Cognitive neuroscience investigations of self-experience have mainly focused on the mental attribution of features to the self (self-related processing). In this paper, we highlight another fundamental, yet neglected, aspect of self-experience, that of being an agent. We propose that this aspect of self-experience depends on self-specifying processes, ones that implicitly specify the self by implementing a functional self/non-self distinction in perception, action, cognition and emotion. We describe two paradigmatic cases – sensorimotor integration and homeostatic regulation – and use the principles from these cases to show how cognitive control, including emotion regulation, is also self-specifying. We argue that externally directed, attention-demanding tasks, rather than suppressing self-experience, give rise to the self-experience of being a cognitive-affective agent. We conclude with directions for experimental work based on our framework.

Binocular rivalry provides a useful situation for studying the relation between the temporal flow of conscious experience and the temporal dynamics of neural activity. After proposing a phenomenological framework for understanding temporal aspects of consciousness, we review experimental research on multistable perception and binocular rivalry, singling out various methodological, theoretical, and empirical aspects of this research relevant to studying the flow of experience. We then review an experimental study from our group explicitly concerned with relating the temporal dynamics of rivalrous experience to the temporal dynamics of cortical activity. Drawing attention to the importance of dealing with ongoing activity and its inherent changing nature at both phenomenological and neurodynamical levels, we argue that the notions of recurrence and variability are pertinent to understanding rivalry in particular and the flow of experience in general.

This chapter discusses the brain-in-a-vat thought experiment and attempts to determine what needs to be specified so that one can properly imagine a brain in a vat. Daniel Dennett notes that philosophers often fail to set up their intuition pumps properly by failing to think carefully about the requirements and implications of their imagined scenarios. His suggestion is considered here and a careful look at the brain-in-a-vat thought experiment is proposed. The chapter puts the thought experiment to new use, namely, to address the biology of consciousness and to develop some new considerations in support of the enactive approach in cognitive science. Its main argument is that the brain-in-vat thought experiment, when spelled out with the requisite detail, suggests precisely that the body is not merely causally enabling for consciousness, but also constitutive.

Key words: thought experiment, Daniel Dennett, intuition pumps, biology of consciousness, enactive approach

We present here ongoing patterns of distributed brain synchronous activity that correlate with the spontaneous flow of perceptual dominance during binocular rivalry. Specific modulation of the magnetoencephalographic (MEG) response evoked during conscious perception of a frequency-tagged stimulus was evidenced throughout rivalry. Estimation of the underlying cortical sources revealed, in addition to strong bilateral striate and extrastriate visual cortex activation, parietal, temporal pole and frontal contributions. Cortical activity was significantly modulated concomitantly to perceptual alternations in visual cortex, medial parietal and left frontal regions. Upon dominance, coactivation of occipital and frontal regions, including anterior cingulate and medial frontal areas, was established. This distributed cortical network, as measured by phase synchrony in the frequency tag band, was dynamically modulated in concert with the perceptual dominance of the tagged stimulus. While the anteroposterior pattern was recurrent through subjects, individual variations in the extension of the network were apparent.

Key words: binocular rivalry, cortical activity, perceptual dominance.

One of the outstanding problems in the cognitive sciences is to understand how ongoing conscious experience is related to the workings of the brain and nervous system. Neurodynamics offers a powerful approach to this problem because it provides a coherent framework for investigating change, variability, complex spatiotemporal patterns of activity, and multiscale processes (among others). In this chapter, we advocate a neurodynamical approach to consciousness that integrates mathematical tools of analysis and modeling, sophisticated physiological data recordings, and detailed phenomenological descriptions. We begin by stating the basic intuition: Consciousness is an intrinsically dynamic phenomenon and must therefore be studied within a framework that is capable of rendering its dynamics intelligible. We then discuss some of the formal, analytical features of dynamical systems theory, with particular reference to neurodynamics. We then review several neuroscientific proposals that make use of dynamical systems theory in characterizing the neurophysiological basis of consciousness. We continue by discussing the relation between spatiotemporal patterns of brain activity and consciousness, with particular attention to processes in the gamma frequency band. We then adopt a critical perspective and highlight a number of issues demanding further treatment. Finally, we close the chapter by discussing how phenomenological data can relate to and ultimately constrain neurodynamical descriptions, with the long-term aim being to go beyond a purely correlational strategy of research.

Key words: Consciousness, neurodynamics, dynamical system theory, complex brain patterns, large-scale integration, gamma band, phase synchrony, phenomenological descriptions.

