A midbrain neural basis for the perceptualoscillations of binocular rivalry is suggestedon the basis of fMRI studies of rivalry andinferences from the properties of rivalry thatcannot be explained from the known propertiesof primary visual cortical (V1) neurons. Therivalry switch is proposed to activatehomologous areas of each cerebral hemispherealternately, by means of a bistable oscillatorcircuit that straddles the midline of theventral tegmentum. This bistable oscillatoroperates at the same slow rate that ischaracteristic of perceptual rivalryalternations. Whilst attempting to (...) divert thepresent preoccupation with cortical mechanismsfor rivalry, the new proposal integrates manycortical areas, in keeping with recent evidencethat binocular rivalry involves widespreadareas of the hemispheres. By linking rivalry tointerhemispheric switching mechanisms in thisway, the new proposal for the switch makes theprediction that binocular rivalry will besubject to high level influences such as moodand motivation. These predictions are beingfulfilled, with rivalry playing an increasingrole in the diagnosis and understanding if mooddisorders, schizophrenia and other psychiatricconditions. (shrink)

Among psychologists and vision scientists,binocular rivalry has enjoyed sustainedinterest for decades dating back to the 19thcentury. In recent years, however, rivalry''saudience has expanded to includeneuroscientists who envision rivalry as a tool for exploring the neural concomitants ofconscious visual awareness and perceptualorganization. For rivalry''s potential to berealized, workers using this tool need toknow details of this fascinating phenomenon,and providing those details is the purpose ofthis article. After placing rivalry in ahistorical context, I summarize major findingsconcerning (...) the spatial characteristics and thetemporal dynamics of rivalry, discuss two majortheoretical accounts of rivalry ( eye vs stimulus rivalry) and speculate on possibleneural concomitants of binocular rivalry. (shrink)

In addressing thescientific study of consciousness, Crick and Koch state, It is probable that at any moment some active neuronal processes in your head correlate with consciousness, while others do not: what is the difference between them? (1998, p. 97). Evidence from electrophysiological and brain-imaging studies of binocular rivalry supports the premise of this statement and answers to some extent, the question posed. I discuss these recent developments and outline the rationale and experimental evidence for the interhemispheric switch hypothesis (...) of perceptual rivalry. According to this model, the perceptual alternations of rivalry reflect hemispheric alternations, suggesting that visual consciousness of rivalling stimuli may be unihemispheric at any one time (Miller et al., 2000). However, in this paper, I suggest that interhemispheric switching could involve alternating unihemispheric attentional selection of neuronal processes for access to visual consciousness. On this view, visual consciousness during rivalry could be bi hemispheric because the processes constitutive of attentional selection may be distinct from those constitutive of visual consciousness. This is a special case of the important distinction between the neuronal correlates and constitution of visual consciousness. (shrink)

Physiological studies of binocular rivalry have provided important clues to the relationship between neural activity in the brain and visual awareness.However, uncertainty about these insights has been raised by a recent study showing that the events underlying binocular rivalry occur earlier in the visual pathway than was previously thought.

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)

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. (shrink)

The neural basis of binocular rivalry has beenthe subject of vigorous debate. Do discrepantmonocular patterns rival for awareness becauseof neural competition among patternrepresentations or monocular channels? In thisarticle, I briefly review psychophysical andneurophysiological evidence pertaining to boththeories and discuss important new neuroimagingdata which reveal that rivalry is fullyresolved in monocular visual cortex. These newfindings strongly suggest that interocularcompetition mediates binocular rivalry and thatV1 plays an important role in the selection ofconscious visual information. They furthersuggest that (...) rivalry is not a unitaryphenomenon. Interocular competition may fullyaccount for binocular rivalry whereas aseparate mechanism involving patterncompetition likely accounts for monocular andstimulus rivalry. (shrink)

