Application of nonlinear DCM to single subject fMRI data from an attention to motion paradigm [17]. The figure is reproduced, with permission, from Figure 7 in [30].
A. Maximum a posteriori estimates of all parameters. PPC = posterior parietal cortex.
B. Posterior density of the estimate for the nonlinear modulation parameter for the V1→V5 connection. Given the mean and variance of this posterior density, we have 99.1% confidence that the true parameter value is larger than zero or, in other words, that there is an increase in gain of V5 responses to V1 inputs that is mediated by PPC activity.