Voltage-Sensitive Fluorescent Proteins for Optical Electrophysiology

Abstract

Genetically encoded voltage indicators (GEVIs) enable the simultaneous monitoring of plasma membrane voltage from defined neuronal subpopulations across multiple spatial scales. Overcoming past challenges, recent rapid developments in indicator performance bring them a decisive step closer to routine application. In this chapter, we outline the history and principles of sensing neuronal activity with fluorescent indicators, focusing on GEVIs. We show examples of experiments conducted with GEVIs in brain slices and in living animals. We highlight remaining challenges in indicator development and application, especially when combining GEVIs with optogenetic actuators. We give an overview of the optical equipment used in experiments and provide guidance on how to optimize signal strength. We outline the analysis of data obtained with fluorescent activity probes and offer a short guide on how to choose a GEVI for particular applications.