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Odelade, Mobolaji. "P300 Control Matrix| A Novel Approach to P300 Speller Matrix." Thesis, North Carolina Agricultural and Technical State University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10976563.
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Over the years, researchers have been able to prove Brain Computer Interface (BCI) -P300 Speller as an effective communication tool. The first P300 speller was developed by Farwell and Donchin (1988), using the oddball paradigm to evoke a P300 response from a speller matrix. This P300 speller matrix has been a strong basis for studies that aimed at using BCI-P300 protocol for spelling, cursor movement, internet navigation or even control and manipulation of devices. However, application of P300 based BCI to controlling and manipulation of devices often involves the user relating with multiple interfaces. These multiple interfaces could be a distraction or have negative effects on the user (Fazel-Rezai et al. 2012) and as a consequence hinders the evoking of P300 potential and causing inaccurate classification. For this research, a novel P300 control matrix is developed by replacing the alphabets in the traditional P300 speller matrix with arrow images. Then the novel P300 control matrix was investigated to compare the P300 latency and amplitude to that of the traditional P300 speller matrix. The elements in the novel P300 control matrix were in form of arrows facing upward, left, right and downward directions, while elements in the P300 speller matrix were alphabets U, L, R and D for the upward, left, right and downward directions respectively. The participants were presented with a set of randomly sequenced directions, and each participant decides which of the arrows or letters to focus on based on the direction presented to them. Electroencephalography (EEG) was used to record the brainwaves using the international 10-20 system of electrode placement. This research is potentially a more efficient approach for controlling devices using P300-based BCI systems by eradicating the need for multiple interfaces associated with BCI-robotic control systems that are based on P300 speller.
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Iyer, N. G. "Functional characterisation of p300." Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.604977.
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p300, originally discovered as an adenoviral El A binding protein, is a putative tumour suppressor gene. Mutational analysis done in our laboratory found truncating mutations in a range of cell lines and primary tumours, in some cases associated with loss of the second allele. In order to study the possible pathways leading from p300 loss to cancer, I adopted a somatic cell line knock out strategy to study the gene function in a human epithelial system. Using homologous recombination mediated gene targeting I successfully disrupted p300 in HCT116, by targeting the single expressed, truncated allele. Resultant cells were null for p300 protein. Rescue clones were generated by re-introducing full-length p300 cDNA into the knock-out clones. p300 knock-out (KO) cells were defective in proliferation, with prolonged doubling times and increased S-phase. A fraction of cells were in senescence/quiescence, and included a flat cell phenotype. These changes were reversed in the rescue clones. KO cells also showed a Gl to S-phase transition defect with early S phase entry after serum depletion and nocodazole arrest and release experiments. Rb pathways were deranged, principally by Rb phosphorylation defects, which probably led to the activation of the E2F pathway and early S-phase entry. KO cells also demonstrated abnormalities in p21 response during the cell cycle, which could have contributed to the cell cycle phenotype. In addition, KO cells were found to have reduced cell-cell adhesion, due to a decrease in E-cadherin at tight junctions and total E-cadherin levels. DNA damage experiments suggest that p300 KO cells are especially sensitive to UV mediated DNA damage with increased apoptosis seen 24 h after irradiation. This was due to abnormalities in the p53 pathway- a combination of increased stability of p53, reduced acetylation at lysine 382 and abnormal transactivation of downstream factors. In contrast, long term growth of KO cells after UV and XR irradiation showed increased resistance to DNA damage.
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Kaper, Matthias. "P300 based brain computer interfacing." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=979538203.
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Cota, Navin Gupta. "Advancing the P300 based BCI design." Thesis, University of Essex, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.617085.
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Brain Computer Interface (BCI) systems capture brain signals and convert them into commands without using peripheral nerves or muscles. This doctoral thesis embarks on advancing the design of P300 based BCI system using electroencephalogram (EEG) responses to visual and audio stimuli. This research work investigates techniques for pre processing, feature extraction as well as attempts some variations in paradigm design from a P300/0ddball paradigm perspective. Pre-processing is an important module in BCI systems. This thesis proposes a fully automated method (GALME-=ICA) to reduce artefacts effectively for an offline scenario. The method uses the recorded EEG channels only and does not require recorded EOG channels. The P300/0ddball systems were designed so as to reduce perceptual errors, thereby making them participant friendly. Few variations in paradigm design . reported here have not been attempted before. In one study, the spatial effect of the target stimuli location with respect to the non-target stimuli was explored. In another study limiting interference from irrelevant task related stimuli was studied. Results are discussed in terms of classification accuracies and bit rates. This thesis also proposes the usage of gamma band features with P300 time domain features for RSVP and audio based oddball paradigms for BCI based applications. An attractive integration of EEG-NIRS for monitoring participant concentration was also attempted. Preliminary results highlight the importance in selecting training datasets for good online classification results from an EEG viewpoint. There is no denying the fact that recent advances in BCI field have led researchers to explore new applications like cursor control and game control. However, there are many challenging problems which remain to be solved, before a commercial BCI system becomes a reality. Hence there is an urgent need to explore better system design and develop novel signal processing as well as machine learning algorithms. Imagination combined with practicality appears to be the key here. This Doctoral work is a step forward in this direction.