The relationship between brain activity and conscious visual experience is central to our understanding of the neural mechanisms underlying perception. Binocular rivalry, where monocular stimuli compete for perceptual dominance, has been previously used to dissociate the constant stimulus from the varying percept. We report here fMRI results from humans experiencing binocular rivalry under a dichoptic stimulation paradigm that consisted of two drifting random dot patterns with different motion coherence. Each pattern had also a different color, which both (...) enhanced rivalry and was used for reporting which of the two patterns was visible at each time. As the perception of the subjects alternated between coherent motion and motion noise, we examined the effect that these alternations had on the strength of the MR signal throughout the brain. Our results demonstrate that motion perception is able to modulate the activity of several of the visual areas which are known to be involved in motion processing. More specifically, in addition to area V5 which showed the strongest modulation, a higher activity during the perception of motion than during the perception of noise was also clearly observed in areas V3A and LOC, and less so in area V3. In previous studies, these areas had been selectively activated by motion stimuli but whether their activity reflects motion perception or not remained unclear; here we show that they are involved in motion perception as well. The present findings therefore suggest a lack of a clear distinction between ?processing? versus ?perceptual? areas in the brain, but rather that the areas involved in the processing of a specific visual attribute are also part of the neuronal network that is collectively responsible for its perceptual representation. (shrink)

In order to identify the neural correlates of consciousness it is necessary to distinguish these from the neural correlates associated with unconscious information processing. We describe the various techniques, such as masking, which can be used to generate conditions in which the same stimulus is presented either just above or just below a threshold for visibility. Directed attention can also be used to manipulate the extent to which a stimulus gains access to awareness, as can various methods for (...) creating bi‐stable perception. A major problem for these studies is the possible confound of the need for participants to report their awareness and there is currently much interest in developing paradigms in which reporting awareness is not required. We also discuss studies exploring the neural correlates of imagination, illusions and hallucinations in which a perceptual experience occurs in the absence of a physical stimulus. Finally we consider techniques that go beyond correlation and attempt to identify the necessary and sufficient neural processes leading to conscious experience. (shrink)

Philosophers of mind have been arguing for decades about the nature of phenomenal consciousness and the relation between brain and mind. More recently, neuroscientists and philosophers of science have entered the discussion. Which neural activities in the brain constitute phenomenal consciousness, and how could science distinguish the neural correlates of consciousness from its neural constitution? At what level of neural activity is consciousness constituted in the brain and what might be learned from well-studied phenomena like binocular (...) rivalry, attention, memory, affect, pain, dreams and coma? What should the science of consciousness want to know and what should explanation look like in this field? How should the constitution relation be applied to brain and mind and are other relations like identity, supervenience, realization, emergence and causation preferable? Building on a companion volume on the constitution of visual consciousness, this volume addresses these questions and related empirical and conceptual territory. It brings together, for the first time, scientists and philosophers to discuss this engaging interdisciplinary topic. (shrink)

Is consciousness based in prefrontal circuits involved in cognitive processes like thought, reasoning, and memory or, alternatively, is it based in sensory areas in the back of the neocortex? The no-report paradigm has been crucial to this debate because it aims to separate the neural basis of the cognitive processes underlying post-perceptual decision and report from the neural basis of conscious perception itself. However, the no-report paradigm is problematic because, even in the absence of report, subjects might engage (...) in post-perceptual cognitive processing. Therefore, to isolate the neural basis of consciousness, a no-cognition paradigm is needed. Here, I describe a no-cognition approach to binocular rivalry and outline how this approach can help resolve debates about the neural basis of consciousness. (shrink)

In the cognitive neuroscience of consciousness, participants have commonly been instructed to report their conscious content. This, it was claimed, risks confounding the neural correlates of consciousness (NCC) with their preconditions, i.e., allocation of attention, and consequences, i.e., metacognitive reflection. Recently, the field has therefore been shifting towards no-report paradigms. No-report paradigms draw their validity from a direct comparison with no-report conditions. We analyze several examples of such comparisons and identify alternative interpretations of their results and/or methodological issues in (...) all cases. These go beyond the previous criticism that just removing the report is insufficient, because it does not prevent metacognitive reflection. The conscious mind is fickle. Without having much to do, it will turn inward and switch, or timeshare, between the stimuli on display and daydreaming or mind-wandering. Thus, rather than the NCC, no-report paradigms might be addressing the neural correlates of conscious disengagement. This observation reaffirms the conclusion that no-report paradigms are no less problematic than report paradigms. (shrink)

