Microsoft Word - 56241123-file00.docx

Nitric oxide (NO) is thought to play an important neuromodulatory role in olfaction. We are using 5 the hawkmoth Manduca sexta to investigate the function of NO signaling in the antennal lobe (AL; 6 primary olfactory network in invertebrates). We have found previously that NO is present at baseline 7 levels, dramatically increases in response to odor stimulation, and alters the electrophysiology of AL 8 neurons. It is unclear, however, how these effects contribute to common features of olfactory systems 9 such as olfactory learning and memory, odor detection, and odor discrimination. In this study, we have 10 used chemical detection and a behavioral approach to further examine the function of NO in the AL. We 11 have found that basal levels of NO fluctuate with the daily light cycle being higher during the nocturnal 12 active period. NO also appears necessary for short-term olfactory memory. NO does not appear to affect 13 odor detection, odor discrimination between dissimilar odorants, or learning acquisition. These findings 14 may suggest a modulatory role for NO in the timing of olfactory-guided behaviors. 15