Hearing Research
Our goals are to understand neural mechanisms of hearing. In mammals, sound is converted to neural signals in the sensory organ of the inner ear and these signals enter the brain by way of the auditory nerve. The signals are distributed to various neuron classes in the cochlear nucleus before being sent to higher centres. The cochlear nucleus therefore serves as the gateway to the central auditory system because it gives rise to all ascending pathways. How auditory information is processed and where the signals get delivered next will depend greatly on the synaptic organization of auditory nerve inputs.
The relatively homogeneous responses of incoming auditory nerve fibers are transformed into a variety of different response patterns by the different classes of resident neurons. The spectrum of responses depends not only upon the excitatory drive of the auditory nerve but also on inhibitory circuits and descending projections that have a modulatory function. Moreover, we must consider the types and distribution of receptors, ion channels, G proteins, and second messengers. These features form the signaling capabilities for each cell class. In order to understand how sound is normally processed, there is a need to study identified cell populations, to analyze their synaptic connections, and to reveal features of their signal processing capabilities. This kind of information will allow us to follow signals through different circuits in the auditory system as the brain assembles the various components of sound into a cohesive percept. The cochlear nucleus is not only a key structure in normal hearing but also for the consequences of deafness.
Disruption of hearing can occur at anytime during the life of an organism. Hearing loss can be congenital or acquired, complete or partial, and can affect one or both ears. The neuropathology of this loss, however, is not restricted to the inner ear. Abnormalities in synapses and circuits can radiate away from the damaged site and affect wide regions of the auditory system, and these alterations are just beginning to be identified. Restoration of hearing loss requires far more than mere amplification of sound - spatial hearing is compromised, there is a devastating inability to understand speech in noisy environments, and tinnitus or "ringing of the ears" must be addressed. Consequently, our studies seek to provide new knowledge toward understanding basic mechanisms of hearing so that we can begin to plan data-based treatment strategies when problems with hearing arise.
Staff
 Research OfficerMichael Muniak |
 Electron MicroscopistTan Pongstaporn |
 Research AssistantCatherine Connelly |
 Honours StudentKirupa Suthakar |
 Research AssistantAlex Borecki |
