Grant: Operating Grant

Communication is a large part of what makes us human and is vital to personal health. Impediments to communication have consequences to one's confidence, perception of the world, and inclusion in employment and social activities. At times communication for healthy individuals can be challenging, but imagine the difficulty for someone with an auditory deficit. Understanding the brain's code that is the precursor to hearing can mean opening up a whole new world of communication for persons with a hearing disorder. The goal of my research is to understand the rules the mammalian central nervous system uses to encode and process acoustic information. The projects are aimed at discovering mechanisms underlying a specialized form of auditory temporal processing--neural tuning to sound duration--and to relate these mechanisms to behaviour. The auditory midbrain (inferior colliculus) contains neurons with responses highly tuned to signal duration; however, the mechanisms and pathways that create these duration-tuned neurons are still unknown, as is their role to normal hearing. The proposed experiments involve behavioural studies, recording electrical potentials from duration-tuned neurons to sound stimulation and documenting response properties, computational studies and informational analyses of the responses, and the use of drugs to block synaptic inputs and biological dyes for tracing anatomical connections to reveal the circuitry underlying duration tuning. Understanding the neural mechanisms of duration coding addresses broad issues, such as why there are multiple parallel processing pathways in the central auditory system and what role they play in hearing. The foundational knowledge gained from my research will be of enormous benefit to understanding behaviour as diverse as speech recognition and music perception, and ultimately it should have broad applications for the diagnosis and treatment of sensorineural hearing loss and language disorders.