MAPT and Alzheimer disease: Intrahippocampal injections of AD-patients’ CSF into young P301S tau mice resulted in an increased number of AT8 positive hippocampal neurons at the injection level, as compared to CTR CSF inoculated mice (Fig. 1a-c, mean neuron count per area CTR CSF/AD CSF: 0,049/0,611, p = 0,001, for comprehensive overview on the statistical data see Additional file 1: Table S1).