Figure 7.

Time-frequency analysis of IES simulation. (A) The source localization by dipole fit method identified an origin of the simulated IES in the right central sulcus, like described in BECTS (Ishitobi et al., 2005). Locations, orientations (A) and wave shapes (B) of the 1 dipole source, “the model sources,” used to simulate the EEG data. T0 is denoted by the vertical mark on the time base. (B) These topographies reproduced properties expected for the scalp-recorded IES field, including central negativities, with corresponding positivities at lateral sites. (C) The simulated scalp IES in average reference format. The solid lines indicate the noise-free wave forms generated by the dipole sources indicated in Panel A. (C) indicate the signal + noise wave forms that were analyzed. (D) raw data of the simulated EEG and IES. Scalp potentials (33-channel montage) were simulated from dipoles (Berg, 2006) in order to correspond to field produced by the generator within right central sulcus. (E): G_TFR of the simulated IES results with the [−1000 ms; −600 ms] baseline period: G_TFR of the simulated IES demonstrated significant changes between 4 and 30 Hz in the right central sulcus simultaneously with the IES but no change around the IES in regard of the epileptogenic zone or in distant area. (F): G_TFR of the simulated IES results with the [−1000 ms; −600 ms] baseline period: Like for the [−1000 ms; −600 ms] baseline period, G_TFR of the simulated IES demonstrated significant changes between 4 and 30 Hz in the right central sulcus simultaneously with the IES but no change around the IES in regard of the epileptogenic zone or in distant area.