A Theoretically Based Index of Consciousness Independent of Sensory Processing and Behavior

@article{Casali2013ATB,
  title={A Theoretically Based Index of Consciousness Independent of Sensory Processing and Behavior},
  author={Adenauer G. Casali and Olivia Gosseries and Mario Rosanova and M{\'e}lanie Boly and Simone Sarasso and Karina Rabello Casali and Silvia Casarotto and Marie-Aur{\'e}lie Bruno and Steven Laureys and Giulio Tononi and Marcello Massimini},
  journal={Science Translational Medicine},
  year={2013},
  volume={5},
  pages={198ra105 - 198ra105}
}
One challenging aspect of the clinical assessment of brain-injured, unresponsive patients is the lack of an objective measure of consciousness that is independent of the subject's ability to interact with the external environment. [...] Key Method We test PCI on a large data set of TMS-evoked potentials recorded in healthy subjects during wakefulness, dreaming, nonrapid eye movement sleep, and different levels of sedation induced by anesthetic agents (midazolam, xenon, and propofol), as well as in patients who…Expand

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Processing and Behavior A Theoretically Based Index of Consciousness Independent of Sensory
conscious state showing intermediate values (0.32 to 0.49). unconscious (0.19 to 0.31), the two with locked-in syndrome clearly aware (0.51 to 0.62), and those in a minimally patients clearlyExpand
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References

SHOWING 1-10 OF 79 REFERENCES
An information integration theory of consciousness
  • G. Tononi
  • Psychology, Medicine
  • BMC Neuroscience
  • 2004
TLDR
The information integration theory accounts, in a principled manner, for several neurobiological observations concerning consciousness, including the association of consciousness with certain neural systems rather than with others; the fact that neural processes underlying consciousness can influence or be influenced by neural processes that remain unconscious; the reduction of consciousness during dreamless sleep and generalized seizures. Expand
Recovery of cortical effective connectivity and recovery of consciousness in vegetative patients
TLDR
Measurements of effective connectivity by means of transcranial magnetic stimulation combined with electroencephalography can be performed at the bedside while by-passing subcortical afferent and efferent pathways, and without requiring active participation of subjects or language comprehension; hence, they offer an effective way to detect and track recovery of consciousness in brain-injured patients who are unable to exchange information with the external environment. Expand
Event-related potential measures of consciousness: two equations with three unknowns.
This is a brief review of event-related brain potentials (ERPs) as indices of cortical information processing in conditions in which conscious perception of stimuli is supposed to be absent: sleep,Expand
Measuring consciousness: relating behavioural and neurophysiological approaches
TLDR
A series of behavioural and brain-based measures are reviewed, assessing their ability to track graded consciousness and clarifying how they relate to each other by showing what theories are presupposed by each. Expand
Measuring the fading consciousness in the human brain.
  • M. Boly
  • Psychology, Medicine
  • Current opinion in neurology
  • 2011
TLDR
There is an urgent need of validation of functional MRI active paradigms on larger patient populations before they can be used in clinical routine and further research on neural correlates of consciousness should hopefully allow using passive paradigm to assess the patients' conscious state without requiring their active collaboration. Expand
Unresponsiveness ≠ Unconsciousness
TLDR
Potential neurobiological constructs that can explain the need for developing anesthetic regimens and depth of anesthesia monitors that specifically target mechanisms of consciousness, connectedness, and responsiveness are described. Expand
The Neural Correlates of Consciousness
  • G. Tononi, C. Koch
  • Psychology, Medicine
  • Annals of the New York Academy of Sciences
  • 2008
TLDR
This review examines recent advances in the study of brain correlates of consciousness and discusses dynamic aspects of neural activity, such as sustained versus phasic activity, feedforward versus reentrant activity, and the role of neural synchronization. Expand
Experimental and Theoretical Approaches to Conscious Processing
TLDR
Converging neuroimaging and neurophysiological data point to objective neural measures of conscious access: late amplification of relevant sensory activity, long-distance cortico-cortical synchronization at beta and gamma frequencies, and "ignition" of a large-scale prefronto-parietal network. Expand
Neuroimaging and the Vegetative State
TLDR
It is in this latter situation that functional neuroimaging may prove to be most valuable, as a unique clinical tool for probing volition and residual cognition without necessarily assuming that the patient is able to produce any motor output. Expand
Behavioral evaluation of consciousness in severe brain damage.
TLDR
A number of fundamental principles of clinical evaluation that should guide the assessment of consciousness in brain-damaged patients in order to avoid confusion between vegetative state and minimally conscious state are discussed. Expand
...
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5
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