One of the main aspects of a neurobiological theory of language is the problem of meaning (or semantic content) in the brain. A full explanation of meaning requires a combined approach to semantic typing and the semantic success of cerebral states or processes. Pulvermüller presents his Hebbian model of language in the brain (HML) as an account of semantic success. If his proposal turns out to be viable, however, it may also promote a theory of semantic typing.

Stable neuronal assemblies are generally regarded as neural correlates of mental representations. Their temporal sequence corresponds to the experience of a direction of time, sometimes called the psychological time arrow. We show that the stability of particular, biophysically motivated models of neuronal assemblies, called coupled map lattices, is supported by causal interactions among neurons and obstructed by non-causal or anti-causal interactions among neurons. This surprising relation between causality and stability suggests that those neuronal assemblies (...) that are stable due to causal neuronal interactions, and thus correlated with mental representations, generate a psychological time arrow. Yet this impact of causal interactions among neurons on the directed sequence of mental representations does not rule out the possibility of mentally less efficacious non-causal or anti-causal interactions among neurons. (shrink)

Neurophenomenology (Varela 1996) is not only philosophical but also empirical and experimental. Our purpose in this article is to illustrate concretely the efficiency of this approach in the field of neuroscience and, more precisely here, in epileptology. A number of recent observations have indicated that epileptic seizures do not arise suddenly simply as the effect of random fluctuations of brain activity, but require a process of pre-seizure changes that start long before. This has been reported at two different levels of (...) description: on the one hand, the epileptic patient often experiences some warning symptoms that precede seizures from several minutes to hours in the form of very specific lived events. On the other hand, the analyses of brain electrical activities have provided strong evidence that it is possible to detect a pre-seizure state in the neuronal dynamics several minutes before the electro-clinical onset of a seizure. We review here some of the ongoing work of our research group concerning seizure anticipation. In particular, we discuss experimental evidence of upward (local-to-global) formation of conscious experience and its neural substrate, but also of the downward (global-to-local) determination of local neuronal activity by situated conscious activity and its substrate large-scale neural assemblies. This causal role of conscious experience may lead to new kinds of therapy for epileptic patients. (shrink)

The cell assembly model of language posits that words are laid down in the cortex by discrete sets of neurons distributed over specific parts of the brain. The strong internal links of these “word webs” may not only bind articulatory and acoustic knowledge of a lexical item, they may also link word and meaning; for example, by connecting neuron populations related to word forms to those of actions and perceptions to which the words refer. Therefore, the cortical activation elicited by (...) words should reflect aspects of word meaning, a postulate that has received strong support from recent work using neurophysiological and metabolic imaging. Segalowitz & Lane make the point that this neurobiological model can also be used to predict reaction times in behavioral experiments, using the behavioral distinction between content and function words as an example. We acclaim their view, but warn that response times might be related to different mechanisms at the neuronal level, including the cortical distribution and internal connectivity of cell assemblies along with their mutual connections in the grammatical (syntactic and semantic) network. (shrink)

The evolutionary origin of synapses and neurons is an enigmatic subject that inspires much debate. Non-bilaterian metazoans, both with and without neurons and their closest relatives already contain many components of the molecular toolkits for synapse functions. The origin of these components and their assembly into ancient synaptic signaling machineries are particularly important in light of recent findings on the phylogeny of non-bilaterian metazoans. The evolution of synapses and neurons are often discussed only from a metazoan perspective leaving a considerable (...) gap in our understanding. By taking an integrative approach we highlight the need to consider different, but extremely relevant phyla and to include the closest unicellular relatives of metazoans, the ichthyosporeans, filastereans and choanoflagellates, to fully understand the evolutionary origin of synapses and neurons. This approach allows for a detailed understanding of when and how the first pre- and postsynaptic signaling machineries evolved. The evolutionary origin of synapses and neurons is an enigmatic subject that inspires much debate. Most of our knowledge and recent discussions are biased towards a metazoan perspective, leaving a considerable gap in our understanding. Recent work has now revealed important insights into the emergence and co-regulation of complex synaptic signaling machineries from studies in the closest unicellular relatives of metazoans. (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)

This article provides a retrospective, current and prospective overview on developments in brain research and neuroscience. Both theoretical and empirical studies are considered, with emphasis in the concept of multivariability and metastability in the brain. In this new view on the human brain, the potential multivariability of the neuronal networks appears to be far from continuous in time, but confined by the dynamics of short-term local and global metastable brain states. The article closes by suggesting some of the implications (...) of this view in future multidisciplinary brain research. (shrink)

Unresponsive wakefulness syndrome (UWS, previously known as vegetative state) occurs after patients survive a severe brain injury. Patients suffering from UWS have lost awareness of themselves and of the external environment and do not retain any trace of their subjective experience. Current data demonstrate that neuronal functions subtending consciousness are not completely reset in UWS; however, they are reduced below the threshold required to experience consciousness. The critical factor that determines whether patients will recover consciousness is the distance of (...) their neuronal functions from this threshold level. Recovery of consciousness occurs through functional and/or structural changes in the brain, i.e., through neuronal plasticity. Although some of these changes may occur spontaneously, a growing body of evidence indicates that rehabilitative interventions can improve functional outcome by promoting adaptive functional and structural plasticity in the brain, especially if a comprehensive neurophysiological theory of consciousness is followed. In this review we will focus on the pathophysiological mechanisms involved in UWS and on the plastic changes operating on the recovery of consciousness. (shrink)

In this paper we discuss the issue of the processes potentially underlying the emergence of emotional consciousness in the light of theoretical considerations and empirical evidence. First, we argue that componential emotion models, and specifically the Component Process Model , may be better able to account for the emergence of feelings than basic emotion or dimensional models. Second, we advance the hypothesis that consciousness of emotional reactions emerges when lower levels of processing are not sufficient to cope with the event (...) and regulate the emotional process, particularly when the degree of synchronization between the components reaches a critical level and duration. Third, we review recent neuroscience evidence that bolsters our claim of the central importance of the synchronization of neuronal assemblies at different levels of processing. (shrink)

