The philosophical foundations of consciousness science -- The historical foundations of consciousness science -- The conceptual foundations of consciousness science -- Neuropsychological deficits of visual consciousness -- Neuropsychological dissociations of visual consciousness from behaviour -- Neuropsychological disorders of self-awareness -- Methods and design of NCC experiments -- Studies on the neural basis of consciousness as a state -- Studies on the neural basis of visual consciousness.
“Altered State of Consciousness” (ASC) has been defined as a changed overall pattern of conscious experience, or as the subjective feeling and explicit recognition that one's own subjective experience has changed. We argue that these traditional definitions fail to draw a clear line between altered and normal states of consciousness (NSC). We outline a new definition of ASC and argue that the proper way to understand the concept of ASC is to regard it as a representational notion: the alteration that (...) has happened is not an alteration of consciousness (or subjective experience) per se, but an alteration in the informational or representational relationships between consciousness and the world. An altered state of consciousness is defined as a state in which the neurocognitive background mechanisms of consciousness have an increased tendency to produce misrepresentations such as hallucinations, delusions, and memory distortions. Paradigm examples of such generally misrepresentational, temporary, and reversible states are dreaming, psychotic episodes, psychedelic drug experiences, some epileptic seizures, and hypnosis in highly hypnotizable subjects. The representational definition of ASC should be applied in the theoretical and empirical studies of ASCs to unify and clarify the conceptual basis of ASC research. (shrink)
Cognitive functions associated with the frontal lobes of the brain may be specifi cally involved in hypnosis. Thus, the frontal area of the brain has recently been of great interest when searching for neural changes associated with hypnosis. We tested the hypothesis that EEG during pure hypnosis would differ from the normal non-hypnotic EEG especially above the frontal area of the brain. The composition of brain oscillations was examined in a broad frequency band (130 Hz) in the electroencephalogram (EEG) of (...) a single virtuoso subject. Data was collected in two independent data collection periods separated by one year. The hypnotic and non-hypnotic conditions were repeated multiple times during each data acquisition session. We found that pure hypnosis induced reorganization in the composition of brain oscillations especially in prefrontal and right occipital EEG channels. Additionally, hypnosis was characterized by consistent rightside-dominance asymmetry. In the prefrontal EEG channels the composition of brain oscillations included spectral patterns during hypnosis that were completely different from those observed during non-hypnosis. Furthermore, the EEG spectral patterns observed overall during the hypnotic condition did not return to the pre-hypnotic baseline EEG immediately when hypnosis was terminated. This suggests that for the brain, the return to a normal neurophysiological baseline condition after hypnosis is a time-consuming process. The present results suggest that pure hypnosis is characterized by an increase in alertness and heightened attention, refl ected as cognitive and neuronal activation. Taken together, the present data provide support for the hypothesis that in a very highly hypnotizable person (a hypnotic virtuoso) hypnosis as such may be accompanied by a changed pattern of neural activity in the brain. (shrink)
Cortex functional connectivity associated with hypnosis was investigated in a single highly hypnotizable subject in a normal baseline condition and under neutral hypnosis during two sessions separated by a year. After the hypnotic induction, but without further suggestions as compared to the baseline condition, all studied parameters of local and remote functional connectivity were significantly changed. The significant differences between hypnosis and the baseline condition were observable (to different extent) in five studied independent frequency bands (delta, theta, alpha, beta, and (...) gamma). The results were consistent and stable after 1 year. Based on these findings we conclude that alteration in functional connectivity of the brain may be regarded as a neuronal correlate of hypnosis (at least in very highly hypnotizable subjects) in which separate cognitive modules and subsystems may be temporarily incapable of communicating with each other normally. (shrink)
The approach of Hobson et al. is limited to the description of global states of consciousness, although more detailed analyses of the specific contents of consciousness would also be required. Furthermore, their account of the mind-brain relationship remains obscure. Nielsen's discussion suffers from conceptual and definitional unclarity. Mentation during sleep could be clarified by reconceptualizing it as an issue about the contents of consciousness. Vertes & Eastman do not consider the types of memory (emotional) and learning (implicit) that are relevant (...) during REM sleep, and therefore dismiss on inadequate grounds the possibility of memory functions associated with REM sleep. [Hobson et al.; Nielsen; Vertes & Eastman]. (shrink)
commentary on Dainton, B. (2000). Stream of Consciousness: Unity and Continuity in Conscious Experience. London: Routledge. ABSTRACT: Stream of Consciousness is a detailed and insightful analysis of the nature of phenomenal consciousness, especially its unity at a time and continuity over stretches of time. I find Dainton's approach to phenomenal consciousness in many ways sound but I also point out one major source of disgreement between us. Dainton believes that to explain phenomenal unity and continuity, no reference to anything outside (...) experience is required. Thus, he postulates a fundamental experiential relation called co-consciousness which is supposed to do all the explanatory work. On the contrary, I hold that to truly explain features of consciousness such as phenomenal unity and continuity, reference to mechanisms outside the phenomenal realm are necessary. (shrink)
The Gestalt Bubble model of visual consciousness is a courageous attempt to take the first-person perspective as primary in the study of consciousness. I have developed similar ideas as the Virtual Reality Metaphor of consciousness (Revonsuo 1995; 2000). I can, hence, only agree with Lehar about the general shape of a proper research strategy for the study of consciousness. As to the metaphysical basis of the research program, I have, however, several reservations about panexperientialism.