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Teufel, Daniel Paul. "The interactions of p300 with p53." Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613972.
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Delvecchio, Manuela. "Mécanisme de régulation de l'acétyltransférase p300/CBP." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00631344.
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Le p300/CBP acétyltransférase est un co-activateur transcriptionnel très important qui est impliqué dans la régulation d'un grand nombre de processus biologiques, comme la transcription d'ADN, le développement et l'immunité innée. Jusqu'à présent, le rôle de p300/CBP dans la régulation de l'expression des gènes a été largement étudiée, mais les mécanismes qui régulent son activité enzymatique sont encore peu connus. Des études ont montré que le dysfonctionnement de p300/CBP est associé à plusieurs formes de cancer et de maladies neurodégénératives. Dés lors, chaque progrès concernant les mécanismes de régulation de p300/CBP est devenu primordial pour le développement de nouvelles thérapies. Le 'noyau' de p300/CBP contient deux domaines pour la reconnaissance des modifications post-traductionnelles (MPTs), un bromodomaine et un PHD finger (le module BP), adjacent à un domaine HAT (ou domaine histone acétyltransférase). Plusieurs enzymes, modifiant la chromatine, contiennent des domaines de reconnaissance des MPTs. Fréquemment des groupements particuliers de ces domaines sont très conservés et liés, au sein de la même protéine ou du même complexe protéique, suggérant qu'ils réalisent des fonctions coordonnées. Ces domaines adjacents peuvent agir en concertation dans la reconnaissance simultanée de différents MPTs ou peuvent exercer des fonctions différentes de celles qui sont effectuées par ces deux domaines particuliers, tels que les fonctions de régulation enzymatique. Plusieurs études suggèrent que les cycles acétylation/désacétylation dans la boucle d'auto-inhibition, à l'intérieur du domaine HAT, jouent un rôle important dans la régulation de l'activité enzymatique de p300/CBP. La proximité du module BP et du domaine HAT suggère que la spécificité de liaison, appartenant au module BP, peut être intrinsèquement liée à la régulation de l'activité du domaine HAT. L'objectif de ma thèse est de déterminer le rôle du module BP dans la régulation de l'activité du domaine HAT. Je propose que le module BP soit impliqué dans la régulation de p300/CBP de deux façons. La première consiste à établir un lien avec le domaine HAT qui stabilise la conformation auto-inhibée de l'enzyme. La deuxième exige que le module BP joue un rôle dans le choix des substrats de p300/CBP. J'ai été en mesure de montrer que BP peut se lier au domaine HAT et à la chromatine modifiée et qu'il peut reconnaître les modifications effectuées par p300/CBP lui-même. Les données obtenues indiquent que le module BP peut être impliqué dans la régulation de l'activité de p300/CBP et dans son ciblage à la chromatine.
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Weston, Louise. "Functional studies on the p300 cofactor JMY." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.534179.
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Santoso, Buyung. "Transcription repression by coactivator p300 in vitro /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2005. http://wwwlib.umi.com/cr/ucsd/fullcit?p3170244.
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Skinner, Tim. "Effect of Intensity Increment on P300 Amplitude." Scholar Commons, 2004. https://scholarcommons.usf.edu/etd/1251.
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The purpose of this study was to determine the effects of task difficulty on the amplitude and latency of the P300 by altering the intensity of the oddball stimulus. A P300 was obtained on 22 adult subjects ranging in age from 21 to 34 years of age (mean = 24 years) with normal hearing. The "frequent stimulus" was a 1000 Hz or 4000 Hz tone burst, gated with a rise and fall time of 10 msec and 20 msec plateau, presented at 75 dBn HL The "oddball stimulus" was a tone burst of the same frequency (1000 Hz or 4000 Hz)presented at 77, 79, or 81 dBn HL. A four-channel recording was made with linked reference electrodes and the following montages:Cz-A1+A2, Pz-A1+A2, and Fz-A1+A2. The fourth channel was used to monitor "eye blink" activity. The investigation tested the null hypothesis that changing the intensity of the oddball stimuli would not result in a significant change in either the amplitude or latency of the P300.
