Intensity-invariant coding in the auditory system

► How the auditory system represents sounds invariantly across the full intensity range of hearing is an unresolved problem. ► Individual neurons spanning narrow, overlapping dynamic ranges appear to contribute to this ability. ► Individual neurons adapting to recent stimulus statistics in complementary fashion appear to contribute to this ability. ► Unique spectral response classes appear to contribute to this ability. ► How these factors and possibly others combine to create intensity-invariance of sound perception awaits further investigation.