In order to focus on a particular conversation, listeners need to be able to focus on the voice of the speaker they wish to listen to. This process is called selective attention and has been extensively studied within the auditory cortex. However, due to neural feedback from the cortex to lower auditory areas, the auditory brainstem as well as the inner ear, these structures may already actively participate in attending to a particular voice.
We have devised a mathematical method to measure the response of the auditory brainstem to the pitch of natural speech. In a controlled experiment on selective attention, we have then shown that the brainstem responds stronger to the pitch of the voice that a person is listening to than to that of the ignored voice. Our findings demonstrate that the brainstem contributes already actively to selective attention. They also show that the pitch of a voice can be a powerful cue to focus on that voice, which may inspire future speech-recognition technology.
A. E. Forte, O. Etard and T. Reichenbach,
The human auditory brainstem response to running speech reveals a subcortical mechanism for selective attention,
eLife 6:e27203 (2017). [pdf] [bioRxiv]