Cortical Networks of the Elderly with Mild Cognitive Impairment by Partial Directed Coherence Analysis of EEG
1 School of Communication and Information Engineering, Shanghai University, Shanghai 200072, China
2 Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
3 Beijing Key Laboratory of Neuromodulation, Beijing 100053, China
Abstract：The deficiency of brain connectivity has been discovered in cognitive processing of MCI in recent research. It is still unclear that how different brain regions influence each other and what causality is in the brain regions. The aim of this study was to analyze electroencephalography (EEG) directed cortical networks under cognitive task. Thirty elders, including 9 patients with MCI and 21 normal controls, participated in the experiment. We recorded their scalp EEG when they were judging whether the color of two graphics was matched or not. The first 1 seconds EEG data after the stimulus onset were extracted to calculate Partial Directed Coherence. Results showed that the deficiency information flow of right prefrontal cortex and abnormal enhance information flow of left central area were observed in MCI; The input degrees of the front hemisphere were higher than the back hemisphere in both controls and patients. The input degrees of right hemisphere were higher than left hemisphere in controls，but there were not significant differences in patients. Under specific threshold: the input degrees of left hemisphere in controls were lower than MCI under match task (threshold was 0.14, F=3.780，P=0.040); the input degrees of left hemisphere in controls were lower than MCI under no match task (threshold was 0.26, F=3.280，P=0.040); the input degrees of right hemisphere in controls were lower than MCI under no match task (threshold was 0.18, F=3.941，P=0.021). We used the input degree to prove that the MCI had the deficit in right hemisphere under color cognitive task.
［1］Morris JC, Cummings J. Mild cognitive impairment (MCI) represents earlystage Alzheimers disease ［J］. Alzheimers Dis, 2005, 7: 235-239.
［2］Grundman M, Petersen RC, Ferris SH, et al. Mild cognitive impairment can be distinguished from Alzheimer disease and normal aging for clinical trials ［J］. Arch Neurol, 2005, 61: 59-66.
［3］Tao Huaying, Tian Xin. Coherence characteristics of gammaband EEG during rest and cognitive task in MCI and AD ［C］// 27th Annual Conference Engineering in Medicine and Biology. Shanghai: IEEE Press, 2005: 2747-2750.
［4］Ying Liang, He Li, Zhang Junying, et al. Deficiency in anteriorposterior connectivity of Defaultmode network in amnestic mild cognitive impairment: a combined taskrelated and restingstate ［C］// 4th International Conference on Biomedical Engineering and Informatics. NewYork: IEEE Press, 2011, 1: 228-232.
［5］Babiloni C, Ferri R, Binetti G, et al. Frontoparietal coupling of brain rhythms in mild cognitive impairment: A multicentric EEG study ［J］. Brain Res Bull, 2006, 69: 63-73.
［6］Sporns O, Chialvo DR, Kaiser M, et al. Organization, development and function of complex brain networks ［J］. Trends Cogn Sci, 2004, 8(9): 418-425.
［7］Bullmore E, Sporns O. Complex brain networks: graph theoretical analysis of structural and functional systems ［J］. Nature, 2009, 10:186-198.
［8］Stam CJ, de Haan W, Daffertshofer A, et al. Graph theoretical analysis of magnetoencephalographic functional connectivity in Alzheimers disease ［J］. Brain, 2009, 132: 213-224.
［9］Baccalá LA, Sameshima K. Partial directed coherence: a new concept in neural structure determination ［J］. Biol Cybern , 2001, 84: 463-474.
［10］Tang Yingying , Li Yingjie, Wang Ning, et al. The altered cortical connectivity during spatial search for facial expressions in major depressive disorder ［J］. Prog NeuroPsychoph, 2011, 35: 1891-1900.
［11］Abuhassan K, Coyle D. Employing neuronal networks to investigate the pathophysiological basis of abnormal cortical oscillations in Alzheimers disease［C］//33rd Annual International Conference of the IEEE EMBS. Boston: IEEE Press, 2011: 2065-2068.
［12］Stam CJ, Jones BF, Nolte G, et al. Smallworld networks and functional connectivity in Alzheimers disease ［J］. Cerebral Cortex, 2007, 17: 92-99.［13］Gómez C, Stam CJ, Hornero R. Disturbed beta band functional connectivity in patients with mild cognitive impairment: an MEG study ［J］. IEEE Trans Biomed Eng, 2009, 56: 1683-1690.
［14］Wang Yuping, Kong Jian, Tang Xifen, et al. Event related potential N270 is elicited by mental conflict processing in human brain［J］.Neurosci Lett, 2000, 293: 17-20.
［15］Wang Hongjian, Wang Yuping, Wang Dongqi, et al. Cognitive impaiment in Parkinsons disease revealed by event related potential N270［J］. Neurol Sci, 2001, 298: 155-158.
［16］Baccalá LA, Sameshima K. Partial directed coherence: a new concept in neural structure determination ［J］. Biol Cybern, 2001, 84(6): 463-474.
［17］Fallani FD, Cincotti LF, et al. Cortical functional connectivity networks in normal and spinal cord injured patients: Evaluation by graph analysis ［J］. Brain Mapp, 2007, 28: 1334-1346.
［18］Qi Zhigang, Wu Xia, Wang Zhiqun, et al. Impairment and compensation coexist in amnestic MCI default mode network［J］.Nuero Image,2010,50:48-55.
［19］Sun Yu, Hu Sijiang. Graphic patterns of cortical functional connectivity of depressed patients on the basis of EEG measurements［C］// 33rd Annual International Conference of the IEEE EMBS. Boston: IEEE Press, 2011, 7: 1419-1422.
［20］Adam H, Samuel R, Martin M, et al. The role of the right inferior frontal gyrus: inhibition and attentional control ［J］. NeuroImage, 2010, 50: 1313-1319.
［21］Giulia V, Elisa V, Laura C, et al. Enhanced frontocentral EEG connectivity in photosensitive generalized epilepsies: A partial directed coherence study ［J］. Epilepsia, 2012, 53(2): 359-367.
［22］Yao Zhijun, Zhang Yuanchao, Lin Lei, et al. Abnormal Cortical Networks in Mild Cognitive Impairment and Alzheimers Disease. November ［J］. Comput Biol, 2010, 6: 114-119.
［23］毛薇, 韩春玉, 孙伟, 等. 人脑对视觉信息变化的处理过程的时间相关电位研究 ［J］. 神经心理生物学研究, 2009, 23(11): 832-836.
