Figure 1.
Head diagram of the EEG sensor positions and labeling.
The diagram shows the correspondence between the high-density 129-channel Sensor Net (EGI, Inc.) and the International 10–10 System. The Sensor Net locations that match the positions of International 10–10 system are labeled. The 10–10 System names are followed by the numbers of the Sensor Net. The sensors corresponding to the 10–20 System (presented in all the maps hereafter) are in bold. The gray background highlights all the sensors included in the analyses. The sensor locations encircled in green exemplify the first and second neighborhoods for the sensor encircled in brown (sensor 73), i.e., the territory considered in the calculation of a single value of S-estimator.
Figure 2.
Whole-head S-estimator maps for SZ patients and normal controls.
Group-averaged maps for the broad-band resting EEG (1–70 Hz) are shown for patients (A) and controls (B). C: Difference map, Patients vs. Controls. Here and hereafter the clusters of sensors with S-estimator significantly higher or lower in patients than in controls are in red or blue, respectively. There are no significant differences in the gray regions.
Figure 3.
Spectral breakdown of the S-estimator data into conventional EEG bands.
Group-averaged difference S-maps (Patients vs. Controls) are given for the following EEG bands: δ: 1–3 Hz; θ: 3–7 Hz; α: 7–13 Hz; β: 13–30 Hz; and γ: 30–70 Hz.
Figure 4.
Temporal stability of the S-estimator topography in SZ.
Group-averaged difference maps (Patients vs. Controls) for the broad-band EEG from ten patients who participated in the first (A) and second (B) EEG sessions. C: Difference map between the first EEG vs. second EEG of patients. The regions where the S-estimator in the patients' first EEG was significantly higher or lower than that in the second EEG are in red or in blue, respectively. There are no significant differences in the gray regions. D: Map of the likelihood that the synchronization estimations from the first and second EEG can be considered stationary according to Kolmogorov-Smirnov test. The color is inversely related to the probability: the lighter, the more probable.
Figure 5.
Correlation between synchronization and SZ symptoms.
The topographies of correlations between the S-estimator changes in patients and their symptoms as measured by the Positive Symptom Scale (PS), Negative Symptom Scale (NS), and General Psychopathology Scale (GP) are shown. The regions where the significant correlations are direct or inverse are marked in brown or turquoise, respectively. There are no significant correlations in the gray regions.
Figure 6.
Whole-head power maps for SZ patients and normal controls.
The group-averaged maps of absolute power for the broad-band resting EEG are shown for patients (A) and for controls (B). C: Difference map (Patients vs. Controls). In the blue regions the absolute power in patients is significantly lower than that in controls. There are no significant differences in the gray regions.
Figure 7.
Relationship between synchronization and power.
A: Correlation map between the relative changes of S-estimator and the relative changes of power for patients. The correspondence between color and correlation strength is shown by the scale bar. B: Significance map for the correlations shown in A; color convention is as in Fig. 5.