Neural tube defects (NTDs) are very serious malformations for the fetus, causing either low life expectancy or a chance of survival only with costly and difficult surgical interventions. In western countries the average prevalence is 1/1000-2000 and in Turkey it is 4/1000. The aim of the study was to characterize ethical approaches at institutional level to the fetus with an NTD and the mother, and the role of health care professionals in four major centers in Turkey. The authors (...) chose perinatology units of four university hospitals and prepared questionnaires for the responsible professionals concerning their own and their institution’s ethical approaches to the fetus with an NTD and the mother. The investigation revealed that there were no institutional ethical frameworks or ethics committees available to professional teams in the units. The roles of the health care professionals and their individual decisions and approaches based on ethical principles are described. The ethical decision-making process concerning fetuses with NTDs, examples of institutional approaches to the topic and institutional frameworks, and the role of nurses and other health care professionals are all discussed, based on a literature review. The authors suggest that institutional ethical frameworks, ethics committees, professionals’ ethics education and multidisciplinary teamwork should be established for critical situations such as fetuses with an NTD. (shrink)

Neurulation, the curling of the neuroepithelium to form the neural tube, is an essential component of the development of animal embryos. Defects of neural tube formation, which occur with an overall frequency of one in 500 human births, are the cause of severe and distressing congenital abnormalities. However, despite the fact that there is increasing information from animal experiments about the mechanisms which effect neural tube formation, much less is known about the fundamental causes (...) of neural tube defects (NTD). The use of computer models provides one way of gaining clues about the ways in which neurulation may be compromised. Here we employ one computer model to examine the robustness of different cellular mechanisms which are thought to contribute to neurulation. The model, modified from that of Odell et al (Odell, G.M., Oster, G., Alberch, P. and Burnside, B., (1981)) mimics neurulation by laterally propagating a wave of apical contraction along an active zone within a ring of cells. We link the results to experimental evidence gained from studies of embryos in which neurulation has been perturbed. The results indicate that alteration of one of the properties of non-neural tissue can delay or inhibit neurulation, supporting the idea, gained from observation of embryos bearing genes which predispose to NTD, that the tissue underlying the neuroepithelium may contribute to the elevation of the neural folds. The results also show that reduction of the contractile properties of a small proportion of the neuroepithelial cell population may have a profound effect on overall tissue profiling. The results suggest that the elevation of the neural folds, and hence successful neurulation, may be vulnerable to relatively minor deficiencies in cell properties. (shrink)

Abstract:Open neural tube defects or myelomeningoceles are a common congenital condition caused by failure of closure of the neural tube early in gestation, leading to a number of neurologic sequelae including paralysis, hindbrain herniation, hydrocephalus and neurogenic bowel and bladder dysfunction. Traditionally, the condition was treated by closure of the defect postnatally but a recently completed randomized controlled trial of prenatal versus postnatal closure demonstrated improved neurologic outcomes in the prenatal closure group. Fetal surgery, or more (...) precisely maternal-fetal surgery, raises a number of ethical issues that we address including who the patient is, informed consent, surgical innovation and equipoise as well maternal assumption of risk. As the procedure becomes more widely adopted into practice, we suggest close monitoring of new fetal surgery centers, in order to ensure that the positive results of the trial are maintained without increased risk to both the mother and fetus. (shrink)

The now classical idea that programmed cell death contributes to a plethora of developmental processes still has lost nothing of its impact. It is, therefore, important to establish effective three-dimensional reconstruction as well as simulation techniques to decipher the exact patterns and functions of such apoptotic events. The present study focuses on the question whether and how apoptosis promotes neurulation-associated processes in the spinal cord of Tupaia belangeri. Our 3D reconstructions demonstrate that at least two craniocaudal waves of apoptosis consecutively (...) pass through the dorsal spinal cord. The first wave appears to be involved in neural fold fusion and/or in selection processes among premigratory neural crest cells. The second one seems to assist in establishing the dorsal signaling center known as the roof plate. In the hindbrain, in contrast, apoptosis among premigratory neural crest cells progresses craniocaudally but discontinuously, in a segment-specific manner. Unlike apoptosis in the spinal cord, these segment-specific apoptotic events, however, precede later ones that seemingly support neural fold fusion and/or postfusion remodeling. Arguing with Whitehead that biological patterns and rhythms differ in that biological rhythms depend “upon the differences involved in each exhibition of the pattern” we show that 3D reconstruction and simulation techniques can contribute to distinguish between patterns and rhythms of apoptosis. By deciphering novel patterns and rhythms of developmental apoptosis, our reconstructions help to reconcile seemingly inconsistent earlier findings in chick and mouse embryos, and to create rules for computer simulations. (shrink)

