According to the global neuronal workspace model of consciousness, consciousness results from the global broadcast of information throughout the brain. The global neuronal workspace is mainly constituted by a fronto-parietal network. The anterior insular cortex is part of this global neuronal workspace, but the function of this region has not yet been defined within the global neuronal workspace model of consciousness. In this review, I hypothesize that the anterior insular cortex implements a cross-modal priority map, the function of which is (...) to determine priorities for the processing of information and subsequent entrance in the global neuronal workspace. (shrink)

The value of resting electroencephalogram (EEG) in revealing neural constitutes of consciousness (NCC) was examined. We quantified the dynamic repertoire, duration and oscillatory type of EEG microstates in eyes-closed rest in relation to the degree of expression of clinical self-consciousness. For NCC a model was suggested that contrasted normal, severely disturbed state of consciousness and state without consciousness. Patients with disorders of consciousness were used. Results suggested that the repertoire, duration and oscillatory type of EEG microstates in resting condition quantitatively (...) related to the level of consciousness expression in brain-damaged patients and healthy-conscious subjects. Specifically, results demonstrated that (a) decreased number of EEG microstate types was associated with altered states of consciousness, (b) unawareness was associated with the lack of diversity in EEG alpha-rhythmic microstates, and (c) the probability for the occurrence and duration of delta-, theta- and slow-alpha-rhythmic microstates were associated with unawareness, whereas the probability for the occurrence and duration of fast-alpha-rhythmic microstates were associated with consciousness. In conclusion, resting EEG has a potential value in revealing NCC. This work may have implications for clinical care and medical–legal decisions in patients with disorders of consciousness. (shrink)

The clinical and para-clinical examination of residual self-consciousness in non-communicative severely brain damaged patients remains exceptionally challenging. Passive presentation of the patient’s own name and own face are known to be effective attention-grabbing stimuli when clinically assessing consciousness at the patient’s bedside. Event-related potential and functional neuroimaging studies using such self-referential stimuli are currently being used to disentangle the cognitive hierarchy of self-processing. We here review neuropsychological, neuropathological, electrophysiological and neuroimaging studies using the own name and own face paradigm obtained (...) in conscious waking, sleep, pharmacological coma, pathological coma and related disorders of consciousness. Based on these results we discuss what we currently do and do not know about the functional significance of the neural network involved in “automatic” and “conscious” self-referential processing. (shrink)

A pressing issue in neuroscience is the high rate of misdiagnosis of disorders of consciousness. As new research on patients with disorders of consciousness has revealed surprising and previously unknown cognitive capacities, the need to develop better and more reliable methods of diagnosing these disorders becomes more urgent. So too the need to expand our ethical and social frameworks for thinking about these patients, to accommodate new concerns that will accompany new revelations. A recent study on trace conditioning and learning (...) in vegetative and minimally conscious patients shows promise as a potential diagnostic and prognostic tool, both for differentiating between states of diminished consciousness, and for predicting patient outcomes, but it also generates fresh concerns about quality of life in patients previously thought to be completely unaware. Optimism about progress in diagnosing and treating disorders of consciousness must be tempered by the understanding that not all progress will necessarily be good for all patients. The prognosis for most patients remains bleak, and we must remain vigilant to acute questions and concerns about welfare and quality of life. (shrink)

To aid neuroscientists in determining the ethical limits of their work and its applications, neuroethical problems need to be identified, catalogued, and analyzed from the standpoint of an ethical framework. Many hospitals have already established either autonomy or welfare-centered theories as their adopted ethical framework. Unfortunately, the choice of an ethical framework resists resolution: each of these two moral theories claims priority at the exclusion of the other, but for patients with neurological pathologies, concerns about the patient’s welfare are treated (...) as meaningless without consideration of the patient’s expressed wishes, and vice versa. Ethicists have long fought over whether suffering or autonomy should be our primary concern, but in neuroethics a resolution of this question is essential to determine the treatment of patients in medical and legal limbo. I propose a solution to this problem in the form of ethical dualism. This is a conservative measure in that it retains both sides of the debate: both happiness and autonomy have intrinsic value. However, this move is often met with resistance because of its more complex nature—it is more difficult to make a decision when there are two parallel sets of values that must be considered than when there is just one such set. The monist theories, though, do not provide enough explanatory power: namely, I will present two recently publicized cases where it is clear that neither ethical value on its own (neither welfare nor autonomy) can fully account for how a vegetative patient should be treated. From the neuroethical cases of Terri Schiavo and Lauren Richardson, I will argue that a dualist framework is superior to its monist predecessors, and I will describe the main features of such an account. (shrink)

Without exaggeration, it could be said that we are entering a golden age of neuroscience. Informed by recent developments in neuroimaging that allow us to peer into the working brain at both a structural and functional level, neuroscientists are beginning to untangle mechanisms of recovery after brain injury and grapple with age-old questions about brain and mind and their correlates neural mechanisms and consciousness. Neuroimaging, coupled with new diagnostic categories and assessment scales are helping us develop a new diagnostic nosology (...) about disorders of consciousness which will likely improve prognostication and suggest therapeutic advances. Historically such diagnostic refinement has yield therapeutic advances in medicine and there is no reason to doubt that this will be the case for disorders of consciousness, perhaps bringing relief to a marginalized population now on the periphery of the therapeutic agenda. In spite of this promise, the translation of research findings into the clinical context will be difficult. As we move from descriptive categories about disorders of consciousness, like the vegetative or minimally conscious states, to ones further specified by integrating behavioral and neuroimaging findings, humility not hubris should be the virtue that guides the ethical conduct of research and practice. (shrink)

In this essay I examine the formal structure of the concept of futility, enabling identification of the appropriate roles played by patient, professional, and society. I argue that the concept of futility does not justify unilateral decisions to forego life-sustaining medical treatment over patient or legitimate surrogate objection, even when futility is determined by a process or subject to ethics committee review. Furthermore, I argue for a limited positive ethical obligation on the part of health care professionals to assist patients (...) in achieving certain restricted goals, including the preservation of life, even in circumstances in which most would agree that that life is of no benefit to the patient. Finally, I address the objection that professional integrity overrides this limited obligation and find the objection unconvincing. In short, my aim in this essay is to see the concept of futility finally buried, once and for all. (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)

Access to other minds once presupposed other individuals’ expressions and narrations. Today, several methods have been developed which can measure brain states relevant for assessments of mental states without 1st person overt external behavior or speech. Functional magnetic resonance imaging and trace conditioning are used clinically to identify patterns of activity in the brain that suggest the presence of consciousness in people suffering from severe consciousness disorders and methods to communicate cerebrally with patients who are motorically unable to communicate. The (...) techniques are also used non-clinically to access subjective awareness in adults and infants. In this article we inspect technical and theoretical limits on brain–machine interface access to other minds. We argue that these techniques hold promises of important medical breakthroughs, open up new vistas of communication, and of understanding the infant mind. Yet they also give rise to ethical concerns, notably misuse as a consequence of hypes and misinterpretations. (shrink)