PDE4A and memory impairment: General pan-PDE4 inhibitors such as rolipram reverse learning and memory impairments in animal models of Alzheimer’s disease, psychosis, stress, and ischemia (Henkel-Tigges and Davis, 1990; Imanishi et al., 1997; Bach et al., 1999; Gong et al., 2004; Chen et al., 2010; Wiescholleck and Manahan-Vaughan, 2012; Sierksma et al., 2014).