The brain ventricular system is a series of connected cavities, filled with cerebrospinal fluid (CSF), that forms within the vertebrate central nervous system (CNS). The hollow neural tube is a hallmark of the chordate CNS, and a closed neural tube is essential for normal development. Development and function of the ventricular system is examined, emphasizing three interdigitating components that form a functional system: ventricle walls, CSF fluid properties, and activity of CSF constituent factors. The cellular lining (...) of the ventricle both can produce and is responsive to CSF. Fluid properties and conserved CSF components contribute to normal CNS development. Anomalies of the CSF/ventricular system serve as diagnostics and may cause CNS disorders, further highlighting their importance. This review focuses on the evolution and development of the brain ventricular system, associated function, and connected pathologies. It is geared as an introduction for scholars with little background in the field. (shrink)

During development of the Xenopus embryo, the formation of the nervous system depends on an inductive interaction between mesoderm and ectoderm. The result is a neural tube that is regionally differentiated along the anterior–posterior axis from forebrain to spinal cord (Fig. 1). The discovery of genes whose transcripts can be used as molecular markers for different regions of the nervous system has permitted reassessment of the existing theories of neural tissue formation. Although the neural inducing molecules (...) remain elusive, the mechanism by which cells interact to form a regionally differentiated nervous system is becoming clearer. (shrink)

Neural crest cells are remarkable in their extensive and stereotypic patterns of migration. The pathways of neural crest migration have been documented by cell marking techniques, including interspecific neural tube grafts, immunocytochemistry and Dil‐labelling. In the trunk, neural crest cells migrate dorsally under the skin or ventrally through the somites, where they move in a segmental fashion through the rostral half of each sclerotome. The segmental migration of neural crest cells appears to be prescribed (...) by the somites, perhaps by an inhibitory cue from the caudal half. Within the rostral sclerotome, neural crest cells fill the available space except for a region around the notochord, suggesting the notochord may inhibit neural crest cells in its vicinity. In the cranial region, antibody perturbation experiments suggest that multiple cell‐matrix interactions are required for proper in vivo migration of neural crest cells. Neural crest cells utilize integrin receptors to bind to a number of extracellular matrix molecules. Substrate selective inhibition of neural crest cell attachment in vitro by integrin antibodies and antisense oligonucleotides has demonstrated that they possess at least three integrins, one being an α1β1 integrin which functions in the absence of divalent cations. Thus, neural crest cells utilize complex sets of interactions which may differ at different axial levels. (shrink)

A unique feature of the vertebrate brain is the ventricular system, a series of connected cavities which are filled with cerebrospinal fluid (CSF) and surrounded by neuroepithelium. While CSF is critical for both adult brain function and embryonic brain development, neither development nor function of the brain ventricular system is fully understood. In this review, we discuss the mystery of why vertebrate brains have ventricles, and whence they originate. The brain ventricular system develops from the lumen of the neural (...) tube, as the neuroepithelium undergoes morphogenesis. The molecular mechanisms underlying this ontogeny are described. We discuss possible functions of both adult and embryonic brain ventricles, as well as major brain defects that are associated with CSF and brain ventricular abnormalities. We conclude that vertebrates have taken advantage of their neural tube to form the essential brain ventricular system. (shrink)

Neural tube defects are one of the commonest human birth defects, with more than 0.5% of some populations affected. Mouse models are being used in an attempt to identify genes that could be involved in these malformations. Only two mouse mutations are known to lead to craniorachischisis, failure of closure of almost the entire neural tube. Two recent papers report that the gene for one of these, Loop‐tail, has now been identified and sequenced.1, 2 It has (...) been given the designation Ltap/Lpp1 and appears to function in floor plate formation. It will be of great interest to investigate the role of this gene in human neural tube defects. BioEssays 24:580–583, 2002. © 2002 Wiley Periodicals, Inc. (shrink)

