Semester

Summer

Date of Graduation

2014

Document Type

Thesis

Degree Type

MS

College

Eberly College of Arts and Sciences

Department

Biology

Committee Chair

Kevin C. Daly

Committee Co-Chair

Andrew M. Dacks

Committee Member

Jorge Flores

Abstract

Behavioral states of animals change throughout the day and the brain has developed several mechanisms in order for neural circuits to modify network function in order to produce these states. Neuromodulation allows the animal to alter neural circuits to make them more or less responsive to a given input. Little research has been conducted to understand the functional role of serotonin (5-HT), a neuromodulator,on olfactory behavioral responses. In this study, we aimed to identify the functional role of 5-HT in Manduca sexta olfactory function. Using a Pavlovian-Conditioning Paradigm, we conditioned moths to 2-hexanone and tested them using two different assays, a detection threshold assay and a generalization gradient assay. We found that 5-HT significantly increased olfactory sensitivity and significantly sharpened generalization gradients. Blocking 5-HT had no effect on detection thresholds but did lower behavioral responsiveness to odors in the generalization gradient assay.These results support similar studies focused on pheromone processing and perception and indicate that 5HT tunes the sensitivity of the olfactory system.

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