title: Combining Partial Directed Coherence and Graph Theory to Analyse Effective Brain Networks of Different Mental Tasks.
abstract: OBJECTIVE
  The aim of this study is to qualify the network properties of the brain networks between two different mental tasks (play task or rest task) in a healthy population.
  
  
  METHODS
  EEG signals were recorded from 19 healthy subjects when performing different mental tasks. Partial directed coherence (PDC) analysis, based on Granger causality (GC), was used to assess the effective brain networks during the different mental tasks. Moreover, the network measures, including degree, degree distribution, local and global efficiency in delta, theta, alpha, and beta rhythms were calculated and analyzed.
  
  
  RESULTS
  The local efficiency is higher in the beta frequency and lower in the theta frequency during play task whereas the global efficiency is higher in the theta frequency and lower in the beta frequency in the rest task.
  
  
  CONCLUSIONS
  This study reveals the network measures during different mental states and efficiency measures may be used as characteristic quantities for improvement in attentional performance.
authors.affiliation: School of Life Science and Technology, Xidian UniversityXi'an, China; Department of Radiology, Medical Physics, University Medical Center FreiburgFreiburg, Germany.
authors.forename: Dengfeng
authors.initials: D
authors.lastname: Huang
authors.affiliation: School of Electronic Engineering, Xidian University Xi'an, China.
authors.forename: Aifeng
authors.initials: A
authors.lastname: Ren
authors.affiliation: School of Electronic Engineering, Xidian University Xi'an, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Shang
authors.affiliation: School of Life Science and Technology, Xidian University Xi'an, China.
authors.forename: Qiao
authors.initials: Q
authors.lastname: Lei
authors.affiliation: School of Life Science and Technology, Xidian University Xi'an, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Life Science and Technology, Xidian University Xi'an, China.
authors.forename: Zhongliang
authors.initials: Z
authors.lastname: Yin
authors.affiliation: School of Life Science and Technology, Xidian University Xi'an, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: School of Life Science and Technology, Xidian University Xi'an, China.
authors.forename: Karen M
authors.initials: KM
authors.lastname: von Deneen
authors.affiliation: School of Life Science and Technology, Xidian University Xi'an, China.
authors.forename: Liyu
authors.initials: L
authors.lastname: Huang
keywords: effective networks; electroencephalogram (EEG); graph theory; mental tasks; partial directed coherence