A, CNQX (10 μm, n= 7), bicuculline (10 μm, n= 7) and strychnine (4 μm, n= 6) all significantly reduced power amplitudes and power areas of 4-AP (50 μm) induced rhythmic oscillatory activity whereas d-AP5 (50 μm, n= 4) had no effect. B, carbenoxolone (100 μm, n= 7), octanol (1 mm, n= 10), quinine (250 μm, n= 9) and mefloquine (500 nm, n= 9) significantly reduced power amplitudes and power areas of spectra derived from 4–12 Hz rhythmic oscillatory activity. All data for drug effects are expressed as percentage reductions against values obtained in 4-AP alone.