Abstract

Mapping the anatomical patterns, topology, and dynamics of cortical connectivity, both functional and structural, is central for elucidating the systems-level mechanisms governing brain dynamics in vivo. Complementing the large body of studies using MRI -based fMRI and DTI /DSI maps of functional and structural connectivity, respectively, several approaches have recently been presented for using MEG and EEG in the electrophysiological mapping of cortical connectivity. In my presentation, I will discuss our pipeline for MEG /EEG-source-reconstruction based interaction mapping as well as both the commonly and the more rarely acknowledged pitfalls in the identification of phase and amplitude correlations in electrophysiological data.

The phenomenology and functional significance of oscillatory coupling can be addressed both with resting-state analyses and cognitive paradigms. I will present our recent MEG and SEEG observations linking transient brain dynamics with the traditional connectivity estimates. We have also used MEG to map the networks of within- and cross-frequency phase synchrony observed during visual working memory retention. These phase interactions are memory load dependent and behaviorally significant, and may hence yield insight both into the neuronal substrates of working memory and into the mechanisms bridging neuronal processing taking place concurrently in multiple frequency bands. Overall, these data emphasize both the putative functional significance of the interactions among cortical oscillations and that several technical challenges must be overcome to fully utilize the potential of electrophysiological methods in the study of the human connectome.