If, at a basketball game, a basketball is deflected into an unsuspecting group of spectators, some will duck, others will freeze, while others may make defensive arm gestures to protect their head. This project seeks to determine the neural mechanisms that enable a single stimulus (like an approaching basketball) to generate a rich repertoire of behavioral responses. To tackle this question, this project investigates visually-evoked avoidance behaviors in the fruit fly, Drosophila melanogaster. Drosophila, like humans, are capable of generating diverse behaviors to an object approaching on a direct collision course. Drosophila also provide cutting edge genetic tools for precisely manipulating and recording activity from specific neurons during these behaviors. This project applies these tools to uncover the neural pathways involved in these behaviors and determine how their activity generates behavioral diversity. Upon completion of this project, these findings will apply broadly to understanding how behavioral diversity arises and how appropriate behavioral responses are selected. This research may guide future efforts to restore behavioral responses in neurodevelopmental disorders and neurodegenerative diseases. This work may also support the development of assistive therapies to aid patients who have difficulties in selecting or executing actions. Finally, through educational outreach, experimental tools and outcomes will be disseminated through hands-on activities and active learning paradigms that target communities underrepresented in STEM careers and higher education.

When faced with a looming stimulus, like a predator approaching on a direct collision course, Drosophila select amongst a range of behavioral possibilities, including running, freezing, and flight initiation. Drosophila also exhibit flexible control over the duration and timing of these behaviors to optimize their chance of survival. Here, newly discovered, genetically and electrophysiologically accessible sensorimotor pathways in Drosophila melanogaster are probed to uncover how behavioral responses are selected and coordinated. Nine of these pathways project within regions of the brain that process the visual features of an approaching object and terminate on motor centers in the ventral nerve cord (fly spinal cord) that control the leg and wing movements of avoidance maneuvers. Preliminary data support the hypothesis that the selection and coordination of avoidance maneuvers results from differential activation timing across these pathways. To evaluate this hypothesis, the research objectives will (1) link pathway activity to behavioral responses and (2) determine the mechanisms underlying differential activation timing. Objectives will be delivered by employing a newly developed behavioral assay, computer vision algorithms for detailed kinematic tracking and behavioral analysis, whole-cell electrophysiology in behaving animals, and computational modeling. As the ability to generate diverse collision avoidance behaviors is conserved from flies to humans, the neural substrates and mechanisms that drive looming evoked behaviors in Drosophila will provide models for how these behaviors emerge within larger nervous systems, and provide general principles for how actions may be selected through parallel sensorimotor pathways.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

National Science Foundation (NSF)
Division of Integrative Organismal Systems (IOS)
Standard Grant (Standard)
Application #
Program Officer
Sridhar Raghavachari
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Drexel University
United States
Zip Code