Fig. 2

Spectral slope: effect of experimental condition and rank-order stability. (A, B) Cortical distribution of the 35–45 Hz spectral slope coefficients in the three groups of participants in the eyes-open (A) and eyes-closed (B) conditions. The activity of the cortical sources was estimated using the linearly constrained minimum variance (LCMV) beamformer method. (C) Rank-order stability of the 35–45 Hz spectral slope between the eyes-open and the eyes-closed conditions: cortical distribution of intraclass correlation coefficients (ICC) for 83 participants for whom data from both conditions were available. (D) 35–45 Hz spectral slope averaged over all cortical sources in the two experimental conditions. Thin lines show individual subjects; thick lines—the group average. Colors correspond to different groups of participants. TD, typically developing children; ASD, autism spectrum disorder; ASD_>85, children with ASD and Mental Processing Index above 85; and ASD_<85, children with ASD and Mental Processing Index below 85