GEVIBench › All sensors › ASAP3
ASAP3
3rd-gen ASAP sensor with large fluorescence modulation and fast kinetics.
- Category: VSD-cpGFP GEVI
- Published: 2019-12-12 — Cell 2019
- Derived from: ASAP2s
- Response polarity: negative-going (fluorescence decreases on depolarization)
- Spectrum: excitation peak 490 nm, emission peak 509 nm (ASAP3)
- Two-photon compatible: yes
- Plasmid: Addgene #132331
- Tags: cpGFP, Two-photon
Headline values (as shown in the GEVIBench table)
| Metric | Value | Definition |
|---|---|---|
| Brightness (B/B_EGFP) | 0.45× 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) | 6.8 / 11 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 | -51% (median of 5 measurements: −49.3%) | 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 | 0.68% | 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 | 18% (median of 7 measurements: 13.3%) | 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) | 5.7 ms | Full width at half maximum of the optical spike waveform. |
| Photostability t75% @ 100 mW/mm² | 52 s | 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) | 27 | 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 2.7 ms, τ_off 6.72 ms at 32-35°C — Villette 2019, Table 1
- τ_on 13.23 ms, τ_off 3.58 ms at 37°C — Hao 2024, Table S2
- τ_on 12.12 ms, τ_off 32.34 ms at 22-23°C — Villette 2019, Table 1
- τ_on 4.49 ms, τ_off 21.54 ms at 32-35°C — Liu 2022, Table S2
- τ_on 8.73 ms, τ_off 25.85 ms at 21-23°C — Liu 2022, Table S2
- τ_on 9.11 ms, τ_off 18.8 ms at 23°C — Hao 2024, Table S2
ΔF/F per 100 mV
- -51%, 1P — Villette 2019, Table 1
- -49.3%, 1P — Milosevic 2020, Fig. 2D
- -51%, 1P — Rühl 2026, Table S1
- -43.5%, 1P — Lu 2023, Fig. 2c
- -47%, 1P — Hao 2024, Table S2
ΔF/F per mV (subthreshold)
- 0.46%/mV — Villette 2019, Fig. S5E
- 0.9%/mV — Hao 2024, Fig. S1C
ΔF/F per action potential
- 18%, 1P — Villette 2019, Table 1
- 10.2%, 1P — Evans 2023, Fig. 3c
- 16.5%, 1P — Lu 2023, Fig. 2n
- 10.2%, 1P — Piatkevich 2019, Ext. Fig. 5c
- 17%, 2P — Villette 2019, Fig. 3C
- 8.3%, 2P — Villette 2019, Fig. 3E
- 37.3%, 2P — Villette 2019, Fig. 3H
AP width (FWHM)
- 5.8 ms at 987 Hz sampling, HEK293A cells, optical response to a single AP-like command waveform, whole-cell voltage clamp, 1P, 25°C — Lu 2023, Fig. 2f
- 12.7 ms at undefined Hz sampling, Cultured rat hippocampal neurons, optical response to current-evoked single APs, current clamp, room temperature, 1P, 25°C — Villette 2019, Fig. 2F
- 3.4 ms at 3750 Hz sampling, Mouse, cortex, in vivo (ASAP3), 2P — Villette 2024, Fig. 3f
- 5.6 ms at 1000 Hz sampling, HEK293A cells, optical response to a single AP-like command waveform (2-ms FWHM, +30 mV peak), whole-cell voltage clamp, 1P, 25°C — Liu 2022, Fig. S4F
Brightness comparisons
- 0.446× the brightness of EGFP — Villette 2019, Table 1
- 0.682× the brightness of ArcLight — Villette 2019, Table 1
- 197× the brightness of Archon1 — Villette 2019, Table 1
- 556× the brightness of QuasAr2 — Villette 2019, Table 1
- 0.167× the brightness of Ace2N-mNeon — Villette 2019, Table 1
- 0.87× the brightness of ASAP2s — Lu 2023, Fig. 2h
- 556× the brightness of paQuasAr3 — Villette 2019, Table 1
- 1.0638297872340425× the brightness of ASAP1 — Nair 2025, Fig. 2C
- 2.2381378692927485× the brightness of ASAP4b — Evans 2023, Ext. Fig. 3d
- 2.7624309392265194× the brightness of ASAP4e — Evans 2023, Ext. Fig. 3d
- 1× the brightness of ASAP5 — Hao 2024, Fig. 1G
- 0.4098360655737705× the brightness of JEDI-1P — Lu 2023, Fig. 2h
- 0.5847953216374269× the brightness of JEDI-1P — Nair 2025, Fig. 2C
- 0.5988023952095809× the brightness of JEDI-2P — Liu 2022, Fig. 2I
