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Emotion, Impatience, and Addictive Behavior
Charlie Dorison
Graduate Student, Public Policy

Smoking remains the leading cause of preventable death in the United States, despite government spending in excess of $500 million annually on prevention efforts. Our research extends theory on emotion and decision making and sheds light on a weakness in many publicly funded smoking-cessation communications. First, in a nationally representative sample, Study 1 documents a unique positive association between smoking and sadness, above and beyond other negative emotions. Second, Study 2 documents a causal effect of sadness on impatience for smoking using a novel behavioral economic paradigm. Finally, Study 3 documents that anti-smoking public service announcements elicit sadness as a primary strategy to reduce smoking behavior, a practice that may be ineffective or even backfire.

Secrets of the Zombie Fly: Determining the Neurological Basis of Behavioral Manipulation in Drosophila
Carolyn Elya
Postdoctoral Fellow, Organismic and Evolutionary Biology

Many microbes induce striking behavioral changes in their animal hosts, but how they achieve this is poorly understood at the molecular or neural circuit level. This is due in part to the difficulty of studying non-model organisms with limited tools. As a graduate student, I discovered a strain of the fungal behavior-manipulating fly pathogen Entomophthora muscae infecting wild drosophilids and developed methods to reliably propagate the infection in lab-reared Drosophila melanogaster. Before sunset on their final day of life, my infected flies manifest the trio of moribund behaviors characteristic of E. muscae infections: they climb to a high location, extend their proboscises, and raise their wings in a pose that promotes spore dispersal. In characterizing the course of infection, I discovered that E. muscae invades the host nervous system, which could provide a direct route for altering host behavior. As a postdoctoral researcher, I am leveraging high-throughput behavior assays along with the power of fruit fly neurogenetic tools to understand how the fungus induces this dramatic behavioral manipulation. I have begun by focusing on summiting behavior, hypothesizing that the fly’s endogenous gravitactic circuitry is manipulated by the fungus to induce upward climbing immediately before death. In developing a high-throughput assay to measure summiting behavior, I have discovered stereotypic patterns of speed and attraction to food in moribund flies that are absent in controls. I have used these features to design a real time classifier that will track and flag individuals as they progress through the behavioral stages of infection. With this precise staging, I will be able to analyze the biochemical content of manipulated individuals, and identify compounds mediating that manipulation. Combining these results with those of a neuronal inactivation screen (to identify fly neurons required for the execution of manipulated behaviors), I aim to begin defining the pathways by which E. muscae induces summiting behavior in its fly host.