Open-uterine surgery to repair spina bifida, or ‘fetal surgery of open neural tube defects,’ has generated questions throughout its history—and continues to do so in a variety of contexts. As clinical ethics consultants who worked (Mark J. Bliton) and trained (Virginia L. Bartlett) at Vanderbilt University—where the first successful cases of open-uterine repair of spina bifida were carried out—we lived with these questions for nearly two decades. We worked with clinicians as they were developing and offering the procedure, (...) with researchers in refining and studying the procedure, and with pregnant women and their partners as they considered whether to undergo the procedure. From this experience in the early studies at Vanderbilt, we learned that pregnant women and their partners approach the clinical uncertainty of such a risky procedure with a curious and unique combination of practicality, self-reflection, fear, and overwhelming hope. These early experiences were a major contributing factor to the inclusion of an ethics-focused interview in the informed consent process for the Management of Myelomeningocele Study (MOMS) trial study design. (shrink)

The discovery by Hans Spemann of the “organizer” tissue and its ability to induce the formation of the amphibian embryo’s neural tube inspired leading embryologists to attempt to elucidate embryonic inductions’ underlying mechanism. Joseph Needham, who during the 1930s conducted research in biochemical embryology, proposed that embryonic induction is mediated by a specific chemical entity embedded in the inducing tissue, surmising that chemical to be a hormone of sterol-like structure. Along with embryologist Conrad H. Waddington, they conducted research (...) aimed at the isolation and functional characterization of the underlying agent. As historians clearly pointed out, embryologists came to question Needham’s biochemical approach; he failed to locate the hormone he sought and eventually abandoned his quest. Yet, this study finds that the difficulties he ran into resulted primarily from the limited conditions for conducting his experiments at his institute. In addition, Needham’s research reflected the interests of leading biochemists in hormone and cancer research, because it offered novel theoretical models and experimental methods for engaging with the function of the hormones and carcinogens they isolated. Needham and Waddington were deterred neither by the mounting challenges nor by the limited experimental infrastructure. Like their colleagues in hormone and cancer research, they anticipated difficulties in attempting to establish causal links between complex biological phenomena and simple chemical triggering. (shrink)

The current debate regarding the suitability of anencephalics as organ donors is due primarily to misunderstandings. The anatomical and neurophysiological literature shows that the anencephalic lacks a cerebrum because of the failure of neuralplate fusion. However, even the incomplete function of an atrophic brain stem is currently accepted at law in most if not all countries as sufficient for brain life: which is to say, cessation of breathing is currently required in order to make the diagnosis of brain death. Because (...) of the extensive incompleteness of the anencephalic's brain, it is not possible to postpone death significantly by mechanical ventilation and intravenous feeding. It is acceptable to maintain life for a short period of time in order to allow organ transplantation subsequent to the declaration of death at the point of cessation of the capacity for spontaneous respiration. The most important issue is not transplantation, but the issue of brain life raised by the case of anencephalics. Since brain life in any significant sense begins only after the closure of the neural tube on the 30th day after conception, it is reasonable to take this as the point at which brain life begins. Laws should be amended in all countries to allow the abortion of anencephalics at any time, in that they do not at any time possess brain life. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Being an Interpreter—Beyond LinguisticsPatricia CoronadoInterpreting refers specifically to the process of listening to and analyzing a message received in one language, then recreating the same message and delivering it in another language, all while preserving the meaning. An interpreter should always maintain a professional distance and be neutral to both sides of the conversation. Could I truly walk this line and perform by the book for each encounter?At one (...) of my medical encounters as a Spanish interpreter, I found myself in the midst of a heart-wrenching situation that involved grappling with life and death. No mother ever wants to hear that her baby has a condition that could lead to death either at birth or shortly thereafter. I had the profound experience of witnessing a woman in the final days of her pregnancy come to terms with a devastating reality.Just before I began my duties as an interpreter, I was informed that the baby had a congenital defect in which they would be born without parts of the brain, a condition called anencephaly. If babies with anencephaly are born alive, they usually live only a few hours or days. They have no forebrain or cerebrum (the main thinking structure of the brain), and the remaining brain tissue is often not covered by bone or skin. The baby will be blind, deaf, unconscious, and unable to feel pain.I learned that anencephaly is a serious birth defect, and the cause is not completely understood, but it's believed to be caused by a combination of genetic factors such as mutations or abnormalities, family history of neural tube defects, folic acid deficiency and exposure to certain toxins, medications, chemicals or substances. Hispanic women are more likely than women of other ethnicities to have a baby with anencephaly.During my first session, the medical team had many questions for the mom. For each question, the mother's responses were brief; either a yes or no answer, even when I was acting as a clarifier to make sure there were no misunderstandings. In my head, I thought:• Maybe she is in denial.• Maybe she has faith that a miracle will happen.• Maybe she is just afraid to ask questions.The registered nurse wanted to make sure that mom had what she would need to be comfortable for the day of her delivery. I remember questions like:• Will the baby be baptized?• Would you like to have a priest or a chaplain from the hospital or church?• Would mom or dad cut the umbilical cord?• Do you have a special blanket to shelter the baby? [End Page E10]The mother remained strong and resilient, keeping her emotions inside, at least from my perspective. The meeting was calm.There was a second session in which the medical team invited me to be part of a private meeting to go over key points about this case prior to the delivery. I remember being introduced to the neonatologist, this extraordinary doctor who played a vital role as part of the medical care team.I immediately did my own research about the functions of a neonatologist—a medical professional who manages the care of babies who are born prematurely or with an illness or congenital disability, such as prematurity or congenital malformations (birth defects), among others.I was present on the day of delivery. As I interpreted the emotional complexity of this event, a deep sense of empathy washed over me. I realized I could serve by giving my love through my words, my silence, and my presence. I interpreted for the mom when there were English-speaking care providers, focusing on interpreting for the patient's mom and spouse when needed. I was quiet in the times when a Spanish-speaking care provider spoke to the patient and family. Lastly, I was available—the only person outside of the family who was present during the actual delivery who was not a nurse or doctor—to help interpret and provide support whenever needed.Even with intensely emotional encounters such as this, my commitment to providing support and assistance remained unwavering. I stayed calm, silently praying for the mother and her baby. In an... (shrink)

