This book brings together an international group of neuroscientists and philosophers who are investigating how the content of subjective experience is...

The search for the neural correlates of consciousness is in need of a systematic, principled foundation that can endow putative neural correlates with greater predictive and explanatory value. Here, we propose the predictive processing framework for brain function as a promising candidate for providing this systematic foundation. The proposal is motivated by that framework’s ability to address three general challenges to identifying the neural correlates of consciousness, and to satisfy two constraints common to many theories of consciousness. Implementing the search (...) for neural correlates of consciousness through the lens of predictive processing delivers strong potential for predictive and explanatory value through detailed, systematic mappings between neural substrates and phenomenological structure. We conclude that the predictive processing framework, precisely because it at the outset is not itself a theory of consciousness, has significant potential for advancing the neuroscience of consciousness. (shrink)

At present, the science of consciousness is structured around the search for the neural correlates of consciousness. One of the alleged advantages of the NCCs framework is its metaphysical neutrality—the fact that it begs no contested questions with respect to debates about the fundamental nature of consciousness. Here, we argue that even if the NCC framework is metaphysically neutral, it is structurally committed, for it presupposes a certain model—what we call the Lite-Brite model—of consciousness. This, we argue, represents a serious (...) liability for the NCC framework for the plausibility of the Lite-Brite model is very much an open question, and the science of consciousness would be better served by a framework that does not presuppose it. Drawing on interventionist ideas in the philosophy of science, we suggest that the Difference-Maker framework can provide just such an alternative. Instead of searching for the neural correlates of consciousness, we ought to be searching for the difference makers of consciousness. We detail how a shift to searching DMCs will change both the practice of consciousness science and the interpretation of existing results. (shrink)

Contrasting brain states when subjects are aware compared to unaware of a presented stimulus has allowed researchers to isolate candidate neural correlates of consciousness. Here we propose that an important next step in this research program is to investigate, perhaps paradoxically, brain states that covary with reports of absences of awareness. Specifically, we propose that in order to distinguish content-specific and content-invariant neural correlates of consciousness, a distinction needs to be made between the neural correlates of awareness of stimulus absence, (...) and the neural correlates of absence of awareness. We ground this distinction in higher-order computational models of consciousness, where the state of higher-order nodes is invariant to the specific contents of awareness. To map the different levels of these models to neurophysiological correlates, we suggest two empirical approaches – inverted designs and two-dimensional awareness reports – in which reports about awareness and stimulus presence can be dissociated. (shrink)

The notion of a global state of consciousness is an increasingly important construct in the science of consciousness. However, exactly what a global state of consciousness is remains poorly understood. In this paper I offer an account of global states of consciousness as consciousness-related capacity modulations. On this view global states are not themselves phenomenal states – they are not occurring experiences. Rather, they are states that specify which of a creature’s overall consciousness-related capacities are currently online. Given that the (...) search for the neural correlates of consciousness, as it is currently conceived, is the search for the neural basis of occurrent experiences, the NCC framework is incapable of revealing the neural basis of global states. As such, a mature science of consciousness will need to move beyond the search for NCCs, as that project is currently conceived. (shrink)

The present paper was written as a contribution to ongoing methodological debates within the NCC project. We focus on the neural correlates of conscious perceptual episodes. Our claim is that the NCC notion, as applied to conscious perceptual episodes, needs to be reconceptualized. It mixes together the processing related to the perceived contents and the neural substrate of consciousness proper, i.e. mechanisms making the perceptual contents conscious. We thus propose that the perceptual NCC be divided into two constitutive subnotions. The (...) main theoretical idea that emerges as a consequence of this reconceptualization is that the neural correlate of a perceptual episode is formed in the neural interaction between content-processing and consciousness-conferring mechanisms. The paper elaborates this distinction, marshals some initial arguments in its favour, and tests it against some of the most debated theories of consciousness. (shrink)

Can we make progress exploring consciousness? Or is it forever beyond human reach? In science we never know the ultimate outcome of the journey. We can only take whatever steps our current knowledge affords. This paper explores today's evidence from the viewpoint of Global Workspace theory. First, we ask what kind of evidence has the most direct bearing on the question. The answer given here is ‘contrastive analysis’ -- a set of paired comparisons between similar conscious and unconscious processes. This (...) body of evidence is already quite large, and constrains any possible theory . Because it involves both conscious and unconscious events, it deals directly with our own subjective experience, as anyone can tell by trying the demonstrations in this article. (shrink)

This expanded edition of C L Hardin's ground-breaking work on colour features a new chapter, 'Further Thoughts: 1993', in which the author revisits the dispute ...

Some proponents of the Integrated Information Theory of consciousness profess strong views on the Neural Correlates of Consciousness, namely that large swathes of the neocortex, the cerebellum, at least some sensory cortices, and the so-called limbic system are all not essential for any form of conscious experiences. We argue that this connection is not incidental. Conflation between strong and weak versions of the theory has led these researchers to adopt definitions of NCC that are inconsistent with their own previous definitions, (...) inadvertently betraying the promises of an otherwise fruitful empirical endeavour. (shrink)

The idea that the thalamo-cortical system is the crucial constituent of the neurobiological mechanisms of consciousness has a long history. For the last few decades, however, consciousness research has to a large extent overlooked the interplay between the cortex and thalamus. Here we revive an integrated view of the neurobiology of consciousness by presenting and discussing several recent major findings about the role of the thalamocortical interactions in consciousness. Based on these findings we propose a specific cellular mechanism how thalamic (...) nuclei modulate the integration of different processing streams within single cortical pyramidal neurons. This theory is inspired by recent work done in rodents, but it integrates decades of work conducted on various species. We illustrate how this new view readily explains various properties and experimental phenomena associated with conscious experience. We discuss the implications of this idea and some of the experiments that need to be done in order to test it. Our view bridges two long-standing perspectives on the neural mechanisms of consciousness and proposes that cortical and thalamo-cortical processing interact at the level of single pyramidal cells. (shrink)