Representative photographs of fluorescence in coronal brain sections collected 30 min after injection of the Y39-1 fluorescent tracer in the cisterna magna of WT mice (top two rows) or A 2A R -KO mice (bottom two rows), previously exposed either to normal light or to a 30 min period of 40 Hz light flickering; numbers indicate the anteroposterior distance from bregma in mm (scale bars, 1 mm).
