The integrated information theory (IIT) is one of the most influential scientific theories of consciousness. It functions as a guiding framework for a great deal of research into the neural basis of consciousness and for attempts to develop a consciousness meter. In light of these developments, it is important to examine whether its foundations are secure. This article does just that by...
To test the specific effects of hypnosis on the attentional components of visual awareness, we developed a posthypnotic suggestion for peripheral visual inattention inspired on the "tunnel vision" symptom of the Balint Syndrome. We constructed a dual-target visibility and discrimination paradigm, in which single-digit numerical targets were placed both on the hypnotically affected peripheral...
In our ASSC20 symposium, “Does unconscious perception really exist?”, the four of us asked some difficult questions about the purported phenomenon of unconscious perception, disagreeing on a number of points. This disagreement reflected the objective of the symposium: not only to come together to discuss a single topic of keen interest to the ASSC community, but to do so in a way that would...
This is a subjective summary of the recent meeting of the Association for the Scientific Study of Consciousness (ASSC) in Buenos Aires (2016), with some highlights, as well as reflections on the state of the field in general. I argue that we are likely at a critical point where the field is in the process of transforming itself, and the ASSC meeting is accordingly becoming the premier venue to...
Vividness is an aspect of consciousness related to mental imagery and prospective episodic memory. Despite being harshly criticized in the past for failing to demonstrate robust correlations with behavioral measures, currently this construct is attracting a resurgent interest in cognitive neuroscience. Therefore, an updated examination of the validity of this construct is timely. A corpus of...
This article summarizes key advances in hypnosis research during the past two decades, including (i) clinical research supporting the efficacy of hypnosis for managing a number of clinical symptoms and conditions, (ii) research supporting the role of various divisions in the anterior cingulate and prefrontal cortices in hypnotic responding, and (iii) an emerging finding that high hypnotic...
Abstract Over the last 30 years, our understanding of the neurocognitive bases of consciousness has improved, mostly through studies employing vision. While studying consciousness in the visual modality presents clear advantages, we believe that a comprehensive scientific account of subjective experience must not neglect other exteroceptive and interoceptive signals as well as the role of...
Key to understanding the neuronal basis of consciousness is the characterization of the neural signatures of changes in level of consciousness during sleep. Here we analysed three measures of dynamical complexity on spontaneous depth electrode recordings from 10 epilepsy patients during wakeful rest (WR) and different stages of sleep: (i) Lempel-Ziv complexity, which is derived from how...
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...
It has been argued that the bandwidth of perceptual experience is low-that the richness of experience is illusory and that the amount of visual information observers can perceive and remember is extremely limited. However, the evidence suggests that this postulated poverty of experiential content is illusory and that visual phenomenology is immensely rich. To properly estimate perceptual...
Providing objective metrics of conscious state is of great interest across multiple research and clinical fields-from neurology to artificial intelligence. Here we approach this challenge by proposing plausible mechanisms for the phenomenon of structured experience. In earlier work, we argued that the experience we call reality is a mental construct derived from information compression. Here we...
Nightly transitions into sleep are usually uneventful and transpire in the blink of an eye. But in the laboratory these transitions afford a unique view of how experience is transformed from the perceptually grounded consciousness of wakefulness to the hallucinatory simulations of dreaming. The present review considers imagery in the sleep-onset transition-"microdreams" in particular-as an...
The science of dreaming constitutes a relevant topic in modern-day neuroscientific research and provides major insights into the study of human consciousness. Linking specific, universal, and regularly occurring stages of sleep with dreaming encourages the direct and systematic investigation of a topic that has fascinated humankind for centuries. In this review, we explore to what extent...
Hypnotic amnesia is a functional dissociation from awareness during which information from specific neural processes is unavailable to consciousness. We test the proposal that changes in topographic patterns of cortical oscillations in upper-alpha (10-12 Hz) band selectively inhibit the recall of memories during hypnotic amnesia by blocking availability of locally processed information at...
Integrated information theory (IIT) has established itself as one of the leading theories for the study of consciousness. IIT essentially proposes that quantitative consciousness is identical to maximally integrated conceptual information, quantified by a measure called Φmax, and that phenomenological experience corresponds to the associated set of maximally irreducible cause-effect repertoires...
A recent fMRI study by Webb et al. (Cortical networks involved in visual awareness independent of visual attention, Proc Natl Acad Sci U S A 2016;113:13923-28) proposes a new method for finding the neural correlates of awareness by matching attention across awareness conditions. The experimental design, however, seems at odds with known features of attention. We highlight logical and...
There has been increasing interest in the integrated information theory (IIT) of consciousness, which hypothesizes that consciousness is integrated information within neuronal dynamics. However, the current formulation of IIT poses both practical and theoretical problems when empirically testing the theory by computing integrated information from neuronal signals. For example, measuring...
Neocortical pyramidal cells can integrate two classes of input separately and use one to modulate response to the other. Their tuft dendrites are electrotonically separated from basal dendrites and soma by the apical dendrite, and apical hyperpolarization-activated currents (Ih) further isolate subthreshold integration of tuft inputs. When apical depolarization exceeds a threshold, however, it...
A step towards a theory of consciousness would be to characterize the effect of consciousness on information processing. One set of results suggests that the effect of consciousness is to interfere with computations that are optimally performed non-consciously. Another set of results suggests that conscious, system 2 processing is the home of norm-compliant computation. This is contrasted with...
Abstract A fundamental component of conscious experience involves a first-person perspective (1PP), characterized by the experience of being a subject and of being directed at the world. Extending earlier work on multisensory perceptual mechanisms of 1PP, we here asked whether the experienced direction of the 1PP (i.e. the spatial direction of subjective experience of the world) depends on...
Causal interactions within complex systems such as the brain can be analyzed at multiple spatiotemporal levels. It is widely assumed that the micro level is causally complete, thus excluding causation at the macro level. However, by measuring effective information—how much a system’s mechanisms constrain its past and future states—we recently showed that causal power can be stronger at macro...
Self-specific processes (SSPs) specify the self as an embodied subject and agent, implementing a functional self/nonself distinction in perception, cognition, and action. Despite recent interest, it is still undetermined whether SSPs are all-or-nothing or graded phenomena; whether they can be identified in neuroimaging data; and whether they can be altered through attentional training. These...
Response bias (or criterion) contamination is insidious in studies of consciousness: that observers report they do not see a stimulus may not mean they have absolutely no subjective experience; they may be giving such reports in relative terms in the context of other stimuli. Bias-free signal detection theoretic measures provide an excellent method for avoiding response bias confounds, and many...
In his paper 'Are we ever aware of concepts? A critical question for the Global Neuronal Workspace, Integrated Information, and Attended Intermediate-Level Representation theories of consciousness' (2015, this journal), Kemmerer defends a conservative account of consciousness, according to which concepts and thoughts do not characterize the contents of consciousness, and then uses that account...
In a famous series of experiments, Libet investigated the subjective timing of awareness of an intention to move, a task that can be considered a metacognitive judgement. The ability to strategically produce inaccurate metacognitions about intentions has been postulated to be central to the changes in judgements of agency common to all hypnotic responding. Therefore, differences in...