Perhaps the best studied aspect of AS and other Ube3a mouse models are the electrophysiological properties of affected neurons. Reduced LTP has been observed in hippocampal CA synapses (Jiang et al., 1998; Weeber et al., 2003) as well as in visual cortex (Yashiro et al., 2009; Sato and Stryker, 2010) of AS model mice. Like dendritic spine density, LTP in visual cortex is not significantly different between wild-type and Ube3am−/p+ mice that were raised in darkness (Yashiro et al., 2009). In addition, reduced NMDA-dependent LTD has been reported in the visual cortex of Ube3am−/p+ mice raised in normal conditions (Yashiro et al., 2009), whereas enhanced mGluR-dependent LTD has been reported in hippocampal CA1 synapses (Pignatelli et al., 2014). A decreased AMPA/NMDA current ratio has also been reported in Ube3am−/p+ CA1 hippocampal neurons (Greer et al., 2010), but this ratio is unchanged in Ube3a2xTg barrel cortex (Smith et al., 2011). Whole-cell patch clamp recording revealed reduced frequency and amplitude of mEPSCs in the dorsomedial striatum of Ube3am−/p+ mice, but not in the dorsolateral striatum (Hayrapetyan et al., 2013). Layer 2/3 pyramidal
