Curriculum vitae

Current research

Brains produce complex behavior enabeling organisms to respond in a beneficial and adaptive way to changing environmental conditions. I want to understand how a stimulus can induce behavior. What are the computations when information in form of electric currents flows through networks of neurons? How does neural activity eventually lead to observable behavior?

For my thesis, I have developed a novel genetic tool to induce neural activity in identified olfactory sensory neurons (OSNs) in the freely behaving fruit fly Drosophila melanogaster. Using this tool I can activate selected OSN classes that are usually activated as part of an ensemble together with other OSN classes. I began to assess the effect of selective OSN activation for behavior in a choice paradigm.

Johannes Larsch^1,2, Mathias Ditzen¹ & Leslie B. Vosshall^1
1Laboratory of Neurogenetics and Behaviour, The Rockefeller University , 1230 York Avenue, Box 63, New York, New York 10065, USA.
²Biology Department, University of Konstanz, 78457 Konstanz, Germany

6. -10. Sept. 2008. Abstract for Neurofly, Würzburg, Germany.
In recen t years, the fruit fly Drosophila melanogaster has emerged as one of the major model systems for studying olfaction. In Drosophila, olfactory sensory neurons (OSNs) express one type of olfactory receptor (OR) which defines their sensitivity to odors. Most odors activate several OSNs, thereby eliciting complex patterns of neural activity. To Drosophila, these odors can have innate hedonic values, leading to behaviorally measurable responses such as attraction or avoidance. While a large body of knowledge exists about the response profiles of different ORs, very little is known about the hedonic properties conveyed by the OSNs themselves. To study the characteristics that render a particular pattern of OSN activity as either attractive or repulsive, we have developed a new genetic tool, which allows us to induce neural activity in select OSNs of behaving adult flies. Using a modified T-Maze assay, we test whether such single input channels indeed induce stereotyped attraction and avoidance behavior. Applying this approach to OSNs located on the maxillary palps, we establish a hedonic map for this olfactory organ. In future experiments, we will extend this map to select antennal OSNs and examine the hierarchy according to which co-active OSNs contribute to behavioral avoidance and attraction.