Dissertations / Theses on the topic 'Pulvinus'

Fundação de Amparo a Pesquisa do Estado de Minas Gerais
Although the majority of species in the deciduous forests lose their leaves during the dry season, some of them present alternative strategies, such as the leaf movement position (from horizontal to vertical ) in order to reduce transpiration. This study describes the leaf anatomy of nine plant species that reduce water loss during the dry season using the strategy of leaf movement rather than leaf abscission. The studied species were Piper aduncum sp. L. (Piperaceae), Acalypha Müll gracilis. Arg. (Euphorbiaceae), Casearia sylvestris Sw (Salicaceae), Bauhinia L. ungulata (Fabaceae: Caesalpinoideae) Calyptranthes widgreniana Berg. (Myrtaceae), Trichilia elegans A. Juss (Meliaceae) Guarea guidonia (L.) Sleumer (Meliaceae), Myrsine umbellata Mart. (Myrsinaceae) e Psychotria carthagenensis Jacq. (Rubiaceae), from the Parque Estadual do Pau Furado (Triângulo Mineiro), Brazil. Samples of the leaf blades and petioles were processed according to the usual techniques for plant anatomy. No general anatomical petiole pattern was found. However, some characteristics are common to all species: (a) supporting tissue, usually represented by collenchyma; (b) large cortical cells with thin walls and small intercellular spaces and (c) reduction or absence of lignified fibers. All these features could enhance the petiole flexibility allowing leaf changing position. The leaf blade anatomy revealed structural traits that promote water savings, as well as efficient mechanisms against predation by herbivores. These important features can effectively contribute to the maintenance and existence of these species in deciduous forests.
Embora a maioria das espécies ocorrentes nas florestas estacionais deciduais perca suas folhas durante a estação seca, algumas delas apresentam estratégias alternativas, tais como, a mudança no posicionamento das folhas de horizontal para vertical, para reduzir a transpiração. Este estudo descreve a anatomia foliar de nove dessas espécies de planta que reduzem a perda de água, durante a estação seca, usando a estratégia do movimento foliar e não a de apresentarem abscisão foliar. As espécies estudadas foram Piper aduncum sp. L. (Piperaceae), Acalypha gracilis Müll. Arg. (Euphorbiaceae), Casearia sylvestris Sw. (Salicaceae), Bauhinia ungulata L. (Fabaceae: Caesalpinoideae), Calyptranthes widgreniana Berg. (Myrtaceae), Trichilia elegans A. Juss (Meliaceae), Guarea guidonia (L.) Sleumer (Meliaceae), Myrsine umbellata Mart. (Myrsinaceae) e Psychotria carthagenensis Jacq. (Rubiaceae) do Parque Estadual do Pau Furado (Triângulo Mineiro). As amostras do limbo e do pecíolo foram processadas de acordo com as técnicas usuais para anatomia vegetal. Nenhum padrão anatômico geral foi encontrado para o pecíolo nas espécies analisadas. No entanto, foram observadas algumas características anatômicas comuns a todas elas, como: (a) tecido de sustentação, geralmente, representado pelo colênquima, (b) células corticais grandes, de paredes delgadas e com pequenos espaços intercelulares e (c) redução ou ausência de fibras lignificadas. Todas essas características poderiam garantir a flexibilidade ao pecíolo e assim, permitir a mudança de posição das folhas. A anatomia do limbo revelou características estruturais que favorecem a economia de água, além de mecanismos eficientes contra a herbivoria, características estas importantes e que poderiam contribuir efetivamente para a manutenção e existência dessas espécies nas florestas estacionais deciduais.
Mestre em Ecologia e Conservação de Recursos Naturais

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Os ajustes no posicionamento foliar em leguminosas, causados pelos pulvinos, representam um mecanismo eficiente que permite a maximização da fotossíntese em condições adversas. De um modo geral, os pulvinos de diferentes leguminosas apresentam um padrão estrutural que propicia grande flexibilidade a esta região da folha, incluindo córtex parenquimático desenvolvido com endoderme típica, sistema vascular central, reduzida lignificação de tecidos e extensiva conexão simplástica. Além disso, o conteúdo celular da endoderme parece determinar a velocidade do movimento foliar. Tradicionalmente, considera-se que a curvatura do pulvino é causada principalmente pela mudança de turgor das células corticais, as chamadas células motoras; entretanto, alguns estudos sugerem que o sistema vascular do pulvino também participa do seu funcionamento. Contudo, a maior parte das informações em literatura sobre anatomia e ultra-estrutura dos pulvinos refere-se a poucas espécies de leguminosas, sendo Mimosa pudica a mais estudada e caracterizada por movimentos foliares seismonásticos rápidos. Este trabalho descreve a estrutura do pulvino primário de nove espécies de leguminosas nativas de cerrado, com ênfase nas características celulares da endoderme e do sistema vascular, utilizando técnicas usuais em anatomia vegetal e microscopia eletrônica de transmissão. Foram selecionadas espécies com diferentes tipos e velocidades de movimento foliar: movimentos nictinástico e heliotrópico lentos (Bauhinia rufa, Copaifera langsdorffii, Senna rugosa - Caesalpinioideae; Andira humilis e Dalbergia miscolobium - Faboideae; Stryphnodendron polyphyllum - Mimosoideae), movimento heliotrópico lento (Zornia diphylla - Faboideae) e movimentos seismonástico rápido e nictinástico e heliotrópico lentos (Mimosa rixosa e Mimosa flexuosa...
