What resolves this contention: Different bottleneck identification for the GEVI…

What resolves this contention: Different bottleneck identification for the GEVI field: one paper identifies a multi-parameter trade-off among near-infrared indicators, the other identifies a 2P excitation-mode failure of FRET-opsin GEVIs that can be circumvented by photocycle-aware illumination. The two limits coexist but emphasize different obstacles to scalable voltage imaging. / Neither GEVI characterized here surpasses in all three key parameters (brightness, kinetics, and sensitivity), so there is no unequivocal preference for one of the two. / However, the voltage sensitivity of most FRET-opsin GEVIs has been reported to decrease or vanish under two-photon (2P) excitation.