In this article a concept of non-local consciousness will be described, based on recent scientific research on near-death experiences . Since the publication of several prospective studies on NDEs in survivors of cardiac arrest, with strikingly similar results and conclusions, the phenomenon of the NDE can no longer be scientifically ignored. In the last thirty years several theories have been proposed to explain an NDE. The challenge to find a common explanation for the cause and content of an NDE is (...) complicated by the fact that an NDE can be experienced during various circumstances, such as severe injury of the brain as in cardiac arrest to conditions when the brain seems to function normally. The NDE is an authentic experience which cannot be simply reduced to imagination, fear of death, hallucination, psychosis, the use of drugs, or oxygen deficiency. Patients appear to be permanently changed by an NDE during a cardiac arrest of only some minutes duration. According to these aforementioned studies, the current materialistic view of the relationship between consciousness and the brain as held by most physicians, philosophers, and psychologists is too restricted for a proper understanding of this phenomenon. There are good reasons to assume that our consciousness does not always coincide with the functioning of our brain: enhanced or non-local consciousness can sometimes be experienced separately from the body. (shrink)

Although the study of epileptic absence seizures has the potential to contribute a great deal to the scientific understanding of consciousness, this potential has yet to be fully exploited. There have been a number of insightful discussions of consciousness in the context of epileptic seizures, but the basic conceptual issues are still poorly understood and many empirical questions remain unexplored. In this paper I review a number of questions that are of interest to consciousness scientists and identify ways in which (...) the study of absence seizures might bear on their investigation. (shrink)

It appears that consciousness science is progressing soundly, in particular in its search for the neural correlates of consciousness. There are two main approaches to this search, one is content-based (focusing on the contrast between conscious perception of, e.g., faces vs. houses), the other is state-based (focusing on overall conscious states, e.g., the contrast between dreamless sleep vs. the awake state). Methodological and conceptual considerations of a number of concrete studies show that both approaches are problematic: the content-based approach seems (...) to set aside crucial aspects of consciousness; and the state-based approach seems over-inclusive in a way that is hard to rectify without losing sight of the crucial conscious-unconscious contrast. Consequently, the search for the neural correlates of consciousness is in need of new experimental paradigms. (shrink)

Explanation does not exist in a metaphysical vacuum. Conceptions of the structure of a phenomenon play an important role in guiding attempts to explain it, and erroneous conceptions of a phenomenon may direct investigation in misleading directions. I believe that there is a case to be made for thinking that much work on the neural underpinnings of consciousness—what is often called the neural correlates of consciousness—is driven by an erroneous conception of the structure of consciousness. The aim of this paper (...) is lay bare some connections between the explanation of consciousness and the structure of consciousness, and to argue for a conception of the structure of consciousness that is more adequate than that which currently drives much research into the neural correlates of consciousness. (shrink)

Anesthesia research has focused on showing learning in the absence of awareness for good practical reasons. Crucially, continued learning during otherwise clinically adequate anesthesia may affect patients’ well-being on recovery. Theoretically, preserved perceptual priming during anesthesia offers a useful starting point for consciousness research by determining the limits of memory function during minimal consciousness. The big question for consciousness research is not to demonstrate absolutely unconscious processing, but rather to map out the cognitive and neurobiological processes that enable conscious experience (...) itself. (shrink)

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)

Local Recurrency Theory (LR) holds that recurrent loops of neural activity localized to the visual cortex are necessary and sufficient for visual consciousness (if certain background conditions obtain). LR’s popularity has recently waned in favor of theories holding that higher-level types of processing are necessary for consciousness (for example, the Global Neuronal Workspace Theory and Higher-order Theory). This has been in part because of empirical evidence thought to disconfirm LR. However, these competing theories now face challenges of their own, often (...) coming in the form of evidence showing that higher-level brain areas (that is, in the prefrontal cortex) are probably not essential for consciousness. Given growing challenges to LR's competitors, it would be timely to re-assess the prospects for LR. This article carries out such an investigation, first laying out the theory precisely, then going on to survey the evidence presented against it. What will be found is that none of the evidence necessarily undermines LR, but instead just fosters its theoretical enrichment. The overall conclusion: LR remains among our most promising neuroscientific theories of visual consciousness. (shrink)

We consider the relationship between neural and behavioural evidence for animal consciousness. We critically examine two recent studies: one neural and one behavioural. The first, on crows, finds different neural activity depending on whether a stimulus is reported as seen or unseen. However, to implicate this neural activity in consciousness, we must assume that a specific conditioned behaviour is a report of conscious experience. The second study, on macaques, records behaviours strikingly similar to patterns of conscious and unconscious perception in (...) humans. However, confounds are only ruled out in human subjects, presupposing substantial neural similarity between humans and macaques. Taken together, the two studies reveal a sense in which neural and behavioural research rely on each other. Looking ahead, these two types of evidence could prove to be either mutually reinforcing or mutually undermining. The science of animal consciousness needs both neural and behavioural evidence, ideally obtained as part of a single coordinated programme. (shrink)

