Visual functions in the healthy and schizophrenic brain : from stimulus control to illusory perceptions using electrical neuroimaging

ABSTRACT (FRENCH)Ce travail de thèse basé sur le système visuel chez les sujets sains et chez les patients schizophrènes, s'articule autour de trois articles scientifiques publiés ou en cours de publication. Ces articles traitent des sujets suivants : le premier article présente une nouvelle méthode de traitement des composantes physiques des stimuli (luminance et fréquence spatiale). Le second article montre, à l'aide d'analyses de données EEG, un déficit de la voie magnocellulaire dans le traitement visuel des illusions chez les patients schizophrènes. Ceci est démontré par l'absence de modulation de la composante PI chez les patients schizophrènes contrairement aux sujets sains. Cette absence est induite par des stimuli de type illusion Kanizsa de différentes excentricités. Finalement, le troisième article, également à l'aide de méthodes de neuroimagerie électrique (EEG), montre que le traitement des contours illusoires se trouve dans le complexe latéro-occipital (LOC), à l'aide d'illusion « misaligned gratings ». De plus il révèle que les activités démontrées précédemment dans les aires visuelles primaires sont dues à des inférences « top- down ».Afin de permettre la compréhension de ces trois articles, l'introduction de ce manuscrit présente les concepts essentiels. De plus des méthodes d'analyses de temps-fréquence sont présentées. L'introduction est divisée en quatre parties : la première présente le système visuel depuis les cellules retino-corticales aux deux voix du traitement de l'information en passant par les régions composant le système visuel. La deuxième partie présente la schizophrénie par son diagnostic, ces déficits de bas niveau de traitement des stimuli visuel et ces déficits cognitifs. La troisième partie présente le traitement des contours illusoires et les trois modèles utilisés dans le dernier article. Finalement, les méthodes de traitement des données EEG seront explicitées, y compris les méthodes de temps-fréquences.Les résultats des trois articles sont présentés dans le chapitre éponyme (du même nom). De plus ce chapitre comprendra les résultats obtenus à l'aide des méthodes de temps-fréquenceFinalement, la discussion sera orientée selon trois axes : les méthodes de temps-fréquence ainsi qu'une proposition de traitement de ces données par une méthode statistique indépendante de la référence. La discussion du premier article en montrera la qualité du traitement de ces stimuli. La discussion des deux articles neurophysiologiques, proposera de nouvelles d'expériences afin d'affiner les résultats actuels sur les déficits des schizophrènes. Ceci pourrait permettre d'établir un marqueur biologique fiable de la schizophrénie.ABSTRACT (ENGLISH)This thesis focuses on the visual system in healthy subjects and schizophrenic patients. To address this research, advanced methods of analysis of electroencephalographic (EEG) data were used and developed. This manuscript is comprised of three scientific articles. The first article showed a novel method to control the physical features of visual stimuli (luminance and spatial frequencies). The second article showed, using electrical neuroimaging of EEG, a deficit in spatial processing associated with the dorsal pathway in chronic schizophrenic patients. This deficit was elicited by an absent modulation of the PI component in terms of response strength and topography as well as source estimations. This deficit was orthogonal to the preserved ability to process Kanizsa-type illusory contours. Finally, the third article resolved ongoing debates concerning the neural mechanism mediating illusory contour sensitivity by using electrical neuroimaging to show that the first differentiation of illusory contour presence vs. absence is localized within the lateral occipital complex. This effect was subsequent to modulations due to the orientation of misaligned grating stimuli. Collectively, these results support a model where effects in V1/V2 are mediated by "top-down" modulation from the LOC.To understand these three articles, the Introduction of this thesis presents the major concepts used in these articles. Additionally, a section is devoted to time-frequency analysis methods not presented in the articles themselves. The introduction is divided in four parts. The first part presents three aspects of the visual system: cellular, regional, and its functional interactions. The second part presents an overview of schizophrenia and its sensoiy-cognitive deficits. The third part presents an overview of illusory contour processing and the three models examined in the third article. Finally, advanced analysis methods for EEG are presented, including time- frequency methodology.The Introduction is followed by a synopsis of the main results in the articles as well as those obtained from the time-frequency analyses.Finally, the Discussion chapter is divided along three axes. The first axis discusses the time frequency analysis and proposes a novel statistical approach that is independent of the reference. The second axis contextualizes the first article and discusses the quality of the stimulus control and direction for further improvements. Finally, both neurophysiologic articles are contextualized by proposing future experiments and hypotheses that may serve to improve our understanding of schizophrenia on the one hand and visual functions more generally.