Objective: Caloric vestibular stimulation has traditionally been used as a tool for neurological diagnosis. More recently, however, it has been applied to a range of phenomena within the cognitive neurosciences. Here, we provide an overview of such studies and review our work using CVS to investigate the neural mechanisms of a visual phenomenon - binocular rivalry. We outline the interhemispheric switch model of rivalry supported by this work and its extension to a metarivalry model of interocular-grouping phenomena. (...) In addition, studies showing a slow rate of binocular rivalry in bipolar disorder are discussed, and the relationship between this finding and the interhemispheric switch model is described. We also review the effects of CVS in various clinical contexts, explain how the technique is performed and discuss methodological issues in its application. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:The Philosophic Foundations of Mimetic Theory and Cognitive Science(Including Artificial Intelligence)Jean-Pierre Dupuy (bio)In the mid 1970s I discovered at the same time cognitive science and mimetic theory. Being a philosopher with a scientific background, I immediately brought them together and tried to reconceptualize the latter in terms of the former. In a sense, I haven't stopped doing that in the last 45 years. That is why I feel fully (...) at home with the goals pursued by the organizers of this conference.I do not believe it is feasible or even desirable to operate the rapprochement between the two disciplines at a global level. The history of cognitive science is exceedingly involved, and the part played by artificial intelligence in it compared to the part played by the neurosciences has varied greatly over time.1 Only a piecemeal approach makes sense. I present here four short case studies that cover the whole period, from the beginnings in cybernetics to today's artificial intelligence (AI).In order to better situate these studies within a broader frame, I propose the diagram in Figure 1. To comment on it would require more time than available for my whole presentation. Let me just say the following. [End Page 1]It is essential to distinguish between two kinds of AI. The first to bear this name was launched by economist Herbert Simon and computer scientist Allan Newell at a Dartmouth conference in 1956. It was based on the premise that thinking is computing, with this computation bearing on sentences of a "language of thought" implementable in a digital computer. It turns out that this AI(1) was progressively substituted from the 1980s onward by an AI(2), which, to some extent, was a return to a fundamental result obtained by cybernetics in 1943. Neurophysiologist Warren McCulloch and mathematician Walter Pitts had constructed a mathematical model of a network of elementary calculators called "neurons" and explored its properties. The capacity to "think" was one of these. It was not situated at the elementary level, as was the case in AI(1), but it emerged at the collective level from the interactions between the neurons.This model was heavily criticized by the supporters of AI(1),2 and its first implementations, in the notorious "Perceptron" in particular (1957), were pitiful failures. However, the emergence of "second-order cybernetics" under the guidance of cybernetician Heinz von Foerster and the theory of complex, self-organizing systems that it helped develop, in cooperation and rivalry with similar efforts in the physical sciences, enabled the neural network model to come to a second life under different names: formal neurons, deep learning, big data, and the like. Together, they constitute AI(2).The following network of influences wouldn't have been possible without its stem, that is, the boxes containing the names of Kurt Gödel and Alan Turing. The former revolutionized logic by showing that reasoning about arithmetic and arithmetic are one and the same, insofar as it is possible to code in a 1-to-1 fashion propositions about integers (for instance, "7 is a prime number") by means of integers. The latter demonstrated that some mechanisms can self-transcend inasmuch as they generate an ensemble of outputs that cannot be defined mechanistically. Later, John von Neumann, who is credited along with Alan Turing with having invented the digital computer, would use this logical possibility to define complexity: A mechanism is complex if it is capable of generating one more complex than itself. The gate was open for the theories of complex, self-organizing systems to thrive and, by way of consequence, for AI(2) to emerge.fascination with modelsHerbert Simon (1916–2001), winner of the Nobel Prize in economics for his work on what he called "bounded rationality," is generally considered to be one [End Page 2] Click for larger view View full resolutionFigure 1.of the founders of artificial intelligence. Some cognitive scientists still rely on the computer program that he devised with Alan Newell to simulate the creative processes of human thought—a program aptly named "General Problem Solver." The title of one of his principal works, The Sciences of the... (shrink)

