Reaching across the abyss: recent advances in functional magnetic resonance imaging and their potential relevance to disorders of consciousness
Disorders of consciousness (DOC) raise profound scientiﬁc, clinical, ethical, and philosophical issues. Growing knowledge on fundamental principles of brain organization in healthy individuals offers new opportunities for a better understanding of residual brain function in DOCs. We here discuss new perspectives derived from a recently proposed scheme of brain organization underlying consciousness in healthy individuals. In this scheme, thalamo-cortical networks can be divided into two, often antagonistic, global systems: (i) a system of externally oriented, sensory-motor networks (the ‘‘extrinsic’’ system); and (ii) a system of inward-oriented networks (the ‘‘intrinsic’’ or default system). According to this framework, four distinct mental states would be possible that could be relevant for understanding DOCs. In normal healthy volunteers and locked-in syndrome patients, a state of high functionality of both the extrinsic and intrinsic or default systems is expected — associated with full awareness of environment and self. In this case, mental imagery tasks combined with fMRI can be used to detect covert awareness in patients that are unable to communicate. According to the framework, two complementary states of system imbalance are also possible, in which one system is in a hyperfunctional state, while the other is hypoactive. Extrinsic system hyperfunction is expected to lead to a state of total sensory-motor ‘‘absorption’’ or ‘‘lost self.’’ In contrast, intrinsic or default system hyperfunction is expected to lead to a state of complete detachment from the external world. A state where both extrinsic and intrinsic systems are hypofunctional is predicted to lead to markedly impaired consciousness as seen in DOCs. Finally, we review the potential use of ultra-slow ﬂuctuations in BOLD signal as a tool for assessing the functional integrity of extrinsic and intrinsic systems during ‘‘resting state’’ fMRI acquisitions..
|Keywords||No keywords specified (fix it)|
|Categories||categorize this paper)|
References found in this work BETA
No references found.
Citations of this work BETA
No citations found.
Similar books and articles
Introduction: Reconsidering Disorders of Consciousness in Light of Neuroscientific Evidence.Ralf J. Jox & Katja Kuehlmeyer - 2013 - Neuroethics 6 (1):1-3.
Two Distinct Neuronal Networks Mediate the Awareness of Environment and of Self.Christophe Phillips, Athena Demertzi, Manuel Schabus & Quentin Noirhomme - unknown
Right (to a) Diagnosis? Establishing Correct Diagnoses in Chronic Disorders of Consciousness.Kirsten Brukamp - 2013 - Neuroethics 6 (1):5-11.
Using Functional Magnetic Resonance Imaging to Detect Covert Awareness in the Vegetative State.Adrian M. Owen, Martin R. Coleman, Melanie Boly, Matthew H. Davis, Steven Laureys & John D. Pickard - 2007 - Archives of Neurology 64 (8):1098-1102.
Identifying the Default-Mode Component in Spatial IC Analyses of Patients with Disorders of Consciousness.Christophe Phillips & Rafael Malach - unknown
EEG Oscillatory States as Neuro-Phenomenology of Consciousness as Revealed From Patients in Vegetative and Minimally Conscious States.Alexander A. Fingelkurts, Andrew A. Fingelkurts, Sergio Bagnato, Cristina Boccagni & Giuseppe Galardi - 2012 - Consciousness and Cognition 21 (1):149-169.
The Centrecephalon and Thalamocortical Integration: Neglected Contributions of Periaqueductal Gray.D. F. Watt - 2000 - Consciousness and Emotion 1 (1):91-114.
DMN Operational Synchrony Relates to Self-Consciousness: Evidence From Patients in Vegetative and Minimally Conscious States.Andrew A. Fingelkurts, Alexander A. Fingelkurts, Sergio Bagnato, Cristina Boccagni & Giuseppe Galardi - 2012 - Open Neuroimaging Journal 6:55-68.
A Case for Increased Caution in End of Life Decisions for Disorders of Consciousness.Jakob Hohwy & David Reutens - 2009 - Monash Bioethics 28 (2):13.1-13.13.
Extrinsic and Intrinsic Irreversibility in Probabilistic Dynamical Laws.Harald Atmanspacher - manuscript
Consciousness Without a Cortex, but What Kind of Consciousness is This?Anton M. L. Coenen - 2007 - Behavioral and Brain Sciences 30 (1):87-88.
Neural Game Theory and the Search for Rational Agents in the Brain.Gregory S. Berns - 2003 - Behavioral and Brain Sciences 26 (2):155-156.
Advances in Functional Neuroimaging of Psychopathology.Lisa J. Burklund & Matthew D. Lieberman - 2012 - Philosophy, Psychiatry, and Psychology 18 (4):333-337.
Added to index2010-12-22
Total downloads26 ( #194,101 of 2,158,810 )
Recent downloads (6 months)1 ( #354,157 of 2,158,810 )
How can I increase my downloads?