Analyses of Variance (ANOVA) indicate that P300 latency and amplitude did not differ significantly by run, stimulus frequency, intensity of the oddball, or montage. Thus the null hypothesis was supported.
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Harpur, Timothy John. "Determining cerebral lateralisation : the use of the P300." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25418.
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The P300 component of the average evoked potential was recorded at Pz during two divided visual field tasks. During a lexical decision task, reaction time and P300 latency were faster to stimuli in the right visual field, indicating that the latency of the P300 may be a useful measure in laterality research. A right visual field advantage was obtained for reaction time in a face perception task and the P300 latency difference showed a similar but non-significant advantage. Use of the P300 latency to assess the validity of the assumptions underlying the application of an additive factors model to divided visual field studies of cerebral assymetry was discussed. The present evidence suggests that the assumptions are valid.Arts, Faculty of
Psychology, Department of
Graduate
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Hamed, Munerah. "Effect of p300 HAT Activity on Myogenic Differentiation." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/23707.
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Skeletal muscle specification and differentiation programs are regulated by the myogenic regulatory factors which include Myf5, MyoD, myogenin and Mrf4. Upstream of the MRFs, the transcription co-activators and other intracellular and extracellular signals play crucial roles in regulating skeletal myogenesis. Histone acetyltransferase activity of p300 is required for Myf5 and MyoD expression. Furthermore, the MyoD core enhancer region is indispensable for MyoD expression. However, the mechanism by which p300 activates MyoD gene expression is to be determined. The histone acetyltransferase activity of p300 can be inhibited by small molecule inhibitors such as curcumin. Thus, using the inhibitor approach on stem cells is useful to investigate the role of p300 in activating MyoD expression during myogenesis. We here show that curcumin was able to inhibit stem cell determination and differentiation into skeletal myocytes. We also show that p300 is present, and histone acetylation is high at the core enhancer region. Therefore, we provide evidence that p300 is directly involved in MyoD gene expression during skeletal myogenesis.
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Furuhashi, Takeshi, Tomohiro Yoshikawa, and Hiromu Takahashi. "A Novel Selective Stimulus Presentation for P300 Speller." IEEE, 2011. http://hdl.handle.net/2237/20707.
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Junqueira, Cinthia Amorim de Oliveira. "Investigação da estabilidade inter e intra-examinador na identificação do P300 auditivo: análise de erros." Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/59/59134/tde-30082002-112247/.
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O P300 auditivo é um potencial evocado que reflete a atividade neurofisiológica das habilidades cognitivas auditivas de atenção, memória, discriminação e tomada de decisão. A possibilidade de correlacionar aspectos do comportamento auditivo a fenômenos fisiológicos observáveis tem despertado o interesse de profissionais de diversas áreas interessados no estudo das disfunções auditivas. Por ser um procedimento novo, os métodos de análise e interpretação dos resultados ainda não estão padronizados e, portanto, devem ser explorados e discutidos visando maior segurança para aplicação clínica e científica. Este estudo investigou a estabilidade na análise e interpretação do P300 auditivo seguindo um conjunto de regras (critério) pré-determinadas. Para isso, quatro profissionais da área audiológica analisaram, em 2 momentos diferentes, 70 traçados de P300 de crianças e adolescentes saudáveis entre 8 e 18 anos de idade, seguindo as mesmas regras para a identificação das ondas (N1, P2, N2 e P3) e marcação de suas medidas de latência. As medidas de latência da onda P300 foram submetidas a análises qualitativa e quantitativa. A análise qualitativa investigou os tipos de erros cometidos pelo examinador no uso do critério de determinação do P300 (5,9% do total de 560 medidas obtidas). Os erros mais freqüentes no uso do critério foram: não identificar o P300 como a maior onda logo após o complexo N1-P2-N2 e identificar uma falsa onda P300. A análise quantitativa investigou a variabilidade da medida da latência do P300 atribuível ao examinador. Os resultados mostraram que não houve diferença significante entre as análises inter e intra-examinador, tendo sido encontradas correlações significantes entre as medidas de latência, indicando boa fidedignidade no teste-reteste e alta concordância entre os examinadores no modo como analisaram os traçados das ondas. O critério usado neste estudo demonstrou ser útil na determinação do P300, podendo ser sugerido com segurança para uso clínico e científico.The P300 auditory is an evoked potential which reflects the neurophysiological activity of auditory cognitive abilities: attention, memory, discrimination and making decision