We propose a neurophysiological hypothesis on the emergence of consciousness, which postulates that the slow cortical potential (SCP) recorded from the surface of the brain provides an index of the activities of superficial-layer pyramidal neurons that directly contribute to the emergence of conscious awareness. This hypothesis is supported by existing data from manipulations of conscious awareness in normal human subjects and by data from altered states of consciousness such as general anesthesia and recovery from vegetative states; it further makes experimentally testable predictions. Given a relationship between the SCP and the functional magnetic resonance imaging (fMRI) signal that has now been revealed, this hypothesis also provides a potential bridge between existing neuroimaging and electrophysiological studies on consciousness.
Conscious processes have a number of distinct properties that need to be accounted for by neuronal mechanisms supporting conscious experience. It is proposed that synchronization of distributed neuronal activity patterns meets most of these requirements. A major problem for the identification of neuronal correlates of consciousness is the distinction between the processes that lead to conscious experience and those that follow once contents have become conscious. Criteria for this distinction are discussed in the context of published evidence.
There is evidence to suggest that synchronised neuronal activity, particularly that in the gamma frequency range (~30–100Hz) might contribute to conscious perception. In this chapter I shall discuss what we know about the mechanisms that underlie the generation of gamma frequency activity and the changes known to occur in diseases such as schizophrenia. Until recently it was difficult to test the role of individual neuronal subtypes in the generation of network oscillations. However, using the newly developed optogenetic techniques (in which cells are genetically modulated to make them responsive to specific wavelengths of light) it should now be possible to directly test the contribution of different neuronal classes to the generation of network oscillations and perhaps, therefore, consciousness.
The dopamine system has a number of functions in the brain, from regulation of movement to controlling emotional expression and facilitating cognitive or conscious processes. Dopamine exerts these actions via its regulation of systems interactions. In particular, the influence of this transmitter system on the balance of afferent input to the nucleus accumbens potently modulates decision-making processes. An increase in dopamine outflow potentiates afferents from the hippocampus subiculum, which are involved in context-dependent processes. In contrast, dopamine will also attenuate the ability of the prefrontal cortex to switch behavioral tasks. In this manner, the dopamine system is positioned to alter the propensity to focus conscious attention on a current task versus flexibly altering behavior to more effectively achieve goals.
The endocannabinoid system acts as a neuromodulator, interacting with other neuromodulators such as the opioids. It influences all vital body functions and sets the tone of every conscious thought and feeling. It operates largely below conscious levels but occasionally floats into consciousness where it is perceived as perfect bliss and pain-free calm.
We discuss the molecular and cognitive mechanisms of general anaesthesia and their relevance to the science of consciousness. General anaesthetics serve as an important tool to explore the transitions from conscious to unconscious processing, as these drugs rapidly induce a complete and reversible cessation of consciousness. With 40,000,000 patients undergoing general anaesthesia each year in North America alone, the highly controlled and monitored setting of the operating room can become the ultimate consciousness laboratory.
Consciousness is described in this article as a perception of self that is constructed for guidance of voluntary goal-directed behaviour, including neural mechanisms for mental time travel into the future during planning and into the past during episodic retrieval. Neural time travel draws on the distributed cortical perceptual processes for detecting the state of the self along multiple dimensions, including spatial location, head direction, speed, temporal duration, and egocentric relationships to items. These circuit mechanisms are regulated by neuromodulatory influences such as muscarinic acetylcholine receptors that activate intrinsic properties of neurons involved in maintaining an internal representation of self.
A commonly held assumption is that consciousness is a defining feature that distinguishes explicit memory (with conscious awareness) from implicit memory (without conscious awareness). Although early studies support this notion, recent evidence suggests that conscious and non-conscious memory systems may share crucial underlying processes. Here, we propose that one locus of interaction between some types of explicit and implicit memory may be the non-conscious processes associated with recollection, or detailed remembering, that are mediated by the hippocampus.
Unconscious processes come in two varieties, the preconscious, whose contents may become conscious, and the never-conscious, whose contents may not. In this chapter we make use of Global Workspace Theory and its LIDA model to catalogue never-conscious and preconscious processes, and offer an explanation of the functionally of the distinction. The LIDA/GWT model suggests that the functional distinction between never-conscious and preconscious processes derives from one of the major purposes of an agent’s consciousness mechanism: that is to select the most salient portion of the agent’s current situation to which to attend, in order for it to be broadcast globally, in order to choose the best next action.