The research program defended by O'Regan & Noë (O&N) cannot give any plausible explanation for the fact that during REM-sleep the brain regularly generates subjective experiences (dreams) where visual phenomenology is especially prominent. This internal experience is almost invariably organized in the form of “being-in-the-world.” Dreaming presents a serious unaccountable anomaly for the sensorimotor research program and reveals that some of its fundamental assumptions about the nature of consciousness are questionable.
I disagree with Ross about the location of colors: They are in the brain, not in the external world. It is difficult to deny that there are colors in our conscious visual experience, and if we take the causal theory of perception seriously, we cannot identify these colors with the beginning of the causal chain in perception (external objects in the distal stimulus field), but we must search for them at the end of the causal chain (in the brain). Several (...) lines of compelling evidence from cognitive neuroscience (e.g., synesthesia, dreaming, and achromatopsia) demonstrate unambiguously that color is in the brain. Furthermore, it seems that Ross has failed to consider one substantial version of subjectivism in his article. This monistic approach to color and consciousness appears to be the least implausible alternative when we try to understand what colors are and where they reside. (shrink)
The most challenging objections to the Threat Simulation Theory (TST) of the function of dreaming include such issues as whether the competing Random Activation Theory can explain dreaming, whether TST can accommodate the apparently dysfunctional nature of post-traumatic nightmares, whether dreams are too bizarre and disorganized to constitute proper simulations, and whether dream recall is too biased to reveal the true nature of dreams. I show how these and many other objections can be accommodated by TST, and how several lines (...) of new supporting evidence are provided by the commentators. Accordingly TST offers a promising new approach to the function of dreaming, covering a wide range of evidence and theoretically integrating psychological and biological levels of explanation. (shrink)
Several theories claim that dreaming is a random by-product of REM sleep physiology and that it does not serve any natural function. Phenomenal dream content, however, is not as disorganized as such views imply. The form and content of dreams is not random but organized and selective: during dreaming, the brain constructs a complex model of the world in which certain types of elements, when compared to waking life, are underrepresented whereas others are over represented. Furthermore, dream content is consistently (...) and powerfully modulated by certain types of waking experiences. On the basis of this evidence, I put forward the hypothesis that the biological function of dreaming is to simulate threatening events, and to rehearse threat perception and threat avoidance. To evaluate this hypothesis, we need to consider the original evolutionary context of dreaming and the possible traces it has left in the dream content of the present human population. In the ancestral environment human life was short and full of threats. Any behavioral advantage in dealing with highly dangerous events would have increased the probability of reproductive success. A dream-production mechanism that tends to select threatening waking events and simulate them over and over again in various combinations would have been valuable for the development and maintenance of threat-avoidance skills. Empirical evidence from normative dream content, children's dreams, recurrent dreams, nightmares, post traumatic dreams, and the dreams of hunter-gatherers indicates that our dream-production mechanisms are in fact specialized in the simulation of threatening events, and thus provides support to the threat simulation hypothesis of the function of dreaming. Key Words: dream content; dream function; evolution of consciousness; evolutionary psychology; fear; implicit learning; nightmares; rehearsal; REM; sleep; threat perception. (shrink)
The binding problem is frequently discussed in consciousness research. However, it is by no means clear what the problem is supposed to be and how exactly it relates to consciousness. In the present paper the nature of the binding problem is clarified by distinguishing between different formulations of the problem. Some of them make no mention of consciousness, whereas others are directly related to aspects of phenomenal experience. Certain formulations of the binding problem are closely connected to the classical philosophical (...) problem of the unity of consciousness and the currently fashionable search for the neural correlates of consciousness. Nonetheless, only a part of the current empirical research on binding is directly relevant to the study of consciousness. The main message of the present paper is that the science of consciousness needs to establish a clear theoretical view of the relation between binding and consciousness and to encourage further empirical work that builds on such a theoretical foundation. (shrink)
