Limbic hyperconnectivity in the vegetative state.
OBJECTIVE
To investigate functional connectivity between the default mode network (DMN) and other networks in disorders of consciousness.


METHODS
We analyzed MRI data from 11 patients in a vegetative state and 7 patients in a minimally conscious state along with age- and sex-matched healthy control subjects. MRI data analysis included nonlinear spatial normalization to compensate for disease-related anatomical distortions. We studied brain connectivity data from resting-state MRI temporal series, combining noninferential (independent component analysis) and inferential (seed-based general linear model) methods.


RESULTS
In DMN hypoconnectivity conditions, a patient's DMN functional connectivity shifts and paradoxically increases in limbic structures, including the orbitofrontal cortex, insula, hypothalamus, and the ventral tegmental area.


CONCLUSIONS
Concurrently with DMN hypoconnectivity, we report limbic hyperconnectivity in patients in vegetative and minimally conscious states. This hyperconnectivity may reflect the persistent engagement of residual neural activity in self-reinforcing neural loops, which, in turn, could disrupt normal patterns of connectivity.
From the Department of Neuroradiology (C.D.P., A.P., P.V.), National Neurological Institute C. Mondino, Pavia; Department of Neuroradiology (S.B.), Neurological Institute C. Mondino, University of Pavia, Italy; Coma Science Group (C.D.P., S.L.), Cyclotron Research Centre and Neurology Department, University and University Hospital of Liège, Belgium; Department of Cognitive Neuroscience (C.D.P., F.D.S.), Faculty of Psychology and Neuroscience, Maastricht University, the Netherlands; Department of Neuroradiology (A.J.B.), University of Heidelberg, Germany; Functional MRI of the Brain (A.J.B.), University of Oxford, UK; Neurorehabilitation Unit (C.P., G.M.), IRCCS, S. Maugeri Foundation, Via Maugeri, Pavia, Italy; Department of Surgical Sciences, University of Pavia (L.M.), Department of Anesthesiology and Critical Care Medicine (R.I.), Fondazione IRCCS, Policlinico S. Matteo, Pavia; University of Salerno (F.D.S.), Medical Faculty; and Fondazione Eugenio Medea (F.D.S.), Lecco, Italy.
Carol
C
Di Perri
Stefano
S
Bastianello
Andreas J
AJ
Bartsch
Caterina
C
Pistarini
Giorgio
G
Maggioni
Lorenzo
L
Magrassi
Roberto
R
Imberti
Anna
A
Pichiecchio
Paolo
P
Vitali
Steven
S
Laureys
Francesco
F
Di Salle
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D054022:Cerebrum / Q000503:physiopathology*; D005260:Female; D059907:Functional Neuroimaging / Q000295:instrumentation / Q000379:methods; D006801:Humans; D008032:Limbic System / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000503:physiopathology*; D018458:Persistent Vegetative State / Q000503:physiopathology*; D055815:Young Adult