No description available.

The goal of this thesis is to improve graphical user interface of Tone Mapping Studio(TMS) program. This program is being developed on the Faculty of Information Technology(FIT), Brno University of Technology (BUT) by doc. Ing. Martin Čadík, PhD. The current program is using framework Qt3 , which is old and not compatible with modern libraries. This program has to be rewritten to support current version Qt5. I will analyze other programs in the area of working with High Dynamic Range (HDR) images and video. Changes for improving the interface will be proposed and UX tests will be done. Second part will consist of comparing plug-ins for converting images to grayscale that already exists in TMS.

Stroke is the main cause of adult motor disability. Nevertheless, recent meta-analyses show that the theoretical models conceived to explain the post-stroke brain reorganization are inaccurate and therefore misleading in laying the theoretical foundation for rehabilitation protocols. Mixed results are reported especially in works investigating the excitability properties of the stroke injured brain. Shedding light on the reasons that brought to such mixed results is the central topic of this doctoral thesis. In particular, this confounding evidence is here discussed and tackled in the light of recent works employing brain-state dependent stimulation protocols. These works have been of paramount importance, as they showed that the effects of non-invasive stimulation (TMS and/or rTMS) on the hand knob of the motor cortex depend on the instantaneous sensorimotor state. This local state is largely determined by the phase of the mu-alpha oscillations, with the negative peak representing a high excitability condition. Brain-state dependent results show that controlling for the local state at the moment of stimulation is crucial in order to reduce variability in studies investigating cortical excitability: an approach that has never been employed in stroke literature, so far. In this doctoral thesis, new evidence is provided on affected and unaffected hemispheres’ excitability properties depending on the local state at the moment of stimulation. This previously uncontrolled state-dependent variability is here proposed as one of the factors at the basis of the mixed results in stroke literature. Furthermore, the current models aimed at explaining post-stroke brain reorganization do not take into account factors that recent works suggest might contribute to stroke recovery. In fact, it is here suggested that: interhemispheric inhibition should not be interpreted as competition, structural reserve should be assessed also at the level of the corpus callosum, diaschisis processes should be taken into account and structural and functional connectivity patterns should be included in patients’ assessment. Finally, the excitability properties of the stroke brain have been often inferred comparing stroke patients’ with young healthy controls’. In this regard, it is here proposed that only healthy peers should be included in the control groups, as brain structural changes due to healthy aging have an impact on corticospinal excitability. The aforementioned functional and structural issues are addressed in the following chapters by means of different techniques (i.e. TMS-EEG, MRI, MEG). In particular, in Chapter 1, a new framework of post-stroke brain reorganization is proposed, in which previously over-looked factors are suggested to be essential in the understanding of the potential plastic changes following stroke. Specifically, a new account where interhemispheric inhibition is interpreted in terms of integration and not competition, is supported. Moreover, the proposed framework includes recent pieces of evidence suggesting that structural reserve should be evaluated in the individual patient not only at the level of the cortex, but also in the different sections of the callosum. Finally, it is proposed that structural damage is not static, but rather dynamic as it continues also after the stroke episode through dischiasis processes. In Chapter 2, new knowledge is provided on the different excitability properties of the two hemispheres of stroke patients. In this chapter, TMS-EEG data of stimulation on both the affected and unaffected motor cortex in severe chronic strokes are analysed with a brain-state dependent approach. For the first time, it is shown that the excitability properties of the affected and unaffected hemispheres differ as the local state at the moment of stimulation influences the two hemispheres’ response differently. In particular, the strong and simplified TMS-evoked response in the affected hemisphere, previously reported in severe patients, is shown to depend on a disruption of the differentiation between the high and low excitability states of the motor cortex, determined by the instantaneous phase of alpha oscillations. This low differentiation between excitability states in the affected hemisphere should be systematically investigated, as it could be a potential feature of patients who experience poor recovery. Furthermore, in Chapter 3, connectivity at the individual alpha peak is investigated in a big cohort of healthy participants, in a resting state MEG dataset. This work was implemented because alpha connectivity networks have been shown to predict stroke recovery. For this reason, there is a necessity to reliably assess connectivity at alpha before and after rehabilitation, as this could be informative on the efficacy of rehabilitation. Specifically, it is shown that using complementary phase-coherence metrics is more effective to estimate connectivity patterns at source level. This compound approach is proposed as a tool to better control the modulatory effects of rehabilitation stimulation protocols, in order to identify which are the changes in activity patterns that are potentially responsible for recovery. Finally, in Chapter 4 brain structural changes associated with healthy aging are investigated in a big cohort of participants aged between 18 and 90 years old, both in terms of cortical thinning and cortical myelin concentration loss. In particular, given recent evidence on the relationship between cortical myelin content and corticospinal excitability, it is shown that age-dependent myelin loss occurs mostly at the level of the premotor, motor and sensory cortices. These structural changes need to be taken into account when stroke patients are compared with controls. In fact, since stroke patients are often in their elderly, these age-related structural changes need to be controlled by including only age-matched healthy participants in control groups, as this is not often a fulfilled criterion in stroke studies. To conclude, this doctoral thesis proposes that the current models’ inaccuracy depends on 1) patients’ individual structural and functional factors that have not been taken into account in previous models of brain reorganization post-stroke (Chapter 1), 2) brain-state dependent variability in stimulation effects that have not been controlled for in stroke literature (Chapter 2), 3) a lack of a systematic method to assess the effects of stimulation rehabilitation protocols (Chapter 3) and 4) structural brain changes due to healthy aging, that affect also the stroke brain, and that are not taken into account when patients are compared with young controls in corticospinal excitability studies (Chapter 4). To the author’s knowledge, this is the first work aimed at explaining mixed results in stroke literature from different perspectives and using different neuroimaging techniques for functional and structural anomalies, exploiting recent brain-state dependent approaches for the analysis of stroke patients’ data.

