The Nature-Nurture controversy has been with us since it was first outlined by Plato and Aristotle. Nobody likes it anymore. All reasonable scholars today agree that genes and environment interact to determine complex cognitive outcomes. So why does the controversy persist? First, it persists because it has practical implications that cannot be postponed (i.e., what can we do to avoid bad outcomes and insure better ones?), a state of emergency that sometimes tempts scholars to stake out claims they cannot defend. Second, the controversy persists because we lack a precise, testable theory of the process by which genes and environment interact. In the absence of a better theory, innateness is often confused with (1) domain specificity (Outcome X is so peculiar that it must be innate), (2) species specificity (we are the only species who do X, so X must lie in the human genome), (3) localization (Outcome X is mediated by a particular part of the brain, so X must be innate), and (4) learnability (we cannot figure out how X could be learned, so X must be innate). We believe that an explicit and plausible theory of interaction is now around the corner, and that many of the classic maneuvers to defend or attack innateness will soon disappear. In the interim, some serious errors can be avoided if we keep these confounded issues apart. That is the major goal of this paper, i.e., not to attack innateness but to clarify what

Introduction Methods Results Discussion Conclusions Figures References ABSTRACT Definition in the living premature infant of the anatomical and temporal characteristics of development of critical brain structures is crucial for insight into the time of greatest vulnerability of such brain structures. We utilized 3D Magnetic Resonance Imaging (3D-MRI) and image processing algorithms to quantitate total brain volume and total volumes of cerebral gray matter (GM), unmyelinated white matter (WM), myelinated WM and cerebrospinal fluid (CSF) in 78 premature and mature newborns (postconceptional ages: 29 to 41 weeks). Total brain tissue volume was shown to increase linearly at a rate of 22cc per week. Total GM showed a linear increase in relative intracranial volume of approximately 1.4% or 15cc in absolute volume per week. The pronounced increase in total GM reflected primarily a four-fold increase in cortical GM. Unmyelinated WM was found to be the most prominent brain tissue class in t...

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understanding of numerical quantities is the notation used for the numbers (Chochon et al., 1999; driven by a magnitude representation associated with Dehaene et al., 1999; Gruber et al., 2001; Naccache et the intraparietal sulcus and possibly under genetic al., 2002; Pesenti et al., 2000; Pinel et al., 2001). Even control. The aim of this study was to investigate, using the simple presentation of numbers without explicit fMRI and structural imaging, the interaction between magnitude processing appears sufficient to specifically the abnormal development of numerical representa- activate the intraparietal sulci (Eger et al., 2003). To- tion in an X-linked condition, Turner syndrome (TS), gether, these results suggest that number-driven intra- and the development of the intraparietal sulcus. fMRI parietal activations reflect automatic access to an ab- during exact and approximate calculation in TS showed stract representation of numerical quantity. an abnormal modulation of intrapa

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The representations of visual hemifields in the extrastriate areas of various species exhibit field discontinuities and islands. We propose that these violations of retinotopy are a developmental consequence of the elongated shape of the respective cortical areas. To substantiate this claim, we investigate a model of activity driven map formation. In agreement with observations, this model yields maps with field discontinuities if the cortical areas exceed a threshold elongation. Moreover, within the same model also island representations in the periphery and of the area centralis can be understood. A multistability of solutions in the model gives a very simple explanation for the observed interindividual variability of maps in cats. The model leads to a prediction for the radial dependence of the areal magnification factor near field discontinuities, which could be accessible for a high precision mapping experiment. Revised Version 14.10.1993 submitted to Biological Cybernetics 1 In...

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The Nature-Nurture controversy has been with us since it was first outlined by Plato and Aristotle. Nobody likes it anymore. All reasonable scholars today agree that genes and environment interact to determine complex cognitive outcomes. So why does the controversy persist? First, it persists because it has practical implications that cannot be postponed (i.e., what can we do to avoid bad outcomes and insure better ones?), a state of emergency that sometimes tempts scholars to stake out claims they cannot defend. Second, the controversy persists because we lack a precise, testable theory of the process by which genes and environment interact. In the absence of a better theory, innateness is often confused with (1) domain specificity (Outcome X is so peculiar that it must be

In the developing human brain, the cortical sulci formation is a complex process starting from 14 weeks of gestation onward. The potential influence of underlying mechanisms (genetic, epigenetic, mechanical or environmental) is still poorly understood, because reliable quantification in vivo of the early folding is lacking. In this study, we investigate the sulcal emergence noninvasively in 35 preterm newborns, by applying dedicated postprocessing tools to magnetic resonance images acquired shortly after birth over a developmental period critical for the human cortex maturation (26--36 weeks of age). Through the original three-dimensional reconstruction of the interface between developing cortex and white matter and correlation with volumetric measurements, we document early sulcation in vivo, and quantify changes with age, gender, and the presence of small white matter lesions. We observe a trend towards lower cortical surface, smaller cortex, and white matter volumes, but equivalent sulcation in females compared with males. By precisely mapping the sulci, we highlight interindividual variability in time appearance and interhemispherical asymmetries, with a larger right superior temporal sulcus than the left. Thus, such an approach, included in a longitudinal follow-up, may provide early indicators on the structural basis of cortical functional specialization and abnormalities induced by genetic and environmental factors.

Abstract. Neocortical neuroblast cell lines were used to clone G-protein-coupled receptor (GPCR) genes to study signaling mechanisms regulating cortical neurogenesis. One putative GPCR gene displayed an in situ expression pattern enriched in cortical neurogenic regions and was therefore named ventricular zone gene-! (vzg-1). The vzg-1 cDNA hybridized to a 3.8-kb mRNA transcript and encoded a protein with a predicted molecular mass of 41--42 kD, confirmed by Western blot analysis. To assess its function, vzg-1 was overexpressed in a cell line from which it was cloned, inducing serum-dependent "cell rounding. " Lysophosphatidic acid (LPA), a bioactive lipid present in high concentrations in serum, reproduced the effect seen with serum alone. Morphological responses to other related