Working memory performance of early MS patients correlates inversely with modularity increases in resting state functional connectivity networks

OLGA LUCIA GAMBOA; ENZO TAGLIAZUCCHI; FREDERIC VON WEGNER; ALINA JURCOANE; MATTHIAS WAHL; HELMUT LAUFS; ULF ZIEMANN

NEUROIMAGE.

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: Amsterdam; Año: 2014

1053-8119

Multiple sclerosis (MS) is an autoimmune inflammatory demyelinating and neurodegenerative disorder of thecentral nervous system characterized by multifocal white matter brain lesions leading to alterations in connectivityat the subcortical and cortical level. Graph theory, in combination with neuroimaging techniques, has been recentlydeveloped into a powerful tool to assess the large-scale structure of brain functional connectivity.Considering the structural damage present in the brain of MS patients, we hypothesized that the topologicalproperties of resting-state functional networks of early MS patients would be re-arranged in order to limit theimpact of disease expression. A standardized dual task (Paced Auditory Serial Addition Task simultaneously performedwith a paper and pencil task) was administered to study the interactions between behavioral performanceand functional network re-organization. We studied a group of 16 early MS patients (35.3 ± 8.3 years,11 females) and 20 healthy controls (29.9 ± 7.0 years, 10 females) and found that brain resting-state networksof the MS patients displayed increased network modularity, i.e. diminished functional integration betweenseparate functional modules. Modularity correlated negatively with dual task performance in the MS patients.Our results shed light on how localized anatomical connectivity damage can globally impact brain functionalconnectivity and how these alterations can impair behavioral performance. Finally, given the early stage of theMS patients included in this study, network modularity could be considered a promising biomarker for detectionof earliest-stage brain network reorganization, and possibly of disease progression