Browsing by Author "Henriquez Barraza, Fernando Jose"

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    Boundary integral formulation for the electrical response of a nerve to an extracellular stimulation
    (IEEE, 2013) Henriquez Barraza, Fernando Jose; Jerez Hanckes, Carlos F.; Altermatt Couratier, Fernando René
    We present a two-dimensional boundary integral formulation of nerve impulse propagation. A nerve impulse is a potential difference across the cellular membrane that propagates along the nerve fiber. The traveling transmembrane potential is produced by the transfer of ionic species between the intra- and extra-cellular mediums. This current flux across the membrane-composed of conduction, diffusion and capacitive terms- is regulated by passive and active mechanisms that are highly complicated to describe mathematically from a microscopic point of view. Based on the Hodgkin and Huxley axon model, we propose a well-posed integral formulation based on a quasi-static approximation amenable to time-stepping schemes and discuss first results.
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    Dynamic finite-element model of axon extracellular stimulation
    (IEEE, 2013) Henriquez Barraza, Fernando Jose; Jerez Hanckes, Carlos F.; Altermatt Couratier, Fernando René
    We study the electrical influence of an electrode over an axon of nonzero thickness in time using a two-dimensional finite element formulation. Although our inspiration comes from the practice of peripheral nerve stimulation, other types of neural tissue excitation can benefit from the model. Our formulation combines a Hodgkin-Huxley model to account for nerve dynamics with electrostatic intra- and extracellular potentials. Thus, the influence of external electrode geometry and parameters can be addressed instead of simplifying them to point current sources. We show first numerical results for different extracellular stimuli and explore future enhancement directions.