There are two categories of Bi-Spectral analyses in NeuroGuide. First is the spectral analyses of the time series of instantaneous absolute power, relative power, coherence, phase differences, amplitude asymmetry and phase reset (1st derivative of straightened phase). The first spectrum is the Hilbert transform of the EEG micro volt time series x(t) using Complex Demodulation to produce a new time series x'(t) of instantaneous power and magnitude and coherence and phase. The new time series is defined within frequency bands at specific center frequencies. The Bi-Spectrum is the Fourier transform of the Hilbert transformed time series from each electrode at each time point [(x'(t); y'(t) ..... n'(t)] to produce the instantaneous time series Bi-spectrum.

To activate this Bi-Spectral analysis click View > Dynamic Bi-Spectrum.

The second is the Cross-Frequency Bi-Spectrum which includes the cross-frequency power correlation (1 Hz to 50 Hz) and the Cross-Frequency Phase Shift Duration and the Cross-Frequency Phase Lock Duration.

To activate the Cross-Frequency Bi-Spectra click Analysis > Bi-Spectral Analysis.

This is a hyperlink to the mathematical and computational details.

The Bi-Spectral analyses are an add on product that includes:

Spectrum of the Time Series of Instantaneous Power

Spectrum of the Time Series Relative Power

Spectrum of the Time Series of Instantaneous Coherence

Spectrum of the Time Series of Instantaneous Phase Differences

Spectrum of the Time Series of Instantaneous Amplitude Differences

Spectrum of the Time Series of Phase Reset

Cross-Frequency Power Correlation (1Hz to 50 Hz)

Cross-Frequency Phase Shift Duration (n:m phase synchrony)

Cross-Frequency Phase Lock Duration (n:m phase synchrony)