Recent experiments have shown that the amplitudes of cortical gamma band oscillatory activities that occur during anesthesia are often greater than amplitudes of similar activities that occur without anesthesia. This result is apparently at odds with the hypothesis that synchronized oscillatory activities constitute the neural correlate of consciousness. We argue that while synchronization and oscillatory patterning are necessary conditions for consciousness, they are not sufficient. Based on the results of a binocular rivalry study of Fries et al. (1997), (...) we propose that the degrees of oscillatory strength and synchronization of neuronal activities determine the degree of awareness those activities produce. On the other hand, the overal firing rates of neurons in cortical sensory areas are not correlated with the degree of awareness the activities of those neurons produce. The results of the experiment of Fries et al. (1997) appear to conflict with the results of another binocular rivalry experiment, in which monkeys were trained to pull a lever in order to report which stimulus object was being perceived (Leopold & Logothetis, 1996). In the latter experiment, it was demonstrated that the firing rates of neurons in striate cortex did not change during perceptual alterations, while 90% of neurons in inferior and superior temporal cortices changed their firing rate when the perceived image changed. This result led to the conclusion that activities in temporal cortex are correlated with visual awareness, but those in striate cortex are not. We argue that activities in temporal cortex contribute little, if anything, to perceptual awareness, and that their primary function is computational. Thus the correlation between the firing rates of neurons in these areas and the responses of the monkeys is due to the recognition of a particular stimulus object, which in turn is due to the computations made there. (shrink)

Current neurobiological research on temporal binding in binocular rivalry settings contributes to a better understanding of the neural correlate of perceptual consciousness. This research can easily be integrated into a theory of conscious behavior, but if it is meant to promote a naturalistic theory of perceptual consciousness itself, it is confronted with the notorious explanatory gap argument according to which any statement of psychophysical correlations (and their interpretation) leaves the phenomenal character of, e.g., states of perceptual consciousness open. (...) It is argued that research on temporal binding plays no role in a naturalistic theory of consciousness if the gap argument can be solved on internal philosophical grounds or if it turns out to be unsolvable at the time being. But there may be a way to dissolve or deconstruct it, and the accessibility of this way may well depend on scientific progress, including neurobiological research on the neural correlate of perceptual consciousness. (shrink)

This paper considers clinical psychoanalysis together with developmental psychology (particularly attachment theory), evolution, and neuroscience in the context a Bayesian account of confirmation and disconfrimation. -/- In it I argue that these converging sources of support indicate that the combination of relatively low predictive power and broad explanatory scope that characterise the theories of both Freud and Darwin suggest that Freud's theory, like Darwin's, may strike deeply into natural phenomena. -/- The same argument, however, suggests that conclusive confirmation for Freudian (...) hypotheses, as in the case of Darwin's, will come from outside the original domain of explanation sketched out by Freud. As in Darwin's case conclusive confirmation came from understanding the physical mechanisms or reproduction, in Freud's case it will come from understanding the neural mechanisms that realise the phenomena described in psychoanalysis. (shrink)

In this chapter, we discuss a selection of current views of the neural correlates of consciousness (NCC). We focus on the different predictions they make, in particular with respect to the role of prefrontal cortex (PFC) during visual experiences, which is an area of critical interest and some source of contention. Our discussion of these views focuses on the level of functional anatomy, rather than at the neuronal circuitry level. We take this approach because we currently understand more about (...) experimental evidence at this coarse level and because these results are appropriate for arbitrating between current theoretical frameworks. We discuss the Two-Visual-Systems Hypothesis (Milner & Goodale 1995; 2006), Local Recurrency (Lamme 2010; Lamme 2006), Higher Order (Lau 2008; Lau & Rosenthal 2011) and Global Workspace theories (Baars 1997; Baars 2005; Dehaene & Naccache 2001; Dehaene 2014). Despite the apparent stark differences between conscious and unconscious perceptual processing, available evidence suggests that their neural substrates must be largely shared. This indicates that the difference in neural activity between conscious and unconscious perceptual processing is likely to be subtle and highly specialized. We argue that current experimental evidence about the involvement of specific activity in prefrontal cortex supports the higher order neural theory of consciousness. In consequence, imaging techniques that focus only on marked differences between conscious and unconscious level of activity are likely to be insensitive to the relevant neural activity patterns that underlie conscious experiences. Finally, it follows from the evidence we discuss that the functional advantages of conscious over unconscious perceptual processing may be more limited than commonly thought. (shrink)

