Dr. Albert J. Berger

The overall theme of our research program is respiratory neurobiology. Currently we are using a mammalian in vitro brainstem slice to investigate an important class of central respiratory neuron, the hypoglossal motoneuron. Activity of these motoneuronscauses the tongue muscle to contract, 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 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 investigating these cells. In all projects we record whole-cell currents and single channel activity from motoneurons that are directly visualized in slices using infra-red illumination and differential interference optics. In one project we are studying the development of GABA and Glycine mediated co-transmission to hypoglossal motoneurons. Glycinergic and GABAergic spontaneous synaptic currents are differentiated based on their pharmacological and kinetic properties. Quantitative assessments are made using templates for glycine-receptor and GABAA-receptor mediated synaptic events from individual neonate and juvenile HMs. We are assessing whether these template weightings change with postnatal development. In another project we are studying in hypoglossal motoneurons the postsynaptic mechanisms whereby ethanol modulates glycine-receptor mediated synaptic currents. We hypothesize that ethanol increases the affinity of glycine-receptors for glycine and thereby potentiates inhibitory synaptic events. In another project we are using a recently developed rhythmic slice preparation to investigate whether glycine and/or GABA receptor-mediated synaptic events are important for the respiratory-related behavior of hypoglossal motoneurons. We hypothesize that glycine and/or GABA-mediated synaptic events shape the inspiratory phase behavior of these motoneurons, most of the effects occurring via a shunting inhibition of excitatory respiratory drive.

Referee: Journal of Comparative Neurology, 1980-1981/1986-1991;
Respiration Physiology, 1979-1980;
Associate Editor, American Journal of Physiology: Lung Cellular and Molecular Physiology, 1988-1992;
Editorial Board, American Journal of Physiology: Integrative and Comparative Physiology, 1988-95;
Journal of Neurophysiology, 1998-present;
Consultant, Time-Life Inc., 1993;
Reviewer: NIH-NIGMS Special Institutional Training Grant Review Committee, 1992-1993;
NATO Scientific Affairs Division, 1990;
National Science Foundation, 1980-1981/1983;
Ad hoc member, Respiratory and Applied Physiology Study Section, National Institutes of Health, 1988;
Tau Beta Pi;
Phi Eta Sigma;
Phi Kappa Phi;
Senior International Fellowship, Fogarty International Center, National Institutes of Health, 1988-1989;
Javits Neuroscience Investigator Awards, National Institutes of Health, 1985-1991/1991-1998;
Science in Medicine Lecturer, University of Washington School of Medicine, 1984;
Fellow, Guggenheim Foundation, 1981-1982