Cognitive functions like perception, memory, language, or consciousness are based on highly parallel and distributed information processing by the brain. One of the major unresolved questions is how information can be integrated and how coherent representational states can be established in the distributed neuronal systems subserving these functions. It has been suggested that this so-called ''binding problem'' may be solved in the temporal domain. The hypothesis is that synchronization of neuronal discharges can serve for the integration of distributed neurons into (...) cell assemblies and that this process may underlie the selection of perceptually and behaviorally relevant information. As we intend to show here, this temporal binding hypothesis has implications for the search of the neural correlate of consciousness. We review experimental results, mainly obtained in the visual system, which support the notion of temporal binding. In particular, we discuss recent experiments on the neural mechanisms of binocular rivalry which suggest that appropriate synchronization among cortical neurons may be one of the necessary conditions for the buildup of perceptual states and awareness of sensory stimuli. (shrink)

Laboratoire de Neurosciences Cognitives et Imagerie Ce´re´brale (LENA), Hoˆpital de La Salpeˆtrie`re, Centre National de la Recherche Scientifique (CNRS).

cal basis of consciousness. We continue by discussing the relation between spatiotem- One of the outstanding problems in the cog- poral patterns of brain activity and con- nitive sciences is to understand how ongo- sciousness, with particular attention to pro- ing conscious experience is related to the cesses in the gamma frequency band. We workings of the brain and nervous system. then adopt a critical perspective and high-.

If one looks at the current discussion of self-awareness there seems to be a general agreement that whatever valuable philosophical contributions Husserl might have made, his account of self-awareness is not among them. This prevalent appraisal is often based on the claim that Husserl was too occupied with the problem of intentionality to ever really pay attention to the issue of self-awareness. Due to his interest in intentionality Husserl took object-consciousness as the paradigm of every kind of awareness and therefore (...) settled with a model of self-awareness based upon the subject-object dichotomy, with its entailed difference between the intending and the intended. As a consequence, Husserl never discovered the existence of pre-reflective self- awareness, but remained stuck in the traditional, but highly problematic reflection model of self-awareness. (shrink)

This paper responds to the issues raised by D. Chalmers by offering a research direction which is quite radical because of the way in which methodological principles are linked to scientific studies of consciousness. Neuro-phenomenology is the name I use here to designate a quest to marry modern cognitive science and a disciplined approach to human experience, thereby placing myself in the lineage of the continental tradition of Phenomenology. My claim is that the so-called hard problem that animates these Special (...) Issues can only be addressed productively by gathering a research community armed with new pragmatic tools for the development of a science of consciousness. I will claim that no piecemeal empirical correlates, nor purely theoretical principles, will really help us at this stage. We need to turn to a systematic exploration of the only link between mind and consciousness that seems both obvious and natural: the structure of human experience itself. In what follows I motivate my choice by briefly examining the current debate about consciousness at the light of Chalmer’s hard problem. Next, I outline the phenomenological strategy. Finally I conclude by discussing some of the main difficulties and consequences of this strategy. (shrink)

The paper presents a research programme for the neuroscience of consciousness called 'neurophenomenology' and illustrates it with a recent pilot study . At a theoretical level, neurophenomenology pursues an embodied and large-scale dynamical approach to the neurophysiology of consciousness . At a methodological level, the neurophenomenological strategy is to make rigorous and extensive use of first-person data about subjective experience as a heuristic to describe and quantify the large-scale neurodynamics of consciousness . The paper focuses on neurophenomenology in relation to (...) three challenging methodological issues about incorporating first-person data into cognitive neuroscience: first-person reports can be biased or inaccurate; the process of generating first-person reports about an experience can modify that experience; and there is an 'explanatory gap' in our understanding of how to relate first-person, phenomenological data to third-person, biobehavioural data. (shrink)

Cognitive science has wholeheartedly embraced functional brain imaging, but introspective data are still eschewed to the extent that it runs against standard practice to engage in the systematic collection of introspective reports. However, in the case of executive processes associated with prefrontal cortex, imaging has made limited progress, whereas introspective methods have considerable unfulfilled potential. We argue for a re-evaluation of the standard ‘cognitive mapping’ paradigm, emphasizing the use of retrospective reports alongside behavioural and brain imaging techniques. Using all three (...) sources of evidence can compensate for their individual limitations, and so triangulate on higher cognitive processes. (shrink)

Traditional explanations of multistable visual phenomena (e.g. ambiguous figures, perceptual rivalry) suggest that the basis for spontaneous reversals in perception lies in antagonistic connectivity within the visual system. In this review, we suggest an alternative, albeit speculative, explanation for visual multistability – that spontaneous alternations reflect responses to active, programmed events initiated by brain areas that integrate sensory and non-sensory information to coordinate a diversity of behaviors. Much evidence suggests that perceptual reversals are themselves more closely related to the expression (...) of a behavior than to passive sensory responses: (1) they are initiated spontaneously, often voluntarily, and are influenced by subjective variables such as attention and mood; (2) the alternation process is greatly facilitated with practice and compromised by lesions in non-visual cortical areas; (3) the alternation process has temporal dynamics similar to those of spontaneously initiated behaviors; (4) functional imaging reveals that brain areas associated with a variety of cognitive behaviors are specifically activated when vision becomes unstable. In this scheme, reorganizations of activity throughout the visual cortex, concurrent with perceptual reversals, are initiated by higher, largely non-sensory brain centers. Such direct intervention in the processing of the sensory input by brain structures associated with planning and motor programming might serve an important role in perceptual organization, particularly in aspects related to selective attention. (shrink)

