BACKGROUND: Mechanisms of anesthesia-induced loss of consciousness remain poorly understood. Resting-state functional magnetic resonance imaging allows investigating whole-brain connectivity changes during pharmacological modulation of the level of consciousness. METHODS: Low-frequency spontaneous blood oxygen level-dependent fluctuations were measured in 19 healthy volunteers during...
Evidence from functional neuroimaging studies on resting state suggests that there are two distinct anticorrelated cortical systems that mediate conscious awareness: an "extrinsic" system that encompasses lateral fronto-parietal areas and has been linked with processes of external input (external awareness), and an "intrinsic" system which encompasses mainly medial brain areas and has been...
The relationship between mind and brain has philosophical, scientific, and practical implications. Two separate but related surveys from the University of Edinburgh (University students, n= 250) and the University of Liège (health-care workers, lay public, n= 1858) were performed to probe attitudes toward the mind-brain relationship and the variables that account for differences in views. Four...
The origin of within-subject variability in perceptual experiments is poorly understood. We here review evidence that baseline brain activity in the areas involved in sensory perception predict subsequent variations in sensory awareness. We place these findings in light of recent findings on the architecture of spontaneous BOLD fluctuations in the awake human brain, and discuss the possible...
Spontaneous brain activity has recently received increasing interest in the neuroimaging community. However, the value of resting-state studies to a better understanding of brain-behavior relationships has been challenged. That altered states of consciousness are a privileged way to study the relationships between spontaneous brain activity and behavior is proposed, and common resting-state...
Additional data, supported by relevant functional neuroimaging literature, confirm that the “normal” patterns of brain activity reported in a patient who was clinically diagnosed as vegetative could not have occurred “automatically” in the absence of conscious awareness. The most parsimonious explanation remains that this patient was consciously aware despite her diagnosis of vegetative state.
We used functional magnetic resonance imaging to demonstrate preserved conscious awareness in a patient fulfilling the criteria for a diagnosis of vegetative state. When asked to imagine playing tennis or moving around her home, the patient activated predicted cortical areas in a manner indistinguishable from that of healthy volunteers.
Although we admire Ned Block's effort to include cognitive neuroscience in his philosophical work, we cannot agree with his interpretation of the evidence [1xTwo neural correlates of consciousness. Block, N. Trends Cogn. Sci. 2005; 9: 46–52Abstract | Full Text | Full Text PDF | PubMed | Scopus (252)See all References[1]. Block has long argued that there are two kinds of consciousness:...
The interest of functional imaging in patients in a vegetative state is twofold. First, the vegetative state continues to represent a major clinical and ethical problem, in terms of diagnosis, prognosis, treatment, everyday management and end-of-life decisions. Second, it offers a lesional approach to the study of human consciousness and adds to the international research effort on identifying...
In this chapter, we aimed at further characterizing the functional neuroanatomy of the human rapid eye movement (REM) sleep at the population level. We carried out a meta-analysis of a large dataset of positron emission tomography (PET) scans acquired during wakefulness, slow wave sleep and REM sleep, and focused especially on the brain areas in which the activity diminishes during REM sleep....
Near-death experiences (NDEs) are often studied using both structured questionnaires and narrative reports, yet these representations cannot be assumed to provide interchangeable representations of the same experience. Narratives allow flexible expression of different aspects of the experience, whereas questionnaires organize reports into predefined dimensions and retrospective evaluations. How...