Fig. 8.

Sampled spectral responses. (A) Top: Spectral phase-diagram illustrating the maximal frequency band over the u and γ₃₁^E dimensions for the neural-mass model using the modulation transfer function sampled from the centre manifold. The diagram shows a good comparison between this and the full (non-sampled) estimates shown in Fig. 2A. Bottom: The spectral prediction at u = 6.25 mA and γ₃₁^E = 0.25 (white circle) contains a peak at 14 Hz, in the alpha range and a secondary peak at 17 Hz, in the beta range. This illustrates the ability of the model to generate multimodal spectra. (B) Top: Spectral phase-diagram illustrating the maximal frequency band over the u and α dimensions for the neural-mass model. The diagram shows smoother transitions than in Fig. 3A. Bottom: The spectral prediction at u = 5.06 mA and α = 0.279 (white circle) contains peaks in the alpha (11 Hz) and theta (7 Hz) range. (C) Top: Spectral phase-diagram illustrating the maximal frequency band over the u and γ₃₁^E dimensions for the mean-field model. These responses have a similar profile to Fig. 4A. Bottom: For the MFM, the sampling scheme also produces multimodal spectra, with beta (19 Hz) and gamma (39 Hz) peaks for u = 5.06 mA and γ₃₁^E = 0 (white circle). (D) Top: Spectral phase-diagram illustrating the maximal frequency band over the u and α dimensions for the mean-field model. These responses have a similar profile to Fig. 5A. Bottom: For u = 9 mA and α = 0.56 (white circle), the prediction contains two peaks, one in the beta range at 16 Hz, and one in the theta range at 4 Hz.