BME 211
THEORETICAL ELECTROPHYSIOLOGY

This course explores advanced topics on the electrophysiological behavior of nerve and striated muscle. The topics include: source-field models for single fiber and fiber bundles lying in a volume conductor; forward and inverse models for EMG and ENG; bidomain model; electrical stimulation of single fiber and fiber bundle.

Topics covered:

Part I: Potentials, Fields, and Currents in Conductive Tissues

1. Boundary value problems for conductive regions.
   • Homogeneous versus inhomogeneous regions.
   • Isotropic versus anisotropic regions.
2. Analytical solutions by separation of variables.
   • Inhomogeneity and anisotropy.
   • Anisotropy tensor when principal axes are not aligned with the coordinate system.
3. Numerical solutions using a finite element package.
4. Measurement of conductivity in isotropic and anisotropic tissues: Four-electrode resistivity technique.

Part II: Problems Involving Transmembrane Potential

1. Macroscopic vs. cellular-level view of tissues: Setting up boundary value problems involving membranes.
2. Continuum models: core-conductor and bidomain.
   • Connection between a BVP for a single fiber and the core-conductor model.
   • Analytical solutions to passive core-conductor and bidomain models.
   • Bidomain with unequal anisotropy ratios ("dogbone").
3. Discrete models:
   • Tissues with unconnected cells.
   • Tissues with connected cells.

Part III: Bioelectric Engineering

1. Tissue stimulation.
   • Intracellular vs. extracellular stimulation. Activating Function.
   • Stimulation waveforms (monophasic vs. biphasic).
   • Strength-duration relationship.
   • Recruitment.
2. Extracellular recordings.
   • Source-field models for single fiber and fiber bundles lying in a volume conductor.
   • Forward and inverse problems.
3. Electrodes: Impedance, current density, electrochemistry.
4. Tissue damage

Textbook: None. Readings from original articles.

Prerequisites: BME 101 or BME 201 or consent of the instructor.

Grading: Participation in class, homeworks, and computer labs. (4 units)