Neural mechanisms for course control in flying Drosophila.

• Applicant: Dr. Bettina Schnell
• Subject Area: Cognitive, Systems and Behavioural Neurobiology
• Term: from 2017 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 346980159

I am interested in how neural circuits transform sensory information into a motor code that controls behavioral output. Whereas sensory systems have traditionally been studied in restrained preparations by presenting well-defined stimuli, recent research suggests that the behavioral context strongly influences neuronal activity in subsequent processing stages. To study the neuronal processing steps that underlie behavioral control, I will therefore record neuronal activity while an animal is able to perform behavioral actions.To navigate through the world safely, flies must be able to execute precisely controlled steering maneuvers. Among their most widely studied behaviors during flight are compensatory horizontal turning responses, which can be elicited by visual stimuli and measured in tethered flies. In the optic lobe large-field visual interneurons are known that respond to these visual motion stimuli. However, very little is known about how information relevant for course control is integrated in the brain and relayed to the flight motor system. The goal of the proposed project is to close this gap by studying descending neurons involved in steering maneuvers in Drosophila.This project will make use of recent technological advances that allow recording neuronal responses during tethered flight while simultaneously measuring behavioral reactions and presenting sensory stimuli. I will identify descending neurons, whose activity is correlated with steering maneuvers during flight, and characterize their responses to sensory stimulation using whole-cell patch-clamp recording. In preliminary work I already identified a neuron whose membrane potential is correlated with turning around the vertical body axis, showing the feasibility of the approach. The genetic tool kit available in Drosophila makes it possible to reliably target specific cell types and manipulate their function. I will use these tools to analyze the necessity and sufficiency of the descending neurons for visually elicited or spontaneous steering maneuvers. In addition, I will study the molecular mechanisms of computations like temporal integration of visual motion that based on previous work likely involves calcium accumulation in the terminals of visual interneurons.Altogether this project will provide insights into how steering responses in flying flies are controlled on a neuronal level. The signals of descending neurons conveyed to the motor system are the result of the integration of information from different sensory systems and the internal state of the fly. Thus, studying descending neurons will generate hypotheses about the computations performed by the presynaptic circuitry in the brain, which can be tested in further studies and will provide a starting point for a wide field of future research. It can also uncover general mechanisms underlying information processing by the brain.

• DFG Programme: Independent Junior Research Groups