“This article covers the neurochemical basis of three different categories of consciousness (1) clinical, (2) awareness, and (3) phenomenal. the first section covers general anesthesia; desferrioxamine/prochlorperazine coma; and cholinergic nuclei. the second section deals with the family of neuromodulators involved in awareness. the third section covers psychedelic drugs and serotonin 2(a) receptors; the role of acetylcholine in virtual reality and information compression mechanisms in visual perception; the adrenergic system in the medulla and bipolar disorder; and the microanatomy and neurochemistry of schizophrenia.”

“Users of psychedelic drugs often report that their sense of being a self or ‘i’ distinct from the rest of the world has diminished or altogether dissolved. neuroscientific study of such ‘ego dissolution’ experiences offers a window onto the nature of self-awareness. we argue that ego dissolution is best explained by an account that explains self-awareness as resulting from the integrated functioning of hierarchical predictive models which posit the existence of a stable and unchanging entity to which representations are bound. combining recent work on the ‘integrative self’’ and the phenomenon of self-binding with predictive processing principles yields an explanation of ego dissolution according to which self-representation is a useful cartesian fiction: an ultimately false representation of a simple and enduring substance to which attributes are bound which serves to integrate and unify cognitive processing across levels and domains. the self-model is not a mere narrative posit, as some have suggested; it has a more robust and ubiquitous cognitive function than that. but this does not mean, as others have claimed, that the self-model has the right attributes to qualify as a self. it performs some of the right kinds of functions, but it is not the right kind of entity. ego dissolution experiences reveal that the self-model plays an important binding function in cognitive processing, but the self does not exist.’”

“It is often claimed that a minimal form of self-awareness is constitutive of our conscious experience. some have considered that such a claim is plausible for our ordinary experiences but false when considered unrestrictedly on the basis of the empirical evidence from altered states. in this paper i want to reject such a reasoning. this requires, first, a proper understanding of a minimal form of self-awareness – one that makes it plausible that minimal self-awareness is part of our ordinary experiences. i will argue that it should be understood as perspectival first-person awareness (pfp-awareness): a non-conceptual identification-free self-attribution that defines the first-person perspective for our conscious experience. i will offer a detailed characterization of pfp-awareness in semantic and epistemological terms. with this tool in hand, i will review the empirical literature on altered states. i will focus on psychedelics, meditation and dreams, as they have been claimed to present the clearest cases in favor of a radical disruption of self-awareness. i will show that the rejection of the idea that minimal self-awareness is constitutive of our experience on the basis of this evidence is unfounded, for two main reasons. first, although there are good grounds to think that some forms of self-awareness that typically accompany our ordinary experiences are compromised, they do not support the claim that pfp-awareness is absent. secondly, the reports that could make us think of a radical disruption of self-awareness are most probably due to a confirmation bias – and hence we should mistrust them – derived from the expectations and metaphysical views of their subjects.”

“The psychological state elicited by the classic psychedelics drugs, such as lsd and psilocybin, is one of the most fascinating and yet least understood states of consciousness. however, with the advent of modern functional neuroimaging techniques, the effect of these drugs on neural activity is now being revealed, although many of the varied phenomenological features of the psychedelic state remain challenging to explain. integrated information theory (iit) is one of the foremost contemporary theories of consciousness, providing a mathematical formalization of both the quantity and quality of conscious experience. this theory can be applied to all known states of consciousness, including the psychedelic state. using the results of functional neuroimaging data on the psychedelic state, the effects of psychedelic drugs on both the level and structure of consciousness can be explained in terms of the conceptual framework of iit. this new iit-based model of the psychedelic state provides an explanation for many of its phenomenological features, including unconstrained cognition, alterations in the structure and meaning of concepts and a sense of expanded awareness. this model also suggests that whilst cognitive flexibility, creativity, and imagination are enhanced during the psychedelic state, this occurs at the expense of cause-effect information, as well as degrading the brain’s ability to organize, categorize, and differentiate the constituents of conscious experience. furthermore, the model generates specific predictions that can be tested using a combination of functional imaging techniques, as has been applied to the study of levels of consciousness during anesthesia and following brain injury.”

“This review illustrates the relevance of shamanism and its evolution under effects of psilocybin as a framework for identifying evolved aspects of psychedelic set and setting. effects of 5ht2 psychedelics on serotonin, stress adaptation, visual systems and personality illustrate adaptive mechanisms through which psychedelics could have enhanced hominin evolution as an environmental factor influencing selection for features of our evolved psychology. evolutionary psychology perspectives on ritual, shamanism and psychedelics provides bases for inferences regarding psychedelics’ likely roles in hominin evolution as exogenous neurotransmitter sources through their effects in selection for innate dispositions for psychedelic set and setting. psychedelics stimulate ancient brain structures and innate modular thought modules, especially self-awareness, other awareness, ‘mind reading,’ spatial and visual intelligences. the integration of these innate modules are also core features of shamanism. cross-cultural research illustrates shamanism is an empirical phenomenon of foraging societies, with its ancient basis in collective hominid displays, ritual alterations of consciousness, and endogenous healing responses. shamanic practices employed psychedelics and manipulated extrapharmacological effects through stimulation of serotonin and dopamine systems and augmenting processes of the reptilian and paleomammalian brains. differences between chimpanzee maximal displays and shamanic rituals reveal a zone of proximal development in hominin evolution. the evolution of the mimetic capacity for enactment, dance, music, and imitation provided central capacities underlying shamanic performances. other chimp-human differences in ritualized behaviors are directly related to psychedelic effects and their integration of innate modular thought processes. psychedelics and other ritual alterations of consciousness stimulate these and other innate responses such as soul flight and death-and-rebirth experiences. these findings provided bases for making inferences regarding foundations of our evolved set, setting and psychology. shamanic setting is eminently communal with singing, drumming, dancing and dramatic displays. innate modular thought structures are prominent features of the set of shamanism, exemplified in animism, animal identities, perceptions of spirits, and psychological incorporation of spirit others. a shamanic-informed psychedelic therapy includes: a preparatory set…”

“Based on its ability to increase brain complexity, a seemingly reliable index of conscious level, we propose testing the capacity of the classic psychedelic, psilocybin, to increase conscious awareness in patients with disorders of consciousness. we also confront the considerable ethical and practical challenges this proposal must address, if this hypothesis is to be directly assessed.”