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 (A beta(42)) is among the earliest changes in AD. We studied, in cognitively healthy adults, the relationship between A beta(42) 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 A beta(42) <550 pg/mL). Degree, clustering coefficient, and path length were computed at whole brain level and for 90 anatomical areas. Associations between continuous A beta(42) 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 A beta(42) 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 A beta(42) 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 (A beta(42)) is among the earliest changes in AD. We studied, in cognitively healthy adults, the relationship between A beta(42) 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 A beta(42) <550 pg/mL). Degree, clustering coefficient, and path length were computed at whole brain level and for 90 anatomical areas. Associations between continuous A beta(42) 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 A beta(42) 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 A beta(42) levels can be related to gray matter networks disruptions.
KW - Alzheimer's disease
KW - Cognitively normal adults
KW - Amyloid beta
KW - Single-subject
KW - Gray matter
KW - Graph theory
KW - MRI
U2 - 10.1016/j.neurobiolaging.2015.10.015
DO - 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 -