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NJIT Mathematical Biology Seminar

Tuesday, February 9, 2010, 2:30pm
Cullimore Hall 611
New Jersey Institute of Technology

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Modeling self-sustained firing in motoneuron after spinal cord injury

Mini Kurian

Department of Mathematics, Arizona State University

Motoneurons have the ability to generate plateau potentials resulting in self-sustained ring and providing a mechanism to translate short last- ing synaptic inputs into long lasting motor output. During the acute stage of spinal cord injury (SCI) the endogenous ability to generate plateaus is lost; however, during the chronic stage the plateau potentials reappear. We extend previous modeling studies of the physiological changes in spinal motoneurons following SCI in order to investigate mechanisms that might contribute to spasticity due to the self-sustained ring. Experimental data are used to determine the parameters of the two compartment con- ductance based dierential equation model for SCI. Using mathematical analysis and simulation results, we study the ef- fect of changes in kinetics and morphology on motoneuron excitability. Our modeling studies show that changes in morphology following SCI like increase in soma size and decrease in dendritic arbor do not contribute to increases in self-sustained ring. Increases in self-sustained ring are likely to occur due to changes in membrane conductances and changes in synaptic activity, particularly changes in the strength and timing of inhibition.