ABO and Alzheimer disease: To investigate the relative contribution of SST and PV interneurons to the impairment of hippocampal theta and gamma oscillations in AD, we created an AD mouse model by injecting AβO (Villette et al. 2010; Stephan et al. 2003, 2001; Walsh et al. 2002; Meyer-Luehmann et al. 2006) and co-injecting an AAV virus containing a Cre-dependent ChR2 (AAV5-Ef1a-DIO-hChR2(ET/TC)-mCherry) into hippocampal CA1 region unilaterally (Fig. 1a) as well as bilaterally (Online resource Fig. 1) in either SST-Cre or PV-Cre mice.