LRRK2 and Parkinson disease: We extended here our previous studies on adult hippocampal neurogenesis [4,14-16,19] in two different transgenic mice mouse models of PD generated in our laboratory, the Line 61, expressing the human wild type SNCA gene and Line 29 that expresses LRRK2(G2019S), by investigating the effects of MB and PQ exposure and with the aim to model gene x environment interactions in familial and sporadic PD manifestations.