Causal explanations and scientific realism in particle physics

Particle physics studies highly complex processes which cannot be directly observed. Scientific realism claims that we are nevertheless warranted in believing that these processes really occur and that the objects involved in them really exist. This dissertation defends a version of scientific realism, called causal realism, in the context of particle physics. I start by introducing the central theses and arguments in the recent philosophical debate on scientific realism (chapter 1), with a special focus on an important presupposition of the debate, namely common sense realism. Chapter 2 then discusses entity realism, which introduces a crucial element into the debate by emphasizing the importance of experiments in defending scientific realism. Most of the chapter is concerned with Ian Hacking's position, but I also argue that Nancy Cartwright's version of entity realism is ultimately preferable as a basis for further development. In chapter 3,1 take a step back and consider the question whether the realism debate is worth pursuing at all. Arthur Fine has given a negative answer to that question, proposing his natural ontologica! attitude as an alternative to both realism and antirealism. I argue that the debate (in particular the realist side of it) is in fact less vicious than Fine presents it. The second part of my work (chapters 4-6) develops, illustrates and defends causal realism. The key idea is that inference to the best explanation is reliable in some cases, but not in others. Chapter 4 characterizes the difference between these two kinds of cases in terms of three criteria which distinguish causal from theoretical warrant. In order to flesh out this distinction, chapter 5 then applies it to a concrete case from the history of particle physics, the discovery of the neutrino. This case study shows that the distinction between causal and theoretical warrant is crucial for understanding what it means to "directly detect" a new particle. But the distinction is also an effective tool against what I take to be the presently most powerful objection to scientific realism: Kyle Stanford's argument from unconceived alternatives. I respond to this argument in chapter 6, and I illustrate my response with a discussion of Jean Perrin's experimental work concerning the atomic hypothesis. In the final part of the dissertation, I turn to the specific challenges posed to realism by quantum theories. One of these challenges comes from the experimental violations of Bell's inequalities, which indicate a failure of locality in the quantum domain. I show in chapter 7 how causal realism can further our understanding of quantum non-locality by taking account of some recent experimental results. Another challenge to realism in quantum mechanics comes from delayed-choice experiments, which seem to imply that certain aspects of what happens in an experiment can be influenced by later choices of the experimenter. Chapter 8 analyzes these experiments and argues that they do not warrant the antirealist conclusions which some commentators draw from them. It pays particular attention to the case of delayed-choice entanglement swapping and the corresponding question whether entanglement is a real physical relation. In chapter 9,1 finally address relativistic quantum theories. It is often claimed that these theories are incompatible with a particle ontology, and this calls into question causal realism's commitment to localizable and countable entities. I defend the commitments of causal realism against these objections, and I conclude with some remarks connecting the interpretation of quantum field theory to more general metaphysical issues confronting causal realism.

Yhteistoiminnallinen hoitotyö

Opinnäytetyön tarkoituksena on selvittää, mitä on yhteistoiminnallinen hoitotyö. Opinnäyteytössä määritellään yhteistoiminnallisen hoitotyön käsite ja sisältö. Työssä on tarkasteltu yhteistoiminnallisuutta selittäviä käsitteitä. Opinnäytetyö on osa laajempaa projektia, jossa on mukana HUS:n Psykiatriakeskus, Helsingin kaupungin terveyskeskuksen psykiatrian osasto sekä Helsingin ammattikorkeakoulu Stadia. Projekin tarkoituksena on kehittää psykiatrisen hoitotyön käytäntöä yhteistoiminnalliseksi. Opinnäytetyö on tehty soveltaen systemaattisen kirjallisuuskatsauksen mallia. Aineisto koostuu yhteensä kolmestatoista lähteestä. Mukana on väitöskirjoja, pro gradu- tutkielmia sekä tutkimusartikkeleita, jotka on julkaistu hoitotieteellisissä julkaisuissa. Kirjallisuuskatsauksen tuloksina nousi esiin, että yhteistoiminnallinen hoitotyö on potilaan ja hoitajan välistä yhteistyötä. Se on potilaslähtöinen tapa tehdä hoitotyötä, jossa otetaan huomioon potilaan voimavarat ja tarpeet. Potilas on vastuullinen osallistuja. Jokainen hoitoon osallistuva määrittelee hoidon tavoitteen ja kukin osallistuu siihen tasavertaisesti. Yhteistoiminnallisuuteen kuuluu molemminpuolinen luottamus. Kaikki osapuolet vaikuttuvat toisistaan ja dialogisuuden avulla voidana löytää uusia näkökulmia hoitoon. Yhteistoiminnallisuus on uusi käsite hoitotyössä. Sen ymmärtäminen ja toteutuminen vaatii hoitotyön tekijöiden perehdyttämistä syvällisemmin aiheeseen. Se vaatii potilaalta mahdollisuutta osallistua voimavarojensa mukaan hoitoon. Yhteistoiminnallisen hoitotyön avulla voidaan motivoida potilasta aktiivisempaan rooliin omassa hoidossaan.