Leaf position adjustment in leguminous species, occasioned by pulvini, represent an efficient mechanism that allows the photosynthesis maximization in adverse conditions. The pulvini of different leguminous species show a structural pattern that gives large flexibility to this leaf region, including developed parenchymatous cortex with typical endodermis, central vascular system, reduced tissue lignifications and extensive symplastic connections. Furthermore, the endodermis cell content seems to determine the leaf movement velocity. Traditionally, the pulvinus curvature is considered to be caused by turgor changes of the cortical cells, called motor cells; however, some studies suggest that the vascular system also participate in the pulvinus functioning. Nevertheless, the majority of literature information about pulvinus anatomy and ultrastructure refers to few leguminous species, being the most studied Mimosa pudica, specie characterized by fast seismonastic leaf movements. This work describes the primary pulvinus structure of nine leguminous species native from Brazilian cerrado, with emphasis on endodermis and vascular system cell features, using common vegetal anatomy and transmission electronic microscopy techniques. Species with different kinds and velocity of leaf movement were selected: slow nyctinastic and heliotropic movements (Bauhinia rufa, Copaifera langsdorffii, Senna rugosa - Caesalpinioideae; Andira humilis and Dalbergia miscolobium - Faboideae; Stryphnodendron polyphyllum - Mimosoideae), slow heliotropic movement (Zornia diphylla - Faboideae) and fast seismonastic and slow nyctinastic and heliotropic movements (Mimosa rixosa and Mimosa flexuosa - Mimosoideae). The pulvini of the studied species show a similar structural pattern, independent on the subfamily to that they belong and on the movement... (Complete abstract click electronic access below)

Orientador: Silvia Rodrigues Machado
Banca: Denise Maria Trombert de Oliveira
Banca: Élder Antonio Souza e Paiva
Resumo: Os ajustes no posicionamento foliar em leguminosas, causados pelos pulvinos, representam um mecanismo eficiente que permite a maximização da fotossíntese em condições adversas. De um modo geral, os pulvinos de diferentes leguminosas apresentam um padrão estrutural que propicia grande flexibilidade a esta região da folha, incluindo córtex parenquimático desenvolvido com endoderme típica, sistema vascular central, reduzida lignificação de tecidos e extensiva conexão simplástica. Além disso, o conteúdo celular da endoderme parece determinar a velocidade do movimento foliar. Tradicionalmente, considera-se que a curvatura do pulvino é causada principalmente pela mudança de turgor das células corticais, as chamadas células motoras; entretanto, alguns estudos sugerem que o sistema vascular do pulvino também participa do seu funcionamento. Contudo, a maior parte das informações em literatura sobre anatomia e ultra-estrutura dos pulvinos refere-se a poucas espécies de leguminosas, sendo Mimosa pudica a mais estudada e caracterizada por movimentos foliares seismonásticos rápidos. Este trabalho descreve a estrutura do pulvino primário de nove espécies de leguminosas nativas de cerrado, com ênfase nas características celulares da endoderme e do sistema vascular, utilizando técnicas usuais em anatomia vegetal e microscopia eletrônica de transmissão. Foram selecionadas espécies com diferentes tipos e velocidades de movimento foliar: movimentos nictinástico e heliotrópico lentos (Bauhinia rufa, Copaifera langsdorffii, Senna rugosa - Caesalpinioideae; Andira humilis e Dalbergia miscolobium - Faboideae; Stryphnodendron polyphyllum - Mimosoideae), movimento heliotrópico lento (Zornia diphylla - Faboideae) e movimentos seismonástico rápido e nictinástico e heliotrópico lentos (Mimosa rixosa e Mimosa flexuosa... (Resumo completo clicar acesso eletrônico abaixo)
Abstract: Leaf position adjustment in leguminous species, occasioned by pulvini, represent an efficient mechanism that allows the photosynthesis maximization in adverse conditions. The pulvini of different leguminous species show a structural pattern that gives large flexibility to this leaf region, including developed parenchymatous cortex with typical endodermis, central vascular system, reduced tissue lignifications and extensive symplastic connections. Furthermore, the endodermis cell content seems to determine the leaf movement velocity. Traditionally, the pulvinus curvature is considered to be caused by turgor changes of the cortical cells, called motor cells; however, some studies suggest that the vascular system also participate in the pulvinus functioning. Nevertheless, the majority of literature information about pulvinus anatomy and ultrastructure refers to few leguminous species, being the most studied Mimosa pudica, specie characterized by fast seismonastic leaf movements. This work describes the primary pulvinus structure of nine leguminous species native from Brazilian cerrado, with emphasis on endodermis and vascular system cell features, using common vegetal anatomy and transmission electronic microscopy techniques. Species with different kinds and velocity of leaf movement were selected: slow nyctinastic and heliotropic movements (Bauhinia rufa, Copaifera langsdorffii, Senna rugosa - Caesalpinioideae; Andira humilis and Dalbergia miscolobium - Faboideae; Stryphnodendron polyphyllum - Mimosoideae), slow heliotropic movement (Zornia diphylla - Faboideae) and fast seismonastic and slow nyctinastic and heliotropic movements (Mimosa rixosa and Mimosa flexuosa - Mimosoideae). The pulvini of the studied species show a similar structural pattern, independent on the subfamily to that they belong and on the movement... (Complete abstract click electronic access below)
Mestre

Tese (doutorado)—Universidade de Brasília, Faculdade de Ciências da Saúde, 2011.