Can findings from psychology and cognitive neuroscience about the neural mechanisms involved in decision-making can tell us anything useful about the commonly-understood mental phenomenon of making voluntary choices? Two philosophical objections are considered. First, that the neural data is subpersonal, and so cannot enter into illuminating explanations of personal level phenomena like voluntary action. Secondly, that mental properties are multiply realized in the brain in such a way as to make them insusceptible to neuroscientific study. The paper argues (...) that both objections would be weakened by the discovery of empirical generalisations connecting subpersonal properties with the personal level. It gives three case studies that furnish evidence to that effect. It argues that the existence of such interrelations are consistent with a plausible construal of the personal-subpersonal distinction. Furthermore, there is no reason to suppose that the notion subpersonal representation relied on in cognitive neuroscience illicitly imports personal-level phenomena like consciousness or normativity, or is otherwise explanatorily problematic. (shrink)

Logical pluralism is the view that there is more than one correct logic. This very general characterization gives rise to a whole family of positions. I argue that not all of them are stable. The main argument in the paper is inspired by considerations known as the “collapse problem”, and it aims at the most popular form of logical pluralism advocated by JC Beall and Greg Restall. I argue that there is a more general argument available that challenges all variants (...) of logical pluralism that meet the following three conditions: that there are at least two correct logical systems characterized in terms of different consequence relations, that there is some sort of rivalry among the correct logics, and that logical consequence is normative. The hypothesis I argue for amounts to conditional claim: If a position satisfies all these conditions, then that position is unstable in the sense that it collapses into competing positions. (shrink)

In this paper an Artificial Neural Network (ANN) model was used to help cars dealers recognize the many characteristics of cars, including manufacturers, their location and classification of cars according to several categories including: Make, Model, Type, Origin, DriveTrain, MSRP, Invoice, EngineSize, Cylinders, Horsepower, MPG_Highway, Weight, Wheelbase, Length. ANN was used in prediction of the number of miles per gallon when the car is driven in the city(MPG_City). The results showed that ANN model was able to predict MPG_City with (...) 97.50 % accuracy. The factor of DriveTrain has the most influence on MPG_City evaluation. Similar studies can be carried out for the evaluation of other characteristics of cars. (shrink)

Deleuze’s reversal of Platonism shifted the traditional emphasis on thinking that which participates in a concept to that in which a claim to participation occurs. The first part of this article presents a reading of this reversal that highlights the implications of Deleuze’s ontology for his non-ontological account of participation, highlighting how this ontology builds on aspects of Plato’s philosophy recovered from beneath the later Platonic tradition of philosophy and supports Deleuze’s account of the rival claims of philosophy and opinion (...) to participate in thought. The second part outlines the difficulties presented by philosophy’s constitutive participation in friendship, love, and rivalry for it to be able to achieve its distinctive task of creating concepts that defeat opinion’s rival claims to address the problems that present themselves to thought. (shrink)

We investigated binocular rivalry in the twocerebral hemispheres of callosotomized(split-brain) observers. We found that rivalryoccurs for complex stimuli in split-brainobservers, and that it is similar in the twohemispheres. This poses difficulties for twotheories of rivalry: (1) that rivalry occursbecause of switching of activity between thetwo hemispheres, and (2) that rivalry iscontrolled by a structure in the rightfrontoparietal cortex. Instead, similar rivalryfrom the two hemispheres is consistent with atheory that its mechanism is low in the visualsystem, at (...) which each hemisphere conducts asimilar analysis of its half of visual space. (shrink)

Human neural organoid research is advancing rapidly. As Greely notes in the target article, this progress presents an “onrushing ethical dilemma.” We can’t rule out the possibility that suff...

