NPY and epilepsy: Finally, in more specific terms, the present study provides a number of major novel findings to be taken into account for the NPY/Y2 system as a gene therapy approach for epilepsy: (i) the identification of the most optimal serotype, AAV1 over AAV8 and AAV2; (ii) transgene sequence of the vector, NPY/Y2 over Y2/NPY; and finally the ability of this vector to express transgenes in human tissue.