Gliomas can display marked changes in the concentrations of energy metabolism molecules such as creatine (Cr), phosphocreatine (PCr) and lactate, as measured using magnetic resonance spectroscopy (MRS). Moreover, the BOLD (blood oxygen level dependent) contrast enhancement in functional magnetic resonance imaging (fMRI) can be reduced or missing within or near gliomas, while neural activity is not significantly reduced (so-called neurovascular decoupling), so that the location of functionally eloquent areas using fMRI can be erroneous. In this paper, we adapt a previously (...) developed model of the coupling between neural activation, energy metabolism and hemodynamics, by including the venous dilatation Balloon model of Buxton and Frank. We show that decreasing the cerebral blood flow (CBF) baseline value, or the CBF increase fraction, results in a decrease of the BOLD signal and an increase of the lactate peak during a sustained activation. Baseline lactate and PCr levels are not significantly affected by CBF baseline reduction, but are altered even by a moderate decrease of mitochondrial respiration. Decreasing the total Cr and PCr concentration reduces the BOLD signal after the initial overshoot. In conclusion, we suggest that the coupled use of BOLD fMRI and MRS could contribute to a better understanding of the neurovascular and metabolic decoupling in gliomas. (shrink)

In order to make an attempt at grouping the various aspects of brain functional imaging (fMRI, MRS, EEG-MEG, ...) within a coherent frame, we implemented a model consisting of a system of differential equations, that includes: (1) sodium membrane transport, (2) Na/K ATPase, (3) neuronal energy metabolism (i.e. glycolysis, buffering effect of phosphocreatine, and mitochondrial respiration), (4) blood-brain barrier exchanges and (5) brain hemodynamics, all the processes which are involved in the activation of brain areas. We assumed that the correlation (...) between brain activation and metabolism could be due to either changes in the concentrations of ATP and ADP following activation of Na/K ATPase that result from the changes in ion concentrations, or the involvement, in different phases of metabolism, of a second messenger such as calcium. In this article, we show how this type of model enables interpretation of MRS and fMRI published data that were obtained during prolonged stimulations. (shrink)

We examine the consequences of long-range effects on tumour cell migration. Our starting point are previous results of ours where we have shown that the migration patterns of glioma cells are best interpreted if one assumes attractive interactions between cells. Here we complement the cellular automaton model previously introduced by the assumption of the existence of a chemorepellent produced by the main bulk of large spheroids (in the hypoxic/necrotic areas). Visible effects due to the presence of such a substance can (...) be found in the density profiles of cells migrating out of a single spheroid as well as in the angular distribution of cells coming from two close-lying spheroids. These effects depend crucially on the diffusion speed of the chemorepellent. A comparison of the simulation results to experimental data of Werbowetski et al. allows to draw (tentative) conclusions on the existence of a chemorepellent and its properties. (shrink)

Mark Changizi et al. (2008) claim that it is possible systematically to organize more than 50 kinds of illusions in a 7 × 4 matrix of 28 classes. This systematization, they further maintain, can be explained by the operation of a single visual processing latency correction mechanism that they call “perceiving the present” (PTP). This brief report raises some concerns about the way a number of illusions are classified by the proposed systematization. It also poses two general problems—one empirical and (...) one conceptual—for the PTP approach. (shrink)

Neuropsychological findings used to motivate the “two visual systems” hypothesis have been taken to endanger a pair of widely accepted claims about spatial representation in visual experience. The first is the claim that visual experience represents 3-D space around the perceiver using an egocentric frame of reference. The second is the claim that there is a constitutive link between the spatial contents of visual experience and the perceiver’s bodily actions. In this paper, I carefully assess three main sources of evidence (...) for the two visual systems hypothesis and argue that the best interpretation of the evidence is in fact consistent with both claims. I conclude with some brief remarks on the relation between visual consciousness and rational agency. (shrink)

