Analysis of neurophonic potentials evoked with standard clicks. Data from monaural stimulation. A: time course of neurophonic potentials. The x axis shows the time after recording onset. The click was presented at 10 ms after recording onset. The 128 individual traces are stacked on top of each other. Scale bar: 25 mV. B: mean of the 128 traces shown in A. Scale bar: 2.5 mV. C: normalized amplitude of the Fourier transform (512 points) of the mean response from 9.984 ms (data point 480) to the end of the recording. Note the different spectral components. The dotted line indicates the high-pass filter used for the separation of the components. D: high-pass filtered click-evoked mean response (—) and fit of this response with a Gammatone function of order 3 (). The envelope of the Gammatone function is shown by the · - · line. The group delay (τgr) corresponds to the peak of the envelope. The signal-front delay (τfr) and the phase delay (τph) were determined from the filtered, but unfitted data (see also text). Scale bar: 2.5 mV. E: histogram of the variation of the 3 delay measures obtained from 96 recording sites (176 data sets, 89 left and 87 right stimulation, 128 repetitions each). : phase delay, - - -: signal-front delay, —: group delay. The bin width was 10 µs for the phase delay, 20 µs for the group delay, and 30 µs for the signal-front delay. Note that SDs are plotted, allowing for an analysis with a bin width that is smaller than the sampling interval.