SOC critical parameter in terms of oscillating expression modes. Left panels (a) and (b): EGF, no transition case; right panels (c) and (d): HRG, transition case. The bottom of the funnel corresponds to the “core” of the attractor (CP, genes with very low fluctuations that consequently have near zero contribution of fluctuations modes (EGF2, EGF3) and (HRG2, HRG3), respectively.