Investigating Drosophila leg kinematics with an automated behavioral tracking system

Responding to dynamic environmental stimuli, animals quickly adapt and optimize walking behaviors to conform to goal-appropriate locomotive states. However, the precise mechanisms by which animals’ nervous systems regulate these essential movements are largely a mystery, resulting in insufficient courses of action for spinal cord injuries, neurodegenerative diseases and disorders, and prosthetic limb fit and design. With the help of an unparalleled sophisticated genetic toolkit, the fruit fly (Drosophila melanogaster) serves as a useful model system to investigate neuronal control of walking behavior. Thus, analyzing fruit-fly behaviors during activation of locomotion-inducing neurons can facilitate novel treatments. In this study, we developed an automated, multi-camera 3D pose tracking system that precisely quantifies fruit-fly joint positions and angles with markerless pose estimation software. Further, we evaluated the effectiveness of the tracking system by performing kinematic analysis of unilateral turning during optogenetic activation of P9 neurons.