“…The freshly separated hippocampi were sliced at 400 μm thickness using a vibrating slicer ( VT1200S , Leica). After a recovery incubation at room temperature for 2 h (Mathis et al, 2011; Ting et al, 2014) in a solution containing 92 mM NaCl, 2.5 mM KCl, 1.25 mM NaH 2 PO 4 , 30 mM NaHCO 3 , 20 mM HEPES, 25 mM glucose, 2 mM thiourea, 5 mM Na‐ascorbate, 3 mM Na‐pyruvate, 2 mM CaCl 2 , 2 mM MgSO 4 , and 3 mM N‐Acetyl‐ l ‐cysteine, with pH and osmolality set to 7.3–7.4 and 300–310 mOsm, respectively, and saturated with a gas mixture of 5% CO 2 + 95% O 2 with persistent blowing, the slice was transferred to a recording chamber and continuously perfused with aCSF for recording. The stimulation electrode (concentric bipolar tungsten electrode) and recording pipette were placed in the Schaffer collateral commissure fibers and stratum radiatum of the hippocampal CA1 region, respectively.…”