Application of nonlinear DCM to single subject fMRI data from a binocular rivalry paradigm. The figure is reproduced, with permission, from Figure 9 in [30].
A. The structure of the nonlinear DCM fitted to the binocular rivalry data, along with the maximum a posteriori estimates of all parameters. The intrinsic connections between FFA and PPA are negative in both directions; i.e. FFA and PPA mutually inhibited each other. This may be seen as an expression, at the neurophysiological level, of the perceptual competition between the face and house stimuli. This competitive interaction between FFA and PPA is modulated nonlinearly by activity in the middle frontal gyrus (MFG), which showed higher activity during rivalry vs. non-rivalry conditions.
B. Our confidence about the presence of this nonlinear modulation is very high (99.9%), for both connections.