Studying the interface between sensory and motor systems by combining electrophysiology, behavioral experiments and genetic tools.
How do sensory and motor systems interact? Answering this question is key to understanding how neural circuits generate behavior.
Sensory systems encode information about the external world, and motor systems generate movements, but how do the two systems communicate to generate sensory-guided behavior? I record the electrical activity from fly motor neurons during visual stimulation to determine how the motor neurons decode their visual system inputs and generate appropriate behavior. By working in the fly I can draw on the strong Drosophila genetic toolkit that allows me to also manipulate the activity of specific neurons during my experiments.
Considerable scientific effort has gone into understanding how fly visual neurons respond to and encode sensory inputs. Less is known about how the responses of these neurons are used to guide movements of the fly. In the specific case of fly gaze-stabilization behavior, the relevant motor neurons drive muscles that move the head to keep the eyes level. These motor neurons receive direct synaptic inputs from visual neurons. The comparative simplicity of the circuit provides an exciting opportunity to study how motor neurons process their visual system inputs. I perform patch clamp and extracellular recordings from these motor neurons while presenting visual stimuli to determine the algorithms that the motor neurons use to extract appropriate information from the visual system. Studying these questions in Drosophila gives me access to the ever-improving repertoire of genetic tools that allow genetic manipulations to be targeted to specific single neuron types. I use such techniques to manipulate upstream sensory neurons during my motor neuron recordings and behavioral experiments to determine the biological mechanisms that underlie the responses I see.
By studying this system I hope to not only understand how this part of the fly nervous system works, but also to uncover general principles applicable to understanding how the motor and sensory systems of all animals interact at the neural level to generate behavior.
3D visualization of a single pair of neck motor neurons (green) innervating neck muscles (red), which move the head by pulling against the fly’s exoskeleton (blue). Data obtained in collaboration with Igor Siwanowicz (Leonardo Lab).
Illustration of a neck motor neuron’s response to two different visual stimuli that simulate different rotations of the fly.
Fly head movements in response to a horizontally oscillating visual panorama.
Double labelling of a neck motor neuron (green) and a subset of its visual input neurons (magenta). The white trace shows an example response of the neck motor neuron to a visual stimulus. Image taken in collaboration with Rebecca Johnston, Fly Light.