GEVIBench › All sensors › paQuasAr3
paQuasAr3
Photoactivatable QuasAr3 variant that can be selectively activated.
- Category: Opsin GEVI
- Published: 2019-05-01 — Nature 2019
- Derived from: QuasAr2
- Response polarity: positive-going (fluorescence increases on depolarization)
- Spectrum: excitation peak 590 nm, emission peak 715 nm (paQuasAr3)
- Plasmid: Addgene #107703
- Tags: Archaerhodopsin, Far-red, Photoactivated
Headline values (as shown in the GEVIBench table)
| Metric | Value | Definition |
|---|---|---|
| Brightness (B/B_EGFP) | 0.0012× EGFP | Molecular brightness relative to EGFP (extinction coefficient × quantum yield, or a measured ratio). Sensors not measured against EGFP directly are placed through a chain of pairwise brightness comparisons, combined by geometric mean. |
| Kinetics τ_on / τ_off (ms) | 8.1 / 4.7 ms | Activation / decay time constants in ms (amplitude-weighted mean τ for multi-exponential fits). The value shown averages the measurements made at physiological temperature (≥33 °C); if there are none, it is the measurement closest to 33 °C. |
| ΔF/F per 100 mV | +40% | Steady-state fluorescence change for a 100 mV depolarization step (−70 → +30 mV); the sign gives the polarity. The table shows the first listed measurement; the median across measurements (one-photon preferred) is used for sorting. |
| ΔF/F per mV | 0.4% | Subthreshold sensitivity: fluorescence change per mV near rest (−90 to −50 mV). Where no value is reported directly, it is estimated from the F–V curve. |
| ΔF/F per AP | 23.5% | Fluorescence change per single action potential in neurons. The table shows the first listed measurement; the median across measurements (one-photon preferred) is used for sorting. |
| AP width (FWHM, ms) | 1.8 ms | Full width at half maximum of the optical spike waveform. |
| Photostability t75% @ 100 mW/mm² | 3.3 h | Time for fluorescence to fall to 75% of its initial value under one-photon illumination, linearly dose-scaled to 100 mW/mm² (t50% is used where the 75% crossing falls inside a fast initial transient). Two-photon curves are not dose-scaled and are excluded. |
| Papers using it (N_used) | 12 | Number of published research papers, tracked by GEVIBench, that used the sensor for an experiment (a popularity / track-record measure). |
Measurements and sources
Kinetics
- τ_on 9.3 ms, τ_off 5.4 ms at 34°C — Adam 2019, Ext. Fig. 3e
- τ_on 6.8 ms, τ_off 3.9 ms at 34°C — Adam 2019, Ext. Fig. 3e
ΔF/F per 100 mV
- +40%, 1P — Adam 2019, Fig. 1g
ΔF/F per mV (subthreshold)
- 0.4%/mV (0.4%/mV derived from 40 +/- 1.7% per 100 mV voltage sensitivity measured in acute brain slices (Fig. 1g). SNR = 0.93 +/- 0.07 per mV in 1 kHz bandwidth.) — Adam 2019, Fig. 1g
ΔF/F per action potential
- 23.5%, 1P — Piatkevich 2019, Ext. Fig. 5c
AP width (FWHM)
- 1.8 ms at 1000 Hz sampling, Mouse, hippocampus CA1 oriens interneuron, in vivo, 1P, 37°C — Adam 2019, Fig. 1i
Brightness comparisons
- 2× the brightness of QuasAr2 — Adam 2019, Ext. Fig. 3f
- 0.0017985611510791368× the brightness of ASAP3 — Villette 2019, Table 1
Photobleaching
- t75% = 98 s at 12000 mW/mm², 1P — Adam 2019, Ext. Fig. 5a
Fluorescence–voltage (F–V) curve
ΔF/F (%) at each membrane potential, normalized to 0 at −70 mV: -75 mV: 0%; -50 mV: 12%; -25 mV: 23%; 0 mV: 32%; 25 mV: 42%; 50 mV: 52%; 75 mV: 65% — Adam 2019, Ext. Fig. 3d