Post-traumatic stress disorder (PTSD) is a highly debilitating mental illness that is incited by various types of trauma and causes core symptoms of re-experiencing, hyperarousal, avoidance of trauma-related stimuli, and negative cognition and mood. It is accompanied by functional, social, and occupational impairment, as well as higher risks of medical comorbidities and mortality. Estimates indicate that PTSD affects 3.9% of the global population, and 7-9% of the US population, with only 50% of those with persistent PTSD treatment-seeking. The gold standard of PTSD treatment is prolonged exposure therapy and cognitive processing theory, with the addition of antidepressants; however, dropout rates are high likely due to the adverse effects of worsening re-experiencing of trauma and exacerbating behaviors of avoidance. As a result, alternative therapies such as transcranial magnetic stimulation (TMS) represent more tolerable treatment options. Historically, literature on TMS is promising for its low risk of side effects and efficacy, but there is no general consensus on treatment-specific targets, frequency of treatment delivery, or long-term efficacy. This proposed study will evaluate the use of neuroimaging guided intermittent theta burst stimulation, a form of TMS, for core PTSD symptom reduction and its efficacy up to one year in duration to potentially reduce the morbidity and mortality sequelae of PTSD.

No / In this report, we evaluate the role of visual areas responsive to motion in the human brain in the perception of stimulus speed. We first identified and localized V1, V3A, and V5/MT+ in individual participants on the basis of blood oxygenation level-dependent responses obtained in retinotopic mapping experiments and responses to moving gratings. Repetitive transcranial magnetic stimulation (rTMS) was then used to disrupt the normal functioning of the previously localized visual areas in each participant. During the rTMS application, participants were required to perform delayed discrimination of the speed of drifting or spatial frequency of static gratings. The application of rTMS to areas V5/MT and V3A induced a subjective slowing of visual stimuli and ( often) caused increases in speed discrimination thresholds. Deficits in spatial frequency discrimination were not observed for applications of rTMS to V3A or V5/MT+. The induced deficits in speed perception were also specific to the cortical site of TMS delivery. The application of TMS to regions of the cortex adjacent to V5/MT and V3A, as well as to area V1, produced no deficits in speed perception. These results suggest that, in addition to area V5/MT+, V3A plays an important role in a cortical network that underpins the perception of stimulus speed in the human brain. / BBSRC

