Fig. 3.

Model specifications of Forward (F), Backward (B), and Forward-Backward (FB) models based on the previous MEG study (Chen et al., 2010). (a) The basic network configuration has a left hemispheric dominance and extrinsic nonlinear connections (left) and an ‘all-linear’ model (right) is included to test whether nonlinear mechanism is crucial to explain the dataset, in particular, the induced responses. The blue arrows specify the areas which receive the exogenous input perturbation. The exogenous input was modelled using a gamma function with two normally distributed parameters estimated from the data. (b) The modulation effects are allowed in the left hemisphere (red rectangle) in only forward (F model), or backward (B model) or both forward and backward connections (FB model).