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)

One of the most important issues concerning the foundations ofconscious perception centerson thequestion of whether perceptual consciousness is rich or sparse. The overflow argument uses a form of ‘iconic memory’ toarguethatperceptual consciousnessisricher (i.e.,has a higher capacity) than cognitive access: when observing a complex scene we are conscious of more than we can report or think about. Recently, the overflow argumenthas been challenged both empirically and conceptually. This paper reviews the controversy, arguing that proponents of sparse perception are committed to the (...) postulation of (i) a peculiar kind of generic conscious representation that has no independent rationale and (ii) an unmotivated form of unconscious representation that in some cases conflicts with what we know about unconscious representation. (shrink)

In recent times we have seen an explosion in the amount of attention paid to the conscious brain from scientists and philosophers alike. One message that has emerged loud and clear from scientific work is that the brain is a dynamical system whose operations unfold in time. Any theory of consciousness that is going to be physically realistic must take account of the intrinsic nature of neurons and brain activity. At the same time a long discussion on consciousness among philosophers (...) has resulted in our distinguishing several kinds of consciousness. So when we ask where the place of consciousness is in nature we may mean several different things. In this chapter I will argue that it is plausible that all of the kinds of consciousness turn out to be nothing but patterns of synchronized neural activity in various frequencies against a dynamically changing chemical background. (shrink)

This volume takes the first step toward building the necessary local bridges.

This book is the integrated presentation of a large body of work on understanding the operation of biological brains as systems.

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)

The concept of representation has been a key element in the scientific study of mental processes, ever since such studies commenced. However, usage of the term has been all but too liberal—if one were to adhere to common use it remains unclear if there are examples of physical systems which cannot be construed in terms of representation. The problem is considered afresh, taking as the starting point the notion of activity spaces—spaces of spatiotemporal events produced by dynamical systems. It is (...) argued that representation can be analyzed in terms of the geometrical and topological properties of such spaces. Several attributes and processes associated with conceptual domains, such as logical structure, generalization and learning are considered, and given analogues in structural facets of activity spaces, as are misrepresentation and states of arousal. Based on this analysis, representational systems are defined, as is a key concept associated with such systems, the notion of representational capacity. According to the proposed theory, rather than being an all or none phenomenon, representation is in fact a matter of degree—that is can be associated with measurable quantities, as is behooving of a putative naturalistic construct. (shrink)

A standing challenge for the science of mind is to account for the datum that every mind faces in the most immediate – that is, unmediated – fashion: its phenomenal experience. The complementary tasks of explaining what it means for a system to give rise to experience and what constitutes the content of experience (qualia) in computational terms are particularly challenging, given the multiple realizability of computation. In this paper, we identify a set of conditions that a computational theory must (...) satisfy for it to constitute not just a sufficient but a necessary, and therefore naturalistic and intrinsic, explanation of qualia. We show that a common assumption behind many neurocomputational theories of the mind, according to which mind states can be formalized solely in terms of instantaneous vectors of activities of representational units such as neurons, does not meet the requisite conditions, in part because it relies on inactive units to shape presently experienced qualia and implies a homogeneous representation space, which is devoid of intrinsic structure. We then sketch a naturalistic computational theory of qualia, which posits that experience is realized by dynamical activity-space trajectories (rather than points) and that its richness is measured by the representational capacity of the trajectory space in which it unfolds. (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)

Although several studies propose that the integrity of neuronal assemblies may underlie a phenomenon referred to as awareness, none of the known studies have explicitly investigated dynamics and functional interactions among neuronal assemblies as a function of consciousness expression. In order to address this question EEG operational architectonics analysis (Fingelkurts and Fingelkurts, 2001, 2008) was conducted in patients in minimally conscious (MCS) and vegetative states (VS) to study the dynamics of neuronal assemblies and operational synchrony among them as a function (...) of consciousness expression. We found that in minimally conscious patients and especially in vegetative patients neuronal assemblies got smaller, their life-span shortened and they became highly unstable. Furthermore, we demonstrated that the extent/volume and strength of operational synchrony among neuronal assemblies was smallest or even absent in VS patients, intermediate in MCS patients and highest in healthy fully-conscious subjects. All findings were similarly observed in EEG alpha as well as beta1 and beta2 frequency oscillations. The presented results support the basic tenets of Operational Architectonics theory of brain-mind functioning and suggest that EEG operational architectonics analysis may provide an objective and accurate means of assessing signs of (un)consciousness in patients with severe brain injuries. Therefore this methodological approach may complement the existing “gold standard” of behavioral assessment of this population of challenging patients and inform the diagnostic and treatment decision-making processes. (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 majority of the chapters in this edition of The Cognitive Neurosciences are new, and those from the first edition have been completely rewritten and updated ...

