Albert J. Berger

berger@u.washington.edu
Professor, Department of Physiology & Biophysics

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The overall goal of our research program is focused on understanding mechanisms responsible for alteration in excitability of central nervous system neurons important in respiration. Currently we are using an in vitro brainstem slice preparation to investigate an important class of respiratory motoneuron, the hypoglossal motoneuron. Activity of these motoneurons causes tongue muscle contraction, and is therefore important in a variety of behaviors including: respiration, chewing, swallowing, suckling and speech. We expect that knowledge of the motoneurons will reveal roles for these neurons in normal respiratory-related behaviors and also in potentially lethal failures in this system. Failure of the upper airways to remain open during sleep is responsible for obstructive sleep apnea, and we hope that a better understanding of the function, development and synaptic activation of hypoglossal motoneurons will lead to an understanding and treatment for this disorder.

We are pursuing several interrelated projects, in all projects we record from hypoglossal motoneurons or inhibitory interneurons that synapse onto these motoneurons. Each cell type is directly visualized in slices using infra-red illumination and differential interference optics. In one project we are studying in the rhythmic slice preparation whether GABAergic receptor-mediated synaptic events are important for the inspiratory-related behavior of hypoglossal motoneurons. We hypothesize that GABA-mediated synaptic events shape the inspiratory phase behavior of these motoneurons. In another project we are studying both sub-threshold and spike firing resonance behavior of hypoglossal motoneurons. We believe that inspiratory synaptic drive interacts with intrinsic resonance properties of these neurons to more efficiently drive the cells to fire action potentials.