Reichenbach, T. , Etard, O. & Forte, A. E.
Imperial College London
Humans are highly skilled at analysing complex acoustic scenes. We can, for instance, understand a particular speaker even in noisy environments such as a loud bar or restaurant. The segregation of different acoustic streams and the formation of corresponding neural representations is mostly attributed to the auditory cortex. Decoding the focus of selective attention from neuroimaging has therefore focussed on cortical responses to sound. Here, we show that the auditory brainstem response to speech is modulated by attention as well [1]. We achieve this results through developing a novel mathematical method for measuring the brainstem response to the pitch of continuous speech, an acoustic stimulus that does not repeat and that has a high ecological validity. We then employ this method to assess the brainstem's activity when a subject listens to one of two competing speakers, and show that the brainstem response is consistently modulated by attention. Our results show that the auditory brainstem already participates in the active sensing of a speech signal in background noise.
[1] A. E. Forte, O. Etard and T. Reichenbach (2017) The human auditory brainstem response to running speech reveals a subcortical mechanism for selective attention, eLife 6:e27203.