Date of Defense

Spring 4-23-2003

Department

Biological Sciences

First Advisor

Christine Byrd, Biological Sciences

Second Advisor

Cindy Linn, Biological Sciences

Third Advisor

John Spitsbergen, Biological Sciences

Abstract

The mitral cell is the principal relay neuron and the main component in the organization of the olfactory bulb in vertebrates. The morphology of these cells has been studied extensively in mammalian systems and to a lesser degree in teleosts using Golgi impregnation techniques. This study uses a modified Golgi-Kopsch technique and retrograde tract tracing with fluorescent markers in both live and fixed tissue to characterize mitral cells in the adult zebrafish, Danio rerio. In addition, anterograde labeling of the olfactory axons was used simultaneously with retrograde tract tracing in live tissue to characterize the glomerular structures of the zebrafish olfactory bulb and to study the interactions between mitral cell dendritic tufts and arborized olfactory nerve axons in the golmerular area. The mitral cells were found to have large, approximately round somas that had one or more primary dendrites. The primary dendrites, which were thick and rough, branched extensively to form dense dendritic tufts. The majority of the mitral cells that were observed in this study had tight dendritic arborizations close to the somas. Anterograde labeling with DiA demonstrated that the primary olfactory nerve branches into medial and laterial bundles at the olfactory bulbs. The axons from these bundles form distinct gomeruli and diffuse glomerular areas in the glomerular laminae of the olfactory bulb. Multiple mitral cells appear to contact individual glomeruli, but it is unclear based on this study whether multiple glomeruli can be contacted by a single mitral cell. Thus, the synaptic connections between the axons of primary olfactory nerves and mitral cells will be the focus of future studies.

Access Setting

Honors Thesis-Campus Only

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