Although a large proportion of the human brain is dedicated to processing incoming sensory information, much of this processing is not accessible to consciousness. In an effort to understand what differentiates conscious from unconscious processing, we are concerned here with methodological issues in exploring the limits of unconscious processing. We first consider a conscious perceptual experience and establish an operating characteristic to disambiguate perceptual sensitivity from decision criterion. We then apply the same method to dissociate explicit measures of perception from implicit measures of sensory processing. Finally, we evaluate post-decision wagering as a proposed method for measuring awareness.
Noise caused by randomness in the spiking times of neurons in the brain has a number of advantages, including contributing to probabilistic decision-making. However, noise results in the brain operating effectively as a non-deterministic system, which has implications for free will. Noise also results in decisions being taken probabilistically between the reasoning system and the implicit reward system. I propose that free will can be used to describe the operation of the reasoning system, and that consciousness is a property of a reasoning system that must use higher order syntactic thoughts (HOSTs) to correct its first order thoughts. When the implicit system takes a decision, we may confabulate a reason for the decision, and in that case the feeling of free will may be an illusion.
Experiencing oneself as autonomous agent who interacts with others depends on the cognitive capacities of self-consciousness as awareness of ones own mental states and social consciousness as knowledge of other persons minds. The study of neural correlates of these capacities elicits an impressive overlap with the so-called “default mode of brain function” as a neurobiological universal of mammalian brains. This empirical observation stimulates the speculation that one major cognitive function of the neural default mode is social cognition which conversely implies that humans have a disposition for social cognition that is reflected in this neural default mode.
Our conscious control of language and its acquisition is strictly limited. A processing-oriented perspective to explain this will be outlined called MOGUL according to which some linguistic processes are inherently unconscious while others can be either conscious or not. The former involve representations, found in the dedicated, uniquely human language module, whose sealed-off nature does not permit the activation levels necessary for conscious experience to take place. However, language knowledge created by cognitive processes that are not specifically linguistic, that is, created outside the language module, can indeed be raised to consciousness. This is because they are more directly connected to the perceptual system and are accordingly open to much higher levels of activation.
Magicians have developed powerful techniques to manipulate our perception and awareness. Many of these techniques share similarities with phenomena typically investigated by psychologists and neuroscientists. Here a novel approach to the study of consciousness is proposed which utilizes the magician’s expertise to complement more traditional experimental laboratory based research. It is argued that this approach offers new and exciting insights into wide areas of consciousness, such as attention, visual awareness and top-down modulation of perception.
Based on biological realism, that is, the philosophical assumption that consciousness is a real natural biological phenomenon in the brain, we argue that dreaming is a pure form of phenomenality, and suggest that the dreaming brain could be used as a model system for consciousness. The dreaming brain offers the most challenging model system that represents all the theoretically and philosophically interesting features of consciousness. Although difficult to study experimentally, the dreaming brain is the model system that fully preserves all the essential features of consciousness, and cannot be ignored by any theory that aims to explain consciousness.
In this essay, we develop our working hypothesis that consciousness in primates and humans is a state-dependent commodity that has at least two expressions. Waking and dreaming are two such states that differ in conscious awareness. In both states, we are perceptive and emotional. Whereas in dreaming, our thoughts are delusional, however, waking consciousness potentiates volition and reflection. We propose that dreaming is a state of primary consciousness, while usually, secondary consciousness is reserved to waking. Lucid dreaming is an extraordinary state with elements of both waking and dreaming and both primary and secondary consciousness. It is a rare but very real condition which is a promising tool in the study of the brain basis of consciousness.
We believe that conscious mental phenomena (such as feelings) are not epiphenomenal to the workings of the brain. Feelings evolved for good biological reasons; they make specific, concrete contributions to brain functioning. Notwithstanding all the philosophical complexities, therefore, the non-conscious/conscious interactions that are the focus of this book are, in our view, causal interactions. To marginalize consciousness in relation to what is ultimately a cdualistic scientific understanding of how the brain works is likely to lead us astray. We illustrate this view by trying to address the question: why does depression feel bad?
