Figure 3.

Effects of the slow, activity dependent modulation of IPSPs on the inhibitory neuronal population, Γ_ik using the SS1 model of equation (11). The top left panel shows the fluctuation spectrum of the unmodulated “fast” EEG system (Bojak and Liley, 2005). When Γ_ik of this system is slowly modulated (μ_i = 0.001 ms⁻¹, θ_i = 0.1818 mV, k_i = 10 mV s) bursting emerges (top right panel). Bursting is associated with the periodic modulation of Γ_ii (red line, top right panel) on a much longer time scale than that of intra-burst oscillatory activity. Time-frequency analysis (bottom right panel) reveals that intra-burst activity sweeps down through a range of frequencies from low beta (13–30 Hz) to high alpha (8–12 Hz). Parameter values used for the “fast” EEG system can be found in Table 3.