TY - JOUR T1 - Sensitive red protein calcium indicators for imaging neural activity JF - bioRxiv DO - 10.1101/041780 SP - 041780 AU - Hod Dana AU - Boaz Mohar AU - Yi Sun AU - Sujatha Narayan AU - Andrew Gordus AU - Jeremy P. Hasseman AU - Getahun Tsegaye AU - Graham T. Holt AU - Amy Hu AU - Deepika Walpita AU - Ronak Patel AU - John J Macklin AU - Cornelia I. Bargmann AU - Misha B. Ahrens AU - Eric R. Schreiter AU - Vivek Jayaraman AU - Loren L. Looger AU - Karel Svoboda AU - Douglas S. Kim Y1 - 2016/01/01 UR - http://biorxiv.org/content/early/2016/02/29/041780.abstract N2 - Genetically encoded calcium indicators (GECIs) allow measurement of activity in large populations of neurons and in small neuronal compartments, over times of milliseconds to months. Although GFP-based GECIs are widely used for in vivo neurophysiology, GECIs with red-shifted excitation and emission spectra have advantages for in vivo imaging because of reduced scattering and absorption in tissue, and a consequent reduction in phototoxicity. However, current red GECIs are inferior to the state-of-the-art GFP-based GCaMP6 indicators for detecting and quantifying neural activity. Here we present improved red GECIs based on mRuby (jRCaMP1a, b) and mApple (jRGECO1a), with sensitivity comparable to GCaMP6. We characterized the performance of the new red GECIs in cultured neurons and in mouse, Drosophila, zebrafish and C. elegans in vivo. Red GECIs facilitate deep-tissue imaging, dual-color imaging together with GFP-based reporters, and the use of optogenetics in combination with calcium imaging. ER -