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Mecanismos de defesa em primatas dependem do reconhecimento rápido de potenciais predadores e pistas sociais de coespecíficos como expressões faciais de emoção. O complexo amigdaloide (AM) é considerado o centro da circuitaria neural responsável pela detecção de ameaça. Apesar de ser essencial no processamento de estímulos emocionais, a AM parece não estar envolvida nas primeiras etapas deste processo. Várias linhas de investigação vêm recentemente indicando que a via colículo-pulvinar pode preencher essa lacuna, especialmente durante a infância. Para avaliar a contribuição de ambas estruturas (colículo superior e pulvinar) no processamento de estímulos relevantes para sobrevivência, o presente trabalho divide-se em dois estudos. No primeiro estudo, a atividade elétrica individual de neurônios do pulvinar foi registrada durante o reconhecimento de faces emocionais em uma tarefa de escolha diferente do modelo. Nesta tarefa, foram utilizadas faces com diferentes expressões emocionais (tristeza, raiva, alegre, surpresa e neutra), além de figuras geométricas simples como controle de estímulo. De um total de 184 neurônios registrados das regiões lateral e medial do pulvinar de dois macacos japoneses (Macaca fuscata), 22% respondiam a estímulos visuais. Os resultados indicam que 43,9% destes “neurônios visuais” responderam diferencialmente a expressões emocionais de faces. A latência das respostas neuronais no pulvinar variou largamente: o início de disparos para 16 neurônios (39,0%) ocorreu antes de 100 ms, ao passo que, para 13 neurônios (31,7%), ocorreu depois de 300 ms. Essa distribuição variada de latências sugere que os neurônios do pulvinar intermediam conexões intracorticais assim como uma via subcortical mais rápida para a AM. No segundo estudo, filhotes de macaco-prego (Cebus spp.) foram submetidos à lesão neurotóxica bilateral do colículo superior. O comportamento social deles foi avaliado no próprio viveiro (comportamento espontâneo), assim como em dois testes sociais: dominância social e interação com adultos estranhos. Eles também foram testados em um paradigma de conflito ameaça-recompensa em que uma recompensa (comida) foi apresentada junto com um estímulo de ameaça (modelo de serpente de borracha). Os resultados dos testes comportamentais sugerem que a lesão no colículo superior não altera os níveis de interação social. Entretanto os animais lesados mostraram uma clara desinibição comportamental em relação a serpente. Falta de inibição nesta tarefa foi observada até um ano após o primeiro teste. Esse duradouro déficit de reconhecimento de um predador natural é similar ao aspecto de docilidade da Síndrome de Klüver-Bucy e indica um papel importante do colículo superior no reconhecimento de ameaças. Em conjunto, os resultados dos dois estudos sugerem que a via colículo-pulvinar exerce um papel importante no processamento de estímulos relevantes para a sobrevivência, sejam pistas sociais e/ou estímulos de ameaça. ______________________________________________________________________________ ABSTRACT
Defense mechanisms in primates rely on the fast recognition of potential predators and social cues of conspecifics such as facial expressions of emotions. The neural circuitry responsible for the detection of threat is generally thought to be centered on the amygdala. Although it is a pivotal structure in the processing of emotional stimuli, the amygdala does not seem necessary for the early stages of this process. Converging findings from several lines of investigation have been pointing to the colliculo-pulvinar pathway as a possible candidate to fill in this gap, especially during infancy. To evaluate the contribution of both structures (superior colliculus and pulvinar) to the processing of survival-relevant stimuli, the present work is divided into two studies. In the first study, we recorded single-unit activity of pulvinar neurons in two japanese monkeys (Macaca fuscata) during recognition of emotional faces in a delayed non-match-to-sample (DNMS) task, using human face stimuli with differing emotional expressions (sad, angry, happy, surprised and neutral) and simple geometric pattern control figures. From a total of 184 single neurons sampled from lateral and medial pulvinar, 22% were “visually responsive”. The results thus indicate that 43.9% of the visually responsive pulvinar neurons differentially responded to the emotional expressions of human faces. Response latencies of the pulvinar neurons to these facial stimuli ranged very widely; firing onsets for 16 (39.0%, 16/41) neurons were shorter than 100 ms, while for 13 (31.7%, 13/41) it was greater than 300 ms. This wide distribution of response latencies in pulvinar neurons suggests that pulvinar neurons might mediate intracortical connections as well as the fast subcortical pathway to the amygdala. In the second study, infant capuchin monkeys (Cebus spp.) were submitted to bilateral neurotoxic lesion of the superior colliculus. Their social behavior was analyzed in their home cage (spontaneous behavior) as well as in two social tests: social dominance and interaction with strange adults. They were also tested in a threat-reward conflict test where food reward was presented with a threatening stimulus (rubber snake). Results from social behavioral tests suggest that superior colliculus lesion does not affect spontaneous social interaction. Nevertheless, lesioned monkeys were uninhibited by a snake in a food-reward retrieval task. Lack of inhibition in the task was observed over the course of one year. The long lasting recognition impairment of a natural predator observed here is similar to the tameness aspects of Klüver–Bucy syndrome, indicating an important role of this structure in threat recognition. Taken together, results from both studies indicate that the colliculo-pulvinar pathway plays an important role in the processing of survival-relevant stimuli, either social cues and/or threatening stimuli.