Dementing illnesses massively damage the structures and processes thought to underlie consciousness. However, maintained alertness, preserved awareness, and the appearance of hallucinations in people with dementia all suggest that consciousness survives extreme challenge; implying that conscious processes are extremely robust, and conscious content invariably present.
Hearing “voices”, the experience of thoughts as not one’s own, and incoherent speech are symptoms of mental illness (usually termed “schizophrenia”). Here I argue that (1) the “torque” is the feature that defines the human brain as four chambered by comparison with the two chambers of the generalized mammalian brain, (2) by separating “thought” from speech production in the frontal lobes, and “meaning” from speech perception in occipito-parieto-temporal association cortex the torque thereby confers on the species the capacity for language, and (3) the phenomena of psychosis can be seen as “leakage” from one to another of the four quadrants of association cortex. Thus consciousness is the spin-off and schizophrenia is the price that Homo sapiens pays for language.
Information encoded by the autoassociation network of CA3 situates landmarks and objects within an allocentric frame of space and time. Guiding locomotion across the spatial environment, and generally organizing behaviour that transcends space and time, the hippocampus creates phenomenal space and time themselves, thus laying the foundations for conscious awareness. It is argued that conscious experience describes the informational content of self-organizing activity patterns in CA3. Excessive pyramidal cell activity in CA3, due to deficient inhibition by GABAergic basket interneurons, leading to event memory formation unrestrained by entorhinal input may be a mechanism for the generation of hallucinations in schizophrenia.
Neurobiological accounts of consciousness typically partition brain activity into two components: one correlated with conscious experience (the neural correlate of consciousness) and the other not. Here I use evidence derived from visual hallucinations in the context of eye disease – the Charles Bonnet Syndrome – to examine the nature of what might be termed the visual unconscious. Forcing us to reconsider the nature of the unconscious, this hidden system of modular processing underlies our apparently seamless conscious visual experience of the world with many of its complex functions yet to be recognised by visual science.
Auditory consciousness takes many forms. Some of these, such as auditory perception and imagination, are familiar to nearly all people, which others, such as tinnitus or hearing voices, are rare and unfamiliar to most. This chapter proposes a simplified conceptual model of the auditory system, involving bottom-up influences from the lower auditory pathways and top-down influences from higher evaluative mechanisms. This model is used to explain auditory perception, hallucinations and illusions based, for each phenomenon, on only minor variations from the normally functioning system. Neuroimaging and electrophysiological correlates of these processes are discussed, along with their inability to qualitatively differentiate conscious from unconscious processes, and how we might approach this problem in future.
Periodicity, hallucinatory phenomena and lack of awareness of one’s detachment from reality seem to connect the subjective experience of dreaming to that of psychosis. Both can be considered fully conscious states of the brain/mind, with an immediate influence of non-conscious elements caused by an impaired interaction with the external world. Psychological and pharmacological induction of lucidity in dreams may prove useful in the comprehension of acute psychoses and in clinical practice.
The willingness of humans to take psychoactive drugs may reflect an unconscious optimism bias, where users focus on desired aims rather than actual consequences. A series of in-depth interviews will illustrate the experiences and explicit knowledge of recreational Ecstasy/MDMA users. Next an unpublished empirical study will be described, where four subgroups of Ecstasy users reported that MDMA loses its efficacy over time, while drug-related distress increased. As this cost-benefit ratio deteriorates, users take MDMA less frequently, before quitting permanently. The in-depth personal knowledge of experienced Ecstasy users might be useful for drugs education packages, since it could replace unconscious optimism with greater conscious awareness.
The study of the placebo response is basically the study of the psychosocial context around the therapy, which constitutes the ritual of the therapeutic act, and of its effects on the patient’s brain. Many mechanisms are involved, both conscious, like expectation of a future outcome, and unconscious, such as classical conditioning. Overall, recent research indicates that different social stimuli, first and foremost the therapist’s words, may induce cellular and molecular changes in the patient’s brain, thus placing psychotherapy into the neurobiological domain.
Creativity is the crowning jewel of human cognition, the ability that most uniquely characterizes our species. At the heart of subjective accounts of creativity are three deeply paradoxical features. First, creative acts are widely considered acts of self-expression, yet by many accounts the creative experience is selfless and only partially volitional. Second, creative activity is often hypnotically engrossing, while psychological theories about creativity emphasize loose, defocussed thinking. Third, loose associations during creative acts might be profligate and degenerate, but creative products are often highly specific and optimal. Here we present two novel hypotheses which might explain the paradoxical nature of subjective accounts of creativity. First, we suggest that creativity requires a “quiet mind,” simultaneously focused and disinhibited. Second, we describe how this paradoxical activity in the cerebral cortex might support the Darwinian selection engine, a previously-proposed network-level mechanism for organizing and developing mental representations.