The recent discovery of a phenomenon of craniofacial growth, called craniofacial contraction, throws a new light on the process of hominization. The main interest of this discovery lies in a growth principle combining the different craniofacial units, that is to say, the neurocranium, the chondrocranium and the splanchnocranium. Until recent years, these different parts were considered as neighbouring element without any morphogenic or morphodynamic connection. But now, we know that the morphogenesis of the base of the skull governs that of (...) the face. This basicranial morphogenesis is the occipital flexion. It generates morphogenic correlations with the face since embryogenesis. The ontogenic pathway of this phenomenon is the craniofacial contraction. It concerns embryonic dynamics connected with the spatial development of the embryonic neural system, the neural tube. These morphodynamics are common to each primate species, but they are differenciated by the amplitude of the embryonic contraction. We ask ourself the question: is hominization of the neurocephalic embryogenesis, that is the craniofacial contraction, plausible over a very long period, with gradual and chaotic evolutionary pathways, or, on the contrary, is the complexity of such an embryonic phenomenon, a limiting factor generating determined and predictible ontogenic thresholds? The study of extant and fossil primate skulls demonstrates that species are organized around 6 levels of embryonic contraction, which, starting from 60 millions years, evolve from the less to the most contracted skull. Among each ontogenic level, living and fossil species develop from the same embryonic system but between both levels, the embryos suddenly are reorganized. Therefore, I have defined an evolutive ontogenic unity, that is the fundamental ontogenesia. The cephalic pole has a fundamental ontogenesis, meaning that, beyond the diversities, we can see the same contraction in many living and extinct species. The ontogenic diversities are the result of the microevolution and are not predictible. In such a perspective, the ontogenic morphodynamics evolve with chaotic trajectories. But, between two embryonic levels, or two fundamental ontogeneses, evolutionary modalities are different. Eventually, from 60 millions years to XXth century, we observe the same phenomenon than during human ontogenesis; hominization of the cephalic pole is a craniofacial contraction. The evolutive pathway is stable, whatever the number of thresholds, the cranial shape changes but the ontogenic trajectory is preserved. This is a macroevolution because the embryonic system is reorganized. The logics of the phenomenon are an increasing dynamization, the human ontogenesis is the more unstable and the longer morphodynamics to stabilize the craniofacial contraction. To conclude, hominization is an iteration of an ontogenic process when embryos reach successive dynamic thresholds. The attractors are neither static, periodic, nor chaotic because the successive ontogenic trajectories are themselves in a stable evolutive trajectory, and the results with increasing contraction, complexified neocortical tissues and cephalocaudal reorganization are predictible. During hominization, irreversibility and innovations do not emerge with chaotic determinism, but with harmonic determinism in association with the correlations established between the embryonic tissues. When the system is destabilized, the embryonic systems do not forget the previous ontogenic pattern, on the contrary, they develop the pattern with new dynamical conditions. This sort of phenomenon is not described in the sciences of complexity. In the present case, we are in front of many millions years and the necessity to propose new concepts such as a new familly of attractors, namely the harmonic attractors. (shrink)

