GEVIBench › All sensors › ASAP5
ASAP5
Optimized for detecting subthreshold activity, with the steepest F-V slope near resting potential.
- Category: VSD-cpGFP GEVI
- Published: 2024-09-20 — Neuron 2024
- Derived from: ASAP3
- Response polarity: negative-going (fluorescence decreases on depolarization)
- Spectrum: excitation peak 488 nm, emission peak 525 nm (ASAP5)
- Two-photon compatible: yes
- Plasmid: Addgene #225709
- Tags: cpGFP, Two-photon
Headline values (as shown in the GEVIBench table)
| Metric | Value | Definition |
|---|---|---|
| Brightness (B/B_EGFP) | 0.31× 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) | 3.0 / 2.6 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 | -57% (median of 2 measurements: −57%) | 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 | 1.3% | 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 | 34% (median of 2 measurements: 34%) | 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) | 4 ms | Full width at half maximum of the optical spike waveform. |
| Photostability t75% @ 100 mW/mm² | 17 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) | 11 | 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 2.97 ms, τ_off 2.62 ms at 37°C — Hao 2024, Table S2
- τ_on 6.02 ms, τ_off 17.2 ms at 23°C — Hao 2024, Table S2
ΔF/F per 100 mV
- -57%, 1P — Hao 2024, Fig. 1D
- -35.2%, 2P — Land 2026, Ext. Fig. 1b
ΔF/F per mV (subthreshold)
- 1.3%/mV — Hao 2024, Fig. S1C
ΔF/F per action potential
- 34%, 1P — Hao 2024, Fig. 1F
- 13%, 2P — Hao 2026, Fig. 2k
AP width (FWHM)
- 1.3 ms at 7142 Hz sampling, Mouse, visual cortex L2/3 pyramidal neurons, awake behaving, in vivo, soma-targeted ASAP5-Kv (ULoVE 2P), 2P, 37°C — Hao 2024, Fig. S4E
- 6.8 ms at undefined Hz sampling, Rat, cultured cortical neurons, current-evoked APs, in vitro — Hao 2026, Fig. 1c
Brightness comparisons
- 1× the brightness of ASAP3 — Hao 2024, Fig. 1G
- 1.5× the brightness of ASAP4e — Lee 2024, Table S4
- 0.78125× the brightness of ASAP7y — Hao 2026, Fig. 2l
- 0.6896551724137931× the brightness of JEDI-2P — Land 2026, Ext. Fig. 1c
- 0.8× the brightness of JEDI-3hyp — Land 2026, Ext. Fig. 1c
- 0.7194244604316548× the brightness of JEDI-3sub — Land 2026, Ext. Fig. 1c
Photobleaching
- t75% = 37.6 s (extrapolated) at 46 mW/mm², 1P — Hao 2024, Fig. S5E
- curve only (did not reach 75% within the measured window) at 16 mW at 940 nm (2P power-only), 2P — Hao 2026, Fig. 2g
- curve only (did not reach 75% within the measured window) at 25 mW at 920 nm (2P power-only), 2P — Hao 2024, Fig. 3A
- t75% = 970 s at 30-160 mW at 925 nm (2P power-only), 2P — Hao 2024, Fig. S4A
Fluorescence–voltage (F–V) curve
ΔF/F (%) at each membrane potential, normalized to 0 at −70 mV: -120 mV: 57%; -100 mV: 38%; -80 mV: 14%; -70 mV: 0%; -60 mV: -13%; -40 mV: -33%; -20 mV: -45%; 0 mV: -52%; 30 mV: -57%; 50 mV: -59%; 80 mV: -60% — Hao 2024, Fig. 1D
Research papers using ASAP5 (11)
- A fast and responsive voltage indicator with enhanced sensitivity for unitary synaptic events — Hao YA, Lee S, Roth RH, Natale S, Gomez L, Taxidis J, et al., Neuron 2024 (HEK293A cells; cultured rat/human neurons; mouse motor/barrel cortex and hippocampus; Drosophila Mi1 and TPN-II; zebrafish tectum; in vitro and in vivo)
- Ultrasensitive voltage imaging reveals distinct electrical microdomains in neurons — Hao YA, Jayne LL, Lee S, Dittrich MN, Zhang M, et al., bioRxiv 2026 (Drosophila Mi1 and TPN-II neurons, in vivo; cultured cortical neurons; ASAP5 characterized alongside ASAP7y)
- Deep two-photon voltage imaging with adaptive excitation — Zhao S, Hebert E, Gruzdeva A, Mahishi D, Takahashi H, Lee S, Hao YA, Lin MZ, Yapici N, Xu C, Research Square 2024 (Mouse, visual cortex, in vivo)
- A deep learning framework for automated and generalized synaptic event analysis — O'Neill PS, Baccino-Calace M, Rupprecht P, Lee S, Hao YA, Lin MZ, Friedrich RW, Mueller M, Delvendahl I, eLife 2025 (Rat, hippocampal neurons, in vitro)
- Selective life-long suppression of an odor processing channel in response to critical period experience — Leier HC, et al., bioRxiv 2025 (Drosophila, olfactory sensory neurons, in vivo)
- Retroreflective beam multiplexing enables high-throughput two-photon voltage imaging in vivo — Liu Z, Han M, Chen Y, Downs NP, Wu J, bioRxiv 2025 (Mouse, visual cortex, hippocampus, in vivo)
- Kilohertz-rate two-photon voltage imaging of population dynamics in vivo — Zhang M, et al., bioRxiv 2026 (Mouse, cortical neurons, in vivo)
- Designer indicators for two-photon recording of subthreshold voltage dynamics — Land MA, Galdamez M, Villette V, Zhu J, Lu X, Marosi M, et al., Nature Methods 2026 (HEK293 cells, in vitro; Mouse, visual cortex L2/3, in vivo)
- Highly attenuated dendritic propagation of isolated synaptic potentials in vivo — Cornejo VH, Bouazza-Arostegui B, Alejandre-Garcia T, Hao YA, Lee S, Lin MZ, Yuste R, Science Advances 2026 (Mouse, somatosensory cortex L2/3 pyramidal dendrites and spines, in vivo (two-photon voltage imaging with ASAP5 targeted by the PSD95.FingR nanobody, with simultaneous somatic whole-cell patch clamp))
- Structure-guided, physics-aware reconstruction expands scan-limited multiphoton imaging — Liu S, et al., bioRxiv 2026 (Mouse, somatosensory cortex, in vivo (AAV-CaMKIIα-ASAP5-Kv two-photon voltage imaging))
- Voltage imaging of neurons distributed across entire brains of larval zebrafish — Wang Z, et al., Nature Methods 2026 (Zebrafish larva, whole brain, in vivo (sparse transient ASAP5-Kv expression used to verify that spikes resolved at 1,000 Hz survive downsampling to 200 Hz; ASAP5-Kv kinetics also used in the sampling-rate simulations))
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.