Metaethics has recently been confronted by evidence from cognitive neuroscience that tacit emotional processes play an essential causal role in moral judgement. Most neuroscientists, and some metaethicists, take this evidence to vindicate a version of metaethical sentimentalism. In this paper we argue that the ‘dual process’ model of cognition that frames the discussion within and without philosophy does not do justice to an important constraint on any theory of deliberation and judgement. Namely, decision-making is the exercise of a capacity for (...) agency. Agency, in turn, requires a capacity to conceive of oneself as temporally extended: to inhabit, in both memory and imagination, an autobiographical past and future. To plan, to commit to plans, and to act in accordance with previous plans requires a diachronic self, able to transcend the present moment. While this fact about agency is central to much of moral philosophy (e.g. in discussions of autonomy and moral responsibility) it is opaque to the dual process framework and those meta-ethical accounts which situate themselves within this model of cognition. We show how this is the case and argue for an empirically adequate account of moral judgement which gives sufficient role to memory and imagination as cognitive prerequisites of agency. We reconsider the empirical evidence, provide an alternative, agentive, interpretation of key findings, and evaluate the consequences for metaethics. (shrink)

The human urge to represent the three-dimensional world using two-dimensional pictorial representations dates back at least to Paleolithic times. Artists from ancient to modern times have struggled to understand how a few contours or color patches on a flat surface can induce mental representations of a three-dimensional scene. This article summarizes some of the recent breakthroughs in scientifically understanding how the brain sees that shed light on these struggles. These breakthroughs illustrate how various artists have intuitively understand paradoxical properties about (...) how the brain sees, and have used that understanding to create great art. These paradoxical properties arise from how the brain forms the units of conscious visual perception; namely, representations of threedimensional boundaries and surfaces. Boundaries and surfaces are computed in parallel cortical processing streams that obey computationally complementary properties. These streams interact at multiple levels to overcome their complementary weaknesses and to transform their complementary properties into consistent percepts. The article describes how properties of complementary consistency have guided the creation of many great works of art. (shrink)

The NeuroGenderings project is reminiscent of an interdisciplinary program called Critical Neuroscience. But the steps towards a feminist/queer Critical Neuroscience are complicated by the problematic ways in which critical neuroscientists conceive of their critical practices. They suggest that we work and talk across disciplines as if neuroscientists were from Mars and social scientists from Venus, assigning the latter to the traditional feminine role of assuaging conflict. This article argues that brain science studies scholars need to clarify how we want to (...) frame our critical practices—a critique of what and for whom?—and promote interdisciplinarity. The challenge is to articulate a critical stance that could not be collapsed into the all-encompassing claims of neuroscience, Critical Neuroscience included. I suggest we shift focus: from enhanced communication to the study of controversies (but also non-controversies, failed controversies, etc.) and conflicts. I explore the productiveness of this shift through two examples: the non-controversial notion of brain plasticity, and the controversial question of whether gender identity formation in intersex people is a function of their brain or their genitals. Socializing neuroscience with insights from gender and science studies is good; highlighting the conflicting dimensions of social life in the same gesture is even better. (shrink)

We are unlikely to stop seeking pleasure, as this would prejudice our health and well-being. Yet many psychoactive substances providing pleasure are outlawed as illicit recreational drugs, despite the fact that only some of them are addictive to some people. Efforts to redress their prohibition, or to reform legislation so that penalties are proportionate to harm have largely failed. Yet, if choices over seeking pleasure are ethical insofar as they avoid harm to oneself or others, public health strategies should foster (...) ethical choice by moving beyond current risk management practices embodied in the harm reduction movement. The neuroscience of pleasure has much to offer neuroethics and public health strategies. Distinguishing between ‘wanting’ and ‘liking’ fosters new understandings of addiction. These hold promise for directing the search for pharmacotherapies which prevent addiction and relapse or disrupt associated neuromechanisms. They could inform new research into creating lawful psychoactive substances which give us pleasure without provoking addiction. As the health and well being of human and other animals rests upon the experience of pleasure, this would be an ethical objective within public health strategy. Were ethical and neurobiological obstacles to ending addiction to be overcome, problems associated with excessive consumption, the lure of unlawful psychoactive substances and the paucity of lawful means to achieve pleasurable altered states would remain. Non-addictive designer drugs, which reliably provided lawful access to pleasures and altered states, would ameliorate these public health concerns insofar as they fostered citizens’ informed, ethical choices according to a neurobiological taxonomy of pleasures. (shrink)

