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stimulus = dorsoventral vibration (0.01 m/s2 rms for 1-Hz bandwidth, total band = 10 - 1,000 Hz)
{The vertical axis represents time prior to the occurrence of a spike, the horizontal axis represents frequency. The image was formed by taking the difference between the short-term power spectral densities of the noise stimuli in general and the noise stimuli that preceeded spikes. Thus zero (light blue-green) represents no difference. The darker blue areas show regions of time and frequency where the intensity of the spike-producing noise-stimulus intensity was well below the mean level (making the difference negative); the yellow-red areas show regions where it was well above the mean level (making the difference positive).} We take the image to imply that a stimulus that occurred between 2 and 10 ms ago, centered about 250 Hz, would tend to produce a spike now, and that a stimulus in the same frequency range, but occurring 12 to 25 ms ago would tend to inhibit the occurrence of the spike now. As with the lagenar unit. we intepret this inhibition to be among those phenomena commonly labeled "adaptation." We take the image to imply, as well, that a stimulus centered about 370 Hz, occurring between 6 and 9 ms ago, also would tend to inhibit the occurrence of a spike now. Because this stimulus is contempraneous with the stimulus tending to produce the spike now, we interpret this inhibition to be among those phenomena commonly labeled "suppression." Supression of this sort is not present in saccular or lagenar units. Last updated 12/27/2010