Source estimation of the K-complexes and auditory evoked responses using meg and EEG measurements

This study focuses on the sources of the brain electrical activities during sleep, in particular on K-complexes in normal subjects in sleep stage 2. We investigated the relationship between the sources of K-complexes and the sources of auditory evoked responses. We analyzed these waveforms using both topographic electroencephalographic(EEG) and magento-encephalographic (MEG) maps. Based upon the results of the MEG measurements, the source of the K-complexes can be modeled by two current dipoles which are located in parallel at both sides of the midline. The dipoles for the sources of K-complexes are estimated at the locations 5 mm apart from the sources of N100 components of auditory evoked response estimated by the evoked potentials and magnetic fields. This result suggests that the mechanism of K-complexes are closely related to that of auditory evoked responses.