The third edition of a work that defines the field of cognitive neuroscience, with extensive new material including new chapters and new contributors.

A connectionist vehicle theory of consciousness needs to disambiguate its criteria for identifying the relevant vehicles. Moreover, a vehicle theory may appear entirely arbitrary in sorting between what are typically thought of as conscious and unconscious processes.

Various neurophysiological experiments have revealed remarkable correlations between cortical neuronal activity and subjective experiences. However, the mere presence of neuronal electrical activity does not appear to be sufficient to produce these experiences. It has been suggested that the explanation for the neural basis of consciousness might lie in understanding the reason that some types of neuronal activity possess subjective correlates and others do not. Here I propose and develop the idea that this difference may be caused by the existence of (...) an elementary nonarbitrary linkage between temporal or spatiotemporal patterns of neuronal activity and their subjective attributes. I also show how cortical neural circuits capable of generating experience-coding patterns could emerge during evolution and brain development, due to the presence of spontaneous stochastic neuronal activity and activity-dependent synaptic plasticity. This hypothesis leads to several testable predictions, principal among which is the idea that the neural correlates of consciousness are essentially innate and universal. (shrink)

This volume presents a series of studies that expand laws, invariants, and principles of psychophysics beyond its classical domain of sensation.

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)

This book originated at a small and informal workshop held in December of 1992 in Idyllwild, a relatively secluded resort village situated amid forests in the ...

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.

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

A dualistic approach to consciousness is presented that employs Hebbian synaptic dynamics and the basic notion of measurement in science to bridge the so-called explanatory gap between first-person consciousness and third-person science. Unconscious processing by neural circuitry characterizes (i) the neuron as a measuring instrument and (ii) the neural signal as the quantity to be measured. Hebbian synaptic dynamics, effectuating the storage of information, implements the role of an observer of a measurement outcome. The approach extends physical renormalization techniques, as (...) applied to phase changes, to biology. This leads to the proposal of a ramification process in neural systems (brains) from a primitive form of sensation associated with the Hebbian synapse toward more elaborate experiential forms of consciousness (feelings, qualia) associated with hierarchies of neuronal assemblies. Characterizing sensation as a form of mutual information at the synaptic level motivates a relation between consciousness and phase changes of information. (shrink)

In the past, researchers have focused mainly on the effects and consequences of self-awareness; however, they have neglected a more basic issue pertaining to the specific mechanisms that initiate and sustain self-perception. The author presents a model of self-awareness that proposes the existence of 3 sources of self-information. First, the social milieu includes early face-to-face interactions, self-relevant feedback, a social comparison mechanism that leads to perspective taking, and audiences. Second, contacts with objects and structures in the physical environment foster self–world (...) differentiation in infants; this environment also contains self-focusing and reflecting stimuli, such as mirrors and video cameras. Third, the self can develop bodily awareness through proprioception and can reflect on itself using imagery and inner speech. Furthermore, self-awareness is mainly mediated by the prefrontal lobes. The author establishes various links among these different neurological, social, ecological, and cognitive elements of the model. (shrink)

There is a distinction between phenomenal properties and the "phenomenality" of those properties: e.g. between what red is like and what it is like to experience red. To date, reductive accounts explain the former, but not the latter: Nagel is right that they leave something out. This paper attempts a reductive account of what it is like to have a perceptual experience. Four features of such experience are distinguished: the externality, unity, and self-awareness belonging to the content of conscious experience, (...) and the phenomenon of awareness itself. It is argued that these features are accounted for in the work of recent scientists, including F. Crick, G. Edelman, C. Koch and V. Mountcastle. This account reinforces a common way of treating the "knowledge problem.". (shrink)

On the evolution of mind Harry J. Jerison Most of us think of mind as a little person in the head, the 'knower' of reality (cf. Attneave,). ...

At the phenomenal level, consciousness arises in a consistently coherent fashion as a singular, unified field of recursive self-awareness (subjectivity) with explicitly orientational characteristics—that of a subject located both spatially and temporally in an egocentrically-extended domain. Understanding these twin elements of consciousness begins with the recognition that ultimately (and most primitively), cognitive systems serve the biological self-regulatory regime in which they subsist. The psychological structures supporting self-located subjectivity involve an evolutionary elaboration of the two basic elements necessary for extending self-regulation (...) into behavioral interaction with the environment: an orientative reference frame which consistently structures ongoing interaction in terms of controllable spatiotemporal parameters, and processing architecture that relates behavior to homeostatic needs via feedback. Over time, constant evolutionary pressures for energy efficiency have encouraged the emergence of anticipative feedforward processing mechanisms, and the elaboration, at the apex of the sensorimotor processing hierarchy, of self-activating, highly attenuated recursively-feedforward circuitry processing the basic orientational schema independent of external action output. As the primary reference frame of active waking cognition, this recursive self-locational schema processing generates a zone of subjective self-awareness in terms of which it feels like something to be oneself here and now. This is consciousness-as-subjectivity. (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.

