A mathematical apparatus is developed that deals with networks of elements which are connected to each other by well defined connection rules and which perform well defined operations on their inputs. The output of these elements either is transmitted to other elements in the network or – should they be terminal elements – represents the outcome of the computation of the network. The discussion is confined to such rules of connection between elements and their operational modalities as they appear to have anatomical and physiological counter parts in neural tissue. The great latitude given today in the interpretation of nervous activity with regard to what constitutes the “signal” is accounted for by giving the mathematical apparatus the necessary and sufficient latitude to cope with various interpretations. Special attention is given to a mathematical formulation of structural and functional properties of networks that compute invariants in the distribution of their stimuli.

The branch of semiotics called semantics deals with the relation between meanings and representations, widely known as the symbol grounding problem. The other branches of semiotics, syntactics which deals with symbol–symbol relations as in a dictionary, and pragmatics which deals with symbol-action paradigms as in traffic signs, are well done by computers, but semantics has eluded computer simulation. In my view, this is because computer programmers have neglected that aspect of Shannon’s definition by which information has no meaning; computers process information, whereas brains create meaning. Brains obtain information about the world through the consequences of their own embodied actions. The information thus obtained is used in constructing meaning and is then discarded. One kind of information in the world consists of representations made by other brains for social communication. Computers use representations for information processing and symbol manipulation. However, brains have no internal representations. They deploy dynamic neural operators in the form of activity patterns, which constitute and implement meaning but not information, so that the problem of symbol grounding does not arise. Brains construct external representations in the form of material objects or movements as their means for expressing their internal states of meaning, such as words, books, paintings, and music, as well as facial expressions and gestures in animals and humans, but even though those material objects are made with the intent to elicit meaning in other brains, they have no meanings in themselves and do not carry meanings as if they were buckets or placards. Meanings can only exist in brains, because each meaning expresses the entire history and experience of an individual. It is an activity pattern that occupies the entire available brain, constituting a location in the intentional structure of a brain. It is the limited sharing of meanings between brains for social purposes that requires reciprocal exchanges of representations, each presentation by a transmitting brain inducing the construction of new meaning in the receiving brain. EEG data indicate that neural patterns of meanings in each brain occur in trajectories of discrete steps, which are demarcated by first-order state transitions that enable formation of spatiotemporal patterns of spatially coherent oscillations. Amplitude modulation is the mode of expressing meanings. These wave packets do not represent external objects; they embody and implement the meanings of objects for each individual, in terms of what they portend for the future of that individual, and what that individual should do with and about them.

A free-energy principle has been proposed recently that accounts for action, perception and learning. This review looks at some key brain theories in the biological (for example, neural Darwinism) and physical (for example, information theory and optimal control theory) sciences from the free-energy perspective. Crucially, one key theme runs through each of these theories – optimization. Furthermore, if we look closely at what is optimized, the same quantity keeps emerging, namely value (expected reward, expected utility) or its complement, surprise (prediction error, expected cost). This is the quantity that is optimized under the free-energy principle, which suggests that several global brain theories might be unified within a free-energy framework.

Purpose of review To survey recent developments in phenomenological psychopathology. Recent findings We present the concept of embodiment as a key paradigm of recent interdisciplinary approaches from the areas of philosophy, psychology, psychiatry and neuroscience. This requires a short overview on the phenomenological concept of embodiment; in particular, on the distinction of subject and object body. A psychopathology of embodiment may be based on these and other distinctions, in particular on a polarity of disembodiment and hyperembodiment, which is illustrated by the examples of schizophrenia and depression. Recent contributions to phenomenological accounts of these disorders are presented. Finally, the study discusses the relationship of phenomenological and neuropsychiatric perspectives on embodiment. Summary A phenomenology of embodiment may be combined with enactive approaches to cognitive neuroscience in order to overcome dualist concepts of the mind as an inner realm of representations that mirror the outside world. Phenomenological and ecological concepts of embodiment should also be conjoined to enable a new, advanced understanding of mental illness.

Key words: depression, embodiment, enactive cognitive science, phenomenology, psychopathology, schizophrenia

We distinguish between three philosophical views on the neuroscience of predictive models: predictive coding (associated with internal Bayesian models and prediction error minimization), predictive processing (associated with radical connectionism and ‘simple’ embodiment) and predictive engagement (associated with enactivist approaches to cognition). We examine the concept of active inference under each model and then ask how this concept informs discussions of social cognition. In this context we consider Frith and Friston’s proposal for a neural hermeneutics, and we explore the alternative model of enactivist hermeneutics.

Key words: Predictive coding, free energy principle, active inference, social cognition, enactivism, hermeneutics.

The notion of an enactive system requires thinking about the brain in a way that is different from the standard computationalrepresentational models. In evolutionary terms, the brain does what it does and is the way that it is, across some scale of variations, because it is part of a living body with hands that can reach and grasp in certain limited ways, eyes structured to focus, an autonomic system, an upright posture, etc. coping with specific kinds of environments, and with other people. Changes to any of the bodily, environmental, or intersubjective conditions elicit responses from the system as a whole. On this view, rather than representing or computing information, the brain is better conceived as participating in the action.

Recent advances in brain imaging have improved the measure of neural processes related to perceptual, cognitive and affective functions, yet the relation between brain activity and subjective experience remains poorly characterized. In part, it is a challenge to obtain reliable accounts of participant’s experience in such studies. Here we addressed this limitation by utilizing experienced meditators who are expert in introspection. We tested a novel method to link objective and subjective data, using real-time fMRI (rt-fMRI) to provide participants with feedback of their own brain activity during an ongoing task. We provided real-time feedback during a focused attention task from the posterior cingulate cortex, a hub of the default mode network shown to be activated during mind-wandering and deactivated during meditation. In a first experiment, both meditators and non-meditators reported significant correspondence between the feedback graph and their subjective experience of focused attention and mind-wandering. When instructed to volitionally decrease the feedback graph, meditators, but not non-meditators, showed significant deactivation of the posterior cingulate cortex. We were able to replicate these results in a separate group of meditators using a novel step-wise rt-fMRI discovery protocol in which participants were not provided with prior knowledge of the expected relationship between their experience and the feedback graph (i.e., focused attention versus mind-wandering). These findings support the feasibility of using rt-fMRI to link objective measures of brain activity with reports of ongoing subjective experience in cognitive neuroscience research, and demonstrate the generalization of expertise in introspective awareness to novel contexts.

Key words: Real-time neurofeedback, Real-time fMRI, Focused attention, Posterior cingulate cortex, Default mode network, Meditation

One of the central questions of present-day philosophy concerns the link between “language” and “world.” The aim of this essay is to question this link and its assumptions and to develop a non-dualistic view within the context of “virtual reality.” The utility of such a non-dualism is demonstrated in an interdisciplinary discourse in the context of the epistemology of radical constructivism, in the context of current reflection on “consciousness,” and in the context of the neuroscientific and philosophical question of how it is possible that the on/off-principle of neurones conveys “consciousness of something.”

Open peer commentary on the target article “How and Why the Brain Lays the Foundations for a Conscious Self” by Martin V. Butz. Excerpt: I feel that the use of terms such as “code,” “information,” and “symbol” for neural constellations that are not further described defeats the intention of the analysis presented because unless these terms are explicitly given specific neurobiological definitions they inevitably suggest the presence of a consciously reflecting agent.