One of the most important recent developments in the study of concepts has been the resurgence of interest in nativist accounts of the human conceptual system. However, many theorists suppose that a key feature of neural organization—the brain’s plasticity—undermines the nativist approach to concept acquisition. We argue that, on the contrary, not only does the brain’s plasticity fail to undermine concept nativism, but a detailed examination of the neurological evidence actually provides powerful support for concept nativism.

Why is neural activity in a particular area expressed as experience of red rather than green, or as visual experience rather than auditory? Indeed, why does it have any conscious expression at all? These familiar questions indicate the explanatory gap between neural activity and ‘what it’s like’-- qualities of conscious experience. The comparative explanatory gaps, intermodal and intramodal, can be separated from the absolute explanatory gap and associated zombie issues--why does neural activity have any conscious expression at (...) all?. Here I focus on comparative gaps: why is neural activity in a given area expressed as this type of experience rather than that type of experience? (shrink)

RIVALRY AND CENTRAL PLANNING: THE SOCIALIST CALCULATION DEBATE RECONSIDERED by Don Lavoie. New York: Cambridge University Press, 1985. 208 pp., $34.95.

In "Brainshy: Non-neural theories of conscious experience," (this volume) Patricia Churchland considers three "non-neural" approaches to the puzzle of consciousness: 1) Chalmers' fundamental information, 2) Searle's "intrinsic" property of brain, and 3) Penrose-Hameroff quantum phenomena in microtubules. In rejecting these ideas, Churchland flies the flag of "neuralism." She claims that conscious experience will be totally and completely explained by the dynamical complexity of properties at the level of neurons and neural networks. As far as consciousness goes, (...) class='Hi'>neural network firing patterns triggered by axon-to-dendrite synaptic chemical transmissions are the fundamental correlates of consciousness. There is no need to look elsewhere. (shrink)

The rivalry between religions is obvious on a number of fronts: in wars between Christians, Muslims, and Hindus; in sectarian violence between Catholics and Protestants, or between Shia and Sunni; in the persecution of doctrinal heretics; in the splintering of new sects along doctrinal lines; in efforts to proselytize; and so on.

Rivalry is an attempt to understand facets of entrepreneurial societies by integrating the economic analysis with historical, political and psychological considerations, customarily shunned by economists. The author argues that decisions to make new business ventures, and readiness to take risks are both related to concepts of ranking hierarchies on local, national or international levels. He then constructs a theory of business enterprise and of rivalry supported by evidence on entrepreneurship, innovation, advertising, all examined with their historical, political or (...) organisational concerns. This notion of rivalry among businessmen is used to derive guidelines for anti-trust legislation. Instead of pricing, profitability, concentration ratios and other criteria used today to infer non-competitive behaviour, he suggests using a measure of a firm's relative rate of innovation to infer it. By extending the notion of rivalry to the political sphere, national and international, guidelines are derived to evaluate the performance of state-owned enterprises and to examine policies related to free trade. (shrink)

How do minds emerge from developing brains? According to the representational features of cortex are built from the dynamic interaction between neural growth mechanisms and environmentally derived neural activity. Contrary to popular selectionist models that emphasize regressive mechanisms, the neurobiological evidence suggests that this growth is a progressive increase in the representational properties of cortex. The interaction between the environment and neural growth results in a flexible type of learning: minimizes the need for prespecification in accordance with (...) recent neurobiological evidence that the developing cerebral cortex is largely free of domain-specific structure. Instead, the representational properties of cortex are built by the nature of the problem domain confronting it. This uniquely powerful and general learning strategy undermines the central assumption of classical learnability theory, that the learning properties of a system can be deduced from a fixed computational architecture. Neural constructivism suggests that the evolutionary emergence of neocortex in mammals is a progression toward more flexible representational structures, in contrast to the popular view of cortical evolution as an increase in innate, specialized circuits. Human cortical postnatal development is also more extensive and protracted than generally supposed, suggesting that cortex has evolved so as to maximize the capacity of environmental structure to shape its structure and function through constructive learning. (shrink)

