1.1 Bilateral damage to the thalamus abolishes waking consciousness. The critical site of this damage is believed to be a relatively small cluster of neurons, about the size of a pencil eraser on either side of the brain's midline, called the Intra-Laminar Nuclei (ILN) because they are located inside the white layers (laminae) that divide the two thalami into their major groupings of nuclei. The fact that bilateral damage to the ILNs abolishes consciousness is very unusual. There is no other (...) site in the brain that has this property, except the reticular formation in the brain stem. In contrast, huge chunks of cortex can be damaged without abolishing the STATE of consciousness. (Cortical damage does change the CONTENTS of consciousness, of course). (shrink)

This paper explores a remarkable convergence of ideas and evidence, previously presented in separate places by its authors. That convergence has now become so persuasive that we believe we are working within substantially the same broad framework. Taylor's mathematical papers on neuronal systems involved in consciousness dovetail well with work by Newman and Baars on the thalamocortical system, suggesting a brain mechanism much like the global workspace architecture developed by Baars (see references below). This architecture is relational, in the sense (...) that it continuously mediates the interaction of input with memory. While our approaches overlap in a number of ways, each of us tends to focus on different areas of detail. What is most striking, and we believe significant, is the extent of consensus, which we believe to be consistent with other contemporary approaches by Weiskrantz, Gray, Crick and Koch, Edelman, Gazzaniga, Newell and colleagues, Posner, Baddeley, and a number of others. We suggest that cognitive neuroscience is moving toward a shared understanding of consciousness in the brain. (shrink)

The legacy of René Descartes' notorious dualism of mind and body extends far beyond academia into everyday thinking: "These athletes are prepared both mentally and physically," and "There's nothing wrong with your body--it's all in your mind." Even among those of us who have battled Descartes' vision, there has been a powerful tendency to treat the mind (that is to say, the brain) as the body's boss, the pilot of the ship. Falling in with this standard way of thinking, we (...) ignore an important alternative: viewing the brain (and hence the mind) as one organ among many, a relatively recent usurper of control, whose functions cannot properly be understood until we see it not as the boss, but as just one more somewhat fractious servant, working to further the interests of the body that shelters and fuels it, and gives its activities meaning. This historical or evolutionary perspective reminds me of the change that has come over Oxford in the thirty years since I was a student there. It used to be that the dons were in charge, while the bursars and other bureaucrats, right up to the Vice Chancellor, acted under their guidance and at their behest. Nowadays the dons, like their counterparts on American university faculties, are more clearly in the role of employees hired by a central Administration, but from where, finally, does the University get its meaning? In evolutionary history, a similar change has crept over the administration of our bodies. Where resides the "I" who is in charge of my body? In his wonderfully written book, Antonio Damasio seeks to restore our appreciation for the perspective of the body, and the shared balance of powers from which we emerge as conscious persons. (shrink)

In our contribution we will observe phenomenal architecture of a mind and operational architectonics of the brain and will show their intimate connectedness within a single integrated metastable continuum. The notion of operation of different complexity is the fundamental and central one in bridging the gap between brain and mind: it is precisely by means of this notion that it is possible to identify what at the same time belongs to the phenomenal conscious level and to the neurophysiological level of (...) brain activity organization, and what mediates between them. Implications for linguistic semantics, self-organized distributed computing algorithms, artificial machine consciousness, and diagnosis of dynamic brain diseases will be discussed briefly. (shrink)

The understanding of the interrelationship between brain and mind remains far from clear. It is well established that the brain's capacity to integrate information from numerous sources forms the basis for cognitive abilities. However, the core unresolved question is how information about the "objective" physical entities of the external world can be integrated, and how unifiedand coherent mental states (or Gestalts) can be established in the internal entities of distributed neuronal systems. The present paper offers a unified methodological and conceptual (...) basis for a possible mechanism of how the transient synchronization of brain operations may construct the unified and relatively stable neural states, which underlie mental states. It was shown that the sequence of metastable spatial EEG mosaics does exist and probably reflects the rapid stabilization periods of the interrelation of large neuron systems. At the EEG level this is reflected in the stabilization of quasi-stationary segments on corresponding channels. Within the introduced framework, physical brain processes and psychological processes are considered as two basic aspects of a single whole informational brain state. The relations between operational process of the brain, mental states and consciousness are discussed. (shrink)

