Chih-Ying Su

2015 Hellman Fellow

c8su@ucsd.edu

Assistant Professor, Neurobiology
UC San Diego

Project Title: Modulation of Circuits and Behavior by a Non-Synaptic Mechanism

Despite recent advances in our knowledge of brain connectivity, wiring diagrams detailing synaptic connections between neurons cannot fully account for how neural circuits convey and process information. One reason for this limitation is that numerous neuronal types are reported to communicate with one another not only via synapses, but also via direct electrical interaction, known as ephaptic coupling. Previously, little was known about whether and how ephaptic coupling regulates circuits and behavior, because it was impossible to disrupt this robust interaction in vivo. Recently, by means of genetic manipulations, we demonstrated that ephaptic coupling is more important and widespread than previously thought and is critical to modulate odor-driven behavior in Drosophila. However, the principles that govern the strength and directionality of ephaptic interactions remain unclear. In this project, we will combine electrophysiological methods with a novel genetically-encoded Electron Microscopy (EM) marker to test the hypothesis that the relative dendritic caliber of compartmentalized neurons is the critical factor that determines these parameters. The results of this research will define general principles of ephaptic interactions that apply throughout the animal kingdom and will thus broadly enhance our understanding of neuronal circuit interactions that modulate behavior.