The auditory steady-state response (ASSR) to an external tone was measured in an echolocating dolphin to determine if hearing sensitivity changes could be tracked over time scales corresponding to single click-echo pairs. Individual epochs containing click-echo pairs were first extracted from the instantaneous electroencephalogram. Epochs were coherently averaged using the external tone modulation rate as a timing reference, then Fourier transformed using a sliding, 10-ms temporal window to obtain the ASSR amplitude as a function of time. The results revealed a decrease in the ASSR amplitude at the time of click emission, followed by a 25–70 ms recovery.
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2013
U.S. Government
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