- 0.5592841163310962× the brightness of rEstus-NI — Nair 2025, Fig. 2C
- 0.48309178743961356× the brightness of rEstus — Rühl 2024, Table 1
- 0.5847953216374269× the brightness of rEstus — Nair 2025, Table S1
- 0.9276437847866419× the brightness of rEstus2s — Rühl 2026, Table S1
Photobleaching
- t75% = 2.5 s at 920 nm, 20 mW post-objective (ULoVE pattern 3), 2P — Villette 2019, Fig. 4D
- t50% = 295 s (extrapolated) at 46 mW/mm², 1P — Lu 2023, Fig. S4
- t75% = 95 s (extrapolated) at 100 mW/mm², 1P — Evans 2023, Fig. 2b
- t50% = 59 s, 1P — Liu 2022, Fig. S4G
- t75% = 95 s at 25 mW/mm² (475 nm), 1P — Piatkevich 2019, Ext. Fig. 5e
- t75% = 886 s at ~10 µW/mm² (445 nm CW, in vivo), 1P — Hao 2026, Ext. Fig. 3a
Fluorescence–voltage (F–V) curve
ΔF/F (%) at each membrane potential, normalized to 0 at −70 mV: -110 mV: 45%; -90 mV: 23%; -70 mV: 0%; -50 mV: -20%; -30 mV: -35%; -10 mV: -43%; 10 mV: -49%; 30 mV: -51% — Villette 2019, Fig. 2A
Research papers using ASAP3 (27)
- Ultrafast Two-Photon Imaging of a High-Gain Voltage Indicator in Awake Behaving Mice — Villette V, Chavarha M, et al., Cell 2019 (Mouse, visual cortex L2/3, in vivo; Drosophila, olfactory projection neurons, in vivo; HEK293 cells, in vitro)
- Population imaging of neural activity in awake behaving mice — Piatkevich KD, Bensussen S, Tseng HA, et al., Nature 2019 (Mouse, cortex L2/3 brain slices (ASAP3-Kv photostability); in vivo)
- Two-Photon Voltage Imaging of Spontaneous Activity from Multiple Neurons Reveals Network Activity in Brain Tissue — Li B, et al., iScience 2020 (Mouse, somatosensory cortex L2/3; acute slices, in vitro)
- In Vitro Testing of Voltage Indicators: Archon1, ArcLightD, ASAP1, ASAP2s, ASAP3b, Bongwoori-Pos6, BeRST1, FlicR1, and Chi-VSFP-Butterfly — Milosevic MM, et al., eNeuro 2020 (Mouse, cortex; HEK293 cells, in vitro)
- A red fluorescent protein with improved monomericity enables ratiometric voltage imaging with ASAP3 — Kim BB, et al., Scientific Reports 2022 (Rat, hippocampal neurons; human iPSC-derived cardiomyocytes; HEK293 cells, in vitro)
- Sustained deep-tissue voltage recording using a fast indicator evolved for two-photon microscopy — Liu Z, et al., Cell 2022 (Drosophila, visual interneurons, in vivo; mouse, retina, ex vivo; mouse, visual cortex L2/3 and L5, in vivo)
- Electrical signals in the ER are cell type and stimulus specific with extreme spatial compartmentalization in neurons — Campbell EP, et al., Cell Reports 2023 (Rat, hippocampal neurons; HEK293T cells, in vitro)
- High-speed low-light in vivo two-photon voltage imaging of large neuronal populations — Platisa J, et al., Nature Methods 2023 (Mouse, somatosensory cortex L2/3, in vivo; acute slices, in vitro)
- A positively tuned voltage indicator for extended electrical recordings in the brain — Evans SW, et al., Nature Methods 2023 (Mouse, hippocampus, cortex, in vivo; Drosophila, visual interneurons, in vivo; rat, hippocampal neurons, in vitro)
- Widefield imaging of rapid pan-cortical voltage dynamics with an indicator evolved for one-photon microscopy — Lu X, Wang Y, Liu Z, Gou Y, Jaeger D, St-Pierre F, Nature Communications 2023 (HEK293A cells, in vitro (ASAP3 benchmarked against JEDI-1P for response amplitude, spike-waveform width and photostability); rat hippocampal neurons, in vitro (ASAP3-Kv single-AP responses))
- Dendritic mGluR2 and perisomatic Kv3 signaling regulate dendritic computation of mouse starburst amacrine cells — Ledesma HA, et al., Nature Communications 2024 (Mouse, retina, starburst amacrine cells, ex vivo)