& Functional brain imaging offers new opportunities for the begin with single-subject (preprocessed) scan series, and study of that most pervasive of cognitive conditions, human consider the patterns of all voxels as potential multivariate consciousness. Since consciousness is attendant to so much encodings of phenomenal information. Twenty-seven subjects of human cognitive life, its study requires secondary analysis from the four studies were analyzed with multivariate of multiple experimental datasets. Here, four preprocessed methods, revealing analogues of phenomenal structures, datasets from the (...) National fMRI Data Center are considered: particularly the structures of temporality. In a second Hazeltine et al., Neural activation during response competi- interpretive approach, artificial neural networks were used tion; Ishai et al., The representation of objects in the human to detect a more explicit prediction from phenomenology, occipital and temporal cortex; Mechelli et al., The effects of namely, that present experience contains and is inflected by presentation rate during word and pseudoword reading; and past states of awareness and anticipated events. In all of 21 Postle et al., Activity in human frontal cortex associated with subjects in this analysis, nets were successfully trained to spatial working memory and saccadic behavior. The study of extract aspects of relative past and future brain states, in consciousness also draws from multiple disciplines. In this comparison with statistically similar controls. This exploratory article, the philosophical subdiscipline of phenomenology study thus concludes that the proposed methods for provides initial characterization of phenomenal structures ‘‘neurophenomenology’’ warrant further application, includ- conceptually necessary for an analysis of consciousness. These ing the exploration of individual differences, multivariate structures include phenomenal intentionality, phenomenal differences between cognitive task conditions, and explora- superposition, and experienced temporality.. (shrink)

I think, therefore I am. The legendary pronouncement of philosopher René Descartes lingers as accepted wisdom in the Western world nearly four centuries after its author's death. But does thought really come first? Who actually runs the show: we, our thoughts, or the neurons firing within our brains? Walter J. Freeman explores how we control our behavior and make sense of the world around us. Avoiding determinism both in sociobiology, which proposes that persons' genes control their brains' functioning, and in (...) neuroscience, which posits that their brains' disposition is molded by chemistry and environmental forces, Freeman charts a new course--one that gives individuals due credit and responsibility for their actions. Drawing upon his five decades of research in neuroscience, Freeman utilizes the latest advances in his field as well as perspectives from disciplines as diverse as mathematics, psychology, and philosophy to explicate how different human brains act in their chosen diverse ways. He clarifies the implications of brain imaging, by which neural activity can be observed during the course of normal movements, and shows how nonlinear dynamics reveals order within the fecund chaos of brain function. (shrink)

It is now conventional wisdom that conscious experience — or in Nagel’s canonical characterization, “what it is like to be” for an organism — is what makes the mind-body problem so intractable. By the same token, our current conceptions of the mind-body relation are inadequate and some conceptual development is urgently needed. Our overall aim in this paper is to make some progress towards that conceptual development. We first examine a currently neglected, yet fundamental aspect of consciousness. This aspect is (...) the spontaneity of consciousness, by which we mean its inner plasticity and inner purposiveness. We then sketch a “neurophenomenological” framework for thinking about the relationship between the spontaneity of consciousness and dynamic patterns of brain activity as studied in cognitive neuroscience. We conclude by proposing that the conscious mentality of sentient organisms or animals is active and dynamic, and that this “enactive” conception of consciousness can help us to move beyond the classical dichotomy between materialism and dualism. (shrink)

The quantification of phase synchrony between neuronal signals is of crucial importance for the study of large-scale interactions in the brain. Two methods have been used to date in neuroscience, based on two distinct approaches which permit a direct estimation of the instantaneous phase of a signal [Phys. Rev. Lett. 81 (1998) 3291; Human Brain Mapping 8 (1999) 194]. The phase is either estimated by using the analytic concept of Hilbert transform or, alternatively, by convolution with a complex wavelet. In (...) both methods the stability of the instantaneous phase over a window of time requires quantification by means of various statistical dependence parameters (standard deviation, Shannon entropy or mutual information). The purpose of this paper is to conduct a direct comparison between these two methods on three signal sets: (1) neural models; (2) intracranial signals from epileptic patients; and (3) scalp EEG recordings. Levels of synchrony that can be considered as reliable are estimated by using the technique of surrogate data. Our results demonstrate that the differences between the methods are minor, and we conclude that they are fundamentally equivalent for the study of neuroelectrical signals. This offers a common language and framework that can be used for future research in the area of synchronization. © 2001 Published by Elsevier Science B.V. (shrink)

The subjective experience of time is a fundamental constituent of human consciousness and can be disturbed under conditions of mental disorders such as schizophrenia or affective disorders. Besides the scientific domain of psychiatry, time consciousness is a topic that has been extensively studied both by theoretical philosophy and cognitive neuroscience. It can be shown that both approaches exemplified by the philosophical analysis of time consciousness and the neuroscientific theory of cross-temporal contingencies as the neurophysiological basis of human consciousness implemented in (...) the prefrontal cortex converge in 2 respects. Firstly, a tripartite conception of consciousness divides human cognition in 3 different temporal domains comprising retention, presentation, and protention and the past, the present, and the future corresponding to working memory, interference control, and preparatory set. Secondly, both concepts refer to the present as an extended duration that integrates information from the recent past and the future. We propose that the integration of phenomenological and neuroscientific approaches can stimulate the development of enriched pathophysiological concepts of mental disorders. This approach appears to be particularly fruitful with respect to schizophrenia that is interpreted as a structural disturbance of time consciousness. (shrink)