Hochbaum, DanielZhao, YongxinFarhi, SamouilKlapoetke, NathanWerley, Christopher A.Kapoor, VikrantZou, PengKralj, Joel M.Maclaurin, DougalSmedemark-Margulies, NiklasSaulnier, JessicaBoulting, GabriellaStraub, ChristophCho, Yong KuMelkonian, MichaelWong, Gane Ka-ShuHarrison, D. JedMurthy, VenkateshSabatini, BernardoBoyden, Edward S.Campbell, Robert E.Cohen, Adam2015-03-022014Hochbaum, D. R., Y. Zhao, S. L. Farhi, N. Klapoetke, C. A. Werley, V. Kapoor, P. Zou, et al. 2014. “All-optical electrophysiology in mammalian neurons using engineered microbial rhodopsins.” Nature methods 11 (8): 825-833. doi:10.1038/nmeth.3000. http://dx.doi.org/10.1038/nmeth.3000.1548-7091http://nrs.harvard.edu/urn-3:HUL.InstRepos:14065305All-optical electrophysiology—spatially resolved simultaneous optical perturbation and measurement of membrane voltage—would open new vistas in neuroscience research. We evolved two archaerhodopsin-based voltage indicators, QuasAr1 and 2, which show improved brightness and voltage sensitivity, microsecond response times, and produce no photocurrent. We engineered a novel channelrhodopsin actuator, CheRiff, which shows improved light sensitivity and kinetics, and spectral orthogonality to the QuasArs. A co-expression vector, Optopatch, enabled crosstalk-free genetically targeted all-optical electrophysiology. In cultured neurons, we combined Optopatch with patterned optical excitation to probe back-propagating action potentials in dendritic spines, synaptic transmission, sub-cellular microsecond-timescale details of action potential propagation, and simultaneous firing of many neurons in a network. Optopatch measurements revealed homeostatic tuning of intrinsic excitability in human stem cell-derived neurons. In brain slice, Optopatch induced and reported action potentials and subthreshold events, with high signal-to-noise ratios. The Optopatch platform enables high-throughput, spatially resolved electrophysiology without use of conventional electrodes.en-USJournal Article2015-03-0210.1038/nmeth.3000