The perception of sensory events can be enhanced or suppressed by the surrounding spatial and temporal context in ways that facilitate the detection of novel objects and contribute to the perceptual constancy of those objects under variable conditions. In the auditory system, the phenomenon known as auditory enhancement reflects a general principle of contrast enhancement, in which a target sound embedded within a background sound becomes perceptually more salient if the background is presented first by itself. This effect is highly robust, producing an effective enhancement of the target of up to 25 dB (more than two orders of magnitude in intensity), depending on the task. Despite the importance of the effect, neural correlates of auditory contrast enhancement have yet to be identified in humans. Here, we used the auditory steady-state response to probe the neural representation of a target sound under conditions of enhancement. The probe was simultaneously modulated in amplitude with two modulation frequencies to distinguish cortical from subcortical responses. We found robust correlates for neural enhancement in the auditory cortical, but not subcortical, responses. Our findings provide empirical support for a previously unverified theory of auditory enhancement based on neural adaptation of inhibition and point to approaches for improving sensory prostheses for hearing loss, such as hearing aids and cochlear implants.
|Original language||English (US)|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Jul 20 2021|
Bibliographical noteFunding Information:
ACKNOWLEDGMENTS. This study was supported by NIH grant R01 DC012262 (A.J.O.). We thank the two anonymous reviewers for their helpful comments. We thank Patricia Leach and PuiYii Goh for assistance with data collection and Hao Lu for advice regarding EEG data analysis. Stephen Engel provided helpful comments on an earlier draft.
© 2021 National Academy of Sciences. All rights reserved.
- Auditory perception | contrast enhancement | EEG | ASSR | perceptual invariance