Seules les voies cortico-corticales sont prises en compte d'habitude dans le flux d'informations à travers le cortex visuel. Cependant, les expériences et la théorie ont montré que ce mode de transmission posait de nombreux problèmes. Dans cette thèse, j'explore le rôle d'une voie alternative du flux d'information. La hiérarchie corticale visuelle est connecté au noyau Pulvinar du thalamus et cela fournit une seconde voie qui peut lier l'activité des différentes aires corticales. Le Pulvinar a des connexions longue portée qui lui confèrent un rôle de couplage global, conduisant à un raccourci efficace entre les aires corticales. Le but principal de ce travail est de montrer que cela permet une transmission quasi linéaire de l'entrée visuelle tout au long du cortex visuel. Deux modèles théoriques ont été implémentés pour analyser comment le Pulvinar améliore la transmission corticale. Le premier modèle est un réseau de neurones décrits par leur fréquence de décharge. Dans le second modèle, constitué de neurones << intègre-et-décharge >>, l'activité neuronale est décrite par des potentiels d'action. Les résultats de nos simulations montrent que les connexions cortico-corticales déterminent les champs récepteurs visuels à travers les niveaux hiérarchiques, le Pulvinar contrôle le gain de la propagation. De plus, alors que les connexions cortico-corticales sont responsables de la décorrélation du signal transmis à travers le cortex, les bouffées d'activité synchronisées du Pulvinar peuvent << réveiller >> le cortex.

Natural products as sources of novel therapeutic agents experienced a steady increase from around the turn of the twentieth century until it peaked in the 1970s and 1980s. However since this time pharmaceutical research in natural products has experienced a decline. Despite this trend the natural products industry now seems to be experiencing a revival of sorts. This thesis represents a continuation of the work on the isolation and structure elucidation of potential drug leads from terrestrial fungal sources that the natural products group at the University of Canterbury is engaged in. The known compound, pseurotin A (2.7) and two novel diastereomers, pseurotin A2 (2.8) and pseurotin A3 (2.9) were isolated from the extract of a Penicillium sp. of fungus collected from the foreshore of a beach in Vancouver, Canada. The absolute stereochemistry of pseurotin A2 and proposed absolute stereochemistry for A3 were elucidated using a combination of X-ray crystallography (A2 only), circular dichrosim, oxidative cleavage reactions, and J2-resoved 2D NMR experiments. The extract of an as yet unidentified endophytic fungus has yielded eight novel compounds related to the spirobisnaphthalene class of compounds. These eight compounds fall into to distinct groupings. The spiro-mamakones, distinguished by a structurally unprecedented oxygenated spiro-nonene skeleton, comprise five compounds, spiro-mamakones A-E (3.11, 3.15-3.18). In addition to these naturally occurring compounds, the semi-synthetic compounds, 4-oxo-spiro-mamakone A (3.12) and O-acetyl-spiro-mamakone A (3.21), were also synthesised. spiro-Mamakone A was found to be racemic, while X-ray crystallography and optical rotation revealed spiro-mamakone C (3.15) to be present as an enantiomeric mixture (4S*, 5S*, 9R*). Unfortunately the enantiomeric excess was unable to be elucidated. NOE experiments revealed spiro-mamakone B (3.16) to have the relative stereochemistry 4S*, 5S*, 9S*. The relative stereochemistry of spiro-mamakones D (3.17) (4S*, 5S*, 8S*, 9S*) and E (3.18) (4S*, 5S*, 8S*, 9R*) was proposed from comparison of coupling constant calculations from energy-minimised models with those of the experimentally determined values. The second group, comprising three novel compounds named the mamakunoic acids, mamakunoic acid A-C (3.8, 3.7, 3.10), are characterised by their acid substituted dihydro benzofuran system. The low yield obtained of these compounds, unfortunately prevented their stereochemical elucidation. In addition to structure elucidation, biosynthetic studies on spiro-mamakone A and mamakunoic acid B were also carried out. Analysis of the NMR spectra derived from spiro-mamakone A, labelled with isotopic acetate, revealed a situation complicated by the presence of isotopomers and racemisation, resulting in NMR spectra that were somewhat anomalous in appearance. These irregularities however, were resolved leading to the proposal that spiro-mamakone A was derived from a dihydroxynaphthalene (DHN) intermediate, which proceeds through to spiro-mamakone via an epoxide intermediate. Despite problems with purity and low yields of isotopically labelled mamakunoic acid B, it was proposed that like spiro-mamakone A, it proceeded via a DHN intermediate. The extract derived from a Malaysian Scleroderma sp. was found to contain a new dichlorinated pulvinic acid derivative, methyl-3',5'-dichloro-4,4'-di-O-methylatromentate (4.14), the structure of which was confirmed by X-ray crystallography. In addition three previously reported compounds, 4,4'-dimethoxyvulpinic acid (4.11), methyl-3'-chloro-4,4'-di-O-methylatromentate (4.12) and methyl-4,4'-dimethoxyvulpinate (4.13), were also isolated. The extract of another, as yet unidentified endophytic fungus was found to contain the new acetogenin, 1,5-dihydroxy-6-(2-hydroxyethyl)-3-methoxyacetophenone (5.7), differing from the known compound, 2,4-dihydroxy-6-(2-hydroxyethyl)-3-methoxyacetophenone (5.8) only by virtue of the substitution pattern. The structure of 5.7 was confirmed by X-ray crystallography. The implementation of efficient dereplication procedures is paramount for those working in the field of natural products. The recent advances that have been made in the dereplication process in the natural products group at the University of Canterbury are given using examples from this research and where necessary from other group members.

