CNC Presents: Simon Sponberg, PhD (Georgia Tech)

“Task-level representations and control in a nearly complete, spike-resolved motor program for agile flight”

Agile animals must parse complex sensory environments to extract actionable features relevant to behavior. They must also be translated into the animal’s motor program—a set of temporally coordinated spike patterns across multiple muscles that mediate movement. In the hawkmoth Manduca sexta, we can record a nearly complete, spike-resolved motor program, capturing almost every action potential from all muscles that control wing movement. Using this combination of completeness, resolution, and rich behavior, we show that most coordination is achieved with precisely coordinated spike timing patterns that take advantage of specifically tuned sensitivities in muscle physiology and biomechanics. Using deep, but semi-interpretable ML approaches, we can decode both discrete and continuous representations of behavior with nearly perfect accuracy, but only when we utilize spike timing precision down to a millisecond or less. All muscles are involved in every maneuver and spike timing precision in the motor program scales species of moths that use different fundamental wing beat frequencies.  We next combine our comprehensive motor program recordings with simultaneous multi-electrode array recordings from the neck connective to ask how spike precision and representations of sensory cures are integrated into motor action. Using information-theoretic analyses of multiunit recordings, we show that spike timing is less precise across all recorded descending and ascending units in the neck connective compared to peripheral motor units. This suggests that motor commands may be mapped through peripheral reafference into a more precise spike timing code. Looking ahead, the broad accessibility of spike-resolved population activity across multiple stages of motor processing is beginning to reveal algorithmic principles of sensorimotor integration in the insect ventral nerve cord.

South Campus Center 354 and on Zoom