MAPT and semantic dementia: As we will mention below, the mouse transgenic VLW line expressing a 4-repeat tau isoform and bearing three FTDP-17 mutations [149], presents multiple FTDP-17 pathological features [150,151] and shows epileptic activity as well as a higher sensitivity to the GABAA (Gamma aminobutyric acid A) receptor antagonist pentylenetetrazol (PTZ) (Figure 1) [152].