Dans notre environnement, nous sommes constamment exposés à de multiples stimuli sensoriels que notre cerveau doit analyser. Afin d'interagir avec le monde qui nous entoure, nous devons intégrer ces différentes sources d'informations sensorielles. L'étude des processus d'intégration multisensorielle est essentielle pour comprendre comment le cerveau intègre les éléments séparés d'un objet défini par plusieurs composantes sensorielles pour former un percept unifié. Il est maintenant couramment admis que la présentation conjointe de plusieurs informations sensorielles de modalités différentes d'un même stimulus peut faciliter la perception. Cette facilitation multisensorielle semble être soumise à des règles particulières puisque certains facteurs l'influencent. Parmi eux, nous avons étudié, dans notre première étude, l'impact de trois facteurs que sont la saillance, la congruence sémantique et le changement de modalité sur les performances de détection de stimuli naturels chez l'homme et le singe. L'utilisation de stimuli naturels nous a permis de mettre en lumière l'influence des paramètres physiques des stimuli sur l'intégration multisensorielle. De plus, nous avons montré que les effets de ces facteurs sur des stimuli naturels diffèrent de ceux retrouvés avec des stimuli simples. Ces résultats convergent vers des effets multifactoriels sur la facilitation multisensorielle dont la force, les interdépendances et l'ordre varieraient en fonction de la tâche comportementale et de ce fait, de la charge cognitive. D'un point de vue anatomique et plus précisément au niveau cortical, les processus d'intégration multisensorielle paraissaient être jusqu'à récemment une caractéristique que seules possédaient les aires associatives situées au sommet de la hiérarchie du traitement de l'information. On sait maintenant que des aires corticales de bas niveau, pensées jusque-là comme étant unisensorielles, sont impliquées dans les processus multisensoriels, soulevant ainsi la question des aires sous-corticales. Des études anatomiques ont mis en évidence l'existence de noyaux thalamiques qui, par leurs connexions, pourraient permettre un transfert rapide et même une intégration des informations sensorielles. Cette nouvelle littérature témoigne de la grande complexité des réseaux cérébraux de la multisensorialité. Dans deux études électrophysiologiques chez le singe, nous avons examiné les propriétés multisensorielles de deux structures, le gyrus cingulaire postérieur et le pulvinar médian, qui n'avaient jamais été explorées auparavant dans un contexte multisensoriel. Nous avons montré que ces structures sont non seulement multisensorielles mais également intégratives et qu'elles pourraient appartenir à un même système fonctionnel. Ces travaux de thèse ont apporté des éléments supplémentaires quant à notre compréhension des processus d'intégration multisensorielle au niveau comportemental et des réseaux cérébraux sous-jacents et particulièrement ceux liés à l'intégration de stimuli naturels
In our environment, we are constantly exposed to multiple sensory stimuli that our brain has to analyze. To interact with the surrounding world, we have to integrate these different sources of sensory information. The study of the processes of multisensory integration are essential in understanding how our brain integrates the individual parts of an object defined by several sensory components to arrive at a unified percept. It is now widely accepted that the concurrent presentation of several sensory information about the same stimulus in different modalities can facilitate its perception. This multisensory facilitation seems to be subjected to specific rules since some factors influence it. Amongst them, we have studied, in our first experiment, the impact of three factors, namely saliency, semantic congruency and modality switch, on the detection of natural stimuli in humans and monkeys. Using natural stimuli enabled us to highlight the influence of the physical parameters of stimuli on multisensory integration. Moreover, we showed that the effect of these factors on natural stimuli are different from those found with simple stimuli. These results point toward multifactorial effects on multisensory facilitation, of which the force, the interdependency and the order would vary as a function of the behavioral task, and, thus as a function of the cognitive load. From an anatomical point of view and more specifically at the cortical level, the integration mechanism appeared to be, until recently, a characteristic possessed only by associative areas at the top of the hierarchy of information processing. We now know that low level cortical areas, thought up to then to be only unisensory, are implicated in multisensory processes, thus raising the question about subcortical areas. Anatomical studies have shown the existence of thalamic nuclei which, through their connectivity, could allow for a rapid transfer and even an integration of sensory information. This new literature demonstrates the high complexity of the multisensory cerebral networks. In two electrophysiological studies in the monkey, we examined the multisensory properties of two structures, the posterior cingulate gyrus and the median pulvinar, which had never been explored before in a multisensory context. We not only showed that these structures are multisensory, but also integrative and that they could be part of the same functional network. This thesis has brought additional elements towards a better understanding of multisensory integration processes at the behavioral level and about the underlying brain networks, in particular those linked with the integration of natural stimuli

