Structural and functional MRI correlates of Stroop control in benign MS.
The objective of this study was to assess the functional and structural substrates of cognitive network changes in patients with benign multiple sclerosis (BMS), using an analysis of effective connectivity and MR tractography. Using a 3-Tesla scanner, we acquired dual-echo, diffusion tensor (DT) and functional MRI during the performance of the Stroop task from 15 BMS patients and 19 healthy controls. DT MRI tractography was used to calculate DT derived metrics from several white matter (WM) fiber bundles, thought to be involved in cognitive performance. DT MRI metrics from WM fiber bundles not directly related with cognitive performance were also derived. Effective connectivity analysis was performed using statistical parametric mapping. MS patients had significantly abnormal DT MRI metrics in all the structures analyzed. Compared with controls, MS patients had more significant activations of several areas of the cognitive network involved in Stroop performance, bilaterally. Compared with controls, BMS patients also had increased connectivity strengths between several cortical areas of the sensorimotor network and the right (R) inferior frontal gyrus and the R cerebellum, as well as decreased connectivity strengths with the anterior cingulate cortex. Coefficients of altered connectivity were moderately correlated with structural MRI metrics of tissue damage within intra- and inter-hemispheric cognitive-related WM fiber bundles, while no correlations were found with the remaining fiber bundles studied, suggesting that functional cortical changes in patients with BMS might represent an adaptive response driven by damage of specific WM structures.
Neuroimaging Research Unit, University Ospedale San Raffaele, Milan, Italy.
Maria A
MA
Rocca
Paola
P
Valsasina
Antonia
A
Ceccarelli
Martina
M
Absinta
Angelo
A
Ghezzi
Gianna
G
Riccitelli
Elisabetta
E
Pagani
Andrea
A
Falini
Giancarlo
G
Comi
Giuseppe
G
Scotti
Massimo
M
Filippi
D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D001921:Brain / Q000473:pathology* / Q000503:physiopathology*; D001931:Brain Mapping; D003072:Cognition Disorders / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology*; D038524:Diffusion Magnetic Resonance Imaging; D004185:Disability Evaluation; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications / Q000473:pathology* / Q000503:physiopathology*; D009413:Nerve Fibers, Myelinated / Q000473:pathology; D009415:Nerve Net / Q000473:pathology / Q000503:physiopathology; D009434:Neural Pathways / Q000473:pathology / Q000503:physiopathology; D009473:Neuronal Plasticity / Q000502:physiology; D009483:Neuropsychological Tests; D011237:Predictive Value of Tests