Ultrafast Two-Photon Imaging of a High-Gain Voltage Indicator in Awake Behaving Mice

Cell. 2019 Dec 12;179(7):1590-1608.e23. doi: 10.1016/j.cell.2019.11.004.

Abstract

Optical interrogation of voltage in deep brain locations with cellular resolution would be immensely useful for understanding how neuronal circuits process information. Here, we report ASAP3, a genetically encoded voltage indicator with 51% fluorescence modulation by physiological voltages, submillisecond activation kinetics, and full responsivity under two-photon excitation. We also introduce an ultrafast local volume excitation (ULoVE) method for kilohertz-rate two-photon sampling in vivo with increased stability and sensitivity. Combining a soma-targeted ASAP3 variant and ULoVE, we show single-trial tracking of spikes and subthreshold events for minutes in deep locations, with subcellular resolution and with repeated sampling over days. In the visual cortex, we use soma-targeted ASAP3 to illustrate cell-type-dependent subthreshold modulation by locomotion. Thus, ASAP3 and ULoVE enable high-speed optical recording of electrical activity in genetically defined neurons at deep locations during awake behavior.

Keywords: ASAP3; GEVI; RAMP; ULoVE; action potential; electrophysiology; electroporation; theta oscillation; two-photon; voltage imaging.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials
  • Animals
  • Brain / metabolism
  • Brain / physiology*
  • CHO Cells
  • Cells, Cultured
  • Cricetinae
  • Cricetulus
  • Female
  • GTPase-Activating Proteins / genetics*
  • GTPase-Activating Proteins / metabolism
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • HEK293 Cells
  • Humans
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Microscopy, Fluorescence, Multiphoton / methods*
  • Optogenetics / methods*
  • Phosphoric Monoester Hydrolases / genetics
  • Phosphoric Monoester Hydrolases / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Running
  • Theta Rhythm*
  • Wakefulness*

Substances

  • GTPase-Activating Proteins
  • Green Fluorescent Proteins
  • Phosphoric Monoester Hydrolases