Fig. 2
From: Excitation wavelength optimization improves photostability of ASAP-family GEVIs
Improved photostability and performance of ASAP2f with assistive illumination. a (left) An example image showing a hippocampal neuron expressing ASAP2f driven by current pulses (2 ms, 1600pA, 5 Hz; 22 pulses) delivered via a patch pipette to induce APs. Fluorescence intensity at soma (green ROI) and dendrite (red ROI) was measured separately. Scale bar: 5 μm. (middle) Example traces showing soma fluorescence change in response to APs without (−) or with (+) 405-nm assistive illumination. Spike timings are indicated by short vertical bars. (right) Amplified view of relative fluorescence change in soma and dendrite (dend) without (blue) or with (purple) 405-nm light illumination. Scale bar: − 3%, 0.5 s. b (left to right) Summary of fluorescence changes (ΔF/F), relative brightness and relative SNR in response to single APs, and decay time constant of fluorescence in ASAP2f transfected neurons with (+) and without (−) assistive 405-nm illumination. (***) indicates p < 0.001, paired t-test (n = 6); error bars are all SEM. In all experiments, light intensity of 470-nm and 405-nm light was 5 mW/mm2 and 0.5 mW/mm2, respectively. Exposure time was 5 ms for all images