The connectome mapper: an open-source processing pipeline to map connectomes with MRI.

Researchers working in the field of global connectivity analysis using diffusion magnetic resonance imaging (MRI) can count on a wide selection of software packages for processing their data, with methods ranging from the reconstruction of the local intra-voxel axonal structure to the estimation of the trajectories of the underlying fibre tracts. However, each package is generally task-specific and uses its own conventions and file formats. In this article we present the Connectome Mapper, a software pipeline aimed at helping researchers through the tedious process of organising, processing and analysing diffusion MRI data to perform global brain connectivity analyses. Our pipeline is written in Python and is freely available as open-source at www.cmtk.org.

Space for thought: Representation of body boundaries and intellectual efficiency in children

Aim: The psychoanalytic theories of Bion, Anzieu, Berger and Gibello postulate that the development of thinking depends upon the formation of a psychic space. This thinking space has its origin in the body and in our interpersonal relations. This study aims to validate this psychodynamic hypothesis. Method: A group of 8- to 14-year-old children participated in this research. The presence of a thinking space was operationalized by the "barrier" and "penetration" scores on the Rorschach's Fisher and Cleveland scales and intellectual efficiency was measured using a short version of the WISC-IV. Results: Results show that extreme scores on the "barrier" and "penetration" variables predict a lower intellectual level than average scores on the same variables. Conclusion: The development of thinking and personality are undoubtedly linked and the "barrier" and "penetration" variables are useful measures when evaluating the development of a space for thought.

RECHERCHE TRANSLATIONNELLE EN NEUROSCIENCES PSYCHIATRIQUES: DE L'ANIMAL MODELE DE SCHIZOPHRENIE A LA DETECTION D'UNE DESORIENTATION SPATIALE, PRATIQUE OU SYMBOLIQUE CHEZ DES PATIENTS

La modélisation, chez l'animal, de maladies psychiatriques telles que la schizophrénie repose sur différentes démarches visant à induire des perturbations cérébrales similaires à celles observées dans la maladie. Nous avons cherché à étudier chez le rat les effets d'une diminution (50%) transitoire en glutathion (GSH) durant le développement (PND 5 à PND 16) à partir de l'implication, chez des adultes, des conséquences de cette perturbation dans des mécanismes fondamentaux de traitement de l'information sensorielle. Cette thèse évalue et documente les déficits de compétences de navigation spatiale dans ce modèle. Nous avons mis en évidence des effets comportementaux à partir de l'identification de différences particulières dans des tâches d'orientation: des difficultés, chez les rats ayant subi un déficit en GSH, à élaborer une représentation globale de l'environnement dans lequel ils se déplacent, difficultés compensées par une attention particulière aux détails visuels le composant. Cette stratégie réactive compensatoire est efficace lorsque les conditions permettent un ajustement continu aux repères visuels environnementaux. Elle ne permet cependant pas des prédictions et des attentes sur ce qui devrait être rencontré et perçu dans une certaine direction, dès qu'une partie des informations visuelles familières disparaît. Il faudrait pour cela une capacité fondée sur une représentation abstraite, à distance des modalités sensorielles qui en ont permis son élaboration. Notre thèse soutient que les déficits, supposés participer à l'émergence de certains symptômes de la maladie, auraient également des conséquences sur l'élaboration de la représentation spatiale nécessaire à des capacités d'orientation effectives et symboliques. - The study of a psychiatric disease such as schizophrenia in an animal model relies on different approaches attempting to replicate brain perturbations similar to those observed in the illness. In the present work, behavioural consequences of a functional deficit in brain connectivity and coordination were assessed in rats with a transitory glutathione (GSH) deficit induced during the postnatal development (PND 5-PND 16) with daily injections of BSO (1- buthionine-(S,R)- sulfoximine). We searched for a theoretical syndrome associating ecologically relevant behavioural adaptive deficits and resulting from the weakening of sensory integration processes. Our results revealed significant and specific deficit of BSO treated rats in spatial orientation tasks designed to test for cognitive mapping abilities. Treated rats behaved as if impaired in the proactive strategies supported by an abstract representation such as a cognitive map. In contrast their performances were preserved whenever the environmental conditions allowed for adaptative reactive strategies, an equivalent of the visual affordances described by Gibson (1958). This supports our thesis that BSO treated rats expressed difficulties in elaborating a global representation of the environment. This deficit was completely - or - partially compensated by the development of an increased attention to the environment's visual details. This compensatory reactive strategy requires a rich environment allowing for continuous adjustment to visual cues. However, such adjustment doesn't allow to predictions and expectancies about what should be met and perceived in a certain direction, when familiar visual spatial cues are missing. Such competencies require orientation based on the use of an abstract spatial representation, independent from the specific sensory modalities that have participated to its elaboration. The impairment of BSO rats such spatial representation could result from a deficit in the integration and organization of perceptual information. Our model leads to the hypothesis that these fundamental deficits might account for certain symptoms of schizophrenia. They would also interfere with in the capacity to elaborate spatial representation necessary for optimal orientation in natural, artificial or symbolic environment.

