Rise-fall time effects on the brainstem auditory evoked response: mechanisms.

Experiments were conducted to assess the contribution of place mechanisms to the effect of rise--fall time on wave V of the human brainstem auditory evoked response (BAER). Noise bursts of 4- and 10-ms duration were presented at various rise-fall times (0, 1, 2, and 5 ms). Subtractive high-pass masking techniques were used to determine the effect of rise time as a function of derived-band frequency. In general, increasing rise time prolonged wave V latency but did not affect amplitude. Rise-time effects did not depend on derived-band frequency and similar effects were seen in the unmasked conditions. In addition, narrowing the derived band did not alter the observed effects on latency and amplitude. Signal envelope showed no effects on traveling wave velocity. These results suggest that place mechanisms contribute little to changes in the BAER associated with rise--fall time.