We begin by distinguishing computationalism from a number of other theses that are sometimes conflated with it. We also distinguish between several important kinds of computation: computation in a generic sense, digital computation, and analog computation. Then, we defend a weak version of computationalism—neural processes are computations in the generic sense. After that, we reject on empirical grounds the common assimilation of neural computation to either analog or digital computation, concluding that neural computation is sui generis. Analog (...) computation requires continuous signals; digital computation requires strings of digits. But current neuroscientific evidence indicates that typical neural signals, such as spike trains, are graded like continuous signals but are constituted by discrete functional elements (spikes); thus, typical neural signals are neither continuous signals nor strings of digits. It follows that neural computation is sui generis. Finally, we highlight three important consequences of a proper understanding of neural computation for the theory of cognition. First, understanding neural computation requires a specially designed mathematical theory (or theories) rather than the mathematical theories of analog or digital computation. Second, several popular views about neural computation turn out to be incorrect. Third, computational theories of cognition that rely on non-neural notions of computation ought to be replaced or reinterpreted in terms of neural computation. (shrink)

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

and apply it to various examples of neural plasticity in which input is rerouted intermodally or intramodally to nonstandard cortical targets. In some cases but not others, cortical activity ‘defers’ to the nonstandard sources of input. We ask why, consider some possible explanations, and propose a dynamic sensorimotor hypothesis. We believe that this distinction is important and worthy of further study, both philosophical and empirical, whether or not our hypothesis turns out to be correct. In particular, the question of (...) how the distinction should be explained is linked to explanatory gap issues for consciousness. Comparative and absolute explanatory gaps should be distinguished: why does neural activity in a particular area of cortex have this qualitative expression rather than that, and why does it have any qualitative expression at all? We use the dominance/deference distinction to address the comparative gaps, both intermodal and intramodal. We do so not by inward scrutiny but rather by expanding our gaze to include relations between brain, body and environment. (shrink)

Nikos K. Logothetis University of Manchester, Manchester, UK In binocular rivalry, the visual percept alternates stochastically between two dichoptically presented stimuli. It is established that both processes related to the eye of origin and binocular, stimulus-related processes account for these fluctuations in conscious perception. Here we studied how their relative contributions vary over time. We applied brief disruptions to rivalry displays, concurrent with an optional eye swap, at varying time intervals after one stimulus became visible (dominant). We found (...) that early in a dominance phase the dominant eye determined the percept by stabilizing its own contribution (regardless of the stimulus), with an additional yet weaker stabilizing contribution of the stimulus (regardless of the eye). Their stabilizing contributions declined in parallel with time so that late in a dominance phase the stimulus (and in some cases also the eye-based) contribution turned negative, favoring a perceptual (or ocular) switch. Our findings show that depending on the time, first processes related to the eye of origin and then those related to the stimulus can have a greater net influence on the stability of the conscious percept. Their co-varying change may be due to feedback from image- to eyeof-origin representations. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Beyond Rivalry?Rethinking Community in View of Apocalyptical ViolenceAndreas Oberprantacher (bio)But the republic of crime must also be the republic of the suicide of criminals, and down to the last among them—the sacrifice of the sacrificers unleashed in passion.—Jean-Luc Nancy, The Inoperative CommunityThe Crisis and Apocalyptic Intensification of RivalryAt first it seemed as if the "rivalry between two rates of speed"1 set at the center of Derrida's essay (...) "No Apocalypse, Not Now," published more than twenty years ago in Diacritics, had finally come to an end, at least in the form of a general and unmistakable division of the world into two competing geopolitical units. Following the breakdown of the USSR, the former super-enemy of the industrialized Northwest, that part of the world that claimed and still claims to be the sole referent of the adjective free, the dynamics of ideological rivalry had, at first, lost considerable momentum. After half a century of mostly symmetrical even if undeclared wars, the period from 1989 to 1991 was truly significant, [End Page 175] for it marked a moment of epistemological crisis, a moment when political fractions that derived their identity from a binary tension were all of a sudden stunned: no visible enemy anymore to deter, no willing scapegoat to blame, just eschatological abandonment.The aftershocks of this historical event can be traced in today's commentaries on and analyses of the political situation: It is certainly no coincidence that two of the most influential US-American political analysts, Samuel Huntington and Bruce Hoffman, both at the same time direct their attention toward questions about the conditions of social identity and cohesion, though from inverted perspectives. In his recent book, Who Are We? The Challenges to America's National Identity (2004), Huntington bemoans the "deconstruction of the American identity,"2 as it challenges—along with certain political developments—"the substance, and the desirability of this concept of America."3 Huntington's fervent interest in US-American identity and his call for its renewal become readily comprehensible when read against the background of his concern that an existential threat might again be imminent, possibly in the form of jihadist terrorism. In Huntington's argument, however, the United States's potential confrontation with militant Islamist movements—the explicit subtext of his book—is not assessed only in terms of political risks and military expenditures; for Huntington, this confrontation also holds out a unique chance of rediscovering one's own (lost, forgotten) identity. Revealing himself as an attentive reader of Carl Schmitt's The Concept of the Political, Huntington argues that "the absence of an ideological threat produced an absence of purpose.... The ideal enemy for America would be ideologically hostile, racially and culturally different, and militarily strong enough to pose a credible threat to American security."4While Huntington is concerned with reaffirming and securing a phantasmagoric vision of the United States's past glory, Hoffman, on the other hand, may be mentioned as a political analyst deeply worried about the inverse aspect of the epistemological crisis, i.e., worried by the fact that "the United States has utterly failed to fulfill the timeless admonition to 'know your enemy'"5 by declaring an all too abstract global war on terrorism. In his commentary, published in March 2007 under the title "Fighting Blind: We Can't Win if We Don't Know the Enemy" in the Washington Post, he argues that a long-term strategy is desperately needed to identify "our adversaries, who are much too elusive and complicated to be vanquished by mere decapitation."6Taking Huntington's and Hoffman's positions seriously as paradigmatic examples of a wider and well-established discursive strategy that calls for a renewed need for binary-opposed collective identities—us/them; the coalition [End Page 176] of the willing/the axis of evil—in order to affirm a state of potentially ubiquitous and highly moralized rivalry, one may well argue with Schmitt that "a new nomos of the earth" is immanent.7 In Schmitt's understanding, such a new paradigm of warfare will no longer be characterized by relative understandings of enmity, but by enemies declared "totally criminal... (shrink)

