Dysfunctional organization of default mode network before memory impairments in type 2 diabetes.
Episodic memory depends on the maintenance of an intact default mode network (DMN), and is one of the earliest cognitive domains to become impaired in type 2 diabetes mellitus (T2DM). Therefore, exploring the alterations in task-related DMN deactivation and functional connectivity that affect episodic memory in T2DM will help to enhance our understanding of the allocation patterns underlying memory function in T2DM.



The current study assessed changes in DMN activation and architecture during the encoding of a functional magnetic resonance imaging task in 39 patients with T2DM and 41 healthy controls which were recruited from local communities in Beijing, China.



We found that patients with T2DM and intact episodic memory performance exhibited reduced deactivation in the right precuneus and the middle temporal gyrus during the episodic memory task. Furthermore, an anterior-posterior disconnection phenotype and altered topological configuration of the DMN were observed in patients with T2DM using graph-theoretical approaches. Correlation analysis showed that altered deactivation during the episodic memory task was closely related to connectivity dysfunction and topological properties in the DMN.



Our findings demonstrate that the maintenance of memory in patients with T2DM involves reduced deactivation and impaired anterior-posterior connections in the DMN during encoding.
State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, PR China; BABRI Centre, Beijing Normal University, Beijing 100875, PR China.
Yaojing
Y
Chen
State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, PR China; BABRI Centre, Beijing Normal University, Beijing 100875, PR China.
Zhen
Z
Liu
State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, PR China; BABRI Centre, Beijing Normal University, Beijing 100875, PR China.
Ailin
A
Wang
State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, PR China; BABRI Centre, Beijing Normal University, Beijing 100875, PR China.
Junying
J
Zhang
State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, PR China; BABRI Centre, Beijing Normal University, Beijing 100875, PR China.
Sisi
S
Zhang
State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, PR China; BABRI Centre, Beijing Normal University, Beijing 100875, PR China.
Di
D
Qi
Banner Alzheimer's Institute, Phoenix, AZ 85006, USA; BABRI Centre, Beijing Normal University, Beijing 100875, PR China.
Kewei
K
Chen
State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, PR China; BABRI Centre, Beijing Normal University, Beijing 100875, PR China. Electronic address: zhang_rzs@bnu.edu.cn.
Zhanjun
Z
Zhang
D000368:Aged; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000503:physiopathology*; D060825:Cognitive Dysfunction / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology; D063132:Connectome / Q000379:methods*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008569:Memory Disorders / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology; D061212:Memory, Episodic; D008875:Middle Aged
Alzheimer’s disease; Default mode network; Episodic memory; Functional connectivity; Topological organization; Type 2 diabetes mellitus