EPC10 HEKA amplifier, filtered at 2 kHz, digitized at 5–10 kHz using Patchmaster 2x73.2 software (HEKA Elektronik; Bellmore, NY) and stored on hard disk. Stimulation was delivered with a cluster-type stimulating electrode (FHC, Bowdoin, ME) and a DS3 stimulator (Digitimer North America, LLC; Ft. Lauderdale, FL). Stimulating electrodes were placed in the stratum radiatum or stratum lacunosum moleculare, the dendritic fields that receive Schaffer Collateral (SC) and Perforant Path (PP) inputs, respectively. Stimuli of increasing intensity (0.2–25 mA) were applied at a 0.05 Hz frequency to establish maximal slow IPSC amplitude. Slow IPSCs evoked by SC and PP were made in each neuron, and the order of stimulation was counterbalanced across experiments. Only experiments with stable (<20% variation) and low series resistances (<30 MΩ) were analyzed.