In contemporary human brain mapping, it is commonly assumed that the “mind is what the brain does”. Based on that assumption, task-based imaging studies of the last three decades measured differences in brain activity that are thought to reflect the exercise of human mental capacities (e.g., perception, attention, memory). With the advancement of resting state studies, tractography and graph theory in the last decade, however, it became possible to study human brain connectivity without relying on cognitive tasks or constructs. It (...) therefore is currently an open question whether the assumption that “the mind is what the brain does” is an indispensable working hypothesis in human brain mapping. This paper argues that the hypothesis is, in fact, dispensable. If it is dropped, researchers can “meet the brain on its own terms” by searching for new, more adequate concepts to describe human brain organization. Neuroscientists can establish such concepts by conducting exploratory experiments that do not test particular cognitive hypotheses. The paper provides a systematic account of exploratory neuroscientific research that would allow researchers to form new concepts and formulate general principles of brain connectivity, and to combine connectivity studies with manipulation methods to identify neural entities in the brain. These research strategies would be most fruitful if applied to the mesoscopic scale of neuronal assemblies, since the organizational principles at this scale are currently largely unknown. This could help researchers to link microscopic and macroscopic evidence to provide a more comprehensive understanding of the human brain. The paper concludes by comparing this account of exploratory neuroscientific experiments to recent proposals for large-scale, discovery-based studies of human brain connectivity. (shrink)

We introduce the notion of complexity, first at an intuitive level and then in relatively more concrete terms, explaining the various characteristic features of complex systems with examples. There exists a vast literature on complexity, and our exposition is intended to be an elementary introduction, meant for a broad audience. -/- Briefly, a complex system is one whose description involves a hierarchy of levels, where each level is made of a large number of components interacting among themselves. The time evolution (...) of such a system is of a complex nature, depending on the interactions among subsystems in the next level below the one under consideration and, at the same time, conditioned by the level above, where the latter sets the context for the evolution. Generally speaking, the interactions among the constituents of the various levels lead to a dynamics characterized by numerous characteristic scales, each level having its own set of scales. What is more, a level commonly exhibits ‘emergent properties’ that cannot be derived from considerations relating to its component systems taken in isolation or to those in a different contextual setting. In the dynamic evolution of some particular level, there occurs a self-organized emergence of a higher level and the process is repeated at still higher levels. -/- The interaction and self-organization of the components of a complex system follow the principle commonly expressed by saying that the ‘whole is different from the sum of the parts’. In the case of systems whose behavior can be expressed mathematically in terms of differential equations this means that the interactions are nonlinear in nature. -/- While all of the above features are not universally exhibited by complex systems, these are nevertheless indicative of a broad commonness relative to which individual systems can be described and analyzed. There exist measures of complexity which, once again, are not of universal applicability, being more heuristic than exact. The present state of knowledge and understanding of complex systems is itself an emerging one. Still, a large number of results on various systems can be related to their complex character, making complexity an immensely fertile concept in the study of natural, biological, and social phenomena. -/- All this puts a very definite limitation on the complete description of a complex system as a whole since such a system can be precisely described only contextually, relative to some particular level, where emergent properties rule out an exact description of more than one levels within a common framework. -/- We discuss the implications of these observations in the context of our conception of the so-called noumenal reality that has a mind-independent existence and is perceived by us in the form of the phenomenal reality. The latter is derived from the former by means of our perceptions and interpretations, and our efforts at sorting out and making sense of the bewildering complexity of reality takes the form of incessant processes of inference that lead to theories. Strictly speaking, theories apply to models that are constructed as idealized versions of parts of reality, within which inferences and abstractions can be carried out meaningfully, enabling us to construct the theories. -/- There exists a correspondence between the phenomenal and the noumenal realities in terms of events and their correlations, where these are experienced as the complex behavior of systems or entities of various descriptions. The infinite diversity of behavior of systems in the phenomenal world are explained within specified contexts by theories. The latter are constructs generated in our ceaseless attempts at interpreting the world, and the question arises as to whether these are reflections of `laws of nature' residing in the noumenal world. This is a fundamental concern of scientific realism, within the fold of which there exists a trend towards the assumption that theories express truths about the noumenal reality. We examine this assumption (referred to as a ‘point of view’ in the present essay) closely and indicate that an alternative point of view is also consistent within the broad framework of scientific realism. This is the view that theories are domain-specific and contextual, and that these are arrived at by independent processes of inference and abstractions in the various domains of experience. Theories in contiguous domains of experience dovetail and interpenetrate with one another, and bear the responsibility of correctly explaining our observations within these domains. -/- With accumulating experience, theories get revised and the network of our theories of the world acquires a complex structure, exhibiting a complex evolution. There exists a tendency within the fold of scientific realism of interpreting this complex evolution in rather simple terms, where one assumes (this, again, is a point of view) that theories tend more and more closely to truths about Nature and, what is more, progress towards an all-embracing ‘ultimate theory’ -- a foundational one in respect of all our inquiries into nature. We examine this point of view closely and outline the alternative view -- one broadly consistent with scientific realism -- that there is no ‘ultimate’ law of nature, that theories do not correspond to truths inherent in reality, and that successive revisions in theory do not lead monotonically to some ultimate truth. Instead, the theories generated in succession are incommensurate with each other, testifying to the fact that a theory gives us a perspective view of some part of reality, arrived at contextually. Instead of resembling a monotonically converging series successive theories are analogous to asymptotic series. -/- Before we summarize all the above considerations, we briefly address the issue of the complexity of the {\it human mind} -- one as pervasive as the complexity of Nature at large. The complexity of the mind is related to the complexity of the underlying neuronal organization in the brain, which operates within a larger biological context, its activities being modulated by other physiological systems, notably the one involving a host of chemical messengers. The mind, with no materiality of its own, is nevertheless emergent from the activity of interacting neuronal assemblies in the brain. As in the case of reality at large, there can be no ultimate theory of the mind, from which one can explain and predict the entire spectrum of human behavior, which is an infinitely rich and diverse one. (shrink)

