How can we disentangle the neural basis of phenomenal consciousness from the neural machinery of the cognitive access that underlies reports of phenomenal consciousness? We can see the problem in stark form if we ask how we could tell whether representations inside a Fodorian module are phenomenally conscious. The methodology would seem straightforward: find the neural natural kinds that are the basis of phenomenal consciousness in clear cases when subjects are completely confident and we have no reason to doubt their (...) authority, and look to see whether those neural natural kinds exist within Fodorian modules. But a puzzle arises: do we include the machinery underlying reportability within the neural natural kinds of the clear cases? If the answer is ‘Yes’, then there can be no phenomenally conscious representations in Fodorian modules. But how can we know if the answer is ‘Yes’? The suggested methodology requires an answer to the question it was supposed to answer! The paper argues for an abstract solution to the problem and exhibits a source of empirical data that is relevant, data that show that in a certain sense phenomenal consciousness overflows cognitive accessibility. The paper argues that we can find a neural realizer of this overflow if assume that the neural basis of phenomenal consciousness does not include the neural basis of cognitive accessibility and that this assumption is justified by the explanations it allows. (shrink)

The locked-in syndrome is a state of profound paralysis with preserved awareness of self and environment who typically results from a brain stem stroke. Although patients in LIS have great difficulty communicating, their consciousness, cognition, and language usually remain intact. Medical decision-making by LIS patients is compromised, not by cognitive impairment, but by severe communication impairment. Former systems of communication that permitted LIS patients to make only “yes” or “no” responses to questions was sufficient to validate their consent for simple (...) medical decisions but not for consequential medical decisions such as whether to refuse further life-sustaining therapy. Emerging technologies including computer-tracking assistance of retained partial motor function and brain-computer interfaces promise to improve the communication ability of LIS patients and, when better developed, will allow them to fully exercise their right to actively participate in consequential medical decisions about their own medical care. Although so-called “covert cognition” patients clinically diagnosed as vegetative state that are shown to be aware by functional neuroimaging maybe metaphorically considered locked-in, it is nosologically more coherent not to categorize them formally as LIS. (shrink)

Following coma, some patients will recover wakefulness without signs of consciousness (only showing reflex movements, i.e., the vegetative state) or may show non-reflex movements but remain without functional communication (i.e., the minimally conscious state). Currently, there remains a high rate of misdiagnosis of the vegetative state (Schnakers et. al. BMC Neurol, 9:35, 8) and the clinical and electrophysiological markers of outcome from the vegetative and minimally conscious states remain unsatisfactory. This should incite clinicians to use multimodal assessment to detect objective (...) signs of consciousness and validate para-clinical prognostic markers in these challenging patients. This review will focus on advanced magnetic resonance imaging (MRI) techniques such as magnetic resonance spectroscopy, diffusion tensor imaging, and functional MRI (fMRI studies in both “activation” and “resting state” conditions) that were recently introduced in the assessment of patients with.. (shrink)

A survey of the medical, ethical and legal issues that surround this controversial topic.

1Neurology Department and Cyclotron Research Center, University of Lie`ge, Sart Tilman B30, 4000 Liege, Belgium 2Neurorehabilitation Medicine, Hoˆpital Caremeau, CHU Nıˆmes, 30029 Nıˆmes Cedex, France 3Department of Speech Therapy, Hospital Pitie´ Salpe´trie`re, Paris and French Association Locked in Syndrome (ALIS), 225 Bd Jean-Jaures, MBE 182, 92100 Boulogne-Billancourt, France 4Neurosciences et Syste`mes Sensoriels Unite´ Mixte de Recherche 5020, Universite´ Claude Bernard Lyon 1 – CNRS, 69007 Lyon, France 5Intensive Care Medicine, Hoˆpital Erasme, Universite´ Libre de Bruxelles, Route de Lennik 808, 1070 (...) Brussels, Belgium 6Anesthesiology, Reanimation and Pain Clinic, CHU University Hospital, Sart Tilman B33, 4000 Liege, Belgium 7German Association Locked in Syndrome LIS e.V., Evangelischen Krankenhaus Ko¨ningin Elisabeth Herzberge gGmbh (Lehrkrankenhaus der Charite´), Haus 30, Herzbergstrasse 79, 10365 Berlin, Germany 8Intensive Care Medicine, Centre Hospitalier Re´gional de la Citadelle, Boulevard du 12e de Ligne 1, 4000 Liege, Belgium 9Biomedical PET Unit, Hoˆpital Erasme, Universite´ Libre de Bruxelles, Route de Lennik 808, 1070 Brussels, Belgium.. (shrink)

Objectives: Recent fMRI studies have shown that it is possible to reliably identify the defaultmode network (DMN) in the absence of any task, by resting-state connectivity analyses in healthy volunteers. We here aimed to identify the DMN in the challenging patient population of disorders of consciousness encountered following coma. Experimental design: A spatial independent component analysis-based methodology permitted DMN assessment, decomposing connectivity in all its different sources either neuronal or artifactual. Three different selection criteria were introduced assessing anticorrelation-corrected connectivity with (...) or without an automatic masking procedure and calculating connectivity scores encompassing both spatial and temporal properties. These three methods were validated on 10 healthy controls and applied to an independent group of 8 healthy controls and 11 severely brain-damaged patients [locked-in syndrome (n ¼ 2), minimally conscious (n ¼ 1), and vegetative state (n ¼ 8)]. Principal observations: All vegetative patients showed fewer connections in the default-mode areas, when compared with controls, contrary to locked-in patients who showed nearnormal connectivity. In the minimally conscious-state patient, only the two selection criteria considering both spatial and temporal properties were able to identify an intact right lateralized BOLD connectivity pattern, and metabolic PET data suggested its neuronal origin. Conclusions: When assess-. (shrink)

Marie-Aure´lie Bruno,1 Jan L Bernheim,2 Didier Ledoux,1 Fre´de´ric Pellas.