Targeted Occlusion of Individual Pial Vessels of Mouse Cortex

Targeted photothrombosis is a method to occlude individual arterioles and venules that lie on the surface of the cerebral cortex. It has been used to study collateral flow patterns within the pial vascular network following occlusion of single surface vessels (Schaffer et al., 2006; Blinder et al., 2010; Nguyen et al., 2011), as well as to generate localized ischemic strokes following occlusion of single penetrating vessels (Nishimura et al., 2007; Drew et al., 2010; Shih et al., 2013). The intravascular clot is formed by irradiation of a target vessel with a focused green laser after injection of a circulating photosensitizing agent, Rose Bengal (Watson et al., 1985). We briefly describe modifications of custom-designed and commercial two-photon imaging systems required to introduce a green laser for photothrombosis. We further provide instructions on how to occlude a single penetrating arteriole within the somatosensory cortex of an anesthetized mouse.