Exploring the initial findings of neuroscientific research on meditation, new horizons of further inquiry in consciousness research are apparent. While such studies of contemplative practices are still in their infancy, early findings promise to contribute in three key areas. These include: Neuroplasticity – physiological and psychological indices of short and long terms responses of the brain circuits that underlie complex mental functions associated with specific types of meditation techniques ; Mind body Interactions – revealing mechanisms by which such training may exert beneficial effects on physical health; and Subjectivity – well developed introspective skills of practitioners potentially shedding new light on the neural counterpart of subjectivity.
Consciousness can be altered willfully. There are different methods to induce altered state of consciousness including psychological means. While some such induced states are pathological many others are not. Indian and other eastern concepts emphasize one can induce "higher states of consciousness" oneself. Physiological changes are observed in these altered states of consciousness that point to a neural basis.
Does telepathy – a purported means of communication unmediated by the ordinary senses – exist? Experimental evidence, meta-analyses and debates suggesting an affirmative answer can be found in a growing number of mainstream journals, and a physical basis for telepathy appears to be increasingly plausible based upon considerations of quantum holism and advancements in quantum information processing. Future neuroscience models of conscious and unconscious perception may be obliged to take into account a common human experience once dismissed as mere superstition.
Among agents which alter the boundary between conscious and non conscious cognition, the ritualistic use of plant species (often in a spiritual context, hence ‘plants of the gods’) provides an example of long-standing empirical knowledge subsequently verified by scientific (chemical, pharmacological and psychological) evidence. Based on such an impressive record of acquired knowledge, exploration of experiences of the shaman, who deliberately enters an altered state of consciousness to obtain otherwise inaccessible information allegedly from other ‘dimensions’ of consciousness, may contribute new insights in the neuroscience of consciousness.
We propose a neurophysiological hypothesis on the emergence of consciousness, which postulates that the slow cortical potential (SCP) recorded from the surface of the brain provides an index of the activities of superficial-layer pyramidal neurons that directly contribute to the emergence of conscious awareness. This hypothesis is supported by existing data from manipulations of conscious awareness in normal human subjects and by data from altered states of consciousness such as general anesthesia and recovery from vegetative states; it further makes experimentally testable predictions. Given a relationship between the SCP and the functional magnetic resonance imaging (fMRI) signal that has now been revealed, this hypothesis also provides a potential bridge between existing neuroimaging and electrophysiological studies on consciousness.
Conscious processes have a number of distinct properties that need to be accounted for by neuronal mechanisms supporting conscious experience. It is proposed that synchronization of distributed neuronal activity patterns meets most of these requirements. A major problem for the identification of neuronal correlates of consciousness is the distinction between the processes that lead to conscious experience and those that follow once contents have become conscious. Criteria for this distinction are discussed in the context of published evidence.
There is evidence to suggest that synchronised neuronal activity, particularly that in the gamma frequency range (~30–100Hz) might contribute to conscious perception. In this chapter I shall discuss what we know about the mechanisms that underlie the generation of gamma frequency activity and the changes known to occur in diseases such as schizophrenia. Until recently it was difficult to test the role of individual neuronal subtypes in the generation of network oscillations. However, using the newly developed optogenetic techniques (in which cells are genetically modulated to make them responsive to specific wavelengths of light) it should now be possible to directly test the contribution of different neuronal classes to the generation of network oscillations and perhaps, therefore, consciousness.
The dopamine system has a number of functions in the brain, from regulation of movement to controlling emotional expression and facilitating cognitive or conscious processes. Dopamine exerts these actions via its regulation of systems interactions. In particular, the influence of this transmitter system on the balance of afferent input to the nucleus accumbens potently modulates decision-making processes. An increase in dopamine outflow potentiates afferents from the hippocampus subiculum, which are involved in context-dependent processes. In contrast, dopamine will also attenuate the ability of the prefrontal cortex to switch behavioral tasks. In this manner, the dopamine system is positioned to alter the propensity to focus conscious attention on a current task versus flexibly altering behavior to more effectively achieve goals.