Explanatory problems in the philosophy of neuroscience are not well captured by the division between the radical and the trivial neuron doctrines. The actual problem is, instead, whether mechanistic biological explanations across different levels of description can be extended to account for psychological phenomena. According to cognitive neuroscience, some neural levels of description at least are essential for the explanation of psychological phenomena, whereas, in traditional cognitive science, psychological explanations are completely independent of the neural levels of description. The challenge (...) for cognitive neuroscience is to discover the levels of description appropriate for the neural explanation of psychological phenomena. (shrink)
Pessoa et al. fail to make a clear distinction between visual perception and subjective visual awareness. Their most controversial claims, however, concern subjective visual awareness rather than visual perception: visual awareness is externalized to the “personal level,” thus denying the view that consciousness is a natural biological phenomenon somehow constructed inside the brain.
In this paper I develop the thesis that dreams are essential to an understanding of waking consciousness. In the first part I argue in opposition to the philosophers Malcolm and Dennett that empirical evidence now shows dreams to be real conscious experiences. In the second part, three questions concerning consciousness research are addressed. (1) How do we isolate the system to be explained (consciousness) from other systems? (2) How do we describe the system thus isolated? (3) How do we reveal (...) the mechanisms on which this system is based? I suggest that empirical dream research combined with other empirical approaches can help us to sketch answers to all of these questions. I argue that the subjective form of dreams reveals the subjective, macro-level form of consciousness in general and that both dreams and the everyday phenomenal world may be thought of as constructed “virtual realities”. A major task for empirical consciousness research is to find out the mechanisms which bind this experienced world into a coherent whole. (shrink)
Consciousness seems to be an enigmatic phenomenon: it is difficult to imagine how our perceptions of the world and our inner thoughts, sensations and feelings could be related to the immensely complicated biological organ we call the brain. This volume presents the thoughts of some of the leading philosophers and cognitive scientists who have recently participated in the discussion of the status of consciousness in science. The focus of inquiry is the question: "Is it possible to incorporate consciousness into science?" (...) Philosophers have suggested different alternatives -- some think that consciousness should be altogether eliminated from science because it is not a real phenomenon, others that consciousness is a real, higher-level physical or neurobiological phenomenon, and still others that consciousness is fundamentally mysterious and beyond the reach of science. At the same time, however, several models or theories of the role of conscious processing in the brain have been developed in the more empirical cognitive sciences. It has been suggested that non-conscious processes must be sharply separated from conscious ones, and that the necessity of this distinction is manifested in the curious behavior of certain brain-damaged patients. This book demonstrates the dialogue between philosophical and empirical points of view. The writers present alternative solutions to the brain-consciousness problem and they discuss how the unification of biological and psychological sciences could thus become feasible. Covering a large ground, this book shows how the philosophical and empirical problems are closely interconnected. From this interdisciplinary exploration emerges the conviction that consciousness can and should be a natural part of our scientific world view. (shrink)
The cognitive mind-brain is haunted by the ghost of consciousness. Cognitive science must face this ghost, since consciousness is perhaps the most important mental phenomenon: it forms a seemingly united, multimodal phenomenological world around the subject who experiences this world from a certain point of view. Many current approaches to consciousness fail to illuminate the nature of this “experienced world”. Some philosophers want to eliminate consciousness from science for good, others build theories in which the concept of consciousness is distorted (...) beyond recognition. I argue that elimination and Daniel Dennett's “multiple drafts” model do not offer genuine explanations for consciousness. However, certain empirically-based approaches to consciousness succeed in exorcising its ghostly reputation and, at the same time, in preserving the experienced world of consciousness as an important explanandum. (shrink)