Detection of Instantaneous Functional Coupling from MEG Data by the Means of Projection in Sensor-Space Cross-Spectrum and Statistical Testing

We propose a framework to control for false positive connectivity estimates obtained after application of recently developed PSIICOS-projection (Ossadtchi et al., 2018), which allows to neutralize the volume conduction artifacts and preserve zero and near-zero phase coupling. We developed a statistical testing procedure based on Wishart distribution in order to assess the statistical significance of source-space cross-spectral estimates. The high performance of the test was confirmed by realistic simulations. When applied to the real data, the test demonstrates meaningful spatial connectivity patterns, reflecting underlying brain functioning.