It’s the season for parties, get-togethers and crowds. Have you ever had trouble putting background noise in the background and focusing on the conversation that is in front of you?
This discovery may hold the key to explaining why some people, who do not have hearing problems, still find it difficult to keep track of conversations in large crowds.
A group of neurons in the auditory processing areas of the brainstem help us to tune into specific conversations in a crowded room.
It could be that the neurons in their auditory brainstem, associated with receiving pitch signals, are not properly activated.
This process of focusing on the voice of the speaker is called “selective attention” and that it happens in the part of the brain called the auditory cortex, which processes speech information.
Selective attention helps the brain to modulate sound information and to prioritize information over the background noise, such as focusing on one conversation above all others in a crowded room. However, what triggers selective attention in the auditory cortex has been debated by scientists.
The Imperial College London research experiment
Fourteen participants listened to two competing conversations. Electrodes were fitted to the participants’ heads and connected to a computer, which relayed the brain readings in the auditory brainstem. Algorithms devised by the team then decoded the information gathered by the electrodes.
“When the participants chose to focus on one conversation above the other, neurons in the auditory brainstem responded more to the pitch of the voice that they listened to rather than to the pitch of the voice that they ignored. This suggests that an important aspect of selective attention occurs in the auditory brainstem and the neural signal is then relayed to the auditory cortex, where higher level processing of auditory information occurs.”
Pitch is the key
This study shows that the pitch of the speaker’s voice we want to focus on is an important cue that is used in the auditory brainstem to focus on a target speaker. This helps us to concentrate on a voice while filtering out all the background noise.
Understanding this process in more detail could, for example, help engineers to build better hearing aids that are more adept at filtering out background noise for users, which is currently a challenge for those with hearing impairments in noisy places.