as well. The possibility of correlation between aspects of auditory behavior and observable physiological phenomena has increased the interest in the study of auditory dysfunctions among professionals of various fields. Due the fact that the P300 is a recent procedure, the methods of its analysis and interpretation have not been standardized yet. Therefore, they must be explored and debated aiming more security for clinical and scientific application. In this study it was investigated the stability in the analysis and interpretation of P300 auditory, according to a pre-determined set of rules. Four audiologists analyzed twice 70 records of P300 of healthy children and adolescents between 8 and 18 years of age, identifying the waves (N1, P2, N2, P3) and their latencies according to the pre-determined set of rule. The P300 latency measurements were submitted to quantitative and qualitative analysis. The qualitative analysis looked into types of errors made by the examiner during the P300 identification (5.9% in a total of 560 measurements). The no-identification of the P300 as the highest wave following the complex N1-P2-N2, likewise the wrong identification of P300 wave were the most frequent mistakes. In the quantitative analysis we investigated the variability of the P300 latency measurements attributable to the examiner. The results showed that there were no significant differences between the inter- and intra-examiner analyses. Significant correlations were found between the measurements, showing a good test-retest reliability and high concordance among the examiners in the way they analyzed the wave records. We conclude that the rules used in this study are useful to the identification of the P300 in both clinical and scientific situations.
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Sharma, Salil. "MicroRNAs as Effectors for Acetyltransferase p300 in Cardiac Hypertrophy." Scholarly Repository, 2011. http://scholarlyrepository.miami.edu/oa_dissertations/684.
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Myocardial transcriptional response to stress is critically dependent on availability of the histone acetyltransferase p300. p300 is a transcription coactivator which is rapidly induced by hemodynamic stress in the myocardium. This induction is both necessary and sufficient to drive myocardial hypertrophy in vivo. Although short-term elevation of p300 may be adaptive, sustained elevation of p300 increases the risk of heart failure. The mechanism of p300 induction during stress is unknown. The downstream effectors of p300 have been only incompletely elucidated. In this context, the role of microRNAs in regulating p300-driven cardiac hypertrophy can be of potential interest. MicroRNAs are short ~18-25 nucleotide non-coding RNAs that inhibit gene expression by inducing messenger RNA cleavage and blocking translation. Engagement of microRNAs by various transcription factors/coactivators is an important regulatory mechanism in angiogenesis and hypertrophy. However, the extent to which microRNAs act as downstream effectors and/or modulators of the p300-driven hypertrophic response is unknown. Preliminary data showed that miR20a, miR142 and miR374-5p were regulated during p300-driven cardiac hypertrophy and in acute ischemia. In addition, these microRNAs may target p300 as part of a feedback loop as p300 is one of the predicted targets. The goal of this project was to dissect the role of a subset of microRNAs including miR-20a, miR142 and miR374 during p300 regulated hypertophic growth in vitro and in vivo and to verify its targets. This study is important to delineate the role of microRNAs in the p300-dependent signaling network in the myocardium and may result in therapeutic benefit.
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Francetic, Tanja. "The role of p300 in regulation of Myf5 expression." Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28531.
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The commitment of cells to skeletal muscle differentiation is regulated by the myogenic regulatory factors Myf5, MyoD, myogenin and MRF4. Myf5 is the earliest of the MRFs expressed in an embryo. An array of transcriptional factors and signals present in dermomyotome and myotome such as Wnt, Shh, Six1/4, Eya1/2 and Pax3/7 regulate the expression of Myf5. Also, the HAT activity of coactivator p300 is also needed for Myf5 expression. However, the exact function of the p300 HAT activity that is required for expression of Myf5 has not been determined. The spatio-temporal expression of Myf5 is also regulated by a large number of enhancers spread over 140 kb upstream of the transcription start site. The early epaxial enhancer regulates the expression at the earliest time point known. We hypothesized that HAT activity of p300 may be involved in direct regulation of Myf5. We used the embryonal carcinoma P19 cells to study skeletal myogenesis and the chemical inhibitor curcumin to study the role ofp300 HAT activity. Curcumin was able to inhibit commitment into skeletal myogenesis by downregulating expression of Myf5 and MyoD. Furthermore we show that p300 is present at the early epaxial ehancer and that the function ofp300 there may be histone acetylation. Therefore we provide evidence that p300 may be directly involved in regulation of Myf5 expression.
