Figure 6.

In vivo focal photoexcitation of channelrhodopsin-labeled astrocytes leads an increase in capillary blood flow. We used GFAP-Cre+/− mice with an injection of adeno-associated virus serotype 2/5 with a FLEX-ChR2-tdtomato construct (Zhuo et al., 2001). Histological analysis shows that these animals have weak, non-specific expression of Cre recombinase in cortical neurons during adulthood, when the viral injection was made; thus the present data must be considered as preliminary. (A) Schematic of measurement region. (B) Planar image from layer 2/3, obtained with TPLSM, that includes a scanned capillary. (C) Change in capillary red blood cell speed upon activation of ChR2; the black line is a running average to remove heart rate contributions.