It has been argued that complex subjective sense of self is linked to the brain default-mode network (DMN). Recent discovery of heterogeneity between distinct subnets (or operational modules - OMs) of the DMN leads to a reconceptualization of its role for the experiential sense of self. Considering the recent proposition that the frontal DMN OM is responsible for the first-person perspective and the sense of agency, while the posterior DMN OMs are linked to the continuity of ‘I’ experience (including autobiographical (...) memories) through embodiment and localization within bodily space, we have tested in this study the hypothesis that heterogeneity in the operational synchrony strength within the frontal DMN OM among patients who are in a vegetative state (VS) could inform about a stable self-consciousness recovery later in the course of disease (up to six years post-injury). Using EEG operational synchrony analysis we have demonstrated that among the three OMs of the DMN only the frontal OM showed important heterogeneity in VS patients as a function of later stable clinical outcome. We also found that the frontal DMN OM was characterized by the process of active uncoupling (stronger in persistent VS) of operations performed by the involved neuronal assemblies. (shrink)

In this brief overview paper, we analyse information flow in the brain. Although Shannon’s information concept, in its pure algebraic form, has made a number of valuable contributions to neuroscience, information dynamics within the brain is not fully captured by its classical description. These additional dynamics consist of self-organisation, interplay of stability/instability, timing of sequential processing, coordination of multiple sequential streams, circular causality between bottom-up and top-down operations, and information creation. Importantly, all of these processes are dynamic, hierarchically nested and (...) correspond to continuous brain state change, even if the external environment remains constant. This is where metastable coordination comes into play. In a metastable regime of brain functioning, as a result of the simultaneous co-existence of tendencies for independence and cooperation, information is continuously created, preserved for some time and then dissipated through the formation of dynamical and nested spatio-temporal coalitions among simple neuronal assemblies and larger coupled conglomerates of them—so-called delocalised operational modules. (shrink)

The study of consciousness is poised today at interesting crossroads. There has been a surge of research into various neurobiological underpinnings of consciousness in the past decade. The present article looks at the theories regarding this complex phenomenon, especially the ones that neurobiology, cognitive neuroscience and cognitive psychology have to offer. We will first discuss the origin and etymology of word consciousness and its usage. Neurobiological correlates of consciousness are discussed with structures like the ascending reticular activating system, the amygdala, (...) the cerebellum, the thalamus, the frontoparietal circuits, the prefrontal cortex and the precuneus. The cellular and microlevel theories of consciousness and cerebral activity at the neuronal level contributing to consciousness are highlighted, along with the various theories posited in this area. The role of neuronal assemblies and circuits along with firing patterns and their ramifications for the understanding of consciousness are discussed. A section on the role of anaesthesia and its links to consciousness is presented, along with details of split-brain studies in consciousness and altered states of awareness, including the vegetative states. The article finally discusses the progress cognitive psychology has made in identifying and theorising various perspectives of consciousness, perceptual awareness and conscious processing. Both recent and past researches are highlighted. The importance and salient features of each theory are discussed along with the pitfalls, if present. A need for integration of various theories to understand consciousness from a holistic perspective is stressed, to enable one to reach a theory that explains the ultimate neurobiology of consciousness. (shrink)

The study of consciousness is poised today at interesting crossroads. There has been a surge of research into various neurobiological underpinnings of consciousness in the past decade. The present article looks at the theories regarding this complex phenomenon, especially the ones that neurobiology, cognitive neuroscience and cognitive psychology have to offer. We will first discuss the origin and etymology of word consciousness and its usage. Neurobiological correlates of consciousness are discussed with structures like the ascending reticular activating system, the amygdala, (...) the cerebellum, the thalamus, the frontoparietal circuits, the prefrontal cortex and the precuneus. The cellular and microlevel theories of consciousness and cerebral activity at the neuronal level contributing to consciousness are highlighted, along with the various theories posited in this area. The role of neuronal assemblies and circuits along with firing patterns and their ramifications for the understanding of consciousness are discussed. A section on the role of anaesthesia and its links to consciousness is presented, along with details of split-brain studies in consciousness and altered states of awareness, including the vegetative states. The article finally discusses the progress cognitive psychology has made in identifying and theorising various perspectives of consciousness, perceptual awareness and conscious processing. Both recent and past researches are highlighted. The importance and salient features of each theory are discussed along with the pitfalls, if present. A need for integration of various theories to understand consciousness from a holistic perspective is stressed, to enable one to reach a theory that explains the ultimate neurobiology of consciousness. (shrink)

Dr. Vukov analyzing patients with disorders of consciousness, proposed that medical well-regarded policy recommendations cannot be justified by looking solely to patients’ actual levels of consciousness (minimally conscious state – MCS versus vegetative state – VS), but that they can be justified by looking to patients’ potential for consciousness. One objective way to estimate this potential (actual physical possibility) is to consider a neurophysiologically informed strategy. Ideally such strategy would utilize objective brain activity markers of consciousness/unconsciousness. The Operational Architectonics (OA) (...) theory of brain-mind functioning is an example of such a strategy. Besides being mathematically simple, neurophysiologically accurate, and compatible with the cognitive/phenomenal perspectives on consciousness, application of OA strategy to quantitative EEG analysis of patients in VS and MCS revealed that the absence of consciousness in VS is paralleled by impairment of overall EEG operational architecture. Specifically, neuronal assemblies become smaller, their life span shortened, and they became highly unstable and functionally disconnected (desynchronized). At the same time, fluctuating (minimal) awareness in patients in MCS was paralleled by partial restoration of EEG operational architecture (increased size, life span, and stability of neuronal assemblies, together with an increased number and strength of functional connections among them), approaching the level found in healthy fully conscious participants. Moreover OA strategy to EEG analysis allowed predicting the emergence of consciousness in VS patients after six years following the brain trauma. Therefore, the OA methodology could reliably predict which patients may regain consciousness, and thus determine which patients may have the potential for consciousness. (shrink)

