An a.c. overload voltage indicator

All-optical electrophysiology can be a powerful tool for studying neural dynamics in vivo, as it offers the ability to image and perturb membrane voltage in multiple cells simultaneously. The "Optopatch" constructs combine a red-shifted archaerhodopsin (Arch)-derived genetically encoded voltage indicator (GEVI) with a blue-shifted channelrhodopsin actuator (ChR). We used a video-based pooled screen to evolve Arch-derived GEVIs with improved signal-to-noise ratio (QuasAr6a) and kinetics (QuasAr6b). By combining optogenetic stimulation of individual cells with high-precision voltage imaging in neighboring cells, we mapped inhibitory and gap junction-mediated connections, in vivo. Optogenetic activation of a single NDNF-expressing neuron in visual cortex Layer 1 significantly suppressed the spike rate in some neighboring NDNF interneurons. Hippocampal PV cells showed near-synchronous spikes across multiple cells at a frequency significantly above what one would expect from independent spiking, suggesting that collective inhibitory spikes may play an important signaling role in vivo. By stimulating individual cells and recording from neighbors, we quantified gap junction coupling strengths. Together, these results demonstrate powerful new tools for all-optical microcircuit dissection in live mice.

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voltage indicator

10.1007/springerreference_28340 ◽

2011 ◽

Keyword(s):

Voltage Indicator

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Modulating the Voltage-sensitivity of a Genetically Encoded Voltage Indicator

Experimental Neurobiology ◽

10.5607/en.2017.26.5.241 ◽

2017 ◽

Vol 26 (5) ◽

pp. 241-251 ◽

Cited By ~ 3

Author(s):

Arong Jung ◽

Dhanarajan Rajakumar ◽

Bong-June Yoon ◽

Bradley J. Baker

Keyword(s):

Voltage Sensitivity ◽

Voltage Indicator

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Red Fluorescent Genetically Encoded Voltage Indicators with Millisecond Responsiveness

Sensors ◽

10.3390/s19132982 ◽

2019 ◽

Vol 19 (13) ◽

pp. 2982 ◽

Cited By ~ 2

Author(s):

Liubov A. Kost ◽

Violetta O. Ivanova ◽

Pavel M. Balaban ◽

Konstantin A. Lukyanov ◽

Evgeny S. Nikitin ◽

...

Keyword(s):

Fluorescent Protein ◽

Dynamic Range ◽

Response Speed ◽

Red Fluorescent Protein ◽

Positive Slope ◽

Reporter Protein ◽

Fluorescent Indicators ◽

Linker Length ◽

Final Performance ◽

Voltage Indicator

Genetically encoded fluorescent indicators typically consist of the sensitive and reporter protein domains connected with the amino acid linkers. The final performance of a particular indicator may depend on the linker length and composition as strong as it depends on the both domains nature. Here we aimed to optimize interdomain linkers in VSD-FR189-188—a recently described red fluorescent protein-based voltage indicator. We have tested 13 shortened linker versions and monitored the dynamic range, response speed and polarity of the corresponding voltage indicator variants. While the new indicators didn’t show a contrast enhancement, some of them carrying very short interdomain linkers responded 25-fold faster than the parental VSD-FR189-188. Also we found the critical linker length at which fluorescence response to voltage shift changes its polarity from negative to positive slope. Our observations thus make an important contribution to the designing principles of the fluorescent protein-derived voltage indicators.

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Electrophysiological events recorded at presynaptic terminals of the crayfish neuromuscular junction with a voltage indicator

The Journal of Physiology ◽

10.1113/jphysiol.2008.158089 ◽

2008 ◽

Vol 586 (20) ◽

pp. 4935-4950 ◽

Cited By ~ 9

Author(s):

Jen-Wei Lin

Keyword(s):

Neuromuscular Junction ◽

Presynaptic Terminals ◽

Crayfish Neuromuscular Junction ◽

Voltage Indicator

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Single-molecule fluorimetry and gating currents inspire an improved optical voltage indicator

eLife ◽

10.7554/elife.10482 ◽

2015 ◽

Vol 4 ◽

Cited By ~ 19

Author(s):

Jeremy S Treger ◽

Michael F Priest ◽

Francisco Bezanilla

Keyword(s):

Ion Channels ◽

Single Molecule ◽

Single Molecules ◽

Optical Response ◽

Potential Utility ◽

Gating Currents ◽

Voltage Gated ◽

Voltage Gated Ion Channels ◽

The Relationship ◽

Voltage Indicator

Voltage-sensing domains (VSDs) underlie the movement of voltage-gated ion channels, as well as the voltage-sensitive fluorescent responses observed from a common class of genetically encoded voltage indicators (GEVIs). Despite the widespread use and potential utility of these GEVIs, the biophysical underpinnings of the relationship between VSD movement and fluorophore response remain unclear. We investigated the recently developed GEVI ArcLight, and its close variant Arclight', at both the single-molecule and macroscopic levels to better understand their characteristics and mechanisms of activity. These studies revealed a number of previously unobserved features of ArcLight's behavior, including millisecond-scale fluorescence fluctuations in single molecules as well as a previously unreported delay prior to macroscopic fluorescence onset. Finally, these mechanistic insights allowed us to improve the optical response of ArcLight to fast or repetitive pulses with the development of ArcLightning, a novel GEVI with improved kinetics.

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