I dispute that consciousness is generated by core circuitry in the forebrain, with predominance of motor areas, as Cotterillproposes in Enchanted Looms and other theorists do also. Ipropose instead that conscious contents are the momentary modeof action of the integrated cortical field, expressed as a point vector ( dominant focus ), to which, in varying degree, allsectors of the network contribute. Consciousness is the brain''saccess to its own activity space, and is identical with the moment''sdominant mode of activity. The dominant (...) focus is generally weightedtoward enactively encoded percepts. Anticipation and preparation,perception and action, inextricably interdigitate. I also dispute the view of Cotterill and others that consciousnesshas unique agency, which bestowed adaptive advantage when the brain evolved. Being identical with the activity of the network,consciousness can have no additional agency, and it can offerno adaptive advantages beyond those that characterize the network. (shrink)

b>. One major problem many hypotheses regarding the neural correlate of consciousness (NCC) face is what we might call “the why question”: _why _would this particular neural feature, rather than another, correlate with consciousness? The purpose of the present paper is to develop an NCC hypothesis that answers this question. The proposed hypothesis is inspired by the Cross-Order Integration (COI) theory of consciousness, according to which consciousness arises from the functional integration of a first-order representation of an external stimulus and (...) a second-order representation of that first-order representation. The proposal comes in two steps. The first step concerns the “general shape” of the NCC and can be directly derived from COI theory. The second step is a concrete hypothesis that can be arrived at by combining the general shape with empirical considerations. (shrink)

I propose and defend the Allocentric-Egocentric Interface Theory of Con- sciousness. Mental processes form a hierarchy of mental representations with maxi- mally egocentric (self-centered) representations at the bottom and maximally allocentric (other-centered) representations at the top. Phenomenally conscious states are states that are relatively intermediate in this hierarchy. More speci.

A broad consensus has developed in recent years in the cognitive and neurosciences that the cognitive functions of the mind arise out of the activities of an extensive and diverse array of specialized processors operating as a parallel, distributed system. A theoretical perspective is presented which expands upon this "society" model to include globally integrative infuences upon this arrary of processors. This perspective serves as the basis for an explicit neural model of a "global workspace within a system of distributed (...) specialized processors". Anatomical and physiological evidence are reviewed which suggest that this parallel, modular architecture is superceded by a more diffuse, tangential intracortical network capable of integrating underlying modular activites into increasingly global cognitive representations. There follows an explication of the role of this "neural global workspace" in providing the essential basis for the central control of attention and the generation of unified, conscious percepts. Finally the role of thalamic and brainstem activation systems in these integrative processes is discussed. (shrink)

In Enchanted Looms , Rodney Cotterill defends the hypothesisthat conscious sensory experience depends on motor response. Thepositive evidence for this hypothesis is inconclusive, andnegative evidence can be marshaled against it. I present analternative hypothesis according to which consciousness involvesintermediate level sensory processing, attention, and workingmemory. The circuitry of consciousness can be dissociated fromaction systems and may mark an evolutionary advance from a priorphylogenetic stage in which motor outputs and sensory inputswere more intimately bound.

Neural Darwinism (ND) is a large scale selectionist theory of brain development and function that has been hypothesized to relate to consciousness. According to ND, consciousness is entailed by reentrant interactions among neuronal populations in the thalamocortical system (the ‘dynamic core’). These interactions, which permit high-order discriminations among possible core states, confer selective advantages on organisms possessing them by linking current perceptual events to a past history of value-dependent learning. Here, we assess the consistency of ND with 16 widely recognized (...) properties of consciousness, both physiological (for example, consciousness is associated with widespread, relatively fast, low amplitude interactions in the thalamocortical system), and phenomenal (for example, consciousness involves the existence of a private flow of events available only to the experiencing subject). While no theory accounts fully for all of these properties at present, we find that ND and its recent extensions fare well. (shrink)

A recent theoretical emphasis on complex interactions within neural systems underlying consciousness has been accompanied by proposals for the quantitative characterization of these interactions. Here, we distinguish key aspects of consciousness that are amenable to quantitative measurement from those that are not. We carry out a formal analysis of the strengths and limitations of three quantitative measures of dynamical complexity in the neural systems underlying consciousness: neural complexity, information integration, and causal density. We find that no single measure fully captures (...) the multidimensional complexity of these systems and all have practical limitations. Our analysis suggests guidelines for the specification of alternative measures which, in combination, may improve the quantitative characterization of conscious neural systems. Given that some aspects of consciousness are likely to resist quantification altogether, we conclude that a satisfactory theory is likely to be one that combines both qualitative and quantitative elements. (shrink)

There are now various approaches to understand where and how in the brain consciousness arises from neural activity, none of which is universally accepted. Difficulties among these approaches are reviewed, and a missing ingredient is proposed here to help adjudicate between them, that of ''perspectivalness.'' In addition to a suitable temporal duration and information content of the relevant bound brain activity, this extra component is posited as being a further important ingredient for the creation of consciousness from neural activity. It (...) guides the development of what is termed the ''Central Representation,'' which is supposed to be present in all mammals and extended in humans to support self-consciousness as well as phenomenal consciousness. Experimental evidence and a theoretical framework for the existence of the central representation are presented, which relates the extra component to specific buffer working memory sites in the inferior parietal lobes, acting as attentional coordinators on the spatial maps making up the central representation. The article closes with a discussion of various open questions. (shrink)