La seguente tesi è finalizzata alla valutazione della sicurezza e alla progettazione di interventi di adeguamento statico e funzionale del cavalcaferrovia dell’Alpo. Le analisi svolte si basano sulle indicazioni presenti nella normativa italiana, in particolare nelle NTC 2018. La prima fase è quella di conoscenza dell’opera oggetto di studio:questa prende il nome di analisi storico-critica.Nella seconda fase si esegue un accurato rilievo geometrico strutturale e funzionale dell’opera, allo scopo di validare e aggiornare i documenti posseduti; in tale fase si raccolgono anche informazioni relative al degrado in cui versa l’opera. Per la valutazione del degrado vengono compilate delle schede difettologiche per ciascun elemento investigato. Successivamente si esegue una progettazione simulata della struttura, al fine di risalire alle tecniche di progettazione e di rilevare eventuali carenze. A tale scopo si assumono due importanti ipotesi: la prima riguarda l’uso dei carichi dell’epoca, la seconda considera i materiali e le sezioni integre. Si procederà poi ad eseguire una valutazione della sicurezza, definendo due ulteriori ipotesi: la prima relativa ai carichi attualizzati alla normativa NTC 2018 e la seconda relativa ai materiali degradati. Dalla valutazione della sicurezza, si ricaverà:l’indice statico, ζV,i e l’indice di sicurezza sismico, ζE,i. La fase successiva sarà quella di modellazione della struttura, utilizzando il software Midas Gen, allo scopo di ricavare i valori delle sollecitazioni che agiscono sugli elementi dell’opera. In seguito, si procederà ad eseguire, sul modello in questione, delle verifiche statiche e sismiche, riferendosi alla NTC 2018 e confrontando i risultati con le normative dell’epoca di progettazione. Infine, in seguito alle criticità emerse dalla valutazione della sicurezza della struttura, verranno proposti degli interventi provvisori, degli interventi definitivi e funzionali al fine di ottenere l’adeguamento statico dell’opera.

The aim of this study was to determine the effect of different frequency irritation on growth, morphology or seedling mortality of Mimosa pudica. During preparation of the experiment were seeded 200 seeds of M. pudica but only 48 plants were used due to low germination of seeds . They were divided into three groups of equal number and these groups was placed one beside the other in a warm greenhouse with the same temperature and light conditions. The experiment started when sufficient size was reached (approximately 4 leaves per plant). The first ( control ) group was not irritated, the second group was irritated 5 times per day and the third group 15 times per day. Three times during the experiment (1. 9., 11. 9. and 21. 9. 2014) were measured length and counted the number of leaves. During the last measurement was cut and weighed aboveground part of the plants. Also number of internodes in all plants was recorded. During the experiment was also monitored the number of blossoms. All measured values were entered into tables and then statistically evaluated. In the experiment was found that the different frequency irritation affects the stem length and the final weight of the plants. The effect on the number of blossoms, leaves and internodes was not shown. There was no mortality in any of three groups.

The primate pulvinar is connected with several visual areas and is implicated in visual attention and in control of eye movements. Traditionally, the pulvinar has been divided into three broad zones: medial (PM), lateral (PL), and inferior pulvinar (PI). This division was based on cytoarchitecture and the location of prominent fiber bundles and did not correlate to connectional data. Recent studies using various modern neurochemical methods suggest a pattern of organization more consistent with the topography of connections with different visual areas. In monkeys, the ventral pulvinar, consisting of traditional PI and the ventral portion of traditional PL, constitutes a histochemically distinct area termed the inferior pulvinar (PI) complex. The PI complex in monkeys consists of 5, separate zones: the posterior, medial, central, lateral, and the lateral-shell (PIP, PIM, PIC, PIL, and PI L-S) subdivisions, each distinguished by several neurochemical stains There is evidence that the visual system is not spared in neurodegenerative diseases such as Alzheimer's Disease (AD). While AD usually affects memory and attention early in the course of the disease, studies have shown that AD can also affect the visual cortex and visual pathways, including subcortical visual centers. Disruption of functions mediated by the pulvinar may contribute to visual deficits seen in patients with AD. The goal of this study was to investigate the neurochemical organization of the pulvinar and to understand it's role in visuospatial function of non-human primates and humans with or without Alzheimer's Disease, and how certain symptoms of Alzheimer's disease can be related to pathology within this structure We obtained postmortem chimpanzee (Pan troglodytes; n = 8) brains and human brains with no known neurological pathology (n = 5), and brains of patients clinically diagnosed with AD (n = 9). Using cytochrome oxidase (CO) and acetylcholinesterase (AChE) histochemistry, and immunocytochemistry for calbindin D28k, we were able to identify 5 histochernical zones in the chimpanzee PI complex, and 4 zones in the human PI complex. Thioflavin S histochemistry was employed to identify amyloid plaque distribution. Dense plaques were irregularly distributed across the PI complex with a slight trend for PIC having the greatest accumulation
