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Postsynaptic recordings revealed regularly timed bursts of EPSPs in some afferent neurites. Oscillatory hair cells preferentially amplified sinusoidal stimuli at frequencies near their natural oscillation frequency. Partial blockade of I BK changed the amplitude and frequency of oscillations and spikes, and converted some nonspiking cells into spiking cells. Some spiking hair cells fired only a brief train at the onset of a current step, but others could sustain repetitive firing (3–70 Hz). Spiking hair cells were on average taller and thinner than nonspiking hair cells, and had smaller outward currents through delayed rectifier channels ( I KV) and noninactivating calcium-activated potassium channels ( I BK,steady), and larger inward rectifier currents ( I K1). Small depolarizing holding currents, which may serve to replace the in vivo resting MET current, evoked all-or-none calcium spikes (39–75 mV amplitude) in 37% of hair cells tested, and continuous membrane potential oscillations (14–28 mV 15–130 Hz) in an additional 14% of cells. To look for membrane potential oscillations that may contribute to sensory coding or amplification in the ear, we made whole-cell and perforated-patch recordings from hair cells and postsynaptic afferent neurites in the explanted frog sacculus, with mechanoelectrical transduction (MET) blocked.