XB-IMG-137941
Xenbase Image ID: 137941
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Fig. 10. Camera lucida drawing of the central patterning of
cranial nerve nuclei in control and RA-treated Xenopus
brains. (A) Horizontal section showing the normal
positions of cranial nerve motor neurons. The neurons of
nuclei III, IV, V, VI and VII were filled from a preotic
HRP application, and the neurons of the IXth/Xth
complex from a postotic application. Data from two
specimens have been superimposed. (B) Horizontal section
through a RA-treated brain. HRP was applied to the
preotic ganglion. Neurons occupying the positions of Vth
and Vllth nuclei are seen to have a common exit point for
their axons. Neurons of the Vlth nucleus occupy their
normal position just caudal and medial to the Vllth motor
neurons. One neuron in the contralateral IVth nucleus,
and three cells in the IXth/Xth complex were also labelled.
(C) Horizontal section through a RA-treated brain. HRP
was applied to the postotic ganglia on one side and to the
preotic ganglia on the other. The preotic fill has labelled
only a few neurons in the Illrd, Vlth and IXth/Xth nuclei.
Many more cells were labelled by the postotic application
and most of these occupy the normal position of IXth/Xth
neurons. A few neurons in the Vlth and one in the Vllth
nucleus are also labelled. (D) Ventral view of a wholemounted,
RA-treated Xenopus brain. HRP was applied to
the preotic ganglia on one side only. This specimen had
only one median eye and was clearly compressed in the
rostrocaudal axis. Nonetheless the positions of neurons in
the nuclei of III, V, VI, VTI, IX and X are relatively
normal. The neurons within the IXth/Xth nuclei and the
few within the contralateral Vlth and Vllth nuclei were
labelled due to disrupted peripheral pathways of their
neurons. Midline is dashed throughout, m/h is the
midbrain-hindbrain border. Scale bar is 100 um. Image published in: Papalopulu N et al. (1991) Copyright © 1991. Image reproduced with permission of the publisher and the copyright holder. This is an Open Access article distributed under the terms of the Creative Commons Attribution License. Larger Image Printer Friendly View |