Temporal niches in auditory communication

Luc. H Arnal and Keith B. Doelling, Institut de l’Audition, Centre Pasteur, Paris XII.

Communication signals such as speech or music, are complex signals that exploit acoustic features in a wide array of timescales. The auditory system responds differently to each timescale creating opportunity for sound designers, composers and human talkers to exploit these temporal niches to manipulate listeners’ affective states and reactions. Exploring human perception and reactions to a wide range of time scales (from a few to hundreds of milli-seconds) we will show that fast (>30 Hz) and slow (<10 Hz) temporal regularities are processed in a very different manner by the human brain and rely on distinct neural mechanisms. On the one hand, stimuli with high frequency dynamics – such as alarm signals – temporally overload the auditory system to induce aversive percepts, arguably by driving the sustained propagation of information in a bottom-up manner. On the other hand, slower stimuli – as featured in musical rhythms – permit the development of anticipatory processes, relying on slower, top-down oscillatory mechanisms. By analyzing the temporal dynamics in the acoustics of signals with different communicative goals (alarm, music) and their impact on the human brain, we identify and characterize specific neural systems and mechanisms shaping the diversity of auditory communication niches in the temporal domain.