The endocannabinoid system acts as a neuromodulator, interacting with other neuromodulators such as the opioids. It influences all vital body functions and sets the tone of every conscious thought and feeling. It operates largely below conscious levels but occasionally floats into consciousness where it is perceived as perfect bliss and pain-free calm.
We discuss the molecular and cognitive mechanisms of general anaesthesia and their relevance to the science of consciousness. General anaesthetics serve as an important tool to explore the transitions from conscious to unconscious processing, as these drugs rapidly induce a complete and reversible cessation of consciousness. With 40,000,000 patients undergoing general anaesthesia each year in North America alone, the highly controlled and monitored setting of the operating room can become the ultimate consciousness laboratory.
Consciousness is described in this article as a perception of self that is constructed for guidance of voluntary goal-directed behaviour, including neural mechanisms for mental time travel into the future during planning and into the past during episodic retrieval. Neural time travel draws on the distributed cortical perceptual processes for detecting the state of the self along multiple dimensions, including spatial location, head direction, speed, temporal duration, and egocentric relationships to items. These circuit mechanisms are regulated by neuromodulatory influences such as muscarinic acetylcholine receptors that activate intrinsic properties of neurons involved in maintaining an internal representation of self.
A commonly held assumption is that consciousness is a defining feature that distinguishes explicit memory (with conscious awareness) from implicit memory (without conscious awareness). Although early studies support this notion, recent evidence suggests that conscious and non-conscious memory systems may share crucial underlying processes. Here, we propose that one locus of interaction between some types of explicit and implicit memory may be the non-conscious processes associated with recollection, or detailed remembering, that are mediated by the hippocampus.
Unconscious processes come in two varieties, the preconscious, whose contents may become conscious, and the never-conscious, whose contents may not. In this chapter we make use of Global Workspace Theory and its LIDA model to catalogue never-conscious and preconscious processes, and offer an explanation of the functionally of the distinction. The LIDA/GWT model suggests that the functional distinction between never-conscious and preconscious processes derives from one of the major purposes of an agent’s consciousness mechanism: that is to select the most salient portion of the agent’s current situation to which to attend, in order for it to be broadcast globally, in order to choose the best next action.
Although a large proportion of the human brain is dedicated to processing incoming sensory information, much of this processing is not accessible to consciousness. In an effort to understand what differentiates conscious from unconscious processing, we are concerned here with methodological issues in exploring the limits of unconscious processing. We first consider a conscious perceptual experience and establish an operating characteristic to disambiguate perceptual sensitivity from decision criterion. We then apply the same method to dissociate explicit measures of perception from implicit measures of sensory processing. Finally, we evaluate post-decision wagering as a proposed method for measuring awareness.
Noise caused by randomness in the spiking times of neurons in the brain has a number of advantages, including contributing to probabilistic decision-making. However, noise results in the brain operating effectively as a non-deterministic system, which has implications for free will. Noise also results in decisions being taken probabilistically between the reasoning system and the implicit reward system. I propose that free will can be used to describe the operation of the reasoning system, and that consciousness is a property of a reasoning system that must use higher order syntactic thoughts (HOSTs) to correct its first order thoughts. When the implicit system takes a decision, we may confabulate a reason for the decision, and in that case the feeling of free will may be an illusion.
Experiencing oneself as autonomous agent who interacts with others depends on the cognitive capacities of self-consciousness as awareness of ones own mental states and social consciousness as knowledge of other persons minds. The study of neural correlates of these capacities elicits an impressive overlap with the so-called “default mode of brain function” as a neurobiological universal of mammalian brains. This empirical observation stimulates the speculation that one major cognitive function of the neural default mode is social cognition which conversely implies that humans have a disposition for social cognition that is reflected in this neural default mode.
Our conscious control of language and its acquisition is strictly limited. A processing-oriented perspective to explain this will be outlined called MOGUL according to which some linguistic processes are inherently unconscious while others can be either conscious or not. The former involve representations, found in the dedicated, uniquely human language module, whose sealed-off nature does not permit the activation levels necessary for conscious experience to take place. However, language knowledge created by cognitive processes that are not specifically linguistic, that is, created outside the language module, can indeed be raised to consciousness. This is because they are more directly connected to the perceptual system and are accordingly open to much higher levels of activation.
