Intracerebroventricular injection of AAV-tau leads to widespread expression of human tau in the mouse forebrain. (a) Schema of the three tau-encoding sequences with amino acid substitutions. (b) Representative immunolabeling of human tau (HT7 antibody) in sagittal brain section, 3 months after injection of AAV-WT shows broad expression of human tau, mainly in cortex and hippocampus. (c) Representative HT7 immunolabeling in sagittal sections shows human tau-positive neurons in cortex and hippocampus (CA1) of mice injected with either AAV-WT, AAV-P301S or AAV-2P, 3 and 7 months after vector injection. Negative HT7 staining in a control mouse injected with AAV-maxFP is shown for comparison. Scale: 100 µm.