Akerboom, J.Chen, T.-W.Wardill, T. J.Tian, L.Marvin, J. S.Mutlu, S.Calderon, N. C.Esposti, F.Borghuis, B. G.Sun, X. R.Gordus, A.Orger, M. B.Portugues, RubenEngert, FlorianMacklin, J. J.Filosa, A.Aggarwal, A.Kerr, R. A.Takagi, R.Kracun, S.Shigetomi, E.Khakh, B. S.Baier, H.Lagnado, L.Wang, S. S.- H.Bargmann, C. I.Kimmel, B. E.Jayaraman, V.Svoboda, K.Kim, D. S.Schreiter, E. R.Looger, L. L.2013-11-132012Akerboom, Jasper, Tsai-Wen Chen, Trevor J. Wardill, Lin Tian, Jonathan S. Marvin, Sevinç Mutlu, Nicole Carreras Calderon, et al. 2012. Optimization of a GCaMP calcium indicator for neural activity imaging. Journal of Neuroscience 32(40): 13819-13840.0270-6474http://nrs.harvard.edu/urn-3:HUL.InstRepos:11315420Genetically encoded calcium indicators (GECIs) are powerful tools for systems neuroscience. Recent efforts in protein engineering have significantly increased the performance of GECIs. The state-of-the art single-wavelength GECI, GCaMP3, has been deployed in a number of model organisms and can reliably detect three or more action potentials in short bursts in several systems in vivo. Through protein structure determination, targeted mutagenesis, high-throughput screening, and a battery of in vitro assays, we have increased the dynamic range of GCaMP3 by severalfold, creating a family of “GCaMP5” sensors. We tested GCaMP5s in several systems: cultured neurons and astrocytes, mouse retina, and in vivo in Caenorhabditis chemosensory neurons, Drosophila larval neuromuscular junction and adult antennal lobe, zebrafish retina and tectum, and mouse visual cortex. Signal-to-noise ratio was improved by at least 2- to 3-fold. In the visual cortex, two GCaMP5 variants detected twice as many visual stimulus-responsive cells as GCaMP3. By combining in vivo imaging with electrophysiology we show that GCaMP5 fluorescence provides a more reliable measure of neuronal activity than its predecessor GCaMP3. GCaMP5 allows more sensitive detection of neural activity in vivo and may find widespread applications for cellular imaging in general.en-USJournal Article2013-07-09J Akerboom, TW Chen, TJ Wardill, L Tian, JS Marvin, S Mutlu, NC Calderon, F Esposti, BG Borghuis, XR Sun, A Gordus, MB Orger, R2013-11-1310.1523/JNEUROSCI.2601-12.2012