Magicians have developed powerful techniques to manipulate our perception and awareness. Many of these techniques share similarities with phenomena typically investigated by psychologists and neuroscientists. Here a novel approach to the study of consciousness is proposed which utilizes the magician’s expertise to complement more traditional experimental laboratory based research. It is argued that this approach offers new and exciting insights into wide areas of consciousness, such as attention, visual awareness and top-down modulation of perception.
Based on biological realism, that is, the philosophical assumption that consciousness is a real natural biological phenomenon in the brain, we argue that dreaming is a pure form of phenomenality, and suggest that the dreaming brain could be used as a model system for consciousness. The dreaming brain offers the most challenging model system that represents all the theoretically and philosophically interesting features of consciousness. Although difficult to study experimentally, the dreaming brain is the model system that fully preserves all the essential features of consciousness, and cannot be ignored by any theory that aims to explain consciousness.
In this essay, we develop our working hypothesis that consciousness in primates and humans is a state-dependent commodity that has at least two expressions. Waking and dreaming are two such states that differ in conscious awareness. In both states, we are perceptive and emotional. Whereas in dreaming, our thoughts are delusional, however, waking consciousness potentiates volition and reflection. We propose that dreaming is a state of primary consciousness, while usually, secondary consciousness is reserved to waking. Lucid dreaming is an extraordinary state with elements of both waking and dreaming and both primary and secondary consciousness. It is a rare but very real condition which is a promising tool in the study of the brain basis of consciousness.
We believe that conscious mental phenomena (such as feelings) are not epiphenomenal to the workings of the brain. Feelings evolved for good biological reasons; they make specific, concrete contributions to brain functioning. Notwithstanding all the philosophical complexities, therefore, the non-conscious/conscious interactions that are the focus of this book are, in our view, causal interactions. To marginalize consciousness in relation to what is ultimately a cdualistic scientific understanding of how the brain works is likely to lead us astray. We illustrate this view by trying to address the question: why does depression feel bad?
Dementing illnesses massively damage the structures and processes thought to underlie consciousness. However, maintained alertness, preserved awareness, and the appearance of hallucinations in people with dementia all suggest that consciousness survives extreme challenge; implying that conscious processes are extremely robust, and conscious content invariably present.
Hearing “voices”, the experience of thoughts as not one’s own, and incoherent speech are symptoms of mental illness (usually termed “schizophrenia”). Here I argue that (1) the “torque” is the feature that defines the human brain as four chambered by comparison with the two chambers of the generalized mammalian brain, (2) by separating “thought” from speech production in the frontal lobes, and “meaning” from speech perception in occipito-parieto-temporal association cortex the torque thereby confers on the species the capacity for language, and (3) the phenomena of psychosis can be seen as “leakage” from one to another of the four quadrants of association cortex. Thus consciousness is the spin-off and schizophrenia is the price that Homo sapiens pays for language.
Information encoded by the autoassociation network of CA3 situates landmarks and objects within an allocentric frame of space and time. Guiding locomotion across the spatial environment, and generally organizing behaviour that transcends space and time, the hippocampus creates phenomenal space and time themselves, thus laying the foundations for conscious awareness. It is argued that conscious experience describes the informational content of self-organizing activity patterns in CA3. Excessive pyramidal cell activity in CA3, due to deficient inhibition by GABAergic basket interneurons, leading to event memory formation unrestrained by entorhinal input may be a mechanism for the generation of hallucinations in schizophrenia.
Neurobiological accounts of consciousness typically partition brain activity into two components: one correlated with conscious experience (the neural correlate of consciousness) and the other not. Here I use evidence derived from visual hallucinations in the context of eye disease – the Charles Bonnet Syndrome – to examine the nature of what might be termed the visual unconscious. Forcing us to reconsider the nature of the unconscious, this hidden system of modular processing underlies our apparently seamless conscious visual experience of the world with many of its complex functions yet to be recognised by visual science.
Auditory consciousness takes many forms. Some of these, such as auditory perception and imagination, are familiar to nearly all people, which others, such as tinnitus or hearing voices, are rare and unfamiliar to most. This chapter proposes a simplified conceptual model of the auditory system, involving bottom-up influences from the lower auditory pathways and top-down influences from higher evaluative mechanisms. This model is used to explain auditory perception, hallucinations and illusions based, for each phenomenon, on only minor variations from the normally functioning system. Neuroimaging and electrophysiological correlates of these processes are discussed, along with their inability to qualitatively differentiate conscious from unconscious processes, and how we might approach this problem in future.
