Fig. 3.

Spectral response of the neural-mass model. (A) Left: Spectral phase-diagram illustrating the maximal frequency band over the u and α dimensions. Right: phase-diagram illustrating the maximum frequency with 1 Hz resolution, which illustrates the highest maximum frequency of 22 Hz. (B) Bifurcation diagram illustrating maximum and minimum pyramidal cell membrane potential along parameter u for α = 0.279. At u ~ 3.06 mA the system bifurcates and enters a limit-cycle attractor. Then at u ~ 10.6 mA, the system undergoes a second phase transition back to a fixed-point. (C) Time domain and phase domain portraits for one region of the 2-D parameter plane (u = 0.0625 mA; α = 0.279), where the system oscillates with theta frequencies around a fixed-point attractor. (D) A second region in parameter space, here at an alpha limit cycle.