Stimulation-Based Control of Dynamic Brain Networks
Fig 2
Nonlinear brain dynamics and variability.
(a) Excitatory-inhibitory phase space plots depicting behavior for a single Wilson-Cowan oscillator in the presence of no external current input (left; P = 0; low-fixed point), moderate external current input (middle; P = 1.25; limit cycle), and high external current input (right; P = 2.5; high fixed point). All simulations are started with initial conditions E = 0.1, I = 0.1 and nullclines are plotted in green. (b) The corresponding firing rate of the excitatory population plotted as a function of time for the simulations depicted in (a). (c) Box plots showing the value of global coupling parameter at which the system transitions from the low fixed-point state to the oscillatory regime for models derived from three different structural scans from each of eight subjects. (d) Within and between subject reproducibility (left) and variability (right) for the data shown in (c). Reproducibility is measured by the intraclass correlation coefficient (ICC) and is high within subjects indicating a high level of reproducibility between scans of a single subject, but low between subjects indicating a low reproducibility between scans of different subjects. This is additionally reflected in the low within subject variability, measured as the average variance, and high between subject variability.