Integration of olfactory information in a spatial representation enabling accurate arm choice in the radial arm maze

The aim of the present study was to determine whether and how rats can use local olfactory cues for spatial orientation. Rats were trained in an eight-arm radial maze under different conditions as defined by the presence or absence of supplementary olfactory cues marking each arm, the availability of distant visuospatial information, and the illumination of the maze (light or darkness). The different visual conditions were designed to dissociate among the effects of light per se and those of visuospatial cues, on the use of olfactory cues for accurate arm choice. Different procedures with modifications of the arrangement of olfactory cues were used to determine if rats formed a representation of the spatial configuration of the olfactory cues and if they could rely on such a representation for accurate arm choice in the radial maze. The present study demonstrated that the use of olfactory cues to direct arm choice in the radial arm maze was critically dependent on the illumination conditions and implied two different modes of processing of olfactory information according to the presence or the absence of light. Olfactory cues were used in an explicit manner and enabled accurate arm choice only in the absence of light. Rats, however, had an implicit memory of the location of the olfactory cues and formed a representation of the spatial position of these cues, whatever the lighting conditions. They did not memorize the spatial configuration of the olfactory cues per se but needed these cues to be linked to the external spatial frame of reference.

The cells and peripheral representation of sodium taste in mice.

Salt taste in mammals can trigger two divergent behavioural responses. In general, concentrated saline solutions elicit robust behavioural aversion, whereas low concentrations of NaCl are typically attractive, particularly after sodium depletion. Notably, the attractive salt pathway is selectively responsive to sodium and inhibited by amiloride, whereas the aversive one functions as a non-selective detector for a wide range of salts. Because amiloride is a potent inhibitor of the epithelial sodium channel (ENaC), ENaC has been proposed to function as a component of the salt-taste-receptor system. Previously, we showed that four of the five basic taste qualities-sweet, sour, bitter and umami-are mediated by separate taste-receptor cells (TRCs) each tuned to a single taste modality, and wired to elicit stereotypical behavioural responses. Here we show that sodium sensing is also mediated by a dedicated population of TRCs. These taste cells express the epithelial sodium channel ENaC, and mediate behavioural attraction to NaCl. We genetically engineered mice lacking ENaCalpha in TRCs, and produced animals exhibiting a complete loss of salt attraction and sodium taste responses. Together, these studies substantiate independent cellular substrates for all five basic taste qualities, and validate the essential role of ENaC for sodium taste in mice.

A novel vasopressin-induced transcript promotes MAP kinase activation and ENaC downregulation.

