In section Frequency-specific phase coupling methods, we introduced a large set of connectivity methods based on phase coupling of oscillatory signals at the same frequency, which has been hypothesized as a mechanism for communication, at large scale for slower rhythms and at small scale for higher frequencies. Additionally, neuronal oscillations at different frequencies can also couple according to different possible relations between their phases, their amplitudes or in a phase-to-amplitude mode (Jensen and Colgin, 2007). This cross-frequency coupling has been hypothesized as a mechanism for information integration across different spatial scales characteristic of the faster and slower oscillations.