Abstract The current neurosciences contribute to the construction of gender/sex to a high degree. Moreover, the subject of gender/sex differences in cognitive abilities attracts an immense public interest. At the same time, the entanglement of gender and science has been shown in many theoretical and empirical analyses. Although the body of literature is very extensive and differentiated with regards to the dimensions of ‘neuroscience of gender’ and ‘gender in neuroscience’, the feeding back of these findings into the field of neuroscience (...) remains a desideratum. Especially, the question of how gender knowledge, i.e. insights from feminist theory on gender/sex and from gender and science studies on knowledge production, may be integrated and applied within the neurosciences has been strongly neglected. Presumably due to their epistemic culture and epistemological presuppositions, these critical engagements are conceived as externalist by critical scholars and neuroscientists alike. In this context, the question arises of how substantiated gender knowledge may be accounted for in neuroscientific research practice? The article outlines methodological considerations for a critical research agenda in the cognitive neurosciences. I present thoughts on how insights and expertise from gender and science studies can be taken into account in the neuroscientific practice of knowledge production. Starting from the assumption that changes in neuroscientific research practices are possible, my aim is to point out possibilities of integrating gender knowledge into the neurosciences. Content Type Journal Article Category Original Paper Pages 1-15 DOI 10.1007/s12152-011-9135-3 Authors Katrin Nikoleyczik, Department of Mathematics, Gender in Mathematics and Natural Sciences, Universität Hamburg, Bundesstr. 55, 20146 Hamburg, Germany Journal Neuroethics Online ISSN 1874-5504 Print ISSN 1874-5490. (shrink)

I outline the early Heidegger's views on mood and emotion, and then relate his central claims to some recent finding in neuropsychology. These findings complement Heidegger in a number of important ways. More specifically, I suggest that, in order to make sense of certain neurological conditions that traditional assumptions concerning the mind are constitutionally incapable of accommodating, something very like Heidegger's account of mood and emotion needs to be adopted as an interpretive framework. I conclude by supporting Heidegger's insistence that (...) the sciences constitute a derivative means of disclosing the world and our place within it, as opposed to an ontologically and epistemologically privileged domain of inquiry. (shrink)

According to Adina Roskies, the neuroscience of ethics is concerned with a neuroscientific understanding of the brain processes that underpin moral judgment and behavior. The ethics of neuroscience, on the other hand, includes the potential impact advances in neuroscience may have on social, moral and philosophical ideas and institutions, as well as the ethical principles that should guide brain research, treatment of brain disease, and cognitive enhancement. This entry discusses these different aspects of neuroethics, with a special focus on the (...) way in which neuroscience might impact our sense of self and personal responsibility, a concern that cuts across these categories. For example, I discuss whether advancing knowledge of brain states or processes undermine common notions of free will and responsibility. I also examine whether certain treatments of brain abnormality are ethical (is it acceptable to irreversibly ‘cure’ pedophilia or obsessive/compulsive disorder?), a discussion that falls squarely under the category of the ethics of neuroscience. Finally, I discuss whether the neuroscience of ethics can provide insight into who should be deemed criminally responsible via a neuroscientific analysis of intentional action. (shrink)

Affective information processing is analysed considering the emotion circuits within the brain substrates of emotionality. Based on Gärdenfors’ conceptual spaces model we try to examine an emotion episode from its elicitation to the differentiation into affective processes. An affectiveconceptual spaces model is developed taking in consideration Panksepp’s nested BrainMind hierarchies.

Neither personal belief nor a phenomenal self model can exist without attachment to a pre-reflective core self.