Figure 10. ${\displaystyle {\mathbf{\text{R}}}_{\mathrm{P}\mathrm{A}\mathrm{C}}}$, but not MI, detects phase-amplitude coupling in a simple stochastic spiking neuron model.

(A) The phase and amplitude of the low frequency signal (blue) modulate the probability of a high frequency spike (orange). (B) The surfaces ${\displaystyle S_{A_{\mathrm{l}\mathrm{o}\mathrm{w}}}}$ (red) and ${\displaystyle S_{A_{\mathrm{l}\mathrm{o}\mathrm{w}},{\varphi }_{\mathrm{l}\mathrm{o}\mathrm{w}}}}$ (yellow). The phase of maximal ${\displaystyle A_{\mathrm{h}\mathrm{i}\mathrm{g}\mathrm{h}}}$ modulation depends on ${\displaystyle A_{\mathrm{l}\mathrm{o}\mathrm{w}}}$. (C) The modulation index fails to detect this type of PAC.