Physiological recordings of a type 3 tonic acoustic afferent. A, Response to a single 10 msec cricket-like sound pulse (1 msec rise–fall, 5 kHz, 85 dB SPL). Calibration: 2 mV, 10 msec. B, Tonic response for the duration of the 100 msec at its BF, 7 kHz at 85 dB SPL. Calibration: 2 mV, 10 msec. C, Raster and PST histogram of a type 3 afferent in response to the repetition of the 100 msec stimulus at 1 Hz. The latency for the first two spikes is relatively invariant compared with the timing of the subsequent spikes during the rest of the stimulus (bin width, 20 μsec).