GABAergic Interneurons are Required for Generation of Slow CA1 Oscillation in Rat Hippocampus

Complete hippocampal formation in vitro and whole-cell recordings from CA1 PCs and FS cells. A Left, image of a completely isolated rat hippocampus (scale bar, 0.3 cm); right, image of the CA1 cell layer (scale bar, 25 μm; top view). B Representative recordings displaying the low firing rates with adaptation in a pyramidal cell (PC) and sustained firing at high rates in a fast-spiking (FS) cell recorded at depolarizing potentials indicated by arrows. Recordings were performed in the presence of the AMPAR antagonist DNQX (20 μmol/L). C For the two cells shown in B (before DNQX application), spontaneous membrane-potential changes and firing of the PC (left) and FS cell (right; inset, high temporal resolution of the fast afterhyperpolarization after the end of action potentials). Resting potentials are indicated on the left of each trace; action potentials were partially truncated