R. Michael Burger, Ph.D.
The Research
Lehigh University
Efferent loizounction in sound localization processing
Auditory processing relies on precise coding of acoustic features to build an accurate internal representation of the environment. Sensory systems build this representation through faithful encoding of sensory stimuli at the level of sensory organs. This neural signaling is enhanced by active feedback on sensory neurons from higher central processing centers. These "efferent" pathways have been characterized for the cochlea and to some extent, in the midbrain. There is little data efferent function in the early stages of auditory processing in structures that process sound location information. This may be due, in part, to the complexity of this system in mammalian circuits. The bird auditory system is a major model for human sound localization processing. Indeed, birds process ascending circuitry that is strikingly similar to mammals in structure and function, but with efferent circuitry that is appealingly simple. My aim is to investigate this elegant efferent brain stem circuit in birds to build a comprehensive model of its function within this functionally understood auditory circuit. These studies will both characterize the neurons responsible for this feedback, and examine their impact on their targets. The long-term objective is to build a mechanistic understanding of sound localization circuitry in vertebrate systems.