During sleep, consciousness is reduced, associated with a diminished connection of the brain to the environment. This is due to the blocking of the thalamocortical pathway by inhibitory mechanisms. This “thalamic gating” during sleep, however, is not complete, but partial. The stream of information is considerably reduced, but the brain is not fully disconnected from the environment. An inspection of the environment takes place to optimize safety during sleep. Stimuli having a meaning for the individual, or signaling danger, are recognized, (...) and may enter into awareness, leading to a wake-up call, which allows the individual to react. This subconscious stimulus evaluation is regarded as having a guardian function for sleep. The recognition of stimuli during sleep points toward the presence of a sort of consciousness without awareness in the sleeping brain. (shrink)

This article concerns the interplay between two issues that involve both philosophy and neuroscience: whether the content of phenomenal consciousness is 'rich' or 'sparse', whether phenomenal consciousness goes beyond cognitive access, and how it would be possible for there to be evidence one way or the other.

The Global Workspace Theory and Information Integration Theory are two of the most currently accepted consciousness models; however, these models do not address many aspects of conscious experience. We compare these models to our previously proposed consciousness model in which the thalamus fills-in processed sensory information from corticothalamic feedback loops within a proposed 3D default space, resulting in the recreation of the internal and external worlds within the mind. This 3D default space is composed of all cells of the body, (...) which communicate via gap junctions and electrical potentials to create this unified space. We use 3D llustrations to explain how both visual and non-visual sensory information may be filled-in within this dynamic space, creating a unified seamless conscious experience. This neural sensory memory space is likely generated by baseline neural oscillatory activity from the default mode network, other salient networks, brainstem, and reticular activating system. (shrink)

To answer the question of why we have consciousness, I propose the following evolutionary trajectory leading to this feature: Nervous systems appeared for the purpose of orchestrating behavior. As a rule of thumb the challenges facing an animal concern either approach or avoidance. These two options were originally hard-wired as reflexes. Improvements in adaptability of response came with an expansion of the computational aspect of the system and a concomitant shift from simple reflexes to instinctual behavior, learning, and eventually, feelings. (...) The assessment of positive and negative feelings allows organisms to weigh various options, but for this to be a viable strategy, an awareness of hedonic value is required. This was presumably the first neural attribute to evolve that required awareness, and thus the key force in the evolution of consciousness. The attribute first appeared in the early amniotes (the phylogenetic group comprising reptiles, birds and mammals). Support for this model in current accounts of the neurobiology of feelings and consciousness is discussed. (shrink)

I propose that primary conscious awareness arises from synchronized activity in dendrites of neurons in dorsal thalamic nuclei, mediated particularly by inhibitory interactions with thalamic reticular neurons. In support, I offer four evidential pillars: consciousness is restricted to the results of cortical computations; thalamus is the common locus of action of brain injury in vegetative state and of general anesthetics; the anatomy and physiology of the thalamus imply a central role in consciousness; neural synchronization is a neural correlate of consciousness.

Thomas Metzinger has diagnosed the need for a Bewusstseinskultur, a ‘consciousness culture’: a culturally implemented way in which a society as a whole engages with the dawning natural science of consciousness, with phenomenal experiences themselves, and with our increasing capability to manipulate them. A Bewusstseinskultur is an achievement, built by a society-wide orientation on empirical evidence, thorough scientific theorizing and rational deliberation. It affects a broad range of issues from animal ethics, drug policy, end-of-life-care, and robo-ethics to post-humanism. However, this (...) notion has not yet been presented in English, and is so far unconnected to other discussions in philosophy. Here, I remedy this: I present Metzinger's notion of a Bewusstseinskultur and connect it to discussion on transformative experiences, Parfit's meta-hedonic states, and the Access vs. Phenomenal Consciousness distinction. (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)

Following the pragmatic practices of anesthesiologists an individual is defined to be in a state of consciousness empirically by the behavioral ability to respond to simple stimuli and the loss of consciousness is defined by the loss of that facility. Several brain activities are proposed as properties of the state of consciousness. Baseline brain energy consumption has been shown by 13C MRS to be almost completely used for neuronal signaling. PET measurements of glucose or oxygen consumption, from several laboratories, show (...) a widespread ~45% reduction in cerebral energy during anesthesia-induced loss of consciousness. We propose that the high level of brain energy consumption of the awake state is a necessary property of the state of consciousness. Two additional neuronal properties are drastic changes in the patterns of fMRI activation and neuronal population activity at deep vs. light levels of anesthesia, which correspond to low vs. high energy states, respectively. The brain-wide fMRI activity patterns with rat sensory stimulation at the higher energy state collapses to contralateral somatosensory response at the lower energy state. Firing rates of an ensemble of neurons in the rat somatosensory cortex show that most of the energy in light anesthesia is consumed in the spiking frequency range of 20-40 Hz, which include γ-band electrical signals. In deep anesthesia the frequency range shifts to below 10 Hz. The high brain energy consumption, characteristic of the state of consciousness, supports elevated levels of high frequency neuronal firing observed in the resting, awake brain. In our model, necessary brain properties of the state of consciousness create our physical understanding of that state rather than the converse, popular in neuroimaging, in which subjective mental processes are identified to be necessary and sufficient correlates of the state of consciousness. (shrink)