To determine the functional properties of MS-DG projections in regulating GABAergic transmission in DG, we injected AAV5-DIO-YFP-ChR2 into the MS of 6 months old Vgat-WT or Vgat-AD mice (Fig. 5A) and recorded sIPSCs of GCs in response to optogenetic activation of MS-DG GABAergic projections in acute slice preparation (Fig. 5B). This evidence concerns the gene SLC32A1 and Alzheimer disease.