In the principal cell of the renal collecting duct, vasopressin regulates the expression of a gene network responsible for sodium and water reabsorption through the regulation of the water channel and the epithelial sodium channel (ENaC). We have recently identified a novel vasopressin-induced transcript (VIT32) that encodes for a 142 amino acid vasopressin-induced protein (VIP32), which has no homology with any protein of known function. The Xenopus oocyte expression system revealed two functions: (i) when injected alone, VIT32 cRNA rapidly induces oocyte meiotic maturation through the activation of the maturation promoting factor, the amphibian homolog of the universal M phase trigger Cdc2/cyclin; and (ii) when co-injected with the ENaC, VIT32 cRNA selectively downregulates channel activity, but not channel cell surface expression. In the kidney principal cell, VIP32 may be involved in the downregulation of transepithelial sodium transport observed within a few hours after vasopressin treatment. VIP32 belongs to a novel gene family ubiquitously expressed in oocyte and somatic cells that may be involved in G to M transition and cell cycling.

Political representation in Switzerland : democratic or plutocratic ?

Les inégalités économiques se traduisent-elles dans des inégalités politiques à travers le processus de représentation électorale? Telle est la question centrale de cette thèse qui s'attache, par ailleurs, à investiguer les mécanismes qui tendent à produire une représentation biaisée des préférences politiques des citoyens en fonction de leur statut économique. Focalisé sur le cas de la Suisse et faisant usage des données de l'enquête postélectorale Selects de 2007, ce travail démontre que sur les rares sujets qui divisent les citoyens selon des clivages économiques - la redistribution des richesses et la sécurité sociale en particulier - les élus à l'Assemblée fédérale ont des préférences qui reflètent mieux les opinions des citoyens les plus riches. Cette sous-représentation des opinions des citoyens modestes et de ceux faisant partie du centre de la distribution des revenus peut en partie être attribuée à des différences dans les taux de participation et de connaissance politiques entre ces groupes de citoyens. La thèse met également en évidence le rôle joué par la représentation descriptive - autrement dit, la similitude en termes de statut économique entre les représentants et les représentés - dans la représentation des opinions et intérêts des citoyens. Par ailleurs, la structure du système partisan en Suisse ne reflétant pas la multidimensionnalité des préférences politiques des citoyens, les électeurs ne parviennent pas à traduire la complexité de leurs préférences politiques dans un choix de vote, ce qui, dans la configuration actuelle des forces politiques, tend à favoriser l'élection de représentants aux opinions proches de la droite sur les questions économiques. Enfin, une analyse de la représentation politique au niveau cantonal tend à soutenir la thèse selon laquelle le manque de régulation en matière de financement des partis en Suisse pourrait partiellement expliquer les inégalités dans la représentation des opinions politiques des citoyens aux revenus distincts. - Do economic inequalities translate into political inequalities through electoral representation? This is the central research question of this thesis, which also investigates the mechanisms that lead to potential economically based inequalities in the representation of citizens' policy preferences. Focusing on the case of Switzerland and making use of data provided by the post- electoral survey Selects 2007, this research demonstrates that regarding the rare policy domains in which the preferences of citizens are clearly linked to economic cleavages - redistribution and social security in particular - members of the Federal Assembly have policy preferences that best reflect the policy preferences of richer citizens. The under-representation of the opinions of relatively poor citizens and of those being the in the middle of the income distribution can be to some extent be explained by differences in political participation and political information across income groups. The thesis also puts forward the role played by descriptive representation - the similarity between representatives and represented in terms of their socioeconomic status - for the representation of citizens' preferences and interests. In addition, the structure of the party system in Switzerland does not reflect the multidimensionality of policy preferences among citizens who, as a result, have a hard time translating their complex preferences into a vote choice. Given the configuration of political actors, this tends to favour the election of representatives from the right who do not represent the preferences of their voters on economic issues. Finally, an analysis of representation at the cantonal level tends to confirm that the lack of party finance regulations in Switzerland may partially explain inequalities in the representation of citizens with different levels of income.