Hagfishes have long held a key place in discussions of early vertebrate evolution. Frustratingly, one basis for such discussions—namely hagfish embryology—is very incompletely known, because the embryos of these animals are notoriously difficult to obtain.1,2 Fortunately, a recent publication on a Far Eastern hagfish3 describes a workable procedure for obtaining embryos and then uses this precious material to show that the hagfish neural crest arises by cell delamination as in other vertebrates—and not by epithelial outpouchings from the wall of (...) the neural tube as previously claimed.4 Importantly, because hagfish embryos should now be available on a regular basis, the way is open for additional morphological and developmental genetic investigations to help evaluate existing evolutionary scenarios and perhaps suggest new ones. BioEssays 29:833–836, 2007. © 2007 Wiley Periodicals, Inc. (shrink)

In vertebrate development, the HOX genes act to specify cell identity along much of the anterior‐posterior axis of the embryonic central nervous system. In all vertebrates examined to date, the vitamin A metabolite retinoic acid is implicated in the patterning of the anterior posterior axis and the induction of HOX gene expression. Two recent papers have extended the study of retinoic acid induction of HOX genes to the closest relatives of the vertebrates, amphioxus and tunicates(1,2). In both these species, exogenous (...) retinoic acid is able to induce ectopic expression of HOX 1 genes in the anterior central nervous system. This suggests that retinoic acid control of anterior‐posterior axis formation and HOX induction is not specific to vertebrates. However, in the more distantly related echinoderms and arthropods, retinoic acid does not seem to act in the same way. Thus the role of retinoic acid in anterior‐posterior axis specification may be a chordate innovation, perhaps linked to the evolution of another chordate character, the dorsal neural tube. (shrink)

The paper presents some knowledge of history of medicine – especially those from the embryological field – correlated with theological marks in order to motivate the rightfulness of the method of „bringing the mind down into the heart”, a procedure during the Jesus Prayer. The ascetic Fathers mentioned that the mind is an energy which starts from the heart and reaches the brain – which offers the possibility to express itself. It is possible to consider that this transfer begins since (...) the primitive heart is in the same plane and before the cerebral area. Then, after the folding of the embryo, the heart will be placed under the brain. So “bringing the mind down into the heart” is also biologically feasible. Although the primitive heart is structured after the neural tube, it starts beating at 21 to 22 days, unlike the brain which began its function on the 40th day. This explains the theological meaning of the heart, wider than the signification of the mind (attribute of the brain). (shrink)

Environmental ethicists and experts in human health have raised concerns about the effects of hydraulic fracking to access natural oil and gas resources found deep in shale rock formations on surrounding ecosystems and communities. In this study, we analyzed the prevalence of discourse on brain and mental health, and ethics, in the peer-reviewed and grey literature in the five-year period between 2016 and 2022. A total of 84 articles met inclusion criteria for analysis. Seventy-six percent (76%) mentioned impacts on brain (...) (e.g., neural tube defects, neurological symptoms), and mental health (e.g., negative psychological effects, stress, depression) briefly; 11 reports dedicated substantive discourse to either or both together. References to safety (77%) dominated the ethics context. Discussion of environmental injustices as fracking sites disproportionately affect vulnerable communities appeared in 38% of the papers. We examine the findings through the lens of environmental neuroethics that brings human-made changes to the environment, brain and mental health, and ethics together into three interwoven lines of inquiry. (shrink)

