15. Determine the strength and location of each of the three monopole lumped sources. Be sure to include the location (r coordinate) magnitude, sign, and units of each one. 16. Computations of extracellular potentials from membrane currents can be placed into a matrix format: [P2] = [HI] (13.7) Here matrix ! is a column vector containing the values of lumped sources 1 to 3 for time t, Matrix [His set of coefficients by which each source must be multiplied to find one of the extracellular potentials. [P.) is a column vector giving the set of extracellular potentials. Matrices [H] and [Pd] have one row for each extracellular potential to be found. Suppose there are three extracellular potentials to be found, at three field points. The three field points have r positions 30, 31, and 32 mm. They are located at a distance h away from the fiber axis. is the distance a. Define each of the 9 elements of H defined in terms of rij, where from field point i to monopolar source j. b. Find matrix [H] (numerical values) for h= 100 micrometers c. If the monopole sources have values of 3, 4, and I mA, respectively, what are the values of the extracellular potentials at each of the 3 field points? ---+ - + ---- -30 X, mm Figure 13.8. Action potential as a function of distance along the fiber. The action potential was constructed using the template function. This figure is a triangulation of Figure 13.7. 15. Determine the strength and location of each of the three monopole lumped sources. Be sure to include the location (r coordinate) magnitude, sign, and units of each one. 16. Computations of extracellular potentials from membrane currents can be placed into a matrix format: [P2] = [HI] (13.7) Here matrix ! is a column vector containing the values of lumped sources 1 to 3 for time t, Matrix [His set of coefficients by which each source must be multiplied to find one of the extracellular potentials. [P.) is a column vector giving the set of extracellular potentials. Matrices [H] and [Pd] have one row for each extracellular potential to be found. Suppose there are three extracellular potentials to be found, at three field points. The three field points have r positions 30, 31, and 32 mm. They are located at a distance h away from the fiber axis. is the distance a. Define each of the 9 elements of H defined in terms of rij, where from field point i to monopolar source j. b. Find matrix [H] (numerical values) for h= 100 micrometers c. If the monopole sources have values of 3, 4, and I mA, respectively, what are the values of the extracellular potentials at each of the 3 field points? ---+ - + ---- -30 X, mm Figure 13.8. Action potential as a function of distance along the fiber. The action potential was constructed using the template function. This figure is a triangulation of Figure 13.7
