Four-shell ellipsoidal model employing multipole expansion in ellipsoidal coordinates.
Although the head is more closely represented as an ellipsoid than a sphere, calculation in ellipsoidal coordinates is difficult. This paper presents a four shell ellipsoidal model, employing multipole expansion in ellipsoidal coordinates, for EEG, MEG, and evoked potential applications. Computational detail and insight into efficient calculation of the Lamé functions of the first and second kind are provided to demonstrate feasibilty. The Lamé function of the second kind, derived from the Lamé function of the first kind, can be computed at higher degrees by means of partial fraction expansion.
Blimke
John
J
The Max McGee National Research Center For Juvenile Diabetes, Medical College of Wisconsin, Milwaukee, WI 53226, USA. jblimke@mcw.edu
Myklebust
Joel
J
Volkmer
Hans
H
Merrill
Stephen
S
D001921:Brain / Q000033:anatomy & histology; D004569:Electroencephalography; D005073:Evoked Potentials, Somatosensory; D006257:Head / Q000033:anatomy & histology*; D006801:Humans; D015225:Magnetoencephalography; D008953:Models, Anatomic; D008959:Models, Neurological