acase@tulane.edu

The pulvinar nucleus of the thalamus is the largest subcortical visual structure in primates and appears to have increased in size in primate evolution. Pulvinar divisions termed the dorsal pulvinar and inferior pulvinar (PI) complex, as well as subdivisions in the PI complex, have been shown by calbindin and acetylcholinesterase (AChE) staining techniques. These staining techniques provide a reproducible method for quantifying pulvinar volumes in primate species. The present study measures the volumes of total pulvinar, dorsal pulvinar, PI complex, and the medial subdivision of the PI complex (PI M), using primate brain sections. Squirrel monkey, macaque, chimpanzee, and human are the species thought to give the best perspective on the evolution of the pulvinar to its current structure in humans. Because of differing brain sizes, we compare volume ratios, rather than volumes of pulvinar. Our long-term goal is to establish a structural correlation between pulvinar volume ratios and visual behavior. Results show similar PI complex/total pulvinar volume ratios in squirrel monkeys, macaques, and chimpanzees. Using calbindin stains, squirrel monkeys have larger PIM/total pulvinar volume ratios than macaques (6.24% vs. 1.83%) and chimpanzees (6.24% vs. 2.69%, p < 0.05). Chimpanzees and macaques have similar PIM/total pulvinar volume ratios (2.69% vs. 1.83%). Strong connections of PIM with area MT suggest an involvement of PIM in visual motion processing. Thus, differing PIM/total pulvinar volume ratios in squirrel monkeys vs. macaques and chimpanzees correlate structure and visual abilities in different species of primates. Differing volume ratios found for calbindin and AChE-staining suggest future quantification by different staining techniques must control for such differences
acase@tulane.edu

Les neurones du cortex visuel primaire (V1) peuvent emprunter deux voies de communications afin d’atteindre les aires extrastriées : une voie cortico-corticale, et une voie cortico-thalamo-corticale à travers des noyaux thalamiques de haut niveau (HO) comme le pulvinar. Les fonctions respectives de ces deux voies restent toujours méconnues. Un pas vers une meilleure compréhension de celles-ci seraient d’investiguer la nature des signaux qu’elles transmettent. Dans ce contexte, deux grands types de projections cortico-thalamiques (CT) ont été identifiés dans le système visuel : les neurones de type I (modulator) et type II (driver) caractérisés respectivement par des axones minces dotés de petits boutons terminaux et par des axones plus épais et de plus grands boutons respectivement. Une proposition récente a aussi émis l'hypothèse que ces deux types pourraient également être distingués par leur expression de transporteur de glutamate vésiculaire. Cette hypothèse suggère que les projections de type II et de type I peuvent exprimer sélectivement VGLUT2 et VGLUT1, respectivement (Balaram, 2013; Rovo et al, 2012). Chez le chat, les projections de V1 vers le pulvinar se composent principalement de terminaux de type II, tandis que celles de l’aire PMLS présentent une combinaison de terminaux de type I et II suggérant ainsi que, la proportion de terminaux de type I augmente avec le niveau hiérarchique cortical des zones visuelles. Afin de tester cette hypothèse, nous avons cartographié la distribution des terminaux CT du cortex AEV (article 1) ainsi que de l’aire 21a (article 2). Nous avons aussi étudié l’expression de VGLUT 1 et 2 dans le système visuel du chat afin de tester si leurs expressions corrèlent avec les sites de projections de neurones de type I et II (article 3). Nos résultats indiquent que la grande majorité des terminaux marqués dans le pulvinar provenant de l’AEV et de l’aire 21a sont de type I (Article 1 et 2) alors que ceux de V1 sont majoritairement de type II. Une comparaison de la proportion des projections de type I à travers les aires V1, PMLS, 21a et AEV révèlent une corrélation positive de sorte que celle-ci augmente avec le degré hiérarchique des aires visuelles. Nos résultats indiquent que VGLUT 1 et 2 présentent une distribution complémentaire et que leur localisation dans des sites connus pour recevoir une projection de type ‘modulateur’ et ‘déclencheur’ proéminente suggère que leurs expressions peuvent montrer un biais pour celles-ci dans la voie géniculo-strié. Les résultats de cette thèse ont permis de mieux connaitre la nature des projections CT des aires visuelles extrastriées. Ces résultats sont d’autant plus importants qu’ils établissent un lien entre la nature de ces projections et le degré hiérarchique des aires visuelles, suggérant ainsi l’existence une organisation anatomofonctionnelle des voies CT passant par le pulvinar. Enfin, les résultats de cette thèse ont aussi permis une meilleure compréhension des vésicules VGLUT 1 et 2 dans le système visuel du chat et leurs affinités respectives pour les sites de projections de neurones de type I et II.
