Figure 2.

Dye or drug application through the port of a chronic cranial window. The silicone plug can be easily penetrated by a glass or quartz pipette taking into account the steric limitations of the imaging setup like working distance and size of the objective lens (A). A transparent silicone plug allows avoiding blood vessels (B). The image was taken before entering the brain. Two-photon imaging shows bolus loading after penetration of the silicone plug (C). A z-axis projection through the injection site shows the pipette position and silicone/dura displacement during a typical pipette injection (D). Here,1 µM fluorescein was added to the water immersion for visualization. Following pipette retraction the silicone and dura return to their original positions (E, injection track indicated by asterisk), even after multiple injections.