Language comprehension is a fascinating and complex ability unique to humans. Its neurobiology has yielded profound insights through decades of electrophysiological and neuroimaging studies (Chapter 1). Despite these significant advances on the neurobiology of speech comprehension, understanding the precise timing and causal relevance of brain regions within the human language network remains one of the key challenges. This dissertation addresses this challenge by combining transcranial magnetic stimulation (TMS) with electroencephalography (EEG) measurements, providing a means to identify the causal relevance of particular brain regions with high temporal precision. By focusing on the causality of both the time and place of comprehension, this innovative approach offers new insights for developing adequate functional-anatomical models of the neurobiology of language. This dissertation reports data from three distinct studies. Going beyond correlative ev idence, Study 1 (Chapter 2) describes a set of three concurrent TMS-EEG experiments investigating the bottom-up and top-down information flow within the core language network while German native speakers listen to single sentences. Together, the findings of these three experiments indicated that speech comprehension is subserved by the temporally-coordinated interplay between the left inferior frontal and posterior temporal cortex, which may be supported by the left inferior parietal cortex. Going beyond the core system, Study 2 (Chapter 3) describes two EEG experiments that investigated the neurocognitive mechanisms involved in multi-sentence discourse comprehension. Their findings showed that a distinction between a set of positive-going event-related potentials (ERP) reflect general processing principles relevant for interpreting speech in everyday communitive settings. Going beyond this ERP-based timing information, Study 3 (Chapter 4) describes a sequential TMS-EEG probing the causal relevance of brain regions of the semantic (meaning-related) network in the processing of discourse contexts. The findings of this study highlights that the critical contribution of the left inferior parietal cortex in achieving a higher-level interpretation of speech input. In the General Discussion (Chapter 5), the findings of these studies are placed in a wider perspective, addressing their limitations and providing a number of future directions for an even finer-grained understanding of the neurobiology of speech comprehension.

No description available.

Die transkranielle Magnetstimulation (TMS) ist ein nichtinvasives Hirnstimulationsverfahren, mit welchem sowohl die funktionelle Untersuchung umschriebener kortikaler Regionen als auch die Modulation der Erregbarkeit ebendieser sowie die Induktion neuroplastischer Phänomene möglich ist. Sie wurde in der Vergangenheit insbesondere bei der Erforschung des humanen zentralmotorischen Systems angewandt. Dabei zeigte sich, dass ein einzelner über dem primärmotorischen Areal (M1) applizierter TMS-Puls multiple deszendierende Erregungswellen im Kortikospinaltrakt induzieren kann. Von diesen Undulationen besitzt die D-Welle (direkte Welle) die kürzeste Latenz und sie rekurriert auf eine direkte Aktivierung kortikospinaler Neurone, wohingegen I-Wellen (indirekte Wellen) längere Latenzen besitzen und durch transsynaptische Aktivierung dieser Zellen entstehen. Bemerkenswert ist das periodische Auftreten der letztgenannten Erregungswellen mit einer Periodendauer von etwa 1,5 ms. Zwar sind die genauen Mechanismen noch unbekannt, welche der Entstehung dieser I-Wellen sowie dem Phänomen der I-Wellen-Fazilitierung, das sich in geeigneten TMS-Doppelpulsprotokollen offenbart, zugrunde liegen, jedoch existieren hierzu verschiedene Erklärungsmodelle. Im Mittelpunkt der vorliegenden Arbeit steht die repetitive Anwendung eines TMS-Doppelpulsprotokolls, bei dem das Interpulsintervall (IPI) im Bereich der I-Wellen-Periodizität liegt (iTMS) und das gleichsam durch eine Implementierung der I-Wellen-Fazilitierung in der repetitiven TMS charakterisiert ist. Da gezeigt werden konnte, dass iTMS mit einem IPI von 1,5 ms (iTMS_1,5ms) die kortikospinale Erregbarkeit signifikant intra- und postinterventionell zu steigern vermag, und die I-Wellen-Periodizität interindividuellen Schwankungen unterliegt, wurde in der hier vorgestellten Studie an Normalprobanden der Einfluss einer individuellen Anpassung des IPIs (resultierend in der iTMS_adj) auf die intrainterventionelle kortikospinale Erregbarkeit untersucht. In der Tat stellte sich heraus, dass die iTMS_adj der iTMS_1,5ms diesbezüglich überlegen ist. Dieses Ergebnis unterstreicht das Potential einer Individualisierung der interventionellen TMS für erregbarkeitsmodulierende Effekte und macht dasjenige der ohnehin auf physiologische Prozesse abgestimmten iTMS explizit, was insbesondere für klinische Anwendungen relevant sein mag.

