Simultaneous monitoring and manipulation of neuronal activity by co-expression of R-CaMP1.07 and ChR2.

<p><b>A</b>, A projection image of a CA3 pyramidal cell expressing R-CaMP1.07 and ChR2. The cell was whole-cell recorded to measure the number of APs. <b>B</b>, Imaging of ChR2-triggered-APs by changes in the R-CaMP1.07 fluorescence (top). APs were evoked by a pulse of 470-nm light with a duration of 300 to 3000 ms (blue region indicates time of photostimulation). Putative Ca²⁺ increases during the photostimulation are represented by broken lines (Bottom). The number of APs was recorded using the current-clamp mode. <b>C</b>, Δ<i>F</i>/<i>F</i> amplitude of the R-CaMP1.07 responses as a function of the number of APs induced by photostimulation. The peak Δ<i>F</i>/<i>F</i> amplitudes were calculated from the first frames after termination of the photostimulation. Individual data are plotted as black dots and their averages are shown in red. Error bars, s.e.m. (<i>n</i> = 4 cells).