue for entry of LHRH+ and FMRFamide+ axons and neurons into the developing forebrain as has been reported for other therian mammals at a similar developmental stage [Schwanzel-Fukuda et al, 1988;Cummings and Brunjes, 1995;Malz and Kuhn, 2002].…”

Section: Does Olfaction Play a Part In Guidance Of The Newborn Tammarmentioning

confidence: 99%

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Development of the Olfactory System in a Wallaby (Macropus eugenii)

Ashwell¹,

Marotte

Cheng³

2008

Brain Behav Evol

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We used carbocyanine dye tracing techniques in conjunction with hematoxylin and eosin staining, immunohistochemistry for GAP-43, and tritiated thymidine autoradiography to examine the development of the olfactory pathways in early pouch young tammar wallabies (Macropus eugenii). The overarching aim was to test the hypothesis that the olfactory system of newborn tammars is sufficiently mature at birth to contribute to the guidance of the pouch young to the nipple. Although GAP-43 immunoreactive fibers emerge from the olfactory epithelium and enter the olfactory bulb at birth, all other components of the olfactory pathway in newborn tammars are very immature at birth, postnatal day (P0). In particular, maturation of the vomeronasal organ and its projections to the accessory olfactory bulb appears to be delayed until P5 and the olfactory bulb is poorly differentiated until P12, with glomerular formation delayed until P25. The lateral olfactory tract is also very immature at birth with pioneer axons having penetrated only the most rostral portion of the piriform lobe. Interestingly, there were some early (P0) projections from the olfactory epithelium to the medial septal region and lamina terminalis (by the terminal nerve) and to olfactory tubercle and basal forebrain. The former of these is presumably serving the transfer of LHRH⁺ neurons to the forebrain, as seen in eutherians, but neither of these very early pathways is sufficiently robust or connected to the more caudal neuraxis to play a role in nipple finding. Tritiated thymidine autoradiography confirmed that most piriform cortex pyramidal neurons are generated in the first week of life and are unlikely to be able to contribute to circuitry guiding the climb to the pouch. Our findings lead us to reject the hypothesis that olfactory projections contribute to guidance of the newborn tammar to the pouch and nipple. It appears far more likely that the trigeminal pathways play a significant role in this behavior because the central projections of the trigeminal nerve are more mature at birth in this marsupial.

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Section: Does Olfaction Play a Part In Guidance Of The Newborn Tammarmentioning

confidence: 99%

“…These sections had been previously used for developmental studies of the visual cortex [Marotte and Sheng, 2000] and hypothalamus [Cheng et al, 2002]. Full descriptions of the preparation of this material can be found in those papers.…”

Section: Tritiated Thymidine Autoradiographymentioning

confidence: 99%

Development of the Olfactory System in a Wallaby (Macropus eugenii)

Ashwell¹,

Marotte

Cheng³

2008

Brain Behav Evol

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“…The migrating magnocellular neurons and growing axonal bundles, such as the medial forebrain bundle could have been interfering with each other, as proposed in the following. During the embryogenesis of Amniota , magnocellular neurons possibly migrate along radial glia from the 3rd ventricle into ventro-lateral direction; the association of radial glia and magnocellular neurons was reported in the wallaby, the representative of marsupial mammals (Cheng et al, 2002). Similar migrations are known for the radial development of spinal cord, cerebellum and cortex (Hatten, 1999; Nadarajah and Parnavelas, 2002; McDermott et al, 2005) and are also observable in cell culture studies where neuroblasts migrate back and forth until finding their destination (Hatten, 1990).…”

Section: Introductionmentioning

confidence: 99%

Evolution of oxytocin pathways in the brain of vertebrates

Knobloch

Grinevich

2014

Front. Behav. Neurosci.

210

168

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The central oxytocin system transformed tremendously during the evolution, thereby adapting to the expanding properties of species. In more basal vertebrates (paraphyletic taxon Anamnia, which includes agnathans, fish and amphibians), magnocellular neurosecretory neurons producing homologs of oxytocin reside in the wall of the third ventricle of the hypothalamus composing a single hypothalamic structure, the preoptic nucleus. This nucleus further diverged in advanced vertebrates (monophyletic taxon Amniota, which includes reptiles, birds, and mammals) into the paraventricular and supraoptic nuclei with accessory nuclei (AN) between them. The individual magnocellular neurons underwent a process of transformation from primitive uni- or bipolar neurons into highly differentiated neurons. Due to these microanatomical and cytological changes, the ancient release modes of oxytocin into the cerebrospinal fluid were largely replaced by vascular release. However, the most fascinating feature of the progressive transformations of the oxytocin system has been the expansion of oxytocin axonal projections to forebrain regions. In the present review we provide a background on these evolutionary advancements. Furthermore, we draw attention to the non-synaptic axonal release in small and defined brain regions with the aim to clearly distinguish this way of oxytocin action from the classical synaptic transmission on one side and from dendritic release followed by a global diffusion on the other side. Finally, we will summarize the effects of oxytocin and its homologs on pro-social reproductive behaviors in representatives of the phylogenetic tree and will propose anatomically plausible pathways of oxytocin release contributing to these behaviors in basal vertebrates and amniots.

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“…The existence of CD15-positive radial glial cells within circumscribed regions along the ventricular surface has not only been described for the developing mouse [6,7], but also for other mammals like the wallaby [8]. In human development, CD15-ir glia cells are associated with particular differentiating fields of e.g.…”

Section: Introductionmentioning

confidence: 99%

A CD15-Immunoreactive Subpopulation of Radial Glial Cells in the Developing Human Lateral Ganglionic Eminence

et al. 2003

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There is evidence that precursor cells for the different derivatives of the ganglionic eminences arise from topographically different areas of the proliferative neuroepithelium, indicating a molecular specification for this histologically homogeneous region. We describe a regionally differentiated expression pattern within the lateral ganglionic eminence during human fetal development of a subpopulation of radial glial cells stained for CD15. These cells were first observed around 12–13 weeks of fertilization in the ventricular layer of the lateral ganglionic eminence at the corticostriatal sulcus. In the following weeks increasing numbers of cells and their positively stained processes concentrate along the lateral perimeter of the striatum, with processes continuing towards the pial surface defining the border between the olfactory tubercle medially and the piriform cortex laterally. The number of immunoreactive cells and processes increases until 24 weeks. At that time, these cells are found throughout the lateral ganglionic eminence, defining a border against the unstained medial ganglionic eminence. Concomitant with the rise in the number of fibres until 24 weeks of fertilization, there is also an increase in immunoreactivity in the dorsal striatum. According to the accepted role of radial glial cells as a guidance structure for migrating postmitotic neurones, these CD15-immunoreactive fibres may enable the registration between localized proliferation areas within the lateral ganglionic eminence and related differentiation areas, thereby helping to characterize the fundamental subdivisions of the brain.

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Early development of the hypothalamus of a wallaby (Macropus eugenii)

Cited by 13 publications

References 64 publications

Development of the Olfactory System in a Wallaby <i>(Macropus eugenii)</i>

Development of the Olfactory System in a Wallaby <i>(Macropus eugenii)</i>

Evolution of oxytocin pathways in the brain of vertebrates

A CD15-Immunoreactive Subpopulation of Radial Glial Cells in the Developing Human Lateral Ganglionic Eminence

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