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The optic neuropiles and chiasmata of Crustacea.

Elofsson, Rolf LU and Dahl, Erik (1970) In Zeitschrift für Zellforschung und mikroskopische Anatomie1948-01-01+01:001974-01-01+01:00 107. p.343-360
Abstract
On the basis of ontogeny and adult morphology, an interpretation of the arrangement of optic neuropiles and fibre connexions of the Crustacean compound eye is presented. In the embryo of phyllopods and decapods, the ommatidia, the lamina ganglionaris, and the medulla externa are developed synchronously from a common medial proliferation zone. As this zone persists in all investigated adult Crustacea that possess compound eyes, such a derivation of the mentioned structures is taken to be universal within the group. The direction of growth of the lamina ganglionaris is parallel with the row of ommatidia, the growth direction of the medulla externa is perpendicular to it and parallel with the long axis of the eyestalk. This arrangement is... (More)
On the basis of ontogeny and adult morphology, an interpretation of the arrangement of optic neuropiles and fibre connexions of the Crustacean compound eye is presented. In the embryo of phyllopods and decapods, the ommatidia, the lamina ganglionaris, and the medulla externa are developed synchronously from a common medial proliferation zone. As this zone persists in all investigated adult Crustacea that possess compound eyes, such a derivation of the mentioned structures is taken to be universal within the group. The direction of growth of the lamina ganglionaris is parallel with the row of ommatidia, the growth direction of the medulla externa is perpendicular to it and parallel with the long axis of the eyestalk. This arrangement is more or less retained in most adult non-Malacostracan Crustacea, and the axons of fully developed neurons pierce the optic neuropiles and leave and enter on the neuropile side. As a result, there is no chiasma in the non-Malacostracan groups.
The Malacostraca have an extra neuropile, the medulla interna, derived from the medulla terminalis. Chiasmata occur between the lamina ganglionaris and the medulla externa, and between the medulla externa and the medulla interna. This difference from the non-Malacostracans depends on the course of the fibres. Those coming from the lamina ganglionaris leave the lamina on the neuropile side and enter medulla externa between the cell bodies in the perikaryon layer of the medulla externa neurons and the neuropile of the medulla. The fibres from the medulla externa to the lamina come from T-shaped neurons and emanate from the perikaryon layer side, entering the lamina on its neuropile side. The fibre relations between the medulla externa and the medulla interna are similar. Thus in both cases, chiasmata are present from the beginning, but they become obvious when the medulla externa rotates through part of a circle.
The directed growth of the optic neuropiles and the course of the fibre connexions are consequently crucial to the understanding of the topographic relations between the neuropiles. A pattern with short neurons connecting neighbouring optic neuropiles and long neurons connecting the medulla externa with the central nervous system is common to all crustaceans. (Less)
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Contribution to journal
publication status
published
subject
keywords
Compound Eyes, Crustacea, Optic Neuropiles, Chiasmata
in
Zeitschrift für Zellforschung und mikroskopische Anatomie1948-01-01+01:001974-01-01+01:00
volume
107
pages
343 - 360
publisher
Springer Verlag
external identifiers
  • scopus:0014725931
DOI
10.1007/BF00336672
language
English
LU publication?
yes
id
5a64f464-de06-4ee1-a57e-b5889c05cc31
date added to LUP
2016-12-03 16:11:41
date last changed
2017-09-03 05:15:50
@article{5a64f464-de06-4ee1-a57e-b5889c05cc31,
  abstract     = {On the basis of ontogeny and adult morphology, an interpretation of the arrangement of optic neuropiles and fibre connexions of the Crustacean compound eye is presented. In the embryo of phyllopods and decapods, the ommatidia, the lamina ganglionaris, and the medulla externa are developed synchronously from a common medial proliferation zone. As this zone persists in all investigated adult Crustacea that possess compound eyes, such a derivation of the mentioned structures is taken to be universal within the group. The direction of growth of the lamina ganglionaris is parallel with the row of ommatidia, the growth direction of the medulla externa is perpendicular to it and parallel with the long axis of the eyestalk. This arrangement is more or less retained in most adult non-Malacostracan Crustacea, and the axons of fully developed neurons pierce the optic neuropiles and leave and enter on the neuropile side. As a result, there is no chiasma in the non-Malacostracan groups.<br/>The Malacostraca have an extra neuropile, the medulla interna, derived from the medulla terminalis. Chiasmata occur between the lamina ganglionaris and the medulla externa, and between the medulla externa and the medulla interna. This difference from the non-Malacostracans depends on the course of the fibres. Those coming from the lamina ganglionaris leave the lamina on the neuropile side and enter medulla externa between the cell bodies in the perikaryon layer of the medulla externa neurons and the neuropile of the medulla. The fibres from the medulla externa to the lamina come from T-shaped neurons and emanate from the perikaryon layer side, entering the lamina on its neuropile side. The fibre relations between the medulla externa and the medulla interna are similar. Thus in both cases, chiasmata are present from the beginning, but they become obvious when the medulla externa rotates through part of a circle.<br/>The directed growth of the optic neuropiles and the course of the fibre connexions are consequently crucial to the understanding of the topographic relations between the neuropiles. A pattern with short neurons connecting neighbouring optic neuropiles and long neurons connecting the medulla externa with the central nervous system is common to all crustaceans.},
  author       = {Elofsson, Rolf and Dahl, Erik},
  keyword      = {Compound Eyes,Crustacea,Optic Neuropiles,Chiasmata},
  language     = {eng},
  pages        = {343--360},
  publisher    = {Springer Verlag},
  series       = {Zeitschrift für Zellforschung und mikroskopische Anatomie1948-01-01+01:001974-01-01+01:00},
  title        = {The optic neuropiles and chiasmata of Crustacea.},
  url          = {http://dx.doi.org/10.1007/BF00336672},
  volume       = {107},
  year         = {1970},
}