Morphology and projection pattern of medial and dorsal pallial neurons in the frog Discoglossus pictus and the salamander Plethodon jordani
Article first published online: 25 FEB 2002
Copyright © 2002 Wiley-Liss, Inc.
Journal of Comparative Neurology
Volume 445, Issue 2, pages 97–121, 1 April 2002
How to Cite
Westhoff, G. and Roth, G. (2002), Morphology and projection pattern of medial and dorsal pallial neurons in the frog Discoglossus pictus and the salamander Plethodon jordani. J. Comp. Neurol., 445: 97–121. doi: 10.1002/cne.10136
- Issue published online: 25 FEB 2002
- Article first published online: 25 FEB 2002
- Manuscript Accepted: 20 NOV 2001
- Manuscript Revised: 12 JUL 2001
- Manuscript Received: 9 JAN 2001
- Deutsche Forschungsgemeinschaft. Grant Number: SFB 517
- intracellular biocytin labeling;
- axonal projections;
In the frog Discoglossus pictus and the salamander Plethodon jordani, the morphology and axonal projection pattern of neurons in the medial and dorsal pallium were determined by intracellular biocytin labeling. A total of 77 pallial neurons were labeled in the frog and 58 pallial neurons in the salamander. Within the medial pallium (MP) of the frog, four types of neurons were identified on the basis of differences in their axonal projection pattern. Type I neurons have bilateral projections into telencephalic and diencephalic areas; type II neurons have bilateral projections to telencephalic areas and ipsilaterally descending projections to diencephalic regions; type III neurons have only intratelencephalic connections, and a single type IV neuron has ipsilaterally descending projections. The somata of the four types occupy four nonoverlapping zones. Neurons of the dorsal pallium (DP) project exclusively to the ipsilateral MP and to the dorsal edge of the lateral pallium. In the ventral MP of the salamander, neurons have mostly intratelencephalic projections. Neurons in the dorsal MP project bilaterally to diencephalic and telencephalic regions. Neurons in the medial DP project ipsilaterally to the MP, lateral septum, nucleus accumbens, medial amygdala, and the internal granule layer of the olfactory bulb. In five cases, fibers were found in the commissura hippocampi, but in only two cases could these fibers be followed toward the contralateral MP and septum. Neurons in the lateral DP had no contralateral projections; they projected to the ipsilateral MP and in eight cases to the ipsilateral septum as well. Based on similarities of cytoarchitecture and projection pattern in neurons of the MP and DP, it is proposed that both frogs and salamanders have an MP subdivided into a ventral and dorsal portion, and a DP subdivided into a medial and a lateral portion. J. Comp. Neurol. 445:97–121, 2002. © 2002 Wiley-Liss, Inc.