Description
- Abstract:
- To truly understand the function of a system, one must understand the system’s structure and how individual parts interact with one another. The structure of the nervous system arises from the connections between the component neurons. The connections, in turn, arise from the axons of one population of neurons being guided to the dendrites of another population of neurons in a process called axonal guidance. This thesis studies the axonal guidance of olfactory sensory neurons in order to understand the principles that dictate structure and function. Olfactory sensory neurons each express a single odorant receptor gene. These neurons project axons to innervate neuropil structures in the olfactory bulb called glomeruli. All of the neurons expressing a given odorant receptor converge on the same set of glomeruli, the locations of which are spatially conserved between the members of a species. The odorant receptor protein has an established role in the axonal guidance of olfactory sensory neurons but previous studies concerning the mechanisms involved have primarily focused on early development. Since these neurons regenerate throughout adulthood, we studied the axonal guidance of olfactory sensory neurons born after early development. We induced the expression of a transgenic copy of a normally-occurring odorant receptor called MOR28. This caused neighboring neurons expressing only endogenous MOR28 to form supernumerary glomeruli. We then determined that the transgene must be expressed within a critical period, or developmental time window, in order to cause the formation of supernumerary glomeruli. This provides the first evidence for a critical period in the olfactory system. We also determined that after supernumerary glomeruli are formed, they will persist without continuous transgene expression. This provides novel evidence that a transient perturbation in gene expression can cause permanent changes in neuronal circuitry. We conclude that, even though olfactory sensory neurons constantly regenerate, the development of the early neuronal circuits dictates the conformation of later neuronal circuits. This implies that consistency within the structure of the olfactory system is critical for olfactory function.
- Notes:
- Thesis (Ph.D. -- Brown University (2013)
Access Conditions
- Rights
- In Copyright
- Restrictions on Use
- Collection is open for research.
Citation
Tsai, Lulu I.,
"The role of chemoreceptors in the axonal guidance of olfactory sensory neurons"
(2013).
Molecular Biology, Cell Biology, and Biochemistry Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.7301/Z0MP51MX
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Molecular Biology, Cell Biology, and Biochemistry Theses and Dissertations
Theses and Dissertations for the Molecular Biology, Cell Biology, and Biochemistry department....