La dextérité, notamment la pince de précision (i.e., opposition pouce-index) est une fonction très développée chez l’homme. Elle est basée sur l’habileté à contrôler précisément et indépendamment les forces et mouvements des doigts en relation avec les contraintes de la tâche. Les muscles de la main responsables du mouvement des doigts sont gouvernés par le système corticospinal (CS) latéral. La principale source de ce système CS est l’aire motrice primaire (M1), laquelle possède des projections CS directes sur les motoneurones des muscles de la main. Cependant, d’autres projections CS en provenance des aires motrices non primaires ont été trouvées, notamment en provenance de l’aire motrice supplémentaire (SMA). Chez l’homme, la fonctionnalité de cette voie dans le contrôle habile des doigts a peu été étudiée. L’objectif de cette thèse est d’étudier, chez l’homme, l’implication des projections CS de la SMA lors de contrôle manuel précis de force. Pour ce faire, nous avons utilisé la stimulation magnétique transcrânienne (TMS) et l’électroencéphalographie (EEG).A travers différentes études, nous avons pu mettre en évidence l’importante implication de la SMA dans la dextérité. Il semblerait que cette aire puisse agir en parallèle à M1 en régulant directement l’excitabilité des motoneurones de la moelle épinière. En conclusion, nos résultats suggèrent que M1 et SMAp ont une influence directe et efficace sur la production de force pendant des tâches motrices manuelles fines. / Human dexterity is a highly developed function based on the ability to independently and precisely control forces and movements of the fingers related to the constraints of the task. Hand muscles for finger movements are steered by the lateral corticospinal (CS) system. The main source of this CS system is the primary motor area (M1), which has direct CS projections on motoneurons innervating hand muscles. Recently, CS projections from non-primary motor area have also been found, especially from the supplementary motor area (SMA). However, the functionality of this CS tract in human manual force control is little studied. The aim of this thesis was to study the implication of the CS projections from SMA in precision manual force control, using electroencephalography (EEG) and transcranial magnetic stimulation (TMS).Altogether, the results obtained in our different studies show the important implication of SMA in dexterity. It appears that this area can act in parallel with M1, directly influencing excitability of spinal motoneurons. We conclude that M1 and SMA both have direct and efficient influence on force production during fine manual motor tasks.

