Distributed changes in default-mode resting-state connectivity in multiple sclerosis.
BACKGROUND
The default-mode network (DMN) has been increasingly recognized as relevant to cognitive status.


OBJECTIVE
To explore DMN changes in patients with relapsing-remitting (RR) multiple sclerosis (MS) and to relate these to the cognitive status.


METHODS
Eighteen cognitively impaired (CI) and eighteen cognitively preserved (CP) RRMS patients and eighteen healthy controls (HCs), matched for age, sex and education, underwent neuropsychological evaluation and anatomical and resting-state functional MRI (rs-fMRI). DMN functional connectivity was evaluated from rs-fMRI data via independent component analysis. T2 lesion load (LL) was computed by a semi-automatic method and global and local atrophy was estimated by SIENAX and SPM8 voxel-based morphometry analyses from 3D-T1 images.


RESULTS
When the whole group of RRMS patients was compared with HCs, DMN connectivity was significantly weaker in the anterior cingulate cortex, whereas it was significantly weaker in the core but stronger at the periphery of the posterior cingulate cortex. These findings were more evident in CP than CI patients. Observed DMN changes did not correlate with global atrophy or T2-LL, but were locally associated with regional grey matter loss.


CONCLUSIONS
Relapsing-remitting multiple sclerosis patients show a consistent dysfunction of DMN at the level of the anterior node. DMN distribution changes in the posterior node may reflect a possible compensatory effect on cognitive performance.
Department of Neurological Sciences, Second University of Naples, Naples, Italy.
Simona
S
Bonavita
Antonio
A
Gallo
Rosaria
R
Sacco
Marida Della
MD
Corte
Alvino
A
Bisecco
Renato
R
Docimo
Luigi
L
Lavorgna
Daniele
D
Corbo
Alfonso Di
AD
Costanzo
Fabio
F
Tortora
Mario
M
Cirillo
Fabrizio
F
Esposito
Gioacchino
G
Tedeschi
D000328:Adult; D001284:Atrophy / Q000473:pathology / Q000503:physiopathology; D001921:Brain / Q000473:pathology / Q000503:physiopathology*; D001931:Brain Mapping; D003072:Cognition Disorders / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000473:pathology / Q000503:physiopathology* / Q000523:psychology; D009415:Nerve Net / Q000503:physiopathology*; D009483:Neuropsychological Tests; D012720:Severity of Illness Index