The neural basis of acoustic communication in Drosophila

• Applicant: Professor Dr. Jan Clemens
• Subject Area: Cognitive, Systems and Behavioural Neurobiology
• Term: from 2017 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 329518246

Throughout the animal kingdom acoustic communication underlies many social interactions like aggression, courtship, and parental care. However, the neural basis of these behaviors is poorly understood, since they involve fast and complex sensorimotor transformations. Understanding the neural basis of acoustic communication requires 1) identifying the behaviorally relevant signal features and 2) examining their representation and transformation into behavior by the brain. Here, we will use Drosophila melanogaster as a model system since it offers genetic tools for monitoring and manipulating neural activity.Drosophila employs acoustic signals during courtship: The male produces a song whose structure informs the female's mating decisions. While song promotes copulation in females, males also respond to song: it arouses them and induces them to court other males. The song is a complex signal with structure on multiple time scales - how this multiscale structure is processed by the auditory system to guide behavior is unknown. Specifically, we don't know 1) the precise role of auditory neurons in song processing and behavior, 2) the complete set of neurons driving behavioral responses, and 3) the system's motor outputs. Progress on these issues is hampered by a lack of knowledge about behavioral tuning for song features. I have therefore developed a novel behavioral assay in which the male song is substituted by a loudspeaker, thereby providing perfect control over the acoustic signal. This playback assay relies on changes in fly walking speed as a temporally-resolved behavioral readout of female and male responses to song. Using the assay, we will characterize the sex-specific behavioral tuning for song features and examine the behavioral role of individual neurons. Based on the behavioral results we will analyze how the behavioral tuning arises at the neural level. We will first probe the tuning of auditory neurons using Calcium (Ca) imaging to learn how the representation of song is transformed along the auditory pathway. The behavioral role of auditory neurons will be examined by genetically suppressing their activity during behavior. We will then identify novel elements of the auditory pathway and its motor outputs. Whole-brain Ca imaging will provide a complete map of auditory neurons in the brain. Combining optogenetic activation of auditory neurons with Ca imaging of the evoked network activity will reveal the system's functional connectivity. Finally, a behavioral screen will uncover the motor outputs connecting the brain to the motor pattern generators in the nerve chord.Overall, genetic tools, optogenetics, functional imaging and behavioral experiments will provide insight into the neural basis of acoustic communication at an unprecedented level of detail - from the sensory periphery all the way to behavior. This project will uncover general principles underlying pattern recognition, decision making and motor pattern generation.

• DFG Programme: Independent Junior Research Groups
• Major Instrumentation: TiSA laser for two photon microscope ; two photon microscope without laser
• Instrumentation Group: 5060 Mikroskopbeleuchtung ; 5090 Spezialmikroskope