Accuracy of Dipole Localization with a Spherical Homogeneous Model

Accuracy of Two Dipolar Inverse Algorithms Applying Reciprocity for Forward Calculation

“…For the calculation of the lead field L ⌽ the reciprocal source current was set to 1 A which can be done due to the linearity of the problem by scaling the potential field by the applied current (Eq. [1]). This current varies in our model because the current source is set up using constant voltage between the source nodes and the Ohm's law.…”

“…Three different dipole directions (x, y, and z) according to the Cartesian coordinate system shown in the figure were considered for each dipole location. a few cases (Temporal 1, Central 3, and Posterior 4) random noise (1,5,10,20, and 30%) was added to the potentials. The sensitivity of the dipole localization to the changes in the tissue resistivities was demonstrated by setting the resistivity values of the CSF to 0.56 Ωm (35) and the skull to 160.0 Ωm when calculating the surface potentials of three dipoles (Temporal 3, Central 5, and Posterior 2).…”

“…The two algorithms gave otherwise very similar results, except in the case of x-directed dipoles where the performance of the least-squares algorithm was clearly better. Noise (1,5,10,20, and 30 %) was added to the potentials of three dipoles at different locations and directions. The results are very similar for both algorithms and, thus, in Fig.…”

“…Fast analytical methods can be applied in the calculation of geometrically simple volume conductor models, such as concentric and eccentric spheres (1)(2)(3)(4)(5)(6)(7)(8)(9). The shape and the tissue resistivities are major characteristics of the head as a volume conductor.…”

Optimal measurement conditions for spatiotemporal eeg/meg source analysis

“…In the Monte Carlo approach the best sensor conhguration is chosen by comparing simulation results on several conhgurations (Cufhn, 1985;Gaumond, Lin, & Geselowitz, 1983;Hari, Joutsiniemi, & Sarvas, 1988;Huizenga & Molenaar, 1994;Ogura & Sekihara, 1993). This is very time consuming, and therefore not very useful in practice.…”