Extraction of key features of natural speech by ventral cochlear nucleus neurons

Funded Activity Summary

Little is known about how speech is processed and transformed by the central auditory pathway, and how the critical temporal and spectral features that identify a speech sound segment (a phoneme) are extracted. To date, most studies have approached this issue by using synthetic speech and examined the responses of the peripheral auditory nerve only. The aim of this study is to examine how important features of naturally-spoken speech are encoded by the cochlear nucleus (CN) - the first station in the auditory pathway located in the brainstem. The CN is a complex of different cell types that have the capacity to transmit, transform, and encode complex acoustic information in different ways. The proposed experiments involve recording the bioelectrical signal from single CN cells in anaesthetised rats while presenting naturally-spoken syllables, both in quiet and in the presence of noise. It is important to examine what happens to the neural responses in the latter condition, because all animals must cope with the problem of extracting important signals from background noise. While noise clearly interferes with the perception of another sound, the auditory system is in fact quite good at extracting signals in the presence of noise. This is well demonstrated by our ability to understand speech in the presence of quite high noise levels. This ability is severely degraded in the hearing impaired. Thus, one of the aims of this study is to examine the mechanisms and limits of the CN's ability to encode speech in a noisy background. A greater understanding of the mechanisms the nervous system uses to extract critical features of speech will not only build on our knowledge of auditory brainstem processes, but may also provide clues to improving processing strategies for cochlear implants.

Funded Activity Details

Start Date: 01-01-2002

End Date: 01-01-2004

Funding Scheme: NHMRC Project Grants

Funding Amount: $225,330.00

Funder: National Health and Medical Research Council

Research Topics

ANZSRC Field of Research (FoR)

Medical virology

ANZSRC Socio-Economic Objective (SEO)

There are no SEO codes available for this funding activity

Other Keywords

auditory system | brainstem | hearing | neurophysiology | sensory aids/hearing aids/cochlear implants | sensory function | speech | speech perception

Related Links