Extended Data Fig. 8: Detection of 50-Hz AP trains in acute hippocampal slice.

(A) One-photon imaging of patch-clamped CA1 neurons in acute hippocampal slices expressing either ASAP3-Kv (n = 4 cells) or ASAP4b-Kv (n = 4 cells). Spike trains were evoked with current pulses, and voltage waveforms and GEVI (1000 frames per second) were recorded. Mean unfiltered responses of 12 sweeps in total are displayed with gray areas representing SEM. (B) Empirical SNR (ΔF divided by SD of F₀) for single-AP one-photon responses of ASAP3-Kv and ASAP4b-Kv during spike trains. Mean ± SD is plotted. A Kruskal-Wallis test followed by Dunn’s multiple comparison test was used to compare ASAP4b-Kv to ASAP3-Kv for each spiking frequency, revealing significantly higher SNR of ASAP3-Kv at 50 Hz (multiplicity-adjusted p < 0.0001 from 522 spikes for ASAP3-Kv and 351 spikes for ASAP4b-Kv). (C) Two-photon imaging of pyramidal neurons in acute hippocampal slices expressing either ASAP3-Kv (n = 6 cells, 21 sweeps total) or ASAP4b-Kv (n = 5 cells, 15 sweeps total). Mean unfiltered responses are displayed with gray areas representing SEM. (D) Empirical SNR (ΔF divided by SD of F₀) for single-AP one-photon responses of ASAP3-Kv and ASAP4b-Kv during spike trains. Mean ± SD is plotted. A Kruskal-Wallis test followed by Dunn’s multiple comparison test was used to compare ASAP4b-Kv to ASAP3-Kv for each spiking frequency, revealing significantly higher SNR for ASAP4b-Kv at all frequencies (multiplicity-adjusted p < 0.0001, from 475 spikes for ASAP3-Kv and 375 spikes for ASAP4b-Kv).