Detection of 0.02 μm Fluospheres in brain at 30 minutes after i.c. injection. (a) Injection of a 50 μl inoculum with a hand-held syringe. Pink Fluospheres were detected in ventricular (v) walls (yellow arrow) and on meninges (green arrows), but were not detected in brain parenchyma. (b) Microinjection of a 0.5 μl inoculum. Pink Fluospheres were detected in striatum and corpus callosum (yellow arrows), but not in ventricles (v) or on meninges (green arrowhead). Scale is same in each panel, and bar represents 500 μm.