Cluster Structure and Localization of Brain Functional Networks Based on the ERP Signals of Auditory Task

The brain functional networks derived from multi-channel ERP signals are analyzed based on the phase synchronization theory. The nodes of brain functional networks are represented by the channels of ERP signals, and the connectivity of brain functional networks is described by the interaction among the channels. The edge between two different channels exists only if the phase coupling index is beyond certain threshold. The constructed brain functional networks under the resting and task states present robust small world property in consistent with the empirical facts found in previous works. We first uncover that the cluster coefficients get larger when brain is executing auditory task, which means that neighbors of a node prefer to be mutually connected to form more clustered and localized networks. Furthermore, the connectivity of networks is better under the task state. These results suggest that the modularity of brain functional networks emerges to the internal enhanced correlation and localization when the cognitive activity of brain is acting.