title: Returning from oblivion: imaging the neural core of consciousness.
abstract: One of the greatest challenges of modern neuroscience is to discover the neural mechanisms of consciousness and to explain how they produce the conscious state. We sought the underlying neural substrate of human consciousness by manipulating the level of consciousness in volunteers with anesthetic agents and visualizing the resultant changes in brain activity using regional cerebral blood flow imaging with positron emission tomography. Study design and methodology were chosen to dissociate the state-related changes in consciousness from the effects of the anesthetic drugs. We found the emergence of consciousness, as assessed with a motor response to a spoken command, to be associated with the activation of a core network involving subcortical and limbic regions that become functionally coupled with parts of frontal and inferior parietal cortices upon awakening from unconsciousness. The neural core of consciousness thus involves forebrain arousal acting to link motor intentions originating in posterior sensory integration regions with motor action control arising in more anterior brain regions. These findings reveal the clearest picture yet of the minimal neural correlates required for a conscious state to emerge.
authors.affiliation: Turku PET Centre, University of Turku and Turku University Hospital, FI-20521 Turku, Finland.
authors.forename: Jaakko W
authors.initials: JW
authors.lastname: Långsjö
authors.forename: Michael T
authors.initials: MT
authors.lastname: Alkire
authors.forename: Kimmo
authors.initials: K
authors.lastname: Kaskinoro
authors.forename: Hiroki
authors.initials: H
authors.lastname: Hayama
authors.forename: Anu
authors.initials: A
authors.lastname: Maksimow
authors.forename: Kaike K
authors.initials: KK
authors.lastname: Kaisti
authors.forename: Sargo
authors.initials: S
authors.lastname: Aalto
authors.forename: Riku
authors.initials: R
authors.lastname: Aantaa
authors.forename: Satu K
authors.initials: SK
authors.lastname: Jääskeläinen
authors.forename: Antti
authors.initials: A
authors.lastname: Revonsuo
authors.forename: Harry
authors.initials: H
authors.lastname: Scheinin
mesh_terms: D000328:Adult; D000768:Anesthesia, General / Q000379:methods; D001921:Brain / Q000166:cytology / Q000502:physiology; D001931:Brain Mapping / Q000379:methods; D003243:Consciousness / Q000502:physiology*; D005625:Frontal Lobe / Q000166:cytology / Q000502:physiology*; D006801:Humans; D008297:Male; D009415:Nerve Net / Q000166:cytology / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D010296:Parietal Lobe / Q000166:cytology / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology*; D055815:Young Adult