Scale-invariant fluctuations of the dynamical synchronization in human brain electrical activity.

The dynamical properties of large-scale, long-term phase synchronization behavior in the alpha range of electroencephalographic signals were investigated. We observed dynamical phase synchronization and presented evidence of an underlying spatiotemporal ordering. Fluctuations in the duration of episodes of intermittent synchrony are scale-invariant. Moreover, the exponent used to describe this behavior is stable across different normal subjects. The results provide a new feature of self-organization in human brain activity and constitute a quantitative basis for modeling its dynamics.