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Susan L. Wearne, Ph.D.
My general research interest is mathematical neuroscience. This involves the use of analytic, geometric and computational techniques in understanding how biophysical properties of single neurons combine with dynamic properties of networks and systems of neurons to produce functionally relevant dynamical behaviors in a range of neural systems. Examples of these include: Structural Determinants of Neural Dynamics:Despite the extraordinary diversity of dendritic structure in neurons of the central nervous system, our understanding of its role in determining neural dynamics remains rudimentary. Lacking the computational power and imaging technologies available today, early analyses of the role of dendritic geometry in neural electrical behavior relied on reductions of complex geometries and passive propagation of potentials. Recent modeling efforts have demonstrated that by including active dendrites and more realistic dendritic geometries, a wide range of experimentally observed firing patterns can be simulated in single neurons. One goal of our research is to derive reduced models for electrogenesis and voltage spread in active dendrites with arbitrary geometries and nonhomogeneous ion channel distributions. Specific applications of this theory to structural determinants of age-related variations in working memory and neural integration are discussed in the CNIC Research page. Physical and Biological Bases of Fractional Order Dynamical Systems:A major research interest is understanding the physical basis of fractional diffusion and fractional reaction-diffusion equations. This work is in collaboration with Dr. Bruce I. Henry of the Department of Applied Mathematics, University of New South Wales, Australia.These equations describe transport dynamics in complex systems with nonhomogeneous diffusion characteristics, providing realistic models of physically and biologically plausible systems at levels ranging from molecular, cellular and network to whole organisms. Current applications of these techniques in neurobiology include the analysis of neuronal signaling dynamics in nonhomogeneous neural cables and spatial pattern formation in nonhomogeneous media. Of Related Interest:Neural Basis of aVOR Spatial Orientation:Neurons of the central vestibular system combine signals encoding linear and angular accelerations to provide a central representation of head and body orientation in space. This process, termed spatial orientation of the angular vestibulo-ocular reflex (aVOR), allows animals to navigate with respect to an inertial reference frame. While aVOR spatial orientation has been effectively modeled at the system level for many years, the biophysical mechanisms that underlie these dynamic behaviors remain a mystery. A long-range goal of my research is to understand how individual neurons and small networks of these neurons might produce these system-level dynamics. |