This exciting volume brings together the latest work of 26 recognized experts in clinical neuropsychiatry, neuropsychology, neuroscience, and neuroimaging.

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)

It has been shown that visual awareness in the blind hemifield of hemianopic cats that have undergone unilateral ablations of visual cortex can be restored by sectioning the commissure of the superior colliculus or by destroying a portion of the substantia nigra contralateral to the cortical lesion (the Sprague effect). We propose that the visual awareness that is recovered is due to synchronized oscillatory activities in the superior colliculus ipsilateral to the cortical lesion. These oscillatory activities are normally partially suppressed (...) by the inhibitory, GABAergic contralateral nigrotectal projection, and the destruction of the substantia nigra, or the sectioning of the collicular commissure, disinhibits the collicular neurons, causing an increase in the extent of oscillatory activity and/or synchronization between activities at different sites. This increase in the oscillatory and synchronized character is sufficient for the activities to give rise to visual awareness. We argue that in rodents and lower vertebrates, normal visual awareness is partly due to synchronized oscillatory activities in the optic tectum and partly due to similar activities in visual cortex. It is only in carnivores and primates that visual awareness is wholly due to cortical activities. Based on von Baerian recapitulation theory, we propose that, even in humans, there is a period in early infancy when visual awareness is partially due to activities in the superior colliculus, but that this awareness gradually disappears as the nigrotectal projection matures. (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)

This ambitious work apparently has two main aims. The first is to provide a survey of the currently burgeoning field of "Consciousness Studies", presented via the extended metaphor of a horse <span class='Hi'>race</span> whose winning post is a full scientific explanation of consciousness. The second, which receives much more space, is to present Taylor's own cognitive/neuroscientific theory, dubbed "relational consciousness", and to persuade us that it should be the odds-on favourite to win. Neither aim is very well realized.

Over a decade ago, I introduced a large-scale theory of the cognitive brain which explained for the first time how the human brain is able to create internal models of its intimate world and invent models of a wider universe. An essential part of the theoretical model is an organization of neuronal mechanisms which I have named the Retinoid Model (Trehub, 1977, 1991). This hypothesized brain system has structural and dynamic properties enabling it to register and appropriately integrate disparate foveal (...) stimuli into a perspectival, egocentric representation of an extended 3D world scene including a neuronally-tokened locus of the self which, in this theory, is the neuronal origin of retinoid space. As an integral part of the larger neuro-cognitive model, the retinoid system is able to perform many other useful perceptual and higher cognitive functions. In this paper, I draw on the hypothesized properties of this system to argue that neuronal activity within the retinoid structure constitutes the phenomenal content of consciousness and the unique sense of self that each of us experiences. -/- Trehub, A. (1977). Neuronal models for cognitive processes: Networks for learning, perception, and imagination. _Journal of Theoretical Biology_ 65: 141-169. -/- Trehub, A. (1991). _The Cognitive Brain_. MIT Press. -/- . (shrink)

Of all the problems facing science none are more challenging yet fascinating than those posed by consciousness. In The Science of Consciousness leading researchers examine how consciousness is being investigated in the key areas of cognitive psychology, neuropsychology and clinical psychology. Within cognitive psychology, special focus is given to the function of consciousness, and to the relation of conscious processing to nonconscious processing in perception, learning, memory and information dissemination. Neuropsychology includes examination of the neural conditions for consciousness and the (...) effects of brain damage. Finally, mind/body interactions in clinical and experimental settings are considered, including the somatic effects of imagery, biofeedback and placebo effects. Every chapter is written by an expert in the field. They each provide a clear overview of existing research along with an exciting new synthesis of consciousness studies. The The Science of Consciousness will be invaluable for students, researchers and clinicians interested in the developments and directions of this rapidly growing field. (shrink)

The Cambridge Handbook of Consciousness is the first of its kind in the field, and its appearance marks a unique time in the history of intellectual inquiry on the topic. After decades during which consciousness was considered beyond the scope of legitimate scientific investigation, consciousness re-emerged as a popular focus of research towards the end of the last century, and it has remained so for nearly 20 years. There are now so many different lines of investigation on consciousness that the (...) time has come when the field may finally benefit from a book that pulls them together and, by juxtaposing them, provides a comprehensive survey of this exciting field. An authoritative desk reference , which will also be suitable as an advanced textbook. (shrink)