Many philosophers and neuroscientists defend a view we express with the slogan that mental science is neuroscience. We argue that there are two ways of interpreting this view, depending on what is meant by ‘neuroscience’. On one interpretation, the view is that mental science is cognitive neuroscience, where this is the science that integrates psychology with the biology of the brain. On another interpretation, the view is that mental science is biological neuroscience, where this is the investigation concerned with the (...) chemistry, physiology and anatomy of neurons and neuronal assemblies. Since the claim about cognitive neuroscience is a scientific triviality, we concentrate on the claim about biological neuroscience, and criticise two initially promising lines of argument for it, one prompted by reflection on the history of biology, and one prompted by reflection on the neurophysiological process known as long‐term potentiation, which may be implicated in learning. We argue that neither of these arguments is successful in supporting the view that mental science is biological neuroscience. (shrink)

The brain, rather than being homogeneous, displays an almost infinite topological genus, since it is punctured with a high number of “cavities”. We might think to the brain as a sponge equipped with countless, uniformly placed, holes. Here we show how these holes, termed topological vortexes, stand for nesting, non-concentric brain signal cycles resulting from the activity of inhibitory neurons. Such inhibitory spike activity is inversely correlated with its counterpart, i.e., the excitatory spike activity propagating throughout the whole brain tissue. (...) We illustrate how Pascal’s triangles and linear and nonlinear arithmetic octahedrons are capable of describing the three-dimensional random walks generated by the inhbitory/excitatory activity of the nervous tissue. In case of nonlinear 3D paths, the trajectories of excitatory spiking oscillations can be depicted as the operation of filling the numbers of octahedrons in the form of “islands of numbers”: this leads to excitatory neuronal assemblies, spaced out by empty areas of inhibitory neuronal assemblies. These mathematical procedures allow us to describe the topology of a brain of infinite genus, to represent inhibitory neurons in terms of Betti numbers and to highlight how spike diffusion in neural tissues is generated by the random activation of tiny groups of excitatory neurons. Our approach suggests the existence of a strong mathematical background subtending the intricate oscillatory activity of the central nervous system. (shrink)

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)

When words are read, the visual cortex is activated, independent of whether visual or motor associations are elicited. This word-evoked brain activity is significantly influenced by semantic meaning. Such effects occur very early after stimulus presentation (at latencies between 80 and 130 msec), indicating that semantic meaning activates different neuronal assemblies in the human visual cortex when words are processed.

Many philosophers and neuroscientists defend a view we express with the slogan that mental science is neuroscience. We argue that there are two ways of interpreting this view, depending on what is meant by ‘neuroscience’. On one interpretation, the view is that mental science is cognitive neuroscience, where this is the science that integrates psychology with the biology of the brain. On another interpretation, the view is that mental science is biological neuroscience, where this is the investigation concerned with the (...) chemistry, physiology and anatomy of neurons and neuronal assemblies. Since the claim about cognitive neuroscience is a scientific triviality, we concentrate on the claim about biological neuroscience, and criticise two initially promising lines of argument for it, one prompted by reflection on the history of biology, and one prompted by reflection on the neurophysiological process known as long‐term potentiation, which may be implicated in learning. We argue that neither of these arguments is successful in supporting the view that mental science is biological neuroscience. (shrink)

Sleep is a fundamental property conserved across species. The homeostatic induction of sleep indicates the presence of a mechanism that is progressively activated by the awake state and that induces sleep. Several lines of evidence support that such function, namely, sleep need, lies in the neuronal assemblies rather than specific brain regions and circuits. However, the molecular mechanism underlying the dynamics of sleep need is still unclear. This review aims to summarize recent studies mainly in rodents indicating that (...) protein phosphorylation, especially at the synapses, could be the molecular entity associated with sleep need. Genetic studies in rodents have identified a set of kinases that promote sleep. The activity of sleep-promoting kinases appears to be elevated during the awake phase and in sleep deprivation. Furthermore, the proteomic analysis demonstrated that the phosphorylation status of synaptic protein is controlled by the sleep-wake cycle. Therefore, a plausible scenario may be that the awake-dependent activation of kinases modifies the phosphorylation status of synaptic proteins to promote sleep. We also discuss the possible importance of multisite phosphorylation on macromolecular protein complexes to achieve the slow dynamics and physiological functions of sleep in mammals. (shrink)

This paper reviews a theory on the physiological conditions of consciousness. The theory consists of four hypotheses: (1) The occurrence of states of consciousness depends on the formation of higher-order representations that represent the internal state of the brain itself. (2) Higher-order representations are instantiated by the spatio-temporal activity pattern of large-scale neuronal assemblies. (3) The N-methyl-D-aspartate (NMDA) synapse plays a crucial role in the generation of conscious states by implementing the binding mechanism that the brain uses to (...) produce large-scale assemblies. (4) The activation state of the NMDA receptor determines the rate at which representational structures can be built up. Unconsciousness or altered states of consciousness occur if, and only if, NMDA-dependent binding processes are inhibited. (shrink)

Any sort of cognition, perception, and action is necessarily shaped by (re)activation of “schemata.” Any interpretation is schema (re)activation. Schemata are epistemologically speaking “structural” activation patterns which are psychologically and neurologically speaking accommodated, adapted, “learned” by co- and re-activating neuronal assemblies. Six levels of interpretative schema activations (schema interpretations) are outlined from invariable primary “interpretations” through conventional, classificatory, and justificatory, as well as meta-interpretations. Constitutive schema interpretations are unavoidable. Many philosophical problems will have to be reformulated or reinterpreted (...) along these lines, e.g., a sort of moderated pragmatic (interpretational) realism in epistemology. (shrink)

Any kind of knowledge, cognition, perception, and action is necessarily shaped by activation of "schemata". Any interpretation is schema activation. Schemata are epistemologically speaking "structural" activation patterns which are psychologically and neurologically speaking accommodated, adapted, "learned" by activating neuronal assemblies. Six levels of interpretative schema activations are outlined from invariable primary "interpretations" through conventional, classificatory and justificatory as well as meta-interpretations. Constitutive schema interpretations are unavoidable. Many philosophical problems will have to be reformulated or reinterpreted along these lines.

