We review recent methodological advances in electromagnetic source imaging and present EEG data from our laboratory obtained by application of these methods. There are two principal steps in our analysis of multichannel electromagnetic recordings: (i) the determination of functionally relevant time periods in the ongoing electric activity and (ii) the localization of the sources in the brain that generate these activities recorded on the scalp. We propose a temporal segmentation of the time-varying activity, which is based on determination of changes in the topography of the electric fields, as an approach to the first step, and a distributed linear inverse solution based on realistic head models as an approach to the second step. Data from studies of visual motion perception, visuo-motor transfer, mental imagery, semantic decision, and cognitive interference illustrate that this analysis allows us to define the patterns of electric activity that are present at given time periods after stimulus presentation, as well as those time periods where significantly different patterns appear between different stimuli and tasks. The presented data show rapid and parallel activation of different areas within complex neuronal networks, including early activity of brain regions remote from the primary sensory areas. In addition, the data indicate information exchange between homologous areas of the two hemispheres in cases where unilateral stimulus presentation requires interhemispheric transfer.
|Number of pages||11|
|Journal||Brain Research Reviews|
|State||Published - 2001|
Bibliographical noteFunding Information:
The studies presented in this review were supported by the Swiss National Science Foundation and the ‘Programme commun de recherche en génie biomédical’. We thank Denis Brunet for the analysis and display software, and Micah Murray for careful manuscript corrections.
- Brain mapping
- Electric source imaging
ASJC Scopus subject areas
- Neuroscience (all)
- Clinical Neurology