MAPT and Dravet syndrome: We found similar levels of RIPA-soluble tau in the cells treated with brain extracts from control and DS brains (Fig. 6a), but significantly increased RIPA-insoluble tau in the cells treated with the extracts of TC, FC, OC, and CC, but not CBC, of DS compared with corresponding regions from control cases (Fig. 6a,b), indicating tau seeding activity in DS cerebral cortices and CC but not in CBC.