All-optical Electrophysiology in Mammalian Neurons using engineered Microbial Rhodopsins

Published in Nature Methods, 2014

All-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 QuasAr2, which show improved brightness and voltage sensitivity, have microsecond response times and produce no photocurrent. We engineered a channelrhodopsin actuator, CheRiff, which shows high light sensitivity and rapid kinetics and is spectrally orthogonal to the QuasArs. A coexpression vector, Optopatch, enabled cross-talk–free genetically targeted all-optical electrophysiology. In cultured rat neurons, we combined Optopatch with patterned optical excitation to probe back-propagating action potentials (APs) in dendritic spines, synaptic transmission, subcellular microsecond-timescale details of AP 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 rat brain slices, Optopatch induced and reported APs and subthreshold events with high signal-to-noise ratios. The Optopatch platform enables high-throughput, spatially resolved electrophysiology without the use of conventional electrodes.

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  title={All-optical electrophysiology in mammalian neurons using engineered microbial rhodopsins},
    Hochbaum, Daniel R and
    Zhao, Yongxin and
    Farhi, Samouil L and
    Klapoetke, Nathan and
    Werley, Christopher A and
    Kapoor, Vikrant and
    Zou, Peng and
    Kralj, Joel M and
    Maclaurin, Dougal and
    Smedemark-Margulies, Niklas and
    Saulnier, Jessica L and
    Boulting, Gabriella L and
    Straub, Christoph and
    Cho, Yong Ku and
    Melkonian, Michael and
    Wong, Gane Ka-Shu and
    Harrison, D Jed and
    Murthy, Venkatesh N and
    Sabatiny, Bernardo L and
    Boyden, Edward S and
    Campbell, Robert E and
    Cohen, Adam E},
  journal={Nature methods},
  publisher={Nature Publishing Group}