Hippocampal slices were prepared as previously described28 from Baf53b+/− het mice,BAF53ΔHDlow, BAF53ΔHDhigh, and wildtype mice (approximately 2 months of age). Transverse hippocampal slices (300 μm) through the mid-third of the septotemporal axis of the hippocampus were placed in an interface recording chamber containing preheated artificial cerebrospinal fluid (ACSF; in mM): 124 NaCl, 3 KCl, 1.25 KH2PO4, 1.5 MgSO4, 2.5 CaCl2, 26 NaHCO3, and 10 D-glucose and maintained at 31 ± 1°C). Slices were continuously perfused with at a rate of 1.75-2 ml/min while the surface was exposed to warm, humidified 95% O2 / 5% CO2. Recordings began following at least 2 hr of incubation.