The vertebrate nervous system performs the most complex functions of any organ system. This feat is mediated by dedicated assemblies of neurons that must be precisely connected to one another and to peripheral tissues during embryonic development. Motor neurons, which innervate muscle and regulate autonomic functions, form an integral part of this neural circuitry. The first part of this review describes the remarkable progress in our understanding of motor neuron differentiation, which is arguably the best understood model of neuronal (...) differentiation to date. During development, the coordinate actions of inductive signals from adjacent non‐neural tissues initiate the differentiation of distinct motor neuron subclasses, with specific projection patterns, at stereotypical locations within the neural tube. Underlying this specialisation is the expression of specific homeodomain proteins, which act combinatorially to confer motor neurons with both their generic and subtype‐specific properties. Ensuring that specific motor neuron subtypes innervate the correct target structure, however, requires precise motor axon guidance mechanisms. The second half of this review focuses on how distinct motor neuron subtypes pursue highly specific projection patterns by responding differentially to spatially discrete attractive and repulsive molecular cues. The tight link between motor neuron specification and axon pathfinding appears to be established by the dominant role of homeodomain proteins in dictating the ways that navigating motor axons interpret the plethora of guidance cues impinging on growth cones. BioEssays 23:582–595, 2001. © 2001 John Wiley & Sons, Inc. (shrink)

A statewide program in California to detect neural tube and other birth defects may revive enthusiasm for mass prenatal screening. Participation in the program is voluntary, but all expectant mothers are asked to sign a statement of “informed consent/refusal.” So far California's program seems to be working well, but questions for the future include the level of participation, the possibility that normal fetuses will be aborted, the kinds of information given to women, and the elusive nature of free (...) choice. (shrink)

We use the phrase "moral intuition" to describe the appearance in consciousness of moral judgments or assessments without any awareness of having gone through a conscious reasoning process that produces this assessment. This paper investigates the neural substrates of moral intuition. We propose that moral intuitions are part of a larger set of social intuitions that guide us through complex, highly uncertain and rapidly changing social interactions. Such intuitions are shaped by learning. The neural substrates for moral intuition (...) include fronto-insular, cingulate, and orbito-frontal cortices and associated subcortical structure such as the septum, basil ganglia and amygdala. Understanding the role of these structures undercuts many philosophical doctrines concerning the status of moral intuitions, but vindicates the claim that they can sometimes play a legitimate role in moral decision-making. (shrink)

Since its introduction, multivariate pattern analysis, or ‘neural decoding’, has transformed the field of cognitive neuroscience. Underlying its influence is a crucial inference, which we call the decoder’s dictum: if information can be decoded from patterns of neural activity, then this provides strong evidence about what information those patterns represent. Although the dictum is a widely held and well-motivated principle in decoding research, it has received scant philosophical attention. We critically evaluate the dictum, arguing that it is false: (...) decodability is a poor guide for revealing the content of neural representations. However, we also suggest how the dictum can be improved on, in order to better justify inferences about neural representation using MVPA. 1Introduction 2A Brief Primer on Neural Decoding: Methods, Application, and Interpretation 2.1What is multivariate pattern analysis? 2.2The informational benefits of multivariate pattern analysis 3Why the Decoder’s Dictum Is False 3.1We don’t know what information is decoded 3.2The theoretical basis for the dictum 3.3Undermining the theoretical basis 4Objections and Replies 4.1Does anyone really believe the dictum? 4.2Good decoding is not enough 4.3Predicting behaviour is not enough 5Moving beyond the Dictum 6Conclusion. (shrink)

William James described the stream of thought as having two components: (1) a nucleus of highly conscious, often perceptual material; and (2) a fringe of dimly felt contextual information that controls the entry of information into the nucleus and guides the progression of internally directed thought. Here I examine the neural and cognitive correlates of this phenomenology. A survey of the cognitive neuroscience literature suggests that the nucleus corresponds to a dynamic global buffer formed by interactions between different regions (...) of the brain, while the fringe corresponds to a set of mechanisms in the frontal and medial temporal lobes that control the contents of this global buffer. A consequence of this account is that there might be conscious imagistic representations that are not part of the nucleus. I argue that phenomenology can be linked to psychology and neuroscience and a meaningful way that illuminates both. (shrink)