It is the every person's daily phenomenal experience that conscious states represent their contents as occurring now. Following Droege (2009) we could state that consciousness has a peculiar affinity for presence. Some researchers even argue that conscious awareness necessarily demands that mental content is somehow held “frozen” within a discrete progressive present moment. Thus, phenomenal content seems to be minimally conscious if it is integrated into a single and coherent model of reality during a “virtual window” of presence.

Electroencephalogram (EEG) recordings are increasingly used to evaluate patients with disorders of consciousness (DOC) or assess their prognosis outcome in the short-term perspective. However, there is a lack of information concerning the effectiveness of EEG in classifying long-term (many years) outcome in chronic DOC patients. Here we tested whether EEG operational architectonics parameters (geared towards consciousness phenomenon detection rather than neurophysiological processes) could be useful for distinguishing a very long-term (6 years) clinical outcome of DOC patients whose EEGs were registered (...) within 3 months post-injury. The obtained results suggest that EEG recorded at third month after sustaining brain damage, may contain useful information on the long-term outcome of patients in vegetative state: it could discriminate patients who remain in a persistent vegetative state from patients who reach a minimally conscious state or even recover a full consciousness in a long-term perspective (6 years) post-injury. These findings, if confirmed in further studies, may be pivotal for long-term planning of clinical care, rehabilitative programs, medical-legal decisions concerning the patients, and policy makers. (shrink)

The target paper of Dr. Feinberg is a testimony to an admirable scholarship and deep thoughtfulness. This paper develops a general theoretical framework of nested hierarchy in the brain that allows production of mind with consciousness. The difference between non-nested and nested hierarchies is the following. In a non-nested hierarchy the entities at higher levels of the hierarchy are physically independent from the entities at lower levels and there is strong constraint of higher upon lower levels. In a nested hierarchy, (...) higher levels are physically composed of lower levels, and there is no central control of the system resulting in weak constraint of higher upon lower levels. (shrink)

Contemporary psychiatry faces serious challenges because it has failed to incorporate accumulated knowledge from basic neuroscience, neurophilosophy, and brain–mind relation studies. As a consequence, it has limited explanatory power, and effective treatment options are hard to come by. A new conceptual framework for understanding mental health based on underlying neurobiological spatial-temporal mechanisms of mental disorders (already gained by the experimental studies) is beginning to emerge.

If the cortex is an associative memory, strongly connected cell assemblies will form when neurons in different cortical areas are frequently active at the same time. The cortical distributions of these assemblies must be a consequence of where in the cortex correlated neuronal activity occurred during learning. An assembly can be considered a functional unit exhibiting activity states such as full activation (“ignition”) after appropriate sensory stimulation (possibly related to perception) and continuous reverberation of excitation within the (...) assembly (a putative memory process). This has implications for cortical topographies and activity dynamics of cell assemblies forming during language acquisition, in particular for those representing words. Cortical topographies of assemblies should be related to aspects of the meaning of the words they represent, and physiological signs of cell assembly ignition should be followed by possible indicators of reverberation. The following postulates are discussed in detail: (1) assemblies representing phonological word forms are strongly lateralized and distributed over perisylvian cortices; (2) assemblies representing highly abstract words such as grammatical function words are also strongly lateralized and restricted to these perisylvian regions; (3) assemblies representing concrete content words include additional neurons in both hemispheres; (4) assemblies representing words referring to visual stimuli include neurons in visual cortices; and (5) assemblies representing words referring to actions include neurons in motor cortices. Two main sources of evidence are used to evaluate these proposals: (a) imaging studies focusing on localizing word processing in the brain, based on stimulus-triggered event-related potentials (ERPs), positron emission tomography (PET), and functional magnetic resonance imaging (fMRI), and (b) studies of the temporal dynamics of fast activity changes in the brain, as revealed by high-frequency responses recorded in the electroencephalogram (EEG) and magnetoencephalogram (MEG). These data provide evidence for processing differences between words and matched meaningless pseudowords, and between word classes, such as concrete content and abstract function words, and words evoking visual or motor associations. There is evidence for early word class-specific spreading of neuronal activity and for equally specific high-frequency responses occurring later. These results support a neurobiological model of language in the Hebbian tradition. Competing large-scale neuronal theories of language are discussed in light of the data summarized. Neurobiological perspectives on the problem of serial order of words in syntactic strings are considered in closing. Key Words: associative learning; cell assembly; cognition; cortex; ERP; EEG; fMRI; language; lexicon; MEG; PET; word category. (shrink)

In recent years there has been a wealth of studies investigating how memories are allocated in the hippocampus. Some of those studies showed that it is possible to manipulate the identity of neurons recruited to represent a given memory without affecting the memory's behavioral expression. Those findings raised questions about how the hippocampus represents memories, with some researchers arguing that hippocampal neurons do not represent fixed stimuli. Herein, an alternative hypothesis is argued. Neurons in high‐order brain regions can be tuned (...) to multiple dimensions, forming complex, abstract representations. It is argued that such complex receptive fields allow those neurons to show some flexibility in their responses while still representing relatively fixed sets of stimuli. Moreover, it is pointed out that changes induced by artificial manipulation of cell assemblies are not completely redundant—the observed behavioral redundancy does not imply cognitive redundancy, as different, but similar, memories may induce the same behavior. (shrink)

