In this study, the elasmobranch olfactory system was examined in the periphery, primary centers, and secondary centers. The object of the study was to look for signs of topographical arrangements or spatial segregation in the olfactory system. / Carbocyanine dye (DiI) tracing and Cytochrome oxidase staining reveal that the olfactory epithelium presents signs of functional and morphological heterogeneity. However, no orderly spatial arrangement of olfactory receptor neurons was visible using these techniques. / In vitro anterograde tracing of the primary olfactory projections with biocytin or DiI shows that the olfactory bulb is morphologically and functionally compartmentalized into subunits that receive straight and topographically arranged projections from the epithelium. Mitral cells, as revealed by the rapid Golgi method or retrogradely stained with DiI, belong to two morphologically distinct populations, but are homogeneously distributed across the olfactory bulb subunits. Immunohistochemical examination of the olfactory subunits reveals terminal nerve influence via LHRH fibers, homogeneously distributed in the granule layer of all olfactory subunits. No detectable influence of the trigeminal system is visible in a substance P immunohistochemical search. Finally, transmission electron microscopy reveals that the ultrastructure of the olfactory bulb circuitry is different from that of amniotes. The main difference is that mitral cells lack basal dendrites and therefore have to communicate with each other more directly via reciprocal synapes with granule cells. / Retrograde tracing of the secondary olfactory projections with DiI also shows that the secondary input onto the telencephalon is far more restricted than in the mammalian olfactory system, and that it is segregated into two main components. However, the method used does not allow for more precision in terms of topographical arrangement. / The present study concludes that, although there are signs of ordered projections in the olfactory system of elasmobranch fishes, the use of neural space for analyzing olfactory input is not likely to be significant in the encoding of the olfactory information. / Source: Dissertation Abstracts International, Volume: 54-12, Section: B, page: 6073. / Major Professor: P. P. C. Graziadei. / Thesis (Ph.D.)--The Florida State University, 1993.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_77070 |
| Contributors | Dryer, Laurence., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 176 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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