Decades of psychological research have been aimed at modeling how people learn features and categories. The empirical validation of these theories is often based on artificial stimuli with simple representations. Recently, deep neural networks have reached or surpassed human accuracy on tasks such as identifying objects in natural images. These networks learn representations of real‐world stimuli that can potentially be leveraged to capture psychological representations. We find that state‐of‐the‐art object classification networks provide surprisingly accurate predictions of human similarity judgments (...) for natural images, but they fail to capture some of the structure represented by people. We show that a simple transformation that corrects these discrepancies can be obtained through convex optimization. We use the resulting representations to predict the difficulty of learning novel categories of natural images. Our results extend the scope of psychological experiments and computational modeling by enabling tractable use of large natural stimulus sets. (shrink)

This paper proposes an account of neurocognitive activity without leveraging the notion of neural representation. Neural representation is a concept that results from assuming that the properties of the models used in computational cognitive neuroscience must literally exist the system being modelled. Computational models are important tools to test a theory about how the collected data has been generated. While the usefulness of computational models is unquestionable, it does not follow that neurocognitive activity should literally entail the properties (...) construed in the model. While this is an assumption present in computationalist accounts, it is not held across the board in neuroscience. In the last section, the paper offers a dynamical account of neurocognitive activity with Dynamical Causal Modelling that combines dynamical systems theory mathematical formalisms with the theoretical contextualisation provided by Embodied and Enactive Cognitive Science. (shrink)

Processing limitations can be an advantage for a learner. They can filter input to the learner so that the relations to be learned increase in complexity only gradually. The time-course of filtered input can complement the growing neural representations discussed by Quartz & Sejnowski.

Arbib et al.'s comprehensive review of neural organization, over-relies on modernist concepts and restricts our understanding of brain and behavior. Reliance on terms like coding, transformation, and representation perpetuates a “black-box approach” to the study of the brain. Recognition is due to the authors for attempting to introduce postmodern concepts such as chaos and self-organization to the study of neural organization. However, confusion occurs in the implementation of “biologically rooted” schema theory in which schemas are viewed as computer (...) programs. The inclusion of an additional functional level between structure and dynamics is unnecessary in a postmodernist perspective of brain and behavior. (shrink)

Studies have shown that some covertly conscious brain-injured patients, who are behaviorally unresponsive, can reply to simple questions via neuronal responses. Given the possibility of such neuronal responses, Andrew Peterson et al. have argued that there is warrant for some covertly conscious patients being included in low-stakes medical decisions using neuronal responses, which could protect and enhance their autonomy. The justification for giving credence to alleged neuronal responses must be analyzed from various perspectives, including neurology, bioethics, law, and as we (...) suggest, philosophy of mind. In this article, we analyze the warrant for giving credence to neuronal responses from two different views in philosophy of mind. We consider how nonreductive physicalism’s causal exclusion problem elicits doubt about interpreting neural activity as indicating a conscious response. By contrast, such an interpretation is supported by the mind-body powers model of neural correlates of consciousness inspired by hylomorphism. (shrink)

Convolutional neural networks, which automatically learn features from raw data to approximate functions, are being increasingly applied to the end-to-end analysis of electroencephalographic signals, especially for decoding brain states in brain-computer interfaces. Nevertheless, CNNs introduce a large number of trainable parameters, may require long training times, and lack in interpretability of learned features. The aim of this study is to propose a CNN design for P300 decoding with emphasis on its lightweight design while guaranteeing high performance, on the effects (...) of different training strategies, and on the use of post-hoc techniques to explain network decisions. The proposed design, named MS-EEGNet, learned temporal features in two different timescales in an efficient and optimized way, and was validated on three P300 datasets. The CNN was trained using different strategies and was compared with several state-of-the-art algorithms. Furthermore, variants of the baseline MS-EEGNet were analyzed to evaluate the impact of different hyper-parameters on performance. Lastly, saliency maps were used to derive representations of the relevant spatio-temporal features that drove CNN decisions. MS-EEGNet was the lightest CNN compared with the tested SOA CNNs, despite its multiple timescales, and significantly outperformed the SOA algorithms. Post-hoc hyper-parameter analysis confirmed the benefits of the innovative aspects of MS-EEGNet. Furthermore, MS-EEGNet did benefit from transfer learning, especially using a low number of training examples, suggesting that the proposed approach could be used in BCIs to accurately decode the P300 event while reducing calibration times. Representations derived from the saliency maps matched the P300 spatio-temporal distribution, further validating the proposed decoding approach. This study, by specifically addressing the aspects of lightweight design, transfer learning, and interpretability, can contribute to advance the development of deep learning algorithms for P300-based BCIs. (shrink)