An emerging class of theories concerning the functional structure of the brain takes the reuse of neural circuitry for various cognitive purposes to be a central organizational principle. According to these theories, it is quite common for neural circuits established for one purpose to be exapted (exploited, recycled, redeployed) during evolution or normal development, and be put to different uses, often without losing their original functions. Neural reuse theories thus differ from the usual understanding of the role (...) of neural plasticity (which is, after all, a kind of reuse) in brain organization along the following lines: According to neural reuse, circuits can continue to acquire new uses after an initial or original function is established; the acquisition of new uses need not involve unusual circumstances such as injury or loss of established function; and the acquisition of a new use need not involve (much) local change to circuit structure (e.g., it might involve only the establishment of functional connections to new neural partners). Thus, neural reuse theories offer a distinct perspective on several topics of general interest, such as: the evolution and development of the brain, including (for instance) the evolutionary-developmental pathway supporting primate tool use and human language; the degree of modularity in brain organization; the degree of localization of cognitive function; and the cortical parcellation problem and the prospects (and proper methods to employ) for function to structure mapping. The idea also has some practical implications in the areas of rehabilitative medicine and machine interface design. (shrink)

Colombo (Phenomenology and the Cognitive Sciences, 2012) argues that we have compelling reasons to posit neural representations because doing so yields unique explanatory purchase in central cases of social norm compliance. We aim to show that there is no positive substance to Colombo’s plea—nothing that ought to move us to endorse representationalism in this domain, on any level. We point out that exposing the vices of the phenomenological arguments against representationalism does not, on its own, advance the case for (...) representationalism one inch—beyond establishing its mere possibility. We criticize the continual confounding of constitutive and explanatory claims and the lack of recognition of a Hard Problem of having to provide a naturalistic account of content, coupled with an inability to face up to it. We point at the inadequacy of various deflationary moves that end up driving representationalists towards the idea of neural representations with non-standard contents or without content altogether, both of which either render neural representationalism unfit for purpose or vacuous. Referring to possibilities for neural manipulation and control, or to established scientific practice does not help representationalism either. (shrink)