[en] Recent studies on spontaneous fluctuations in the functional MRI blood oxygen level-dependent (BOLD) signal in awake healthy subjects showed the presence of coherent fluctuations among functionally defined neuroanatomical networks. However, the functional significance of these spontaneous BOLD fluctuations remains poorly understood. By means of 3 T functional MRI, we demonstrate absent cortico-thalamic BOLD functional connectivity (i.e. between posterior cingulate/precuneal cortex and medial thalamus), but preserved cortico-cortical connectivity within the default network in a case of vegetative state (VS) studied 2.5 years following cardio-respiratory arrest, as documented by extensive behavioral and paraclinical assessments. In the VS patient, as in age-matched controls, anticorrelations could also be observed between posterior cingulate/precuneus and a previously identified task-positive cortical network. Both correlations and anticorrelations were significantly reduced in VS as compared to controls. A similar approach in a brain dead patient did not show any such long-distance functional connectivity. We conclude that some slow coherent BOLD fluctuations previously identified in healthy awake human brain can be found in alive but unaware patients, and are thus unlikely to be uniquely due to ongoing modifications of conscious thoughts. Future studies are needed to give a full characterization of default network connectivity in the VS patients population.
Disciplines :
Neurology
Author, co-author :
Boly, Mélanie ; Université de Liège - ULiège > Centre de Recherches du Cyclotron - Département des sciences cliniques > Neurologie
Tshibanda, Luaba ; Centre Hospitalier Universitaire de Liège - CHU > Imagerie médicale
Noirhomme, Quentin ; Université de Liège - ULiège > Centre de recherches du cyclotron
Schnakers, Caroline ; Université de Liège - ULiège > Centre de recherches du cyclotron
Ledoux, Didier ; Centre Hospitalier Universitaire de Liège - CHU > Soins intensifs
Boveroux, Pierre ; Centre Hospitalier Universitaire de Liège - CHU > Centre de Recherches du Cyclotron > Anesthésie et réanimation
Garweg, Christophe ; Centre Hospitalier Universitaire de Liège - CHU > Cardiologie
Lambermont, Bernard ; Centre Hospitalier Universitaire de Liège - CHU > Frais communs médecine
Phillips, Christophe ; Université de Liège - ULiège > Centre de recherches du cyclotron - Dép. d'électric., électron. et informat. (Inst.Montefiore)
Luxen, André ; Université de Liège - ULiège > Centre de Recherches du cyclotron - Département de chimie (sciences) > Chimie organique de synthèse - Centre de recherches du cyclotron
Moonen, Gustave ; Centre Hospitalier Universitaire de Liège - CHU > Neurologie Sart Tilman
Bassetti, C.
Maquet, Pierre ; Université de Liège - ULiège > Centre de recherches du cyclotron - Département des sciences cliniques
Laureys, Steven ; Université de Liège - ULiège > Centre de recherches du cyclotron - Département des sciences cliniques
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