Made available in DSpace on 2016-12-08T17:19:38Z (GMT). No. of bitstreams: 1 VIVIANE LILIAN SOETHE.pdf: 4187786 bytes, checksum: ad2945f377ee8ffa2972dbc25afd42a0 (MD5) Previous issue date: 2004-03-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Triode Magnetron Sputtering (TMS) is a system of depositing film characterized by the introduction of a third electrode, which is made up of a grounded mobile screen, located between the cathode (target) and the anode (substrate). The purpose of this screen is to capture cold electrons (at a lower energy level) of discharge. Changing its relative position to the cathode, some of the characteristics of the plasma are changed such as the ignition tension. Based on this, a study was made investigating the relationship between the current and the target voltage by changing the positioning of the screen to the target. Through this study, we could verify that, it s possible to work independently with either of above parameters of deposition. As a result of controlling these parameters, we could verify that the deposition of quality metallic films is possible, by using a TMS equipment on polymeric substrates. By choosing the suitable conditions of deposition, based on a preliminary study, a deposition of Al film on a poly(ethylene terephthalate) substrate was made. It was observed through this study that these films prove to be structurally whole and with few faults. The maintenance of a constant current (0,5A) fir deposition of Al films on polymeric substrates indicates that the change in voltage alters mainly the deposition energy particles, not significantly the superficial property of films. We can still observe that the rate of deposition does not alter significantly with voltage increase, what is evidenced by the little temperature increase in the samples. The Al films deposited submitted to a constant voltage (-700V) displayed a distinct superficial topography due to the current used. The current variation influence was verified notably for the final structure of the deposited film. Besides this, this parameter is directly related to the deposition rate, this being responsible for a temperature increase of the sample caused by increase of condensation heat of deposited atoms. Thus we can say that the sample temperature is more influenced by target current than by target voltage. So, we can observe that depositions made under constant current cause less aggression to polymer and to deposited film than those made under constant voltage. Through TMS, it is possible to control deposition condition and consequently the deposition rate in an accurate way. This makes this method an efficient alternative to metallic film deposition. In view of above, an application of the study of deposited film on polymers was made, altering either the current or voltage of target. Films of Al an Inconel were deposited on Mylar® , a type of PET, with the purpose of investigating film behavior concerning its attenuation characteristics of 4 incident electromagnetic energy. This application range is very wide, including aerospace equipment, radars an so on. When the rate of deposition for the condition used is known, the thickness of film can be altered by varying the time of deposition. A study was conducted of the influence of layer thickness and film material (Al or Inconel) on the characteristics of attenuation of electromagnetic wave energy. According to studies, it was observed that deposited layer thickness and film material influenced attenuating characteristics, so that Al and Inconel deposited films showed a maximum 13% attenuation. This leads us into believing that metallic films can be used with electromagnetic radiation absorbing materials, as long as ideal work thickness and its intrinsic characteristics are known. / O Triodo Magnetron Sputtering (TMS) é um sistema de deposição de filmes caracterizado pela introdução de um terceiro eletrodo, que é constituído de uma tela móvel aterrada, situado entre o catodo (alvo) e o anodo (substrato). Esta tela tem o papel de capturar elétrons frios (menos energéticos) da descarga. Alterando-se a posição relativa desta tela ao catodo, alteram-se algumas das características do plasma como, por exemplo, a tensão de ignição. Baseado nisso, realizou-se um estudo investigando-se a relação entre a corrente e a voltagem do alvo alterando-se a posição relativa da tela ao alvo. Por meio deste estudo, pode-se verificar que é possível tornar independentes estes dois parâmetros de deposição para uma determinada faixa de trabalho. Devido ao controle destes parâmetros, verificou-se que é possível depositar filmes metálicos de qualidade, utilizando um equipamento de TMS sobre substratos poliméricos. Através da escolha adequada das condições de deposição, baseadas no estudo realizado anteriormente, realizou-se a deposição de filmes de Al sobre um substrato de poli(Tereftalato de Etileno). Pode-se observar por meio deste estudo que estes filmes apresentam-se estruturalmente íntegros e com pouca quantidade de defeitos. As deposições de filmes de Al sobre substratos poliméricos mantendo-se a corrente constante (0,5A) indica que a mudança na voltagem altera principalmente a energia das partículas que se depositam, não modificando de forma significativa as propriedades superficiais dos filmes. Pode-se observar ainda que a razão de deposição não sofre alterações significativas com o aumento da voltagem, o que é evidenciado pela pequena elevação da temperatura sofrida pelas amostras. Os filmes de Al depositados sob voltagem constante (-700V) apresentaram topografia superficial distinta em função da corrente utilizada. Pode-se verificar que a variação da corrente influencia de forma significativa a estrutura final do filme depositado. Além disso, este parâmetro está diretamente relacionado com a razão de deposição, sendo este o fator responsável pelo aumento na temperatura da amostra devido a elevação no calor de condensação dos átomos que se depositam. Pode-se desta forma, dizer que a temperatura da amostra é mais influenciada pela corrente que pela voltagem do alvo. Assim, é possível observar que deposições realizadas sob corrente constante provocam menor agressão ao polímero e ao filme depositado que aquelas realizadas sob voltagem constante. Por meio do TMS, é possível controlar-se as condições de deposição e conseqüentemente a razão de deposição de maneira precisa, o que proporciona um controle da camada depositada. Isto faz deste 2 método uma alternativa eficiente para a deposição de filmes metálicos, passível de ser utilizado em muitos ramos de pesquisa. Atentando-se a este fato, realizou-se uma aplicação do estudo dos filmes depositados sobre polímero, alterando-se a corrente ou a voltagem do alvo independentemente. Para isso depositaram-se filmes de Al e Inconel (liga de níquel cromo) sobre Mylar®, um tipo de PET (poli (Tereftalato de etileno)), com a finalidade de investigar o comportamento deste filme quanto as suas características de atenuação de energia eletromagnética incidente. Esta aplicação é bastante vasta envolvendo equipamentos aeronáuticos, radares, e outros. Conhecida a razão de deposição da condição utilizada, pode-se alterar a espessura do filme obtido variando-se o tempo de deposição. Assim, fez-se um estudo da influência da espessura da camada e do material que constitui o filme (Al ou Inconel) nas características de atenuação de energia da onda eletromagnética. De acordo com os estudos, pode-se verificar que a espessura da camada depositada, e o material do filme influenciam nas características atenuadoras, sendo que os filmes de Al e Inconel depositados apresentaram uma atenuação de no máximo 13% . Isto nos leva a crer que filmes metálicos podem ser utilizados com materiais absorvedores de radiação eletromagnética, desde que se conheça a espessura ideal de trabalho e outras características intrínsecas do mesmo.