Here you see a very large “endbulb” synapse in the auditory pathway of the chicken. The auditory nerve (red) contacts its target cell in the brain (green) with a large surface area to ensure secure transmission at this synapse.

GABA B receptors are important signaling molecules for processing sound. Shown are labeled GABA B receptors (purple dots) in an auditory brainstem structrue with dye filled neurons (green) and their input axons (red). Here I show some of the beautiful architecture of the auditory brainstem in birds. The red labeled fibers are axons of neurons in the network devoted to sound localization. The red dots are the cell bodies of neurons

Research

I am interested in how the brain processes information about its sensory environment. The auditory system can process sound information with amazing precision. For example, auditory neurons can detect the tiny microsecond differences in arrival time of a sound between the two ears, a property that is related to a sound's location. The processing of acoustic cues is critical for all animals in a wide range of behaviors including predator-prey interactions and social communication. An elegant and elaborate neural circuitry has evolved in species across the animal kingdom to process this information.

My research centers on the question of how cellular, synaptic, and systems level properties are integrated to allow sensory neurons to extract and represent features of the acoustic environment. The vertebrate auditory system is composed of a rich network of brain regions that process sound signals over interconnected neural pathways. In general, each brain center is devoted to the computation of specific properties of sounds and these properties are encoded by virtue of the synaptic connections and intrinsic properties of neurons in the network.

My specific interest has been the contributions made by inhibition in neural circuits that compute the location of sound stimuli. In both birds and mammals, a striking neural circuitry exists in the brainstem that is devoted to this process. One goal of the lab is to use a comparative approach to evaluate how these two systems have evolved to solve the common problem of locating sound sources.

Students in my lab will learn to utilize a diverse array of techniques to explore the anatomical and electrical properties of neurons and their circuits. The long-term goal of the lab is to gain a holistic and mechanistic picture of this complex sensory network. If you are interested in learning more, please feel free to contact me.

Publications

Book Chapter:
Burger, R. M. and Rubel, E. W. Encoding of interaural timing for sound localization. The Senses: a Comprehensive Reference, Audition.  Eds. Hoy, R., Dallos, P., and Oertel, D., Elsevier Inc., In Press.

Journal Papers:
Howard, M.A., Burger, R.M., and Rubel, EW., A developmental switch from GABAergic excitation to inhibition controlled by K+ conductances. Journal of Neuroscience, 27(8):2112-2123, 2007.

Burger, R.M., Pfeiffer, J.D., Westrum, L.E., Bernard, A., and Rubel, E.W, Expression of GABA B receptor in the avian auditory brainstem: ontogeny, afferent deprivation, and ultrastructure. Journal of Comparative Neurology, 489:11-22, 2005.

Lu, Y., Burger, R.M., and Rubel, E.W. GABA B Receptor Activation Modulates GABA A Receptor-mediated Inhibition in Chicken Nucleus Magnocellularis Neurons. Journal of Neurophysiology, 93:1425-38, 2005

Burger, R.M., Cramer, K.S., Pfeiffer, J.D., and Rubel, E.W, The avian superior olivary nucleus provides divergent inhibitory input to parallel auditory pathways. Journal of Comparative Neurology. 481(1): 6-18. 2005.

Pollak G.D., Burger, R.M., Klug A. Dissecting the circuitry of the auditory system. Trends in Neurosciences. 26(1): 33-9. 2003.

Pollak G.D., Burger, R.M., Park T.J., Klug A., Bauer E.E. Roles of inhibition for transforming binaural properties in the brainstem auditory system. Hearing Research. 168(1-2): 60-78. 2002.

Burger, R.M. and Pollak, G. D. Reversible inactivation of the dorsal nucleus of the lateral lemniscus reveals its role for processing multiple sound sources in the inferior colliculus. Journal of Neuroscience. 21(13): 4830-4843. 2001.

Klug, A.K., Khan, A., Burger, R.M., Bauer, E.E., Hurley, L.M., Yang, L., Grothe, B., Halvorsen, M.B., and Park T.J. Latency as a function of intensity in auditory neurons: transformations along the neuraxis. Hearing Research, 148:107-123. 2000.

Burger, R.M. and Pollak, G.D. Analysis of the role of inhibition in shaping responses to sinusiodally amplitude-modulated signals in the inferior colliculus. Journal of Neurophysiology 80: 1686-1701. 1998.

Links

• http://www.zi.biologie.uni-muenchen.de/institute/zi/abtlgn/neurobiologie/index.html
• http://www.humboldt-foundation.de/en/
• http://depts.washington.edu/rubelab/

Just for fun....

Here I am on the edge of the crater atop Mt. St. Helens with Spirit Lake and Mt. Rainier in the background one year before the current eruption.

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