TY - JOUR T1 - An updated suite of viral vectors for <em>in vivo</em> calcium imaging using local and retro-orbital injections JF - bioRxiv DO - 10.1101/2021.05.14.443815 SP - 2021.05.14.443815 AU - Sverre Grødem AU - Ingeborg Nymoen AU - Guro Helén Vatne AU - Valgerdur Björnsdottir AU - Kristian Kinden Lensjø AU - Marianne Fyhn Y1 - 2021/01/01 UR - http://biorxiv.org/content/early/2021/05/16/2021.05.14.443815.abstract N2 - Calcium imaging using genetically encoded indicators (GECIs) is a widely adopted method to measure neural activity in modern neuroscience. Here, we explore the use of systemically administered viral vectors for brain-wide expression of GECIs, and adapt novel GECIs to optimize signal-to-noise. We show that systemic injections of PHP.eB AAVs to express GECIs is a highly promising technique for imaging neural activity and circumvent the need for transgenic GECI expressing mouse lines. We also establish the use of novel soma-targeted GECIs that outperform current Ca2+ indicators using both systemic and local virus injections.Competing Interest StatementThe authors have declared no competing interest. ER -