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Olfactory bulb projections in the bichir, Polypterus.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Braford, M. R. Northcutt, R. Glenn |
| Copyright Year | 1974 |
| Abstract | The central projections of the olfactory bulb were studied in Polypterus using the Nauta and Fink-Heimer techniques. Two major target areas were identified in the subpallium: the lateral subpallial nucleus and the dorsal and ventral entopeduncular nuclei. The connections are predominantly, if not exclusively, ipsilateral. In the pallium a massive ipsilateral projection to the superficial third of the medial pallium was demonstrated while the remainder of the pallium was found to be free of degeneration. Thus it appears that the pafiium of Polypterus is not uniform throughout, as has been suggested in the literature. This contention is also supported by an analysis of the pallial cyto-architecture. Because the pallium of Polypterus is everted, rather than inverted and evaginated, the topographically medial pallium is in topological correspondence with the lateral pallium of tetrapods. On the basis of this topological correspondence and the similarity of afference from the olfactory bulb, it is argued that the " medial " pallium of Polypterus is homologous to the pyriform pallium of tetrapods. The findings of this study are compared to those of similar studies in teleosts, which also have an everted pallium. An apparent conflict appears and suggestions for resolving it are offered. Polypterus and its close relative, Cala-m o i c h t h y s , inhabit the fresh waters of tropical Africa. Their taxonomic position has been much debated in the literature, and they have been variously assigned to the chondrostean actinopterygians, the crossopterygians, and a higher category of their own, the brachiopterygians. They are generally considered today to be the end representatives of an unknown actino-pterygian lineage (Schaeffer, '69) and are placed by most workers in the Chon-drostei along with the sturgeons and pad-dlefishes (Romer, '66; Moy-Thomas, '71). In Polypterus, as well as the other acti-nopterygian fishes, the adult organization of portions of the telencephalon is achieved by a n embryological strategy which is fundamentally different from that found in other vertebrates (fig. 1). In most vertebrates the lateral walls of the embryonic telencephalon undergo an inversion, which is followed by an evagination (Holmgren, ' 2 2) , but in the actinopterygians the telen-cephalon is everted lateral walls begin to protrude into the ventricles and the lines of attachment of the telencephalic roof plate move laterally and then ventrally (Holmgren, '22; Nieu-wenhuys et al., '69). A major consequence of this eversion process is the mediolateral reversal of the dorsal portion of … |
| Starting Page | 64 |
| Ending Page | 71 |
| Page Count | 8 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://deepblue.lib.umich.edu/bitstream/handle/2027.42/49993/901560204_ftp.pdf;jsessionid=BE81087443480D25A87D4F16B1F74287?sequence=1 |
| Alternate Webpage(s) | https://deepblue.lib.umich.edu/bitstream/handle/2027.42/49993/901560204_ftp.pdf?isAllowed=y&sequence=1 |
| PubMed reference number | 4418625v1 |
| Volume Number | 156 |
| Issue Number | 2 |
| Journal | The Journal of comparative neurology |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Cell Nucleus Cerebral Ventricles Cerebral cortex Fresh Water Olfactory Cortex PersonNameUse - assigned Projection Defense Mechanism Sixty Nine Smell Perception Structure of olfactory bulb Telencephalon Vertebrates Walls of a building pallium glioblast division |
| Content Type | Text |
| Resource Type | Article |
