EEGLAB, SIFT, NFT, BCILAB, and ERICA: New Tools for Advanced EEG Processing
Figure 4
EEG-based brain connectivity analysis and visualization using SIFT. (a) An interactive time-frequency grid demonstrating transient bursts of theta (3–7 Hz) and delta (1–3 Hz) band information flow during error commission, estimated using the direct directed transfer function (dDTF), between a subset of independent component (IC) sources. Dashed vertical line denotes time of erroneous button press. Callout shows an expanded view of information flow to/from sources 8 and 13, obtained by clicking on the respective grid cell. (b) Several frames from an interactive BrainMovie3D animation showing an event-related causal relationship in the theta band between these sources (200 ms (top) and −520, 40, and 600 ms (bottom) relative to an erroneous button press). Ball (node) color and size denotes asymmetry ratio (red: causal source, blue: causal sink) and outflow strength, respectively, for that IC. Cylinder (edge) color and size denote connectivity strength. The event-related potential of IC8 (red, medial), back-projected to a superior electrode is superimposed below each frame (blue bar denotes frame index). This shows a network interpretation of the classic “error-related negativity” (ERN) phenomenon observed during error-processing. (c) A frame from a causal projection movie showing mean net causal inflow (green) and causal outflow (red) in the theta band at each brain location during error commission across 24 subjects. Note the significant causal outflow from or near anterior cingulate cortex, thought to be critically involved in error-processing, during and following the negative peak of the ERN.