Gemins 2–8 and Unr‐interacting protein (UNRIP) are intimate partners of the survival motor neuron (SMN) protein, which is the determining factor for the neuromuscular disorder spinal muscular atrophy (SMA). The most documented role of SMN, Gemins and UNRIP occurs within the large macromolecular SMN complex and involves the cytoplasmic assembly of spliceosomal uridine‐rich small nuclear ribonucleoproteins (UsnRNPs), a housekeeping process critical in all cells. Several reports detailing alternative functions for SMN in either motor neurons or skeletal muscles may, however, hold (...) the answer to the extreme neuromuscular tissue specificity observed in SMA. Recent discoveries indicate that collaboration between SMN and Gemins also extends to these non‐canonical functions, hence raising the possibility that mutations in Gemin genes may be the cause of unlinked neuromuscular hereditary syndromes. This review evaluates the functions of Gemins and UNRIP inside the SMN complex and discusses whether these less notorious SMN complex members are capable of acting independently of SMN. (shrink)

With neurons emergence, life alters itself in a remarkable way. This embodied neurons become carriers of signals, and processing devices: it begins an inexorable progression of functional complexity, from increasingly drawn behaviors to the mind and eventually to consciousness [Damasio, 2010]. In which moment has awareness arisen in the history of life? The emergence of human consciousness is associated with evolutionary developments in brain, behavior and mind, which ultimately lead to the creation of culture, a radical novelty in natural history. (...) It is in this context of biological evolution of conscious brains that we raise the question: how conscious brains connect with each other? In order to answer it, I will explore how brain states and conscious states each participate in dynamic interactive processes involving the whole organism. I will argue that a possible way to overcome the hard problem of consciousness might be based on the notion of embodiment as a process of embedding the mental in the living organism relating dynamically with the environment through the sensorymotor experience. In order to do so, I will provide an assembly between an anthropologic perspective of consciousness with contemporary Philosophy of Mind, Interaction Theory [Gallagher 2001, 2008; Zahavi 2001, 2008; Fuchs and De Jaegher 2009]. (shrink)

[opening paragraph] -- Clark: The `astonishing hypothesis' which you put forward in your book, and which you obviously feel is very controversial, is that `You, your joys and sorrows, your memories and ambitions, your sense of personal identity and free will are, in fact, no more than the behaviour of a vast assembly of nerve cells. As Lewis Carroll's Alice might have phrased it: `You're nothing but a pack of neurons'.' But it seems to me that this is not so (...) astonishing a statement for a scientist to make. Isn't this what reductionist science has always believed? (shrink)

[opening paragraph] -- Clark: The `astonishing hypothesis' which you put forward in your book, and which you obviously feel is very controversial, is that `You, your joys and sorrows, your memories and ambitions, your sense of personal identity and free will are, in fact, no more than the behaviour of a vast assembly of nerve cells. As Lewis Carroll's Alice might have phrased it: `You're nothing but a pack of neurons'.' But it seems to me that this is not so (...) astonishing a statement for a scientist to make. Isn't this what reductionist science has always believed? (shrink)

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)

The neurophysiological evidence from the Miyashita group's experiments on monkeys as well as cognitive experience common to us all suggests that local neuronal spike rate distributions might persist in the absence of their eliciting stimulus. In Hebb's cell-assembly theory, learning dynamics stabilize such self-maintaining reverberations. Quasi-quantitive modeling of the experimental data on internal representations in association-cortex modules identifies the reverberations (delay spike activity) as the internal code (representation). This leads to cognitive and neurophysiological predictions, many following directly from the (...) language used to describe the activity in the experimental delay period, others from the details of how the model captures the properties of the internal representations. (shrink)

Barbara Maria Stafford is at the forefront of a growing movement that calls for the humanities to confront the brain’s material realities. In _Echo Objects,_ she argues that humanists should seize upon the exciting neuroscientific discoveries that are illuminating the underpinnings of cultural objects. In turn, she contends, brain scientists could enrich their investigations of mental activity by incorporating phenomenological considerations—particularly the intricate ways that images focus intentional behavior and allow us to feel thought. As a result, _Echo Objects_ is (...) a stunningly broad exploration of how complex images—or patterns that compress space and time—make visible the invisible ordering of human consciousness. Stafford demonstrates, for example, how the compound formats of emblems, symbols, collage, and electronic media reveal the brain’s grappling to construct mental objects that are redoubled by prior associations. In contrast, she shows that findings in evolutionary biology and the neurosciences are providing profound opportunities for understanding aesthetic conundrums such as the human urge to imitate and the role of narrative and nonnarrative representation. Ultimately, she makes an impassioned plea for a common purpose—for the acknowledgement that, at the most basic level, these separate projects belong to a single investigation. “Heroic.... The larger message of Stafford’s intense, propulsive prose is unassailable. If we are to get much further in the great puzzle of ‘binding’—how the perception of an image, the will to act on intention, or the forging of consciousness is assembled from the tens of thousands of neurons firing at any one moment in time—then there needs to be action on all fronts.”—_Science_. (shrink)

A complex brain network, centered on the hippocampus, supports episodic memories throughout their lifetimes. Classically, upon memory encoding during active behavior, hippocampal activity is dominated by theta oscillations (6-10Hz). During inactivity, hippocampal neurons burst synchronously, constituting sharp waves, which can propagate to other structures, theoretically supporting memory consolidation. This 'two-stage' model has been updated by new data from high-density electrophysiological recordings in animals that shed light on how information is encoded and exchanged between hippocampus, neocortex and subcortical structures such as (...) the striatum. Cell assemblies (tightly related groups of cells) discharge together and synchronize across brain structures orchestrated by theta, sharp waves and slow oscillations, to encode information. This evolving dynamical schema is key to extending our understanding of memory processes. (shrink)

