THE FACTOR ANALYSIS USED TO IMPROVE THE DIPOLE-DENSITY-PLOT (DDP) TO LOCALIZE FOCAL CONCENTRATIONS OF SPONTANEOUS MAGNETIC BRAIN ACTIVITY

INTRODUCTION In previous studies we showed that concentrations of spontaneous, slow wave, focal, magnetic brain activity can be quantificd, localized and markcd in the corresponding MRI slices using thc dipoledensityplot (DDP) (2,3,5,6). We necded this because we found the sources of such activity not only concentrated in the vicinity of structural and verified brain lesions but also in some distance (1,2,4). The concentration effect will bc rcachcd by the following measures: (1) selection of only thosc dipoles which will fit predominantly the single dipole model to omit multifocal or distributed activity, (2) summation of dipole estimations across time to get a spatial avcrage with the chance to increase thc focal concentrations for lower dipole densities by increasing the analyzing time.