Genetically encoded calcium indicators to probe complex brain circuit dynamics in vivo

Abstract

Over the past two decades, genetically encoded calcium indicators (GECIs) have been used extensively to report intracellular calcium (Ca²⁺) dynamics in order to readout neuronal and network activity in living tissue. Single wavelength GECIs, such as GCaMP, have been widely adapted due to advances in dynamic range, sensitivity, and kinetics. Additionally, recent efforts in protein engineering have expanded the GECI color palette to enable direct optical interrogation of more complex circuit dynamics. Here, I discuss the engineering, application, and future directions of the most recently developed GECIs for in vivo neuroscience research.

Keywords: All-optical experiments; Calcium indicator; Genetically encoded fluorescent indicators; Multiplex imaging; Neuronal activity recording; Protein engineering; R-CaMP2; XCaMP.