Research papers using paQuasAr3 (12)
- Voltage imaging and optogenetics reveal behaviour-dependent changes in hippocampal dynamics — Adam Y, Kim JJ, Lou S, Zhao Y, Xie ME, Brinks D, Wu H, Mostajo-Radji MA, Kheifets S, Parot V, Chettih S, Williams KJ, Gmeiner B, Farhi SL, Madisen L, Buchanan EK, Kinsella I, Zhou D, Paninski L, Harvey CD, Zeng H, Arlotta P, Campbell RE, Cohen AE, Nature 2019 (Mouse, hippocampus CA1 and olfactory bulb, in vivo (awake behaving); HEK293T cells and acute brain slices)
- Population imaging of neural activity in awake behaving mice — Piatkevich KD, Bensussen S, Tseng HA, Shroff SN, Lopez-Huerta VG, Park D, Jung EE, Shemesh OA, Straub C, Gritton HJ, Romano MF, Costa E, Sabatini BL, Fu Z, Boyden ES, Han X, Nature 2019 (Mouse, cortex L2/3 and hippocampus, acute slices and in vivo (paQuasAr3-s used as a comparison GEVI for SomArchon))
- All-optical electrophysiology reveals the role of lateral inhibition in sensory processing in cortical layer 1 — Fan LZ, et al., Cell 2020 (Mouse, barrel cortex L1 interneurons, in vivo (awake behaving))
- Scalable measurements of intrinsic excitability in human iPS cell-derived excitatory neurons using all-optical electrophysiology — Williams LA, et al., Neurochemical Research 2019 (Human iPSC-derived excitatory cortical neurons, in vitro)
- Photoactivated voltage imaging in tissue with an archaerhodopsin-derived reporter — Chien MP, et al., Science Advances 2021 (Mouse, hippocampus acute slices and CA1 in vivo)
- High-fidelity estimates of spikes and subthreshold waveforms from 1-photon voltage imaging in vivo — Xie ME, et al., Cell Reports 2021 (Mouse, hippocampus CA1, in vivo; zebrafish spinal cord)
- Linearly polarized excitation enhances signals from fluorescent voltage indicators — Bloxham W, et al., Biophysical Journal 2021 (HEK293 cells and cultured rat hippocampal neurons)
- Video-based pooled screening yields improved far-red genetically encoded voltage indicators — Tian H, et al., Nature Methods 2023 (HEK293 cells, cultured neurons, mouse cortex and hippocampus in vivo)
- Statistically unbiased prediction enables accurate denoising of voltage imaging data — Eom M, et al., Nature Methods 2023 (Mouse, brain tissue (denoising benchmark on paQuasAr3-s datasets))
- Mechanism of sensory perception unveiled by simultaneous measurement of membrane voltage and intracellular calcium — Tokunaga T, et al., Communications Biology 2024 (C. elegans, AWA olfactory neurons (simultaneous voltage + calcium imaging))
- Optical constraints on two-photon voltage imaging — Brooks FP III, et al., Neurophotonics 2024 (Cultured neurons and mouse brain (1P/2P GEVI characterization))
- Robust self-supervised denoising of voltage imaging data using CellMincer — Wang B, et al., npj Imaging 2024 (Primary neurons and iPSC-derived neurons, in vitro)
Data and citation
- llms.txt — summary for language models
- llms-full.txt — every sensor in full (Markdown)
- gevis.json — all values and measurements with sources (JSON)
- gevis.csv — one row per sensor (CSV)
Cite GEVIBench as: Adam E. Cohen and Daozheng Gong (2026). Voltage imaging: A practical guide. Neuron. https://doi.org/10.1016/j.neuron.2026.08.002
Generated from the GEVIBench database on 2026-10-12.