Motor-Cortical Functional Connectivity Analysis Based on ECoG Signals of Finger Flexion

Multi-channel ECoG signals are directly recorded from the surface of brain during finger flexion. Here they are used to construct brain functional networks based on phase synchronization theory. The channels of ECoG signals are considered as the nodes of brain functional networks, and the interactions among the channels suggest the connectivity of brain functional networks. The edge between two different channels exists only if the phase coupling index is beyond a certain threshold. We built the brain functional networks under the resting and task states and uncover that the cluster coefficients get larger when brain is executing motor 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.