Avaruusinstrumentin mekaniikkasuunnittelu

Tämän insinöörityön tarkoituksena on kehittää avaruusinstrumentti, joka on osa Euroopan avaruusjärjestön ESA:n ja Japanin avaruusjärjestön JAXA:n BepiColombo-yhteistyöhanketta. Satelliitti lähetetään Merkurius-planeetan kiertoradalle vuonna 2013. Avaruusaluksen matka Merkuriukseen kestää yhteensä kuusi vuotta ja on perillä vuonna 2019. Yksi BepiColombo-satelliitin tieteellisistä instrumenteista on Oxford Instruments Analytical Oy:n kehittämä SIXS-instrumentti (Solar Intensity X-ray and particle Spectrometer). Instrumentin tarkoituksena on mitata auringosta tulevaa röntgen- ja partikkelisäteilyä. Se toimii yhteistyössä Merkuriuksen pintaa mittaavan MIXS-instrumentin (Mercury Imaging X-ray Spectrometer) kanssa. Tuloksista pystytään analysoimaan ne alkuaineet, joista Merkuriuksen pinta koostuu. Työn alussa esitellään teoriataustaa alkuaineiden mittauksesta niiltä osin, kuin se tämän työn kannalta on tarpeellista. Työssä syvennytään tarkemmin auringosta tulevan säteilyn mittauksesta vastaavan instrumentin tekniikkaan ja mekaniikkasuunnitteluun. Instrumentin lämpöteknisestä suunnittelusta, värähtelymittauksista ja lujuusanalyysista on työhön sisällytetty pääasiat. Työn tuloksena on kehitetty instrumenttiin tulevan partikkelidetektorin prototyyppi sekä instrumenttikotelon malli. Lopullisen koon instrumenttikotelolle määrittää vaadittavan elektroniikan viemä tila. Mittalaitteen kehitystyö jatkuu Oxford Instruments Analytical Oy:ssä vuoteen 2011 saakka.

Man Made Black Holes and Big Bangs: Diffusion and Integration of Scientific Information into Everyday Thinking

Drawing on Social Representations Theory, this study investigates focalisation and anchoring during the diffusion of information concerning the Large Hadron Collider (LHC), the particle accelerator at the European Organisation for Nuclear Research (CERN). We hypothesised that people focus on striking elements of the message, abandoning others, that the nature of the initial information affects diffusion of information, and that information is anchored in prior attitudes toward CERN and science. A serial reproduction experiment with two generations and four chains of reproduction diffusing controversial versus descriptive information about the LHC shows a reduction of information through generations, the persistence of terminology regarding the controversy and a decrease of other elements for participants exposed to polemical information. Concerning anchoring, positive attitudes toward CERN and science increase the use of expert terminology unrelated to the controversy. This research highlights the relevance of a social representational approach in the public understanding of science.

La toxicologie forensique, une discipline scientifique en plein essor [Forensic toxicology, a growing scientific discipline]

La recherche de substances ayant pu jouer un rôle direct ou indirect dans la cause de la mort ou ayant pu modifier le comportement d'un individu constitue la mission première de la toxicologie forensique. L'augmentation de la consommation de substances illégales et de médicaments dans les sociétés modernes a fait connaître à la toxicologie forensique un essor très important ces dernières décennies. D'autre part, les développements technologiques analytiques ont permis d'obtenir des outils très sensibles et spécifiques pour la recherche et le dosage d'une multitude de substances dans une grande variété d'échantillons biologiques, parfois présentes à des concentrations très faibles, conséquence d'une dose équivalente à la prise d'une seule unité galénique. Forensic toxicology has to bring evidence of substances that could have been involved directly or indirectly in the cause of death or that could influence the behaviour of somebody. The increase of the consumption of illegal and legal drugs in modern societies during last decades gave a boost to forensic toxicology. Moreover, improvement with analytical technology gave tools with high degrees of sensitivity and specificity for the screening and quantification of a large amount of substances in various biological specimens, even with very low concentration resulting of a single dose of medication.

