Fig. 3: Two-photon fluorescence microscopy of miRFP720 in the mouse brain.

a Schematic of the AAV-mediated expression of miRFP720 injected at 0.8 mm depth beneath the brain surface. Created in BioRender⁷⁶. b Volumetric two-photon fluorescence microscopy image of the miRFP720-expressing brain of the Blvra^−/− mouse, showing a maximum imaging depth of ~2.2 mm. Three representative images at 0.8 mm, 1.4 mm, and 2.2 mm depth are also presented. The inset image at the 1.2 mm depth showcases two individual cells. The dashed boxes indicate the region of interest (ROI) and background region (BK) for quantitative analysis of the contrast-to-noise ratio. c Two-photon fluorescence microscopy image of the miRFP720 expression in Blvra^−/− brain slice. d Volumetric two-photon fluorescence microscopy image of the miRFP720-expressing brain of the WT mouse, showing a maximum imaging depth of ~1.3 mm. e Representative depth-dependent two-photon fluorescence signal decay for the Blvra^−/− mouse and the WT mice. f Depth-averaged two-photon fluorescence signals of miRFP720 of the Blvra^−/− and WT mice. Data are presented as mean values +/- SD (n = 3 independent injection sites). An unpaired (parametric, two-tailed) Student’s t-test, p = 0.0096. Source data are provided as a Source Data file.