EEG and pairwise pointwise transinformation (PTI) of frontal, central, midtemporal, and occipital derivations. Left and right EOG are displayed additionally. The rapid changes of PTI are visible in the respective regions and different states of vigilance. Note that some increases of PTI are clearly associated with distinct EEG waves (e.g., alpha waves, -complexes, and sleep spindles), while for others, this association is not evident. (a) Waking phase during the night. The rather abrupt changes of PTI with burst-like appearances of synchronization in all derivations (black triangles) and the sometimes waxing and waning characteristics of the occipital synchronization (dotted boxes) are visible. The slow eye movements in the EOG (black bars) have no impact on frontal PTI. (b) NREM sleep stage N2. The burst-like dynamics of PTI is even more evident in the frontal and central derivations than in waking. Synchronization peaks with not only -complexes and sleep spindles (black triangles), but also many other EEG elements like theta waves and less distinct events (arrows). The large potential in the EOG is a -complex, not a REM. (c) REM sleep. As expected, sawtooth waves (black triangles) and alpha waves (arrows) appear highly synchronized. Rapid eye movements (black bars) do not cause increases of frontal synchronization.