Periodicity, hallucinatory phenomena and lack of awareness of one’s detachment from reality seem to connect the subjective experience of dreaming to that of psychosis. Both can be considered fully conscious states of the brain/mind, with an immediate influence of non-conscious elements caused by an impaired interaction with the external world. Psychological and pharmacological induction of lucidity in dreams may prove useful in the comprehension of acute psychoses and in clinical practice.
The willingness of humans to take psychoactive drugs may reflect an unconscious optimism bias, where users focus on desired aims rather than actual consequences. A series of in-depth interviews will illustrate the experiences and explicit knowledge of recreational Ecstasy/MDMA users. Next an unpublished empirical study will be described, where four subgroups of Ecstasy users reported that MDMA loses its efficacy over time, while drug-related distress increased. As this cost-benefit ratio deteriorates, users take MDMA less frequently, before quitting permanently. The in-depth personal knowledge of experienced Ecstasy users might be useful for drugs education packages, since it could replace unconscious optimism with greater conscious awareness.
The study of the placebo response is basically the study of the psychosocial context around the therapy, which constitutes the ritual of the therapeutic act, and of its effects on the patient’s brain. Many mechanisms are involved, both conscious, like expectation of a future outcome, and unconscious, such as classical conditioning. Overall, recent research indicates that different social stimuli, first and foremost the therapist’s words, may induce cellular and molecular changes in the patient’s brain, thus placing psychotherapy into the neurobiological domain.
Creativity is the crowning jewel of human cognition, the ability that most uniquely characterizes our species. At the heart of subjective accounts of creativity are three deeply paradoxical features. First, creative acts are widely considered acts of self-expression, yet by many accounts the creative experience is selfless and only partially volitional. Second, creative activity is often hypnotically engrossing, while psychological theories about creativity emphasize loose, defocussed thinking. Third, loose associations during creative acts might be profligate and degenerate, but creative products are often highly specific and optimal. Here we present two novel hypotheses which might explain the paradoxical nature of subjective accounts of creativity. First, we suggest that creativity requires a “quiet mind,” simultaneously focused and disinhibited. Second, we describe how this paradoxical activity in the cerebral cortex might support the Darwinian selection engine, a previously-proposed network-level mechanism for organizing and developing mental representations.
Exploring the initial findings of neuroscientific research on meditation, new horizons of further inquiry in consciousness research are apparent. While such studies of contemplative practices are still in their infancy, early findings promise to contribute in three key areas. These include: Neuroplasticity – physiological and psychological indices of short and long terms responses of the brain circuits that underlie complex mental functions associated with specific types of meditation techniques ; Mind body Interactions – revealing mechanisms by which such training may exert beneficial effects on physical health; and Subjectivity – well developed introspective skills of practitioners potentially shedding new light on the neural counterpart of subjectivity.
Consciousness can be altered willfully. There are different methods to induce altered state of consciousness including psychological means. While some such induced states are pathological many others are not. Indian and other eastern concepts emphasize one can induce "higher states of consciousness" oneself. Physiological changes are observed in these altered states of consciousness that point to a neural basis.
Does telepathy – a purported means of communication unmediated by the ordinary senses – exist? Experimental evidence, meta-analyses and debates suggesting an affirmative answer can be found in a growing number of mainstream journals, and a physical basis for telepathy appears to be increasingly plausible based upon considerations of quantum holism and advancements in quantum information processing. Future neuroscience models of conscious and unconscious perception may be obliged to take into account a common human experience once dismissed as mere superstition.
Among agents which alter the boundary between conscious and non conscious cognition, the ritualistic use of plant species (often in a spiritual context, hence ‘plants of the gods’) provides an example of long-standing empirical knowledge subsequently verified by scientific (chemical, pharmacological and psychological) evidence. Based on such an impressive record of acquired knowledge, exploration of experiences of the shaman, who deliberately enters an altered state of consciousness to obtain otherwise inaccessible information allegedly from other ‘dimensions’ of consciousness, may contribute new insights in the neuroscience of consciousness.