Nitric oxide (NO) is a gaseous, unconventional chemical messenger suggested to play a fundamental role in olfaction. This thesis focuses on the role of NO in a primary olfactory center, the antennal lobe (AL) of the moth, Manduca sexta (M. sexta), to understand how NO affects olfactory-guided behavior. Studies in M. sexta report that NO is produced upon odor stimulation and has profound effects at the physiological level, but little is known about its significance to behavior. The central hypothesis examined in this thesis is that NO functions as a neuromodulator of olfactory-guided behavior in a circadian fashion. This hypothesis is examined in the following three studies: The first study questions whether basal levels of NO fluctuate with the light cycle. M. sexta are nocturnal animals that actively engage in odor-seeking behaviors at night. Using an NO sensor, NO concentrations were measured in the AL, optic lobe, and the remainder of the brain during subjective day and subjective night. NO concentrations are higher in the AL and optic lobes at night, suggesting that NO is likely involved in olfactory-guided behavior. The second inquiry focuses on developing a technique to manipulate NO levels in the AL and whether a specific behavior is affected. Using the proboscis extension reflex, olfactory conditioning is used to ask three questions: (1) does NO affect odor detection, (2) does NO affect discrimination between odorants, and (3) does NO affect learning and memory? Results indicate that NO affects short-term memory but does not affect odor detection, or discrimination between dissimilar odorants. The third inquiry examines the role of NO in memory and circadian time. It asks: (1) is there an optimal time of day for learning and memory, and (2) does the role of NO in memory change depending on the time of olfactory conditioning? Results indicate that NO in memory is modulated by circadian time. Taken together, these results suggest a unique functional role for NO in olfactory-guided behavior with two main conclusions: (1) NO modulates short-term memory in the AL, and (2) NO may be important for the circadian regulation of memory.

Diel substrate preferences were tested in artificial stream experiments for six cyprinids: redfin shiner (Lythrurus umbratilis), silver shiner (Notropis photogenis), spotfin shiner (Cyprinella spiloptera), central stoneroller (Campostoma anomalum), striped shiner (Luxilus chrysocephalus), and bluntnose minnow (Pimephales notatus). We used experimental pools containing two of three substrate types (sand, cobble, and gravel) per trial to test if habitat preferences differed in day and night observations. Over 85% of specimens were observed over cobble substrate during the day, and all species switched substrate preferences at night for the tanks containing cobble. Our results suggest that day-night differences in habitat use may occur in other small-bodied species. Interpretations for habitat use of these species in the majority of studies that are based on daytime observations may need to be modified. Interpretations for habitat use by fish assemblages in the majority of studies that are based on daytime observations may need to be modified. / Department of Biology

Thesis (M App Sci in Physiotherapy) -- University of South Australia, 1992

Thesis (Ph.D.)--Tufts University, 2000. / Adviser: David Harder. Submitted to the Dept. of Psychology. Includes bibliographical references (leaves 90-116). Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Diss. (sammanfattning) Stockholm : Karol. inst., 2001. / Härtill 5 uppsatser.

Thesis (M.S.)--Western Kentucky University, 2008. / Includes bibliographical references (leaves 54-57).

Thesis (Ph. D.)--Case Western Reserve University, 2008. / [School of Medicine] Department of Genetics. Includes bibliographical references.

Thesis (M.Sc. in Microbiol.) -- Mahidol University, 1970.

Thesis (M.S.)--Oregon State University, 2005. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph. D.)--Rutgers University, 2007. / "Graduate Program in Biochemistry." Includes bibliographical references (p. 121-135).