Visual signals from the primary visual cortex (V1), can take two main communication routes in order to reach higher visual areas: a corticocortical pathway and a cortico-thalamo-cortical (or transthalamic) pathway through high-order thalamic nuclei such as the pulvinar. While these pathways are receiving an increasing interest from the scientific community, their respective functions still remain largely unknown. An important step towards a better understanding of these pathways would be to investigate the nature of the signals they transmit. In this context, two main types of corticothalamic (CT) projections have been identified in the visual system: type I projections (modulators) and type II (drivers) characterized respectively by thin axons with small terminal and by thicker axons and larger terminals. A recent proposal has also hypothesized that these two types can also be distinguished by their expression of vesicular glutamate transporter (VGLUT) in their respective synaptic terminals such that type II (driver) and type I (modulator) projections can selectively express VGLUT 2 and VGLUT 1, respectively (Balaram, 2013; Rovo et al, 2012). In cats, projections from V1 to the LP-pulvinar are mainly composed of type II terminals, while those from the Posteromedial lateral suprasylvian (PMLS) cortex present a combination of type I and II terminals. This observation suggests that, in higher-order (HO) thalamic nuclei, the proportion of type I terminals increases with the hierarchical level of the visual areas. To test this hypothesis, we charted the distribution of CT terminals originating from the Anterior EctoSylvian visual cortex (AEV) (article 1) and from area 21a (article 2). We also studied the expression of VGLUT 1 and 2 in the cat's visual system in order to test whether their expressions correlate with the projection sites of type I and II axon terminals (article 3). Our results from article 1 and 2 indicate that the vast majority of terminals sampled in the pulvinar from the AEV and area 21a are of type I while projections from V1 projections to the pulvinar were mostly composed of type II terminals. A comparison of the proportion of type I projections across areas V1, PMLS, 21a and the AEV revealed a positive correlation such that its proportion increased with the hierarchical rank of visual areas. Our results also indicate that VGLUT 1 and 2 have a complementary distribution pattern which matches prominent projection of type I and II respectively in ascending visual projections but does not in extra-geniculate pathways involving the pulvinar (Article 3). Taken together, results from this thesis have allowed a better understanding of the nature of cortico-thalamic projections originating from extra-striate visual areas (21a and AEV). These results are all the more important in that they establish a link between the nature of these projections and the hierarchical degree of their cortical area of origin, thus suggesting that there is a functional organization of CT pathways passing through the pulvinar. Finally, results of this thesis also enabled a better understanding of the expression of VGLUT 1 and 2 in the visual system and their possible respective biases for type I and type II projections.

The pulvinar, which is located in the posterior thalamus, establishes reciprocal connections with nearly all of the visual cortical areas and is consequently in a strategic position to influence their stimulus decoding processes. Projections from the pulvinar to the primary visual cortex (V1) are thought to be modulatory, altering the response of neurons without changing their basic receptive field properties. Here, we investigate this issue by studying V1 single unit responses to sine wave gratings during the reversible inactivation of the lateral posterior nucleus (LP) - pulvinar complex in the cat. We also studied the contrast response function of V1 neurons, before and during the inactivation of the LP-pulvinar complex. No change in the preferred orientation or direction selectivity of V1 neurons was observed during pulvinar inactivation. However, for the majority of the cells tested the response amplitude to the optimal stimulus was reduced. The contrast response function of neurons was fitted with the Naka-Rushton function and analysis of the effects of pulvinar deactivation revealed a diverse set of modulations: 35% of cells had a decrease in their peak response, 11% had an increase in their C50, 6% showed modulations of the slope factor and 22% exhibited changes in more than one parameter. Our results suggest that the pulvinar modulates activity of V1 neurons in a contrast dependent manner and provides gain control at lower levels of the visual cortical hierarchy.
Le pulvinar, localisé dans le thalamus postérieur, établit des connections réciproques avec la vaste majorité des aires visuelles corticales et il est ainsi dans une position stratégique afin d’influencer les processus de décodage de celles-ci. Les projections du pulvinar au cortex visuel primaire (V1) sont considérées comme étant des projections modulatrices, qui modifieraient les réponses neuronales sans toutefois changer les propriétés de base des champs récepteurs. Dans la présente étude, nous avons étudié les réponses des neurones de V1 suite à l’inactivation réversible du complexe noyau latéral postérieur (LP)-pulvinar chez le chat. Des courbes de réponse au contraste ont été générées par la présentation de réseaux ayant plusieurs niveaux de contraste pendant l’inactivation du LP-pulvinar. Aucun changement n’a été observé concernant l’orientation préférée ou la sélectivité à la direction des neurones de V1 lors de l’inactivation du pulvinar. Néanmoins, pour la majorité des cellules testées, l’amplitude de la réponse aux stimuli optimaux a été réduite. La fonction de Naka-Rushton a été appliquée aux courbes de réponse au contraste et l’analyse des effets de l’inactivation du pulvinar a montré une panoplie d’effets modulateurs : 35% des cellules ont présenté une réduction de leur réponse maximale, 11% ont eu une augmentation de leur C50, 6% ont montré une modulation de la pente et 22% des neurones ont présenté des changements dans plus d’un paramètre. Nos résultats suggèrent que le pulvinar module l’activité des neurones de V1 d’une façon dépendante du contraste et qu’il contrôle le gain des réponses des neurones des aires primaires du cortex visuel.

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In this work the chemistry of the lichens Candelaria fibrosa and Pyxine coccifera have been investigated for the first time using FT-Raman spectroscopy with the help of quantum mechanical DFT calculations to support spectral band assignments. The non-destructive spectral vibrational analysis provided evidence for the presence of pulvinic acid derivatives and conjugated polyenes, which probably belong to a carotenoid with characteristic signatures at ca. 1003, 1158 and 1525 cm−1 assigned respectively to δ(C–CH3), ν(C–C) and ν(Cdouble bond; length as m-dashC) modes. The identification of features arising from chiodectonic acid in the Pyxine species and calycin and pulvinic dilactone pigments in C. fibrosa were assisted by the quantum mechanical DFT calculations. Raman spectroscopy can provide important spectroscopic data for the identification of the biomarker spectral signatures nondestructively for these lichen pigments without the need for chemical extraction processes.