Gray matter network disruptions and amyloid beta in cognitively normal adults

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• 作者：Betty M. Tijms^a ; ^{b.tijms@vumc.nl" class="auth_mail" title="E-mail the corresponding author} ; ^{betty.tijms@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; Mara ten Kate^a ; ^b ; Alle Meije Wink^b ; Pieter Jelle Visser^a ; ^c ; Mirian Ecay^d ; Montserrat Clerigue^d ; Ainara Estanga^d ; Maite Garcia Sebastian^d ; Andrea Izagirre^d ; Jorge Villanua^d ; ^e ; Pablo Martinez Lage^d ; Wiesje M. van der Flier^a ; ^f ; Philip Scheltens^a ; Ernesto Sanz Arigita^d ; ¹ ; Frederik Barkhof^b ; ¹
• 关键词：Alzheimer's disease ; Cognitively normal adults ; Amyloid beta ; Single-subject ; Gray matter ; Graph theory ; MRI
• 刊名：Neurobiology of Aging
• 出版年：2016
• 出版时间：January 2016
• 年：2016
• 卷：37
• 期：Complete
• 页码：154-160
• 全文大小：1077 K

文摘

Gray matter networks are disrupted in Alzheimer's disease (AD). It is unclear when these disruptions start during the development of AD. Amyloid beta 1–42 (Aβ₄₂) is among the earliest changes in AD. We studied, in cognitively healthy adults, the relationship between Aβ₄₂ levels in cerebrospinal fluid (CSF) and single-subject cortical gray matter network measures. Single-subject gray matter networks were extracted from structural magnetic resonance imaging scans in a sample of cognitively healthy adults (N = 185; age range 39–79, mini–mental state examination >25, N = 12 showed abnormal Aβ₄₂ < 550 pg/mL). Degree, clustering coefficient, and path length were computed at whole brain level and for 90 anatomical areas. Associations between continuous Aβ₄₂ CSF levels and single-subject cortical gray matter network measures were tested. Smoothing splines were used to determine whether a linear or nonlinear relationship gave a better fit to the data. Lower Aβ₄₂ CSF levels were linearly associated at whole brain level with lower connectivity density, and nonlinearly with lower clustering values and higher path length values, which is indicative of a less-efficient network organization. These relationships were specific to medial temporal areas, precuneus, and the middle frontal gyrus (all p < 0.05). These results suggest that mostly within the normal spectrum of amyloid, lower Aβ₄₂ levels can be related to gray matter networks disruptions.