GAD1 and major depressive disorder: To investigate the function of LSvGABA–PVN projections in anxiety and depression-like behaviors, AAV-DIO-hM3D(Gq)-mCherry, AAV-DIO-hM4D(Gi)-mCherry, or AAV-DIO-mCherry was injected into the LSv, whereas a retro-AAV containing the GAD1 promoter and Cre element (AAV(Retro)-vGAT1-Cre) was injected into the PVN (Figures 5A,B).