Post-stimulation effects on the auditory brain stem response partial-masking and enhancement.
The auditory brain stem response (ABR) was recorded in human subjects using the stimulus configuration of a tone-on-tone forward-masking paradigm, but with all stimuli at suprathreshold levels. A masking stimulus preceded, by delta t msec, the probe stimulus which elicited the ABR. The latency vs. delta t functions for waves III and V were essentially parallel to each other and were interpreted in terms of a partial forward-masking effect, possibly originating in the cochlea. Likewise, the amplitude function for wave III showed varying degrees of decrement as a function of delta t that was also compatible with a partial forward-masking interpretation. In contrast, wave V showed an amplitude increment relative to the unmasked wave that was maximal for delta t values of 15 and 45 msec. The amplitude increment in wave V was termed enhancement and was interpreted as a central process governed by the timing of sound sequences.
D001933:Brain Stem / Q000502:physiology*; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory; D006801:Humans