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Understanding consciousness remains one of the greatest mysteries for science to solve. How do our brains work? Will we ever be able to read minds? How can we know if some patients in coma have any consciousness left and how could we communicate with them? What are near-death experiences? What is brain death? What happens in our brains during dreaming, hypnosis or meditation? At present, nobody understands how matter (our trillions of neural connections) becomes perception and thought.
We will here briefly review some neurological facts on consciousness and impaired consciousness. While philosophers have pondered upon the mind-brain conundrum for millennia, scientists have only recently been able to explore the connection analytically through measurements and perturbations of the brain’s activity. This ability stems from recent advances in technology and especially from emerging functional neuroimaging and electrophysiology studies. The mapping of conscious perception and cognition in health (e.g., conscious waking, sleep, dreaming, hypnosis, meditation, sleepwalking and anesthesia) and in disease (e.g., coma, near-death, “vegetative” state, seizures, hallucinations etc) is providing exiting new insights into the functional neuroanatomy of human consciousness. Our perception of the outside world (sensory awareness; what we see, hear, etc.) and our awareness of an inner world (self-awareness; the little “voice” inside that “speaks” to ourselves) seemingly depend on two separate networks we could recently identify.
Philosophers might argue that the subjective aspect of the mind will never be sufficiently accounted for by the objective methods of reductionistic science. We here prefer a more pragmatic approach and remain naively optimistic that technological advances might ultimately lead to an understanding of the neural substrate of human consciousness. We will conclude by discussing the ethical consequences of these scientific advances which offer the medical community unique ways to improve the clinical management and quality of life in patients with severe disorders of consciousness.
Steven Laureys MD PhD, is director of the Coma Science Group (http://www.comascience.org) at the GIGA Research and Neurology Department of the University and University Hospital of Liège, Belgium. He is Research Director at the Belgian National Fund for Scientific Research and board-certified in neurology and in end-of-life medicine. He is President of the Association for the Scientific Study of Consciousness and Chair of the World Federation of Neurology Applied Research Group on Coma. His team has an international reputation in the assessment of consciousness and patients come to his center in Liège from all over Europe for neuroimaging tests and medical expertise. His latest book, published by Academic Press, is entitled “The Neurology of Consciousness”.