Together with previous studies indicating elevation of HDAC activity in pathological AD (Francis et al., 2009; Ricobaraza et al., 2009; Govindarajan et al., 2011; Gräff and Tsai, 2013; Sen et al., 2015), these data suggest that histone acetylation could be suppressed by elevated HDAC activity, resulting in deficits in gamma oscillations in PSAPP mice. The gene discussed is HDAC9; the disease is Alzheimer disease.