Altered network properties of the fronto-parietal network and the thalamus in impaired consciousness.
Recovery of consciousness has been associated with connectivity in the frontal cortex and parietal regions modulated by the thalamus. To examine this model and to relate alterations to deficits in cognitive functioning and conscious processing, we investigated topological network properties in patients with chronic disorders of consciousness recovered from coma. Resting state fMRI data of 34 patients with unresponsive wakefulness syndrome and 25 in minimally conscious state were compared to 28 healthy controls. We investigated global and local network characteristics. Additionally, behavioral measures were correlated with the local metrics of 28 regions within the fronto-parietal network and the thalamus. In chronic disorders of consciousness, modularity at the global level was reduced suggesting a disturbance in the optimal balance between segregation and integration. Moreover, network properties were altered in several regions which are associated with conscious processing (particularly, in medial parietal, and frontal regions, as well as in the thalamus). Between minimally conscious and unconscious patients the local efficiency of medial parietal regions differed. Alterations in the thalamus were particularly evident in non-conscious patients. Most of the regions affected in patients with impaired consciousness belong to the so-called 'rich club' of highly interconnected central nodes. Disturbances in their topological characteristics have severe impact on information integration and are reflected in deficits in cognitive functioning probably leading to a total breakdown of consciousness.
Neuroscience Institute & Centre for Neurocognitive Research, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria ; Centre for Neurocognitive Research & Department of Psychology, University of Salzburg, Salzburg, Austria ; Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria.
Julia Sophia
JS
Crone
Coma Science Group, Cyclotron Research Centre, University of Liège, Belgium ; Brain and Mind Institute, Physics & Astronomy Department, Western University, London, Ontario, Canada.
Andrea
A
Soddu
Centre for Neurocognitive Research & Department of Psychology, University of Salzburg, Salzburg, Austria ; Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria.
Yvonne
Y
Höller
Coma Science Group, Cyclotron Research Centre, University of Liège, Belgium.
Audrey
A
Vanhaudenhuyse
Centre for Neurocognitive Research & Department of Psychology, University of Salzburg, Salzburg, Austria.
Matthias
M
Schurz
Neuroscience Institute & Centre for Neurocognitive Research, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria.
Jürgen
J
Bergmann
Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria.
Elisabeth
E
Schmid
Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria.
Eugen
E
Trinka
Coma Science Group, Cyclotron Research Centre, University of Liège, Belgium ; Neurology Department, CHU Sart Tilman Hospital, University of Liège, Belgium.
Steven
S
Laureys
Neuroscience Institute & Centre for Neurocognitive Research, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria ; Centre for Neurocognitive Research & Department of Psychology, University of Salzburg, Salzburg, Austria.
Martin
M
Kronbichler
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016022:Case-Control Studies; D003244:Consciousness Disorders / Q000473:pathology*; D005260:Female; D005625:Frontal Lobe / Q000473:pathology*; D007839:Functional Laterality; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000473:pathology*; D010296:Parietal Lobe / Q000473:pathology*; D013788:Thalamus / Q000473:pathology*
ACC, anterior cingulate cortex; Connectivity; Consciousness; DOC, disorders of consciousness; Graph theory; MCS, minimally conscious state; Network; PCC, posterior cingulate cortex; Small world; VS/UWS, vegetative state/unresponsive wakefulness syndrome; Vegetative state