PT  - JOURNAL ARTICLE
AU  - R. Li
AU  - X. Wu
AU  - K. Chen
AU  - A.S. Fleisher
AU  - E.M. Reiman
AU  - L. Yao
TI  - Alterations of Directional Connectivity among Resting-State Networks in Alzheimer Disease
AID  - 10.3174/ajnr.A3197
DP  - 2012 Jul 12
TA  - American Journal of Neuroradiology
4099  - http://www.ajnr.org/content/early/2012/07/12/ajnr.A3197.short
4100  - http://www.ajnr.org/content/early/2012/07/12/ajnr.A3197.full
AB  - BACKGROUND AND PURPOSE: AD has been documented as a kind of disconnection syndrome by functional neuroimaging studies. The primary focus of this study was to examine, with the use of resting-state fMRI, whether AD would impact connectivity among RSNs. MATERIALS AND METHODS: Fourteen patients with AD and 16 NC were recruited and scanned by using resting-state fMRI. Group independent-component analysis and the BN learning approach were used, respectively, to separate the RSNs and construct the network-to-network connectivity patterns for each group. The convergence index for the special network DMN was measured. RESULTS: Three of the 4 connections were significantly lower in AD compared with NC. Although numerically the AD group had more connections, none was statistically different from that in the NC group except for 1 increased connection from the DMN to the DAN. The convergence index for the DMN node was lower in AD than in NC. CONCLUSIONS: Connections among cognitive networks in AD were more vulnerable to impairment than sensory networks. The DMN decreased its integration function for other RSNs but may also play a role in compensating for the disrupted connections in AD. Abbreviations ADAlzheimer diseaseANauditory networkBNBayesian networkDANdorsal attention networkDMNdefault-mode networkLVNlateral visual networkMVNmedial visual networkNChealthy controlsRSNresting-state networkSMNsensory-motor networkSRNself-referential networkVANventral attention network