To understand how our brains work, we must understand how groups of neurons work together to perform computations on environmental inputs to produce behavior. When neurons in a circuit compute, their activity and the output from the network can often be described by a series of mathematical operations, like addition, subtraction, and multiplication. A canonical example of neural computation is the eye's detection of visual motion, which employs mathematical operations that are present in many circuits in the brains of many animals. This research investigates the mathematical operations that describe the output of this neural computation, as well as how those operations are implemented by specific neurons in the circuit and how the selection of specific operations changes the performance of the circuit. The broader impact of this project focuses on high school outreach, where it will teach a module on visual perception and illusions. The project will also focus on bringing high school and undergraduate students into lab to perform research in an accessible experimental system.
This research focuses on the small circuit of motion detecting neurons in the eye of the fruit fly Drosophila. The fruit fly's eye is an ideal target for study because its circuit is small and increasingly identified; genetic tools allow us to manipulate and measure from individual, identified neuron types in order to test hypotheses; and a long-standing modeling framework can be used to interpret results. To understand the details of the circuit's computation, we will use behavioral psychophysics and in vivo calcium imaging to record circuit responses to specially designed visual stimuli that isolate specific neural computations. We will use responses to these stimuli and others to simulate circuit responses to visual stimuli. Genetic silencing will allow us to identify neurons that are involved in the motion computation. These experiments will lead us to an understanding of which nonlinear operations are implemented in this circuit, and how those operations affect the circuit's performance.
