Abnormalities of resting state functional connectivity are related to sustained attention deficits in MS.
OBJECTIVE
Resting state (RS) functional MRI recently identified default network abnormalities related to cognitive impairment in MS. fMRI can also be used to map functional connectivity (FC) while the brain is at rest and not adhered to a specific task. Given the importance of the anterior cingulate cortex (ACC) for higher executive functioning in MS, we here used the ACC as seed-point to test for differences and similarities in RS-FC related to sustained attention between MS patients and controls.


METHODS
Block-design rest phases of 3 Tesla fMRI data were analyzed to assess RS-FC in 31 patients (10 clinically isolated syndromes, 16 relapsing-remitting, 5 secondary progressive MS) and 31 age- and gender matched healthy controls (HC). Participants underwent extensive cognitive testing.


METHODS
In both groups, signal changes in several brain areas demonstrated significant correlation with RS-activity in the ACC. These comprised the posterior cingulate cortex (PCC), insular cortices, the right caudate, right middle temporal gyrus, angular gyri, the right hippocampus, and the cerebellum. Compared to HC, patients showed increased FC between the ACC and the left angular gyrus, left PCC, and right postcentral gyrus. Better cognitive performance in the patients was associated with increased FC to the cerebellum, middle temporal gyrus, occipital pole, and the angular gyrus.


CONCLUSIONS
We provide evidence for adaptive changes in RS-FC in MS patients compared to HC in a sustained attention network. These results extend and partly mirror findings of task-related fMRI, suggesting FC may increase our understanding of cognitive dysfunction in MS.
Medical University of Graz, Department of Neurology, Graz, Austria.
Marisa
M
Loitfelder
Massimo
M
Filippi
Mara
M
Rocca
Paola
P
Valsasina
Stefan
S
Ropele
Margit
M
Jehna
Siegrid
S
Fuchs
Reinhold
R
Schmidt
Christa
C
Neuper
Franz
F
Fazekas
Christian
C
Enzinger
D000293:Adolescent; D000328:Adult; D001288:Attention / Q000502:physiology*; D001481:Basal Metabolism; D016022:Case-Control Studies; D006179:Gyrus Cinguli / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology* / Q000523:psychology; D009415:Nerve Net / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D009483:Neuropsychological Tests; D055815:Young Adult