Transient visual evoked neuromagnetic responses: Identification of multiple sources

摘要: Neuromagnetic measurements and associated modeling procedures must be able to resolve multiple sources in order localize accurately characterize the generators of visual evoked neuromagnetic activity. Workers have identified at least 11 areas macaque, throughout occipital, parietal, temporal cortex, which are primarily or entirely function. The surface area human occipital lobe is estimated 150--250cm. Primary cortex covers approximately 26cm/sup 2/ while secondary comprise remaining area. For response amplitudes typical MEG data, one report estimates that a two-dipole field may statistically distinguishable from single dipole when separation greater than 1--2 cm. Given expanse devoted processes, along with this estimate resolution limits it likely can activity areas. Researchers noted evidence for existence presenting stimuli half field; however, they did not attempt them. We examined numerous patterns resulting different placements small sinusoidal grating suggest sources. analyses wemore » utilized resolving these studies differ depending on whether there was (1) synchronous activation two spatially discrete (2) asynchronous In some cases we observed appear adequately explained by source changing its orientation location across time. 4 refs., 2 figs.« less