A new discovery in the human auditory system

auditory

Scientists at the Montreal Neurological Institute and Hospital at McGill University have made an important discovery about the human auditory system and how to study it, findings that could lead to better testing and diagnosis of hearing-related disorders.

Discovery will inform further research into hearing disorders and brain training

Scientists at the Montreal Neurological Institute and Hospital at McGill University have made an important discovery about the human auditory system and how to study it, findings that could lead to better testing and diagnosis of hearing-related disorders.

The researchers detected frequency-following responses (FFR) coming from a part of the brain not previously known to emit them. FFRs are neural signals generated in the brain when people hear sounds.

To help pinpoint the source of FFRs, the team used magnetoencephalography (MEG), a technique that allowed them to determine the source of the FFR, because it is not affected by interference from brain and skull tissues like electroencephalography (EEG), the more commonly used method to study electrical signals in the brain.

Twenty people were selected to take part in the study after testing showed they were neurologically healthy and had normal hearing. Subjects’ neural responses to sound were measured using MEG, which records fluctuations in magnetic fields caused by neural activity.

From the MEG signal, researchers were able to detect FFR signals coming from the auditory cortex, in addition to the known sub-cortical generators, something that had not previously been detected.

By Shawn Hayward, Montreal Neurological Institute