An R-CaMP1.07 reporter mouse for cell-type-specific expression of a sensitive red fluorescent calcium indicator
A, Confocal image of a fixed brain slice illustrating R-CaMP1.07 expression across cortical layers of S1 barrel cortex after virus injections. B, Left: In vivo two-photon images of neurons expressing R-CaMP1.07 at different imaging depths down to L6. Right: Example spontaneous calcium transients in three example neurons (marked) per imaging field. C, Simultaneous fluorescence measurement and juxtacellular AP recording from an R-CaMP1.07-expressing L2/3 pyramidal neuron. Inset shows pipette attached to the cell. The ΔF/F trace shows calcium transients with variable amplitude, even resolving single-AP evoked transients. The number of spikes per burst is indicated below the voltage trace. D, Average ΔF/F calcium transient for R-CaMP1.07 in response to a single AP in red and (± S.E.M in grey; n = 49). E, Peak amplitudes of ΔF/F calcium transients as a function of the number of APs within short AP bursts (300-ms time window; mean ± S.E.M.).