Scientific production on the applicability of phenytoin in wound healing

Phenytoin is an anticonvulsant that has been used in wound healing. The objectives of this study were to describe how the scientific production presents the use ofphenytoinas a healing agent and to discuss its applicability in wounds. A literature review and hierarchy analysis of evidence-based practices was performed. Eighteen articles were analyzed that tested the intervention in wounds such as leprosy ulcers, leg ulcers, diabetic foot ulcers, pressure ulcers, trophic ulcers, war wounds, burns, preparation of recipient graft area, radiodermatitis and post-extraction of melanocytic nevi. Systemic use ofphenytoinin the treatment of fistulas and the hypothesis of topical use in the treatment of vitiligo were found. In conclusion, topical use ofphenytoinis scientifically evidenced. However robust research is needed that supports a protocol for the use ofphenytoinas another option of a healing agent in clinical practice.

Assessing the vulnerability of women to sexually transmitted diseases STDS/ HIV: construction and validation of markers

Objective To construct and validate markers of vulnerability of women to STDs/HIV, taking into consideration the importance of STDs/HIV. Method Methodological study carried out in three stages: 1) systematic review and identification of elements of vulnerability in the scientific production; 2) selection of elements of vulnerability, and development of markers; 3) establishment of the expert group and validation of the markers (content validity). Results Five markers were validated: no openness in the relationship to discuss aspects related to prevention of STDs/HIV; no perception of vulnerability to STDs/HIV; disregard of vulnerability to STDs/ HIV; not recognizing herself as the subject of sexual and reproductive rights; actions of health professionals that limit women’s access to prevention of STDs/HIV. Each marker contains three to eleven components. Conclusion The construction of such markers constituted an instrument, presented in another publication, which can contribute to support the identification of vulnerabilities of women in relation to STDs/HIV in the context of primary health care services. The markers constitute an important tool for the operationalization of the concept of vulnerability in primary health care and to promote inter/multidisciplinary and inter/multi-sectoral work processes.


Scientific Literature on the Reliability and Validity of the Manchester Triage System (MTS) Protocol: A Integrative Literature Review

OBJECTIVE To analyze the scientific production about the validity and reliability of the Manchester Triage System (MTS) protocol. METHOD A descriptive study of an integrative literature review. Articles on the validity and reliability of the MTS developed with children and adults published between 1999 and 2013 were included. RESULTS 14 articles were selected from a total of 8438, nine of validity and five of reliability. The reliability of the MTS ranged from moderate to almost perfect, with higher intra-evaluation. Regarding validity, the results seem to point to equivalent and satisfactory sensibility and specificity levels of the MTS. The instrument proved to be a good predictor of the need for hospitalization and of hospital mortality. CONCLUSION The reliability and validity of the MTS obtained in the studies is varied. It is recommended that new studies indicate necessary modifications to the MTS so that it is more safely used by nurses.

Implementation methodology of practices based on scientific evidence for assistance in natural delivery: a pilot study

AbstractOBJECTIVEPresenting methodology for transferring knowledge to improve maternal outcomes in natural delivery based on scientific evidence.METHOD: An intervention study conducted in the maternity hospital of Itapecerica da Serra, SP, with 50 puerperal women and 102 medical records from July to November 2014. The PACES tool from Joanna Briggs Institute, consisting of pre-clinical audit (phase 1), implementation of best practice (phase 2) and Follow-up Clinical Audit (phase 3) was used. Data were analyzed by comparing results of phases 1 and 3 with Fisher's exact test and a significance level of 5%.RESULTSThe vertical position was adopted by the majority of puerperal women with statistical difference between phases 1 and 3. A significant increase in bathing/showering, walking and massages for pain relief was found from the medical records. No statistical difference was found in other practices and outcomes. Barriers and difficulties in the implementation of evidence-based practices have been identified. Variables were refined, techniques and data collection instruments were verified, and an intervention proposal was made.CONCLUSIONThe study found possibilities for implementing a methodology of practices based on scientific evidence for assistance in natural delivery.