Altered functional connectivity related to white matter changes inside the working memory network at the very early stage of MS

• Published in: Journal of cerebral blood flow and metabolism 2005-10, Vol.25 (10), p.1245-1253
• Main Authors: Duong, My-Van Au, Audoin, Bertrand, Boulanouar, Kader, Ibarrola, Daniella, Malikova, Irina, Confort-Gouny, Sylrane, Celsis, Pierre, Pelletier, Jean, Cozzone, Patrick J, Ranjeva, Jean-Philippe
• Format: Article
• Language: English
• Subjects: Acoustic Stimulation; Adult; Biological and medical sciences; Brain - pathology; Brain - physiopathology; Brain Mapping; Case-Control Studies; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Disorders of higher nervous function. Focal brain diseases. Central vestibular syndrome and deafness. Brain stem syndromes; Humans; Magnetic Resonance Imaging; Medical sciences; Memory - physiology; Multiple Sclerosis - pathology; Multiple Sclerosis - physiopathology; Nerve Fibers, Myelinated - pathology; Nerve Net - physiopathology; Nervous system (semeiology, syndromes); Neurology; Vascular diseases and vascular malformations of the nervous system
• ISSN: 0271-678X; 1559-7016
• DOI: 10.1038/sj.jcbfm.9600122

Functional magnetic resonance imaging (fMRI) using paced auditory serial addition test (PASAT) as paradigm was used to study the functional connectivity in 18 patients at the very early stage of multiple sclerosis (MS) compared with 18 controls, to determine the existence of circuitry disturbance inside the working memory network and its relationship with white matter abnormalities assessed by conventional MRI and magnetization transfer ratio (MTR) imaging. The left BA 45/46 was selected as the seed region to compute correlation maps with other brain regions. After obtaining the correlation map for each subject, between-group comparisons were performed using random effect procedure. Compared with controls, patients did not show any greater functional connectivity between left BA 45/46 and other regions during PASAT. In contrast, decrease in functional connectivity was observed in patients between left BA 45/46 and left BA 9, right BA 3, and the anterior cingulate cortex (BA 24). In patients, no correlations were found between altered functional connectivity and clinical data. However, functional connectivity observed between left BA 45/46 and BA 24 in patients was correlated with the MTR of normal appearing white matter, and with brain T2 lesion load. Altered functional connectivity is present inside the working memory network of patients at the very early stage of MS and is related to the extent of diffuse white matter changes.