Strength-dependent perturbation of whole-brain model working in different regimes reveals the role of fluctuations in brain dynamics
Fig 5
Local and Sustained/non-sustained strength-dependent perturbation.
A) The evolution of Susceptibility (first row) and the absolute Information Capability (second row) as a function of the perturbation strength and the perturbed pairs of homotopic nodes. The middle left panel displays the results for the subcritical regime (fluctuations, a = -0.02, G = 2.2 and β = 0), and the middle right panel shows the response of the supercritical regime (oscillations, a = 1.3, G = 0.4 and β = 2.2). The right panels present the perturbative node hierarchy rendered onto the brain cortex for both measures (first and second row) for the case of a perturbation strength of 0.01 indicated with a box in middle left panel. B) Non-sustained PCI: The PCI is obtained by perturbing by pairs of homotopic nodes and different forcing amplitude. In the left column, the PCI results are obtained by perturbing the subcritical model in its corresponding working point with an external periodic force applied by pairs of homotopic nodes as a function of the amplitude of this forcing. In the right column, the same measurement is displayed but, in this case, for the supercritical model in its corresponding working point. The right panel shows the node-perturbative hierarchy in terms of PCI of each region for the maximum value of the forcing amplitude (indicated with black box in the middle-left panel) rendered onto a brain cortex.