Figure 4.
Experimental quiet time distributions for different values of the threshold sc on avalanche size. Already for sc = 80 μV, distributions clearly exhibit one or more additional peaks. Beside the one at large time scales, Δt ≃ 1000–2000 ms, which is related with the characteristic time of up-state recurrence, at least one peak between 60 and 250 ms is always visible on time scales originally characterized by the power law decay and corresponds to the period of β or θ oscillations. This is particularly pronounced in (B,C,D,F), less in (A,E). The distributions in (B,C) exhibit one more peak around 500 ms, related to 2 Hz oscillations. It is worth to notice that the probability P(Δt) for Δt corresponding to the θ (B,C,D,F) and 1–2 Hz oscillations (A,B) is nearly a fixed point for this transformation. Insets: Experimental distributions of waiting times δt, for different values of sc. In this case one more peak appears around 20–30 ms, which corresponds to γ oscillations.