A role for the default mode network in the bases of disorders of consciousness
Version of Record online: 2 OCT 2012
Copyright © 2012 American Neurological Association
Annals of Neurology
Volume 72, Issue 3, pages 335–343, September 2012
How to Cite
Fernández-Espejo, D., Soddu, A., Cruse, D., Palacios, E. M., Junque, C., Vanhaudenhuyse, A., Rivas, E., Newcombe, V., Menon, D. K., Pickard, J. D., Laureys, S. and Owen, A. M. (2012), A role for the default mode network in the bases of disorders of consciousness. Ann Neurol., 72: 335–343. doi: 10.1002/ana.23635
- Issue online: 2 OCT 2012
- Version of Record online: 2 OCT 2012
- Accepted manuscript online: 24 APR 2012 12:14PM EST
- Manuscript Accepted: 20 APR 2012
- Manuscript Revised: 12 APR 2012
- Manuscript Received: 1 JAN 2012
- Spanish Ministries of Science and Innovation. Grant Number: SAF2007-66077
- Education. Grant Number: AP2006-00862
- Medical Research Council. Grant Number: U.1055.01.002.00001.01
- McDonnell Foundation
- Canada Excellence Research Chairs Program
- European Commission
- Fonds de la Recherche Scientifique
- Mind Science Foundation, Belgian French-Speaking Community Concerted Research Action. Grant Number: ARC 06/11_340
- University Hospital of Liège, University of Liège, and Gates Cambridge Trust
Functional connectivity in the default mode network (DMN) is known to be reduced in patients with disorders of consciousness, to a different extent depending on their clinical severity. Nevertheless, the integrity of the structural architecture supporting this network and its relation with the exhibited functional disconnections are very poorly understood. We investigated the structural connectivity and white matter integrity of the DMN in patients with disorders of consciousness of varying clinical severity.
Fifty-two patients—19 in a vegetative state (VS), 27 in a minimally conscious state (MCS), and 6 emerging from a minimally conscious state (EMCS)—and 23 healthy volunteers participated in the study. Structural connectivity was assessed by means of probabilistic tractography, and the integrity of the resulting fibers was characterized by their mean fractional anisotropy values.
Patients showed significant impairments in all of the pathways connecting cortical regions within this network, as well as the pathway connecting the posterior cingulate cortex/precuneus with the thalamus, relative to the healthy volunteers. Moreover, the structural integrity of this pathway, as well as that of those connecting the posterior areas of the network, was correlated with the patients' behavioral signs for awareness, being higher in EMCS patients than those in the upper and lower ranges of the MCS patients, and lowest in VS patients.
These results provide a possible neural substrate for the functional disconnection previously described in these patients, and reinforce the importance of the DMN in the genesis of awareness and the neural bases of its disorders. Ann Neurol 2012;72:335–343.