There is a growing interest in elucidating the role of specific patterns of neural dynamics-such as transient synchronization between distant cell assemblies-in brain functions. Magnetoencephalography (MEG)/electroencephalography (EEG) recordings consist in the spatial integration of the activity from large and multiple remotely located populations of neurons. Massive diffusive effects and poor signal-to-noise ratio (SNR) preclude the proper estimation of indices related to cortical dynamics from nonaveraged MEG/EEG surface recordings. Source localization from MEG/EEG surface recordings with its excellent time resolution could contribute to a better understanding of the working brain. We propose a robust and original approach to the MEG/EEG distributed inverse problem to better estimate neural dynamics of cortical sources. For this, the surrogate data method is introduced in the MEG/EEG inverse problem framework. We apply this approach on nonaveraged data with poor SNR using the minimum norm estimator and find source localization results weakly sensitive to noise. Surrogates allow the reduction of the source space in order to reconstruct MEG/EEG data with reduced biases in both source localization and time-series dynamics. Monte Carlo simulations and results obtained from real MEG data indicate it is possible to estimate noninvasively an important part of cortical source locations and dynamic and, therefore, to reveal brain functional networks.

This paper introduces the use of wavelet analysis to follow the temporal variations in the coupling between oscillatory neural signals. Coherence, based on Fourier analysis, has been commonly used as a first approximation to track such coupling under the assumption that neural signals are stationary. Yet, stationary neural processing may be the exception rather than the rule. In this context, the recent application to physical systems of a wavelet-based coherence, which does not depend on the stationarity of the signals, is highly relevant. This paper fully develops the method of wavelet coherence and its statistical properties so that it can be practically applied to continuous neural signals. In realistic simulations, we show that, in contrast to Fourier coherence, wavelet coherence can detect short, significant episodes of coherence between non-stationary neural signals. This method can be directly applied for an ‘online’ quantification of the instantaneous coherence between two signals.

Key words: wavelet, coherence, synchrony, EEG, LFP

Francisco Varela’s original approach to this “hard problem” presents a subjectivity that is radically intertwined with its biological and physical roots. It must be understood within the framework of his theory of a concrete, embodied dynamics, grounded in his general theory of autonomous systems. Through concepts and paradigms such as biological autonomy, embodiment and neurophenomenology, the article explores the multiple levels of circular causality assumed by Varela to play a fundamental role in the emergence of human experience. The concept of biological autonomy provides the necessary and sufficient conditions for characterizing biological life and identity as an emergent and circular self-producing process. Embodiment provides a systemic and dynamical framework for understanding how a cognitive entity – a mind – can arise in an organism in the midst of its operational cycles of internal regulation and ongoing sensorimotor coupling. Global subjective properties can emerge at different levels from the interactions of components and can reciprocally constrain local processes through an ongoing, recursive morphodynamics. Neurophenomenology is a supplementary step in the study of consciousness. Through a rigorous method, it advocates the careful examination of experience with first-person methodologies. It attempts to create heuristic mutual constraints between biophysical data and data produced by accounts of subjective experience. The aim is to explicitly ground the active and disciplined insight the subject has about his/her experience in a biophysical emergent process. Finally, we discuss Varela’s essential contribution to our understanding of the generation of consciousness in the framework of what we call his “biophysics of being.” Relevance: This paper reviews in detail Francisco Varela’s work on subjectivity and consciousness in the biological sciences.

We argue that the minimal biological requirements for consciousness include a living body, not just neuronal processes in the skull. Our argument proceeds by reconsidering the brain-in-a-vat thought experiment. Careful examination of this thought experiment indicates that the null hypothesis is that any adequately functional “vat” would be a surrogate body, that is, that the so-called vat would be no vat at all, but rather an embodied agent in the world. Thus, what the thought experiment actually shows is that the brain and body are so deeply entangled, structurally and dynamically, that they are explanatorily inseparable. Such entanglement implies that we cannot understand consciousness by considering only the activity of neurons apart from the body, and hence we have good explanatory grounds for supposing that the minimal realizing system for consciousness includes the body and not just the brain. In this way, we put the brain-in-a-vat thought experiment to a new use, one that supports the “enactive” view that consciousness is a life-regulation process of the whole organism interacting with its environment.

One of the major challenges facing neuroscience today is to provide an explanatory framework that accounts for both the subjectivity and neurobiology of consciousness. Although neuroscientists have supplied neural models of various aspects of consciousness, and have uncovered evidence about the neural correlates of consciousness (or NCCs), there nonetheless remains an ‘explanatory gap’ in our understanding of how to relate neurobiological and phenomenological features of consciousness. […] Neurophenomenology is a neuroscientific research program whose aim is to make progress on these issues associated with the explanatory gap. In this paper we give an overview of the neurophenomenological approach to the study of consciousness.