Figure 6.
A, OGB-1 fluorescence transients in response to single action potentials in vivo. OGB-1 reliably reports individual APs in individual recorded traces with SNR > 15. A single AP was elicited every 500 ms (experimental details as in Fig. 5). Traces represent four individual measurements from different boutons (gray) and their mean (black). B, Time constants for the rise of fluorescence changes in response to fast and transient Ca2+ fluctuations. Time constants were determined for the fluorescence signals plotted in Figure 5 (volleys of 10 APs at 100 Hz, first volley analyzed). In general, GECIs with a low KD display fast rise times with the exception of YC2.60. The latter may be because of very high protein concentration. Time constants were determined for data from t = 0 to the peak of the response to the first volley fit by a single-exponential function.