TY - JOUR
T1 - Gray matter network disruptions and amyloid beta in cognitively normal adults
AU - Tijms, Betty M.
AU - ten Kate, Mara
AU - Wink, Alle Meije
AU - Visser, Pieter Jelle
AU - Ecay, Mirian
AU - Clerigue, Montserrat
AU - Estanga, Ainara
AU - Garcia Sebastian, Maite
AU - Izagirre, Andrea
AU - Villanua, Jorge
AU - Martinez Lage, Pablo
AU - van der Flier, Wiesje M.
AU - Scheltens, Philip
AU - Sanz Arigita, Ernesto
AU - Barkhof, Frederik
PY - 2016/1
Y1 - 2016/1
N2 - 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.
AB - 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.
KW - Alzheimer's disease
KW - Amyloid beta
KW - Cognitively normal adults
KW - Graph theory
KW - Gray matter
KW - MRI
KW - Single-subject
U2 - https://doi.org/10.1016/j.neurobiolaging.2015.10.015
DO - https://doi.org/10.1016/j.neurobiolaging.2015.10.015
M3 - Article
C2 - 26559882
SN - 0197-4580
VL - 37
SP - 154
EP - 160
JO - Neurobiology of aging
JF - Neurobiology of aging
ER -