Larval and adult brains 1

@article{Nielsen2005LarvalAA,
  title={Larval and adult brains 1},
  author={Claus Nielsen},
  journal={Evolution \& Development},
  year={2005},
  volume={7}
}
  • C. Nielsen
  • Published 1 September 2005
  • Biology
  • Evolution & Development
Summary Apical organs are a well‐known structure in almost all ciliated eumetazoan larvae, although their function is poorly known. A review of the literature indicates that this small ganglion is the “brain” of the early larva, and it seems probable that it represents the brain of the ancestral, holopelagic ancestor of all eumetazoans, the gastraea. This early brain is lost before or at metamorphosis in all groups. Protostomes (excluding phoronids and brachiopods) appear to have brains of dual… 

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References

SHOWING 1-10 OF 64 REFERENCES

Development of the larval nervous system of the gastropod Ilyanassa obsoleta

This investigation reveals the most extensive larval nervous system described in any mollusc to date and information from this study will be useful for future experimental studies determining the role of larval neurons and investigations of the cellular and molecular mechanisms governing neural development in this taxon.

The radial-symmetric hydra and the evolution of the bilateral body plan: an old body became a young brain.

  • H. Meinhardt
  • Biology
    BioEssays : news and reviews in molecular, cellular and developmental biology
  • 2002
The radial symmetric cnidarians are regarded as being close to the common metazoan ancestor before bilaterality evolved. It is proposed that a large fraction of the body of this gastrula-like

Development and Neural Organization of the Tornaria Larva of the Hawaiian Hemichordate, Ptychodera flava

Scanning and transmission electron microscopic studies of the early development of the Hawaiian acorn worm, Ptychodera flava, provide an immunohistochemical identification of the larval nervous system and finds the tornaria nervous system with ciliary bands and an apical organ is rather similar to the echinoderm bipinnaria larvae.

Trochophora larvae: cell-lineages, ciliary bands, and body regions. 1. Annelida and Mollusca.

  • C. Nielsen
  • Biology
    Journal of experimental zoology. Part B, Molecular and developmental evolution
  • 2004
The trochophora concept and the literature on cleavage patterns and differentiation of ectodermal structures in annelids ("polychaetes") and molluscs are reviewed, showing conspicuous similarities between the early development of the two phyla, related to the highly conserved spiral cleavage pattern.

Structure and metamorphic remodeling of the larval nervous system and musculature of Phoronis pallida (Phoronida)

Data show that several cytological aspects of the larval and juvenile neuromuscular systems also have protostome (lophotrochozoan) characteristics.

Trochophora larvae: cell-lineages, ciliary bands and body regions. 2. Other groups and general discussion.

  • C. Nielsen
  • Biology
    Journal of experimental zoology. Part B, Molecular and developmental evolution
  • 2005
The embryology of sipunculans, entoprocts, nemertines, platyhelminths, rotifers, ectoproCTs, phoronids, brachiopods, echinoderms and enteropneusts is reviewed with special emphasis on cell-lineage and differentiation of ectodermal structures.

The nervous systems of cnidarians.

Using immuno-electronmicroscopy, it is found that the peptides are located in neuronal dense-cored vesicles associated with both synaptic and non-synaptic release sites, which indicate that evolutionarily "old" nervous systems use peptides as transmitters.

The embryonic cell lineage of the nematode Caenorhabditis elegans.

An urbilaterian origin of the tripartite brain: developmental genetic insights from Drosophila

It is shown that the embryonic brain of the fruitfly Drosophila melanogaster expresses all three sets of homologous genes in a similar tripartite pattern, which suggests that a tri partite organization of the embryonicbrain was already established in the last common urbilaterian ancestor of protostomes and deuterostomes.

The pharynx of Caenorhabditis elegans.

  • D. AlbertsonJ. N. Thomson
  • Biology
    Philosophical transactions of the Royal Society of London. Series B, Biological sciences
  • 1976
The anatomy of the pharynx of Caenorhabditis elegans has been reconstructed from electron micrographs of serial sections, and some interpretations of how these neurones function have been offered.
...