A) Overall layout of the multiphoton imaging system. Components and beam path in red represent the femtosecond laser excitation. Components in green represent the fluorescence detection pathways and image acquisition. Components in yellow represent the transmitted light DIC system for visualizing neurons during establishment of whole-cell patch.

B) Photograph of the microscope system. The laser scanner is mounted in the gray box to the left of the microscope. The locations of the upper and lower photomultiplier (PMT) detectors are indicated, together with the dichroic mirror that reflects laser light down to the objective lens. Paths of the laser beam and of emitted fluorescence light are indicated, respectively, in red and green.

C) Close-up photograph looking down on the scan head, after removing the protective cover. The path of the laser beam is indicated in red.