HVCN1 and Alzheimer disease: Given this connection, we investigate the role of Hv1 in AD by performing intrahippocampal stereotaxic injection of AAVs containing human tau (AAV2/8-CAG-TAU-EGFP-3FLAG-WPRE, AAV-hTAU) or a control virus vector (AAV2/8-CAG-MCS-EGFP-3FLAG, AAV–EGFP) in male Hvcn1 knockout (Hvcn1−/−) mice and their littermate controls (Fig. 1a and Supplementary Fig. 1a).