Empirical results suggest that defocusing attention results in primary process or associative thought, conducive to finding unusual connections, while focusing attention results in secondary process or analytic thought, conducive to rule-based operations. Creativity appears to involve both. It is widely believed that it is possible to escape mental fixation by spontaneously and temporarily engaging in a more divergent or associative mode of thought. The resulting insight may be refined in a more analytic mode of thought. The question addressed here is: (...) how does the architecture of memory support these two modes of thought, and what is happening at the neural level when one shifts between them? Recent advances in neuroscience shed light on this. It was demonstrated that activated cell assemblies are composed of multiple ‘neural cliques’, groups of neurons that respond differentially to general or context-specific aspects of a situation. I refer to neural cliques that would not be included in the assembly if one were in an analytic mode, but would be if one were in an associative mode, as ‘neurds’. It is posited that the shift to a more associative mode of thought conducive to insight is accomplished by recruiting neurds that respond to abstract or atypical subsymbolic microfeatures of the problem or situation. Since memory is distributed and content-addressable this fosters remindings and the forging of creative connections to potentially relevant items previously encoded in those neurons. Thus it is proposed that creative thought involves neither randomness, nor search through a space of predefined alternatives, but emerges naturally through the recruitment of neurds. It is suggested this occurs when there is a need to resolve conceptual gaps in ones’ internal model of the world, and resolution involves context-driven actualization of the potentiality afforded by its fine-grained associative structure. (shrink)

Impressions, energy radiated by phenomena in the momentary environmental scene, enter sensory neurons, creating in afferent nerves a data stream. Following Kant, by our inner sense the mind perceives its own thoughts as it ties together sense data into an internalized scene. The mind, residing in the brain, logically a Language Machine, processes and stores items as coded grammatical entities. Kantian synthetic unity in the linguistic brain is able to deliver our experience of the scene as we appear to see (...) it. Uniquely, the brain records its own history, synthesizing a Movie-in-the-Brain, called the Noumenal Cosmos. Attempting thereby to represent the actual Universe, this makes for a sovereign brain that governs itself. The brain is domicile of an Ego, with its selfhood at stake at all times. Yet, it can know itself only by its actions, in which it appears as an actor in its own movie. Phenomena enter garbled, as confused apparitions, and must be put in good form using top–down feedback control by Ego, so that each movie frame makes rational sense within the overall context of the Noumenal Cosmos. A stack of frames is processed typically in 40 Hz rhythm with 300 ms process time each, for about 12 in the stack at any time. Successive neural centers are processing the stack in the brain assembly line, based on data from increasingly global receptive fields. Ego stitches together the movie frames, but only the top frame is in consciousness for 25 ms. The top frame contains the whole scene where the Ego makes an appearance as the actor that imposes Kantian synthetic unity on the scene, merely an assembly of grammatical texts, in a system-internal coded process language, fitting the scene into the Noumenal Cosmos. But Ego observes Ego only to the extent permitted by the objectivity rule, only what it does and thinks, not its true face. From the Noumenal Cosmos, the Ego receives grammatical messages in the internal sense code. They are integrated into a whole in the reaction of the Ego to the momentary scene. The voluntary nature of Ego’s decisions is explained, based on its ability to code in advance its own actions sequentially in time, as it sees fit with a view to an orderly Noumenal Cosmos, records of code being arranged spatially in neural structures. (shrink)

Nuclear bodies contribute to non‐random organization of the human genome and nuclear function. Using a major prototypical nuclear body, the Cajal body, as an example, we suggest that these structures assemble at specific gene loci located across the genome as a result of high transcriptional activity. Subsequently, target genes are physically clustered in close proximity in Cajal body‐containing cells. However, Cajal bodies are observed in only a limited number of human cell types, including neuronal and cancer cells. Ultimately, Cajal (...) body depletion perturbs splicing kinetics by reducing target small nuclear RNA (snRNA) transcription and limiting the levels of spliceosomal snRNPs, including their modification and turnover following each round of RNA splicing. As such, Cajal bodies are capable of shaping the chromatin interaction landscape and the transcriptome by influencing spliceosome kinetics. Future studies should concentrate on characterizing the direct influence of Cajal bodies upon snRNA gene transcriptional dynamics.Also see the video abstract here. (shrink)

This paper reviews and clarifies five misunderstandings about cultural evolution identified by Henrich et al.. First, cultural representations are neither discrete nor continuous; they are distributed across neurons that respond to microfeatures. This enables associations to be made, and cultural change to be generated. Second, ‘replicator dynamics’ do not ensure natural selection. The replicator notion does not capture the distinction between actively interpreted self-assembly code and passively copied self-description, which leads to a fundamental principle of natural selection: inherited information is (...) transmitted, whereas acquired information is not. Third, this principle is violated in culture by the ubiquity of acquired change. Moreover, biased transmission is less important to culture than the creative processes by which novelty is generated. Fourth, there is no objective basis for determining cultural fitness. Fifth, the necessity of randomness is discussed. It is concluded that natural selection inappropriate is an explanatory framework for culture. (shrink)

Phenomenal awareness, the ability to be aware of one's sensations and feelings, emerges from the capacity of evolved brains to represent their own cognitive processes by iterating and self-reapplying the cortical operations that generate representations of the outer world. Search for the neuronal substrate of awareness therefore converges with the search for the neuronal code through which brains represent their environment. The hypothesis is put forward that the mammalian brain uses two complementary representational strategies. One consists of the (...) generation of neurons responding selectively to particular constellations of features, and is based on selective recombination of inputs in hierarchically structured feed-forward architectures. The other relies on the dynamic association of large numbers of distributed neurons into functionally coherent cell assemblies which as a whole represent a content of cognition. Arguments and data are presented in favor of the second strategy as the one according to which meta-representations that support awareness are established. My hypothesis is that such distributed representations self-organize through transient synchronization of the oscillatory activity. Evidence showing that similar brain states are required both for the occurrence of these synchronization phenomena and for awareness is provided. (shrink)