- Two-dimensional electro-optical multiphoton microscopy — Farinella DM, et al., Neurophotonics 2024 (Mouse, visual cortex L2/3, in vivo)
- A novel rhodopsin-based voltage indicator for simultaneous two-photon optical recording with GCaMP in vivo — Villette V, Yang S, Valenti R, Macklin JJ, Bradley J, Mathieu B, Lombardini A, Podgorski K, Dieudonné S, Schreiter ER, Abdelfattah AS, bioRxiv 2024 (Mouse, cortex and cerebellum, in vivo (ASAP3 spike amplitude / spike FWHM / photon flux cross-plotted against 2Photron-ST552 and JEDI-2P-Kv))
- Cl⁻-dependent amplification of excitatory synaptic potentials at distal dendrites revealed by voltage imaging — Higashi R, et al., Science Advances 2024 (Mouse, hippocampal neurons; acute slices, in vitro)
- A fast and responsive voltage indicator with enhanced sensitivity for unitary synaptic events — Hao YA, et al., Neuron 2024 (Mouse, motor cortex, barrel cortex, in vivo; Drosophila, visual interneurons, in vivo; rat, hippocampal neurons, in vitro)
- Volumetric voltage imaging of neuronal populations in the mouse brain by confocal light-field microscopy — Bai L, et al., Nature Methods 2024 (Mouse, cortex, in vivo)
- Development and Application of a Mitochondrial Genetically Encoded Voltage Indicator in Narcosis — Yang RZ, et al., Neuroscience Bulletin 2024 (Mouse, motor cortex, in vivo; cardiomyocytes; HEK293T cells, in vitro)
- An Ultrasensitive Genetically Encoded Voltage Indicator Uncovers the Electrical Activity of Non-Excitable Cells — Rühl P, et al., Advanced Science 2024 (Human cell lines, HEK293T, melanoma, breast cancer, in vitro)
- Functional architecture of intracellular oscillations in hippocampal dendrites — Liao Z, et al., Nature Communications 2024 (Mouse, hippocampus CA1, dendrites, in vivo)
- Absolute Membrane Potential Recording with ASAP-Type Genetically Encoded Voltage Indicators Using Fluorescence Lifetime Imaging — Nair AG, et al., ACS Chemical Neuroscience 2025 (HEK293T cells; melanoma cells; breast cancer cells, in vitro)
- Voltage imaging reveals hippocampal inhibitory dynamics shaping pyramidal memory-encoding sequences — Taxidis J, et al., Nature Neuroscience 2025 (Mouse, hippocampus CA1, PV and SST interneurons, in vivo)
- An axonal brake on striatal dopamine output by cholinergic interneurons — Zhang YF, et al., Nature Neuroscience 2025 (Mouse, striatum, dopamine axons, in vivo; acute slices, ex vivo)
- Imaging high-frequency voltage dynamics in multiple neuron classes of behaving mammals — Haziza S, et al., Cell 2025 (Mouse, hippocampus CA1/CA3, visual cortex, motor cortex, in vivo; freely moving and head-fixed)
- Neuronal activity induces myelin voltage changes that reflect action potential dependent myelin potassium buffering — Labarchède M, et al., bioRxiv 2025 (Mouse, oligodendrocytes, myelin, in vivo)
- Sub-Millivolt Voltage Imaging Reveals Gap Junction-Mediated Bioelectric Contact Inhibition — Rühl P, Hussein R, Reuter S, Frahnert K, Nair AG, Mrowka R, Schönherr R, Heinemann SH, bioRxiv 2026 (HEK293T cells, in vitro (ASAP3 benchmarked alongside rEstus2s))
- Ultrasensitive voltage imaging reveals distinct electrical microdomains in neurons — Hao YA, Jayne LL, Lee S, Dittrich MN, Zhang M, et al., bioRxiv 2026 (Mouse, cortex PV interneurons, in vivo (ASAP3 photostability vs ASAP7y); cultured neurons; HEK293 cells, in vitro)
- Movement-stabilized three-dimensional optical recordings of membrane potential changes and calcium dynamics in hippocampal CA1 dendrites — Gonzalez KC, et al., Neuron 2026 (Mouse, hippocampus CA1, dendrites and soma, in vivo)
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.