title: Effect of hypertension on the resting-state functional connectivity in patients with Alzheimer's disease (AD).
abstract: OBJECTIVE
  Although hypertension is known to be a risk factor for AD, the effects of hypertension on brain function in AD patients are not well understood. We investigated alterations in resting-state functional connectivity according to the presence of hypertension in AD patients by using a method of correlation analysis based on a seed region in the posterior cingulate cortex (PCC). We also determined whether differences in resting-state connectivity were associated with gray matter atrophy.
  
  
  METHODS
  Thirty-seven AD patients (18 patients with hypertension and 19 patients without hypertension) underwent the resting-state functional magnetic resonance imaging. We obtained the PCC maps by a temporal correlation method, to identify alterations in the functional connectivity of the PCC in hypertensive group relative to non-hypertensive group. Voxel-based morphometry analysis was also applied to adjust the confounding effect of gray matter atrophy.
  
  
  RESULTS
  We detected a decreased connectivity to the PCC in the regions of subgenual anterior cingulated cortex (ACC) in hypertensive group relative to non-hypertensive group. However, we observed a pattern of increased connectivity between the PCC and the left inferior parietal cortex in hypertensive group. After correction for gray matter atrophy, all detected regions still remained significant.
  
  
  CONCLUSIONS
  Altered connectivity in AD patients with hypertension suggests the possibility that hypertension impairs resting-state functional connectivity of the AD brain, inducing a compensational process outside the impaired networks or disequilibrium in brain connectivity. This finding may account for an additional contribution of hypertension to the pathophysiology of AD.
authors.affiliation: Department of Psychiatry, Ajou University School of Medicine, San 5, Wonchondong, Yeongtong-gu, Suwon 443-721, Republic of Korea.
authors.forename: Sang Joon
authors.initials: SJ
authors.lastname: Son
authors.affiliation: Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, Yonsei-ro 50, Seodaemun-gu, Seoul 120-752, Republic of Korea.
authors.forename: Jinna
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Psychiatry and Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Yonsei-ro 50, Seodaemun-gu, Seoul 120-752, Republic of Korea.
authors.forename: Eun
authors.initials: E
authors.lastname: Lee
authors.affiliation: Department of Psychiatry and Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Yonsei-ro 50, Seodaemun-gu, Seoul 120-752, Republic of Korea.
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Park
authors.affiliation: Department of Psychiatry and Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Yonsei-ro 50, Seodaemun-gu, Seoul 120-752, Republic of Korea.
authors.forename: Kee
authors.initials: K
authors.lastname: Namkoong
authors.affiliation: Department of Psychiatry, Ajou University School of Medicine, San 5, Wonchondong, Yeongtong-gu, Suwon 443-721, Republic of Korea.
authors.forename: Chang Hyung
authors.initials: CH
authors.lastname: Hong
authors.affiliation: Department of Biomedical Engineering, Keimyung University, Dalgubeol-daero 1095, Daegu 704-701, Republic of Korea. Electronic address: jeonghun.ku@gmail.com.
authors.forename: Jeonghun
authors.initials: J
authors.lastname: Ku
authors.affiliation: Department of Psychiatry and Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Yonsei-ro 50, Seodaemun-gu, Seoul 120-752, Republic of Korea; Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Yonsei-ro 50, Seodaemun-gu, Seoul 120-752, Republic of Korea. Electronic address: kimeosu@gmail.com.
authors.forename: Eosu
authors.initials: E
authors.lastname: Kim
authors.affiliation: Department of Psychiatry and Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Yonsei-ro 50, Seodaemun-gu, Seoul 120-752, Republic of Korea.
authors.forename: Byoung Hoon
authors.initials: BH
authors.lastname: Oh
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000503:physiopathology* / Q000523:psychology*; D001284:Atrophy; D001921:Brain / Q000503:physiopathology; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000473:pathology; D005260:Female; D007839:Functional Laterality; D006179:Gyrus Cinguli / Q000503:physiopathology; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged
keywords: Alzheimer's disease; Functional connectivity; Hypertension; Resting-state functional MRI