Reference-Based Extraction of Phase Synchronous Components
Phase synchronisation is a phenomenon observed in measurements of dynamic systems, composed of several interacting oscillators. It can be quantified by the phase locking factor (plf), which requires knowledge of the instantaneous phase of an observed signal. Linear sources separation methods treat scenarios in which measurements do not represent direct observations of the dynamics, but rather superpositions of underlying latent processes. Such a mixing process can cause spuriously high plfs between the measurements, and camouflage the phase locking to a provided reference signal. The plf between a linear projection of the data and a reference can be maximised as an optimisation criterion revealing the most synchronous source component present in the data, with its corresponding amplitude. This is possible despite the amplitude distributions being Gaussian, or the signals being statistically dependent, common assumptions in blind sources separation techniques without a-priori knowledge, e.g. in form of a reference signal.
KeywordsReference Signal Independent Component Analysis Phase Synchronisation Volume Conduction Singular Spectrum Analysis
Unable to display preview. Download preview PDF.
- 2.Kuramoto, Y.: Chemical Oscillations, Waves and Turbulences. Springer, Berlin (1984)Google Scholar
- 6.Hyvärinen, A., Karhunen, J., Oja, E.: Independent Component Analysis. In: Adaptive and Learning Systems for Signal Processing, Communications, and Control, John Wiley & Sons, Inc., Chichester (2001)Google Scholar
- 8.Ghil, M., Allen, M.R., Dettinger, M.D., Ide, K., Kondrashov, D., Mann, M.E., Robertson, A., Saunders, A., Tian, Y., Yiou, P.: Advanced Spectral Methods for Climatic Time Series. Reviews of Geophysics 40(1) (2001)Google Scholar
- 9.Vigário, R., Jensen, O.: Identifying Cortical Sources of Corticomuscle Coherence During Bimanual Muscle Contraction by Temporal Decorrelation. In: Proceedings of IEEE International Symposium on Signal Processing and Its Applications (2003)Google Scholar
- 10.Meinecke, F.C., Ziehe, A., Kurths, J., Müller, K.R.: Measuring Phase Synchronization of Superimposed Signals. Physical Review Letters 94(8) (2005)Google Scholar
- 11.Nolte, G., Bai, O., Wheaton, L., Mari, Z., Vorbach, S., Hallett, M.: Identifying true brain interaction from EEG data using the imaginary part of coherency. Clinical Neurphysiology 115, 2292–2307 (2004)Google Scholar