Buch, Englisch, Band 55/3, 84 Seiten, Format (B × H): 155 mm x 235 mm, Gewicht: 149 g
Buch, Englisch, Band 55/3, 84 Seiten, Format (B × H): 155 mm x 235 mm, Gewicht: 149 g
Reihe: Advances in Anatomy, Embryology and Cell Biology
ISBN: 978-3-540-09013-7
Verlag: Springer Berlin Heidelberg
In many parts of vertebrate and invertebrate central nervous systems, groups of nerve or receptor cells can be found that are arranged and connected according to a precise, functionally defined pattern (Braitenberg, 1973; Santini, 1975; Strausfeld, 1976; Chan-Palay, 1977). In these cases, groups of cell bodies or synapses appear as basically similar configurations, which, however, are different in detail from each other. Such abstract patterns of connectivity are of a statistical nature and do not allow, in a given example, for the prediction of the localization or connections of a particular cell. "Wiring diagrams", therefore, can be obtained only from a multitude of individual observations. In contrast, in several sensory organs, concrete patterns occur that con sist of a regular, mosaic-like, and geometric arrangement of similar cell types. The constancy of such a mosaic allows predictions about certain units of the pattern on the basis of only a few exemplary observations. Typical examples are found in the visual system: In the compound eye of insects, each ommatidium contains a definite number of visual cells that are grouped around the optical axis in a hexogonal array (Kirsch feld, 1967); in the vertebrate retina, mosaics of geometrically arranged cones are found most frequently in lower vertebrates; they are common among teleosts. A number of studies have dealt with their phylogenetic significance and their functional role as adaptation to specific environments or modes of feeding.
Zielgruppe
Research
Autoren/Hrsg.
Weitere Infos & Material
1. Introduction.- 2. Materials and Methods.- 2.1. Materials.- 2.2. Methods.- 3. Results and Discussion.- 3.1. Cells Participating in the Formation of the External Plexiform Layer.- 3.2. Cell Mosaics.- 3.3. Patterns of Connectivity in the External Plexiform Layer.- 4. Conclusions.- 5. Summary.- 6. References.
