Timbre Encoding in the Inferior Colliculus

Spectral features, such as the spectral centroid and spectral peaks, are critical features of sounds with timbre, including speech and music. This study addresses a critical gap in knowledge about timbre representation in the auditory system by investigating neural encoding of spectral peaks in the inferior colliculus. Results demonstrate that spectral peaks are robustly represented in average rate responses across sound levels, and that neural discrimination thresholds are on a par with human thresholds. We found that a computational model with broad inhibition that is sensitive to neural fluctuations in peripheral responses may underly spectral-peak encoding. These findings extend previous vowel encoding studies to provide broader insights into timbre processing, with potential applications for improving hearing-aid and cochlear-implant technologies.