Based on neurobiological data, modern concepts of self-organization and a careful rationale, the hypothesis is put forward that the fleeting, highly ordered patterns of electric and/or magnetic fields, generated by assemblies of dendritic trees of specialized neuronal networks, should be thought of as the end-product of chaotic, dynamically governed self-organization. Such patterns encode for subjective experiences such as pain and pleasure, or perceiving colours. Because by quantum mechanical definition virtual photons are the theoretical constituents of electric and magnetic (...) fields, the former hypothesis can be re-formulated as follows: it is the highly ordered patterns of virtual photons that encode for subjective experiences. Arguments are then given that consciousness did not emerge during evolution only after neuronal networks had been formed able to generate electric and/or magnetic fields of sufficient complexity but, rather, that subjectivity already existed in a very elementary form as a fundamental property of the omnipresent virtual photons, i.e., of matter. The contribution of neuronal networks to consciousness was to generate highly ordered patterns of germs of subjectivity , so allowing complex subjective experiences. Due to the omnipresence of virtual photons, it follows finally that the whole universe must be imbued with subjectivity. An experimental strategy is proposed to test the hypothesis. (shrink)

Short-term or working memory provides temporary storage of information in the brain after an experience and is associated with conscious awareness. Neurons sensitive to the multiple stimulus attributes comprising an experience are distributed within many brain regions. Such distributed cell assemblies, activated by an event, are the most plausible system to represent the WM of that event. Studies with a variety of imaging technologies have implicated widespread brain regions in the mediation of WM for different categories of information. Each (...) kind of WM may thus be expected to involve many brain regions rather than a local, uniquely dedicated set of cells. Neurons in a distributed “cell assembly” may be self-selected by their temporally coherent activations. The process by which this fragmented representation of the recent past is reassembled to accomplish essentially automatic and reliable recognition of a recurrent event constitutes an important problem. One plausible mechanism to achieve the identification of past with previous events would require that the representational system mediating WM must coexist in spatial extent and somehow overlap in temporal activation with cell ensembles registering input from subsequent events. The detection of such a postulated mechanism required an experimental approach which would focus upon spatial patterns of coherent activation while information about different events was stored in WM and retrieved, rather than focusing upon the temporal sequences of activation in localized regions of interest. For this purpose, the familiar delayed matching from sample task was modified. A series of information-free flashes, or “noncontingent probes,” was presented before an initial series of visual information items, the Priming Sample, which were to be held in WM during a Delay Period. A second series of visual information items were then presented, the Matching Sample. The task required detection of any item in the second series which had beenabsentfrom the initial series. Thirty such trials with a particular category of visual information constituted a single task. Several DMS tasks with this standardized design, but with different categories of visual information, were presented within each test session. The information categories included letters of the alphabet, single digit numbers, or faces from a school yearbook. Event-related potentials , were computed from 21 standardized electrode placements, separately for information-free probes and for information items in each interval of the trials within a task. Because each electrode is particularly sensitive to coherent activation of neurons in the immediately underlying brain regions, topographic maps were constructed and interpolated across the surface of the scalp. The momentary fluctuations of the resulting voltage “landscapes” throughout the task were then subjected to quantitative analysis. Distinctive landscapes sometimes persisted for prolonged periods, implying sustained engagement of very large populations of neurons. “Difference landscapes” were constructed by subtraction of topographic maps evoked by noncontingent probes during the Delay Period from maps of probe ERPs before the presentation of the initial information in the Priming Sample. Such probe difference landscapes displayed recurrent high similarity to momentary landscapes elicited during subsequent presentation of the information items in the Matching Sample. It seemed as if the distributed cell assembly continuously engaged by mediation of WM of the diverse attributes of the initial stimuli was being dynamically compared to the ensembles engaged by registration of the subsequent stimuli. Spatial Principal Component Analysis was applied to the sequences of momentary voltage landscapes observed throughout trials of each task. This method sought a small number of spatial patterns with which these large sets of inhomogeneous spatial distributions of voltage could be reconstructed. This is the spatial analog of the reconstruction of local ERPs by temporal principal components, as often described previously. Five Spatial Principal Components were found which accounted for about 90% of the total variance of voltage across the surface of the scalp throughout every task. Theloadings,or distinguishing topographic features, of these SPCs, were highly similar during every cognitive task for every subject. However,factor scores,or relative average contribution to the overall voltage distributions, of the different SPCs varied substantially among subjects between the tasks and momentarily within successive intervals of each task. These five SPCs may reflect coherent activation of huge distributed ensembles of neurons which comprise independent but interacting functional brain subsystems. These subsystems may correspond to basic resources available to individuals for allocation to mediate conscious evaluation of information during cognitive activity, providing a filter to bind together fractionated representations of the past to evaluate the present. (shrink)

Based on recent insight into the thalamocortical system and its role in perception and conscious experience, a unified pathophysiological framework for hallucinations in neurological and psychiatric conditions is proposed, which integrates previously unrelated neurobiological and psychological findings. Gamma-frequency rhythms of discharge activity from thalamic and cortical neurons are facilitated by cholinergic arousal and resonate in networks of thalamocortical circuits, thereby transiently forming assemblies of coherent gamma oscillations under constraints of afferent sensory input and prefrontal attentional mechanisms. If perception is (...) based on synchronisation of intrinsic gamma activity in the thalamocortical system, then sensory input to specific thalamic nuclei may merely play a constraining role. Hallucinations can be regarded as underconstrained perceptions that arise when the impact of sensory input on activation of thalamocortical circuits and synchronisation of thalamocortical gamma activity is reduced. In conditions that are accompanied by hallucinations, factors such as cortical hyperexcitability, cortical attentional mechanisms, hyperarousal, increased noise in specific thalamic nuclei, and random sensory input to specific thalamic nuclei may, to a varying degree, contribute to underconstrained activation of thalamocortical circuits. The reticular thalamic nucleus plays an important role in suppressing random activity of relay cells in specific thalamic nuclei, and its dysfunction may be implicated in the biological vulnerability to hallucinations in schizophrenia. Combined with general activation during cholinergic arousal, this leads to excessive disinhibition in specific thalamic nuclei, which may allow cortical attentional mechanisms to recruit thalamic relay cells into resonant assemblies of gamma oscillations, regardless of their actual sensory input, thereby producing an underconstrained perceptual experience. Key Words: Charles Bonnet syndrome; gamma oscillations; hallucinations; late paraphrenia; Lewy body dementia; perception; schizophrenia; thalamocortical system. (shrink)