Carte et tableau : approche épistémologique ternaire

Under the referential of a ternary logic, this article aims to focus on the geographical map perceived as a visual object and the question of surfaces of representation. We analyse the status of map making versus landscape representation, the relations between a map and a painted picture. A ternary model of the pictural composition perspective|light/pictural field is proposed. The frame of the map, articulating the space that is cut out and the space included is discussed in a parallel between maps and painted pictures.

Single Subject Finger Somatotopy Mapping at 7T.

Introduction: The primary somatosensory cortex (SI) contains Brodmann areas (BA) 1, 2, 3a, and 3b. Research in non-human primates showed that BAs 3b, 1, and 2 each contain one full representation of the hand with separate representations for each finger. This research also showed that the finger representation in BA3b has larger and clearer finger somatotopy than BA1 and 2. Although several efforts to map finger somatotopy in SI by fMRI have been made at 1.5 and 3T these studies have yielded variable results and were not able to detect single subject finger somatotopy, probably due to the limited spatial extent of the cortical areas representing a digit (close to the resolution in most fMRI experiments), complications due to acquisition of consistent maps for individual subjects (Schweizer et al 2008), or inter-individual variability in sulcal anatomy impeding group studies. Here, we used 7T fMRI to investigate finger somatotopy in SI, some of its functional characteristics, and its reproducibility. Methods: Eight right-handed male subjects were scanned on a 7T scanner (Siemens Medical, Germany) with an 8-channel Tx/Rx rf-coil (Rapid Biomedical, Germany). 1.3x1.3x1.3mm3 resolution fMRI data were acquired using a sinusoidal readout EPI sequence (Speck et al, 2008) and FOV=210mm, TE/TR=27ms/2.5s, GRAPPA=2. Each volume contained 28 transverse slices covering SI. A single EPI volume with 64 slices was acquired to aid coregistration. 1x1x1mm3 anatomical data were acquire using the MP2RAGE sequence (Marques et al, 2009; TE/TR/TI1,2/TRmprage=2.63ms/7.2ms/0.9,3.2s/5s). Subjects were positioned supine in the scanner with their right arm comfortably against the magnet bore. An experimenter was positioned at the entrance of the bore where he could easily reach and stroke successively the two distal phalanxes of each digit. The order of stroked digit was D1 (thumb)-D3-D5-D2-D4, with 20s ON, 10s OFF alternated. This sequence was repeated four times per run and two functional runs were acquired per subject. Realignment, smoothing (FWHM 2 mm), coregistration of the anatomical to the fMRI data and calculation of t-statistics were done using SPM8. An SI mask was obtained via an F-contrast (p<0.001) over all digits. Within the mask, voxels were labeled with the number of the digit demonstrating the highest t-value for that particular voxel. Results: For all subjects, areas corresponding to the five digits were identified in contralateral SI. BA3b showed the most consistent somatotopic finger representation (see an example in Fig.1). The five digits were localized in a consecutive order in the cortex, with D1 most anterior, inferior and distal and D5, most posterior, superior and medial (mean distance between centres of mass of digit representations ±stderr: 4.2±0.7mm; see Fig. 2). The analysis of average beta values within each finger representation region revealed the specificity of the somatotopic region to the tactile input for each tested finger (except digit 4 and 5). Five of these subjects also presented an orderly and consecutive representation of the five digits in BA1 and 2. Conclusions: Our data reveal that the increased BOLD sensitivity at 7T and the high spatial resolution used in this study allow consistent somatotopic mapping using human touch as a stimulus and that human SI contains at least three separate regions that contain five separate representations of all single contralateral fingers. Moreover, adjacent fingers were represented at adjacent cortical regions across the three SI regions. The spatial organization of SI as reflected in individual subject topography corresponds well with previous electrophysiological data in non-human primates. The small distance between digit representations highlights the need for the high spatial resolution available at 7T.