Default mode, executive function, and language functional connectivity networks are compromised in mild Alzheimer's disease.
Alzheimer's disease (AD) is characterized by mental and cognitive problems, particularly with memory, language, visuospatial skills (VS), and executive functions (EF). Advances in the neuroimaging of AD have highlighted dysfunctions in functional connectivity networks (FCNs), especially in the memory related default mode network (DMN). However, little is known about the integrity and clinical significance of FNCs that process other cognitive functions than memory. We evaluated 22 patients with mild AD and 26 healthy controls through a resting state functional MRI scan. We aimed to identify different FCNs: the DMN, language, EF, and VS. Seed-based functional connectivity was calculated by placing a seed in the DMN (posterior cingulate cortex), language (Broca's and Wernicke's areas), EF (right and left dorsolateral prefrontal cortex), and VS networks (right and left associative visual cortex). We also performed regression analyses between individual connectivity maps for the different FCNs and the scores on cognitive tests. We found areas with significant decreases in functional connectivity in patients with mild AD in the DMN and Wernicke's area compared with controls. Increased connectivity in patients was observed in the EF network. Regarding multiple linear regression analyses, a significant correlation was only observed between the connectivity of the DMN and episodic memory (delayed recall) scores. In conclusion, functional connectivity alterations in mild AD are not restricted to the DMN. Other FCNs related to language and EF may be altered. However, we only found significant correlations between cognition and functional connectivity in the DMN and episodic memory performance.
Marina
M
Weiler
Aya
A
Fukuda
Lilian H P
LH
Massabki
Tatila M
TM
Lopes
Alexandre R
AR
Franco
Benito P
BP
Damasceno
Fernando
F
Cendes
Department of Neurology, FCM, University of Campinas (UNICAMP), Cidade Universitaria, Campinas- SP, Brazil, 13083-970. mbalth@unicamp.br.
Marcio L F
ML
Balthazar
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications*; D001921:Brain / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology*; D001931:Brain Mapping; D000077463:Carbamide Peroxide; D060825:Cognitive Dysfunction / Q000209:etiology*; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007802:Language; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000098:blood supply / Q000503:physiopathology*; D009483:Neuropsychological Tests; D010545:Peroxides / Q000097:blood; D014508:Urea / Q000031:analogs & derivatives / Q000097:blood
D010545:Peroxides; D000077463:Carbamide Peroxide; D014508:Urea