title: Brain function in the vegetative state.
abstract: Positron emission tomography (PET) techniques represent a useful tool to better understand the residual brain function in vegetative state patients. It has been shown that overall cerebral metabolic rates for glucose are massively reduced in this condition. However, the recovery of consciousness from vegetative state is not always associated with substantial changes in global metabolism. This finding led us to hypothesize that some vegetative patients are unconscious not just because of a global loss of neuronal function, but rather due to an altered activity in some critical brain regions and to the abolished functional connections between them. We used voxel-based Statistical Parametric Mapping (SPM) approaches to characterize the functional neuroanatomy of the vegetative state. The most dysfunctional brain regions were bilateral frontal and parieto-temporal associative cortices. Despite the metabolic impairment, external stimulation still induced a significant neuronal activation (i.e., change in blood flow) in vegetative patients as shown by both auditory click stimuli and noxious somatosensory stimuli. However, this activation was limited to primary cortices and dissociated from higher-order associative cortices, thought to be necessary for conscious perception. Finally, we demonstrated that vegetative patients have impaired functional connections between distant cortical areas and between the thalami and the cortex and, more importantly, that recovery of consciousness is paralleled by a restoration of this cortico-thalamo-cortical interaction.
authors.affiliation: Cyclotron Research Center, Department of Neurology, CHU Sart Tilman, University of Liège, Liège, Belgium. steven.laureys@ulg.ac.be
authors.forename: Steven
authors.initials: S
authors.lastname: Laureys
authors.forename: Sylvie
authors.initials: S
authors.lastname: Antoine
authors.forename: Melanie
authors.initials: M
authors.lastname: Boly
authors.forename: Sandra
authors.initials: S
authors.lastname: Elincx
authors.forename: Marie-Elisabeth
authors.initials: ME
authors.lastname: Faymonville
authors.forename: Jacques
authors.initials: J
authors.lastname: Berré
authors.forename: Bernard
authors.initials: B
authors.lastname: Sadzot
authors.forename: Martine
authors.initials: M
authors.lastname: Ferring
authors.forename: Xavier
authors.initials: X
authors.lastname: De Tiège
authors.forename: Patrick
authors.initials: P
authors.lastname: van Bogaert
authors.forename: Isabelle
authors.initials: I
authors.lastname: Hansen
authors.forename: Pierre
authors.initials: P
authors.lastname: Damas
authors.forename: Nicolas
authors.initials: N
authors.lastname: Mavroudakis
authors.forename: Bernard
authors.initials: B
authors.lastname: Lambermont
authors.forename: Guy
authors.initials: G
authors.lastname: Del Fiore
authors.forename: Joël
authors.initials: J
authors.lastname: Aerts
authors.forename: Christian
authors.initials: C
authors.lastname: Degueldre
authors.forename: Christophe
authors.initials: C
authors.lastname: Phillips
authors.forename: George
authors.initials: G
authors.lastname: Franck
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Vincent
authors.forename: Maurice
authors.initials: M
authors.lastname: Lamy
authors.forename: André
authors.initials: A
authors.lastname: Luxen
authors.forename: Gustave
authors.initials: G
authors.lastname: Moonen
authors.forename: Serge
authors.initials: S
authors.lastname: Goldman
authors.forename: Pierre
authors.initials: P
authors.lastname: Maquet
mesh_terms: D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003243:Consciousness / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology*; D006801:Humans; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D018458:Persistent Vegetative State / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D020127:Recovery of Function / Q000502:physiology; D013788:Thalamus / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D014055:Tomography, Emission-Computed