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Francis, Yitshak Itsik. "The role of CBP and p300 in Alzheimer's Disease." Thesis, University College London (University of London), 2008. http://discovery.ucl.ac.uk/1443955/.
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Studies of the mechanisms underlying memory formation have defined central roles for CRE-dependent gene expression, which is mediated by the transcription factor CREB and the coactivator CBP. CBP creates a bridge between CREB and the basal transcriptional machinery and acetylates histones, which induces chromosomal changes and results in loss of chromosomal repression. This allows successful transcription of the underlying genes needed for synthesis of proteins underlying memory formation. CBP has been linked to neurodegenerative diseases and cerebral CBP levels were shown to reduce in mice lacking functional presenilins (PSs), a class of enzymes that has been associated with Alzheimer's Disease (AD). In this thesis it is shown that WT PS1 stimulates the transcriptional activating ability of CBP and its close homolog p300, whereas an Alzheimer's disease- associated N terminal mutant of PS1 did not produce this effect. Interestingly, PS1 C terminal mutants produced a reduction in CBP transcriptional activating ability, compared to control levels. Additionally, we showed that wild type PS1 increases the endogenous CBP level. Moreover, an increase in CBP endogenous levels was noted when the cells were transfected with the -M146L N-terminal mutant of PSI. However, these levels were still significantly lower when compared to cells transfected with wild type PSI. We were also able to show that knockdown of endogenous PSI leads to a decrease in endogenous CBP levels and a decrease in CBP activity. Hence, PSI can affect both the level and the activity of CBP. In addition, the activation of CBP by WT PSI involves the PI 3-kinase, p38 MAP kinase and p42/p44 MAP kinase pathways and targets primarily the C terminus of CBP. It is also shown that the effect of wild-type PSI is dependent on the histone acetyltransferase activity (HAT) of CBP. Moreover, it was demonstrated that WT PSI, but not its M146L mutant, could increase the promoter activity of c-fos, a CBP HAT dependent target gene. Additionally, we showed that application of the histone deacetylase inhibitor, TSA, rescued the long-term potentiation and long-term memory defects shown by APP/PS1 mutant mice. Moreover, it was shown that the acetylation level of histone H4 in APP/PS1 mice is lower than that of WT littermates and that TSA injection restores the acetylation of these histones. This is the first study to identify AD as a disease of epigenetic etiology and suggests that enhancing histone acetylation may have potential for the treatment of AD.
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Chan, Ho Man. "Molecular basis of cell cycle control : p300 and pRb." Thesis, University of Glasgow, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326430.
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Gusterson, Rosalind Jane. "The role of CBP and p300 in cardiac hypertrophy." Thesis, University College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399576.
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Martin, Florence. "Potentiels evoques cognitifs (p300) chez des enfants intellectuellement precoces." Nice, 1990. http://www.theses.fr/1990NICE6801.
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Black, Joshua Cranston. "A catalytic switch in p300 regulates preinitiation complex assembly." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1782063051&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Allison, Brendan. "P3 or not P3 : toward a better P300 BCI /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2003. http://wwwlib.umi.com/cr/ucsd/fullcit?p3090451.
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Ferraz, Érika. "Efeitos de um programa de remediação fonológica em escolares com dislexia do desenvolvimento: monitoramento da evolução terapêutica com o uso do P300." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/25/25143/tde-05062013-104036/.
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Dislexia é um dos distúrbios de aprendizagem, sendo um transtorno específico no aprendizado da leitura. Tem origem constitucional, caracterizado pela dificuldade em decodificar palavras simples, mostrando insuficiência no processo fonológico, não esperada para sua idade cronológica, apesar de instrução convencional, adequada inteligência, oportunidade sociocultural e sem distúrbios cognitivos. O uso de atividades terapêuticas de treino das habilidades fonológicas leva a uma melhora quanto à análise fonológica da linguagem escrita, interferindo diretamente na habilidade de leitura e compreensão. É importante que se busquem meios alternativos para monitorar a evolução terapêutica, principalmente quanto à sua capacidade cognitiva. O objetivo deste estudo foi verificar os efeitos de um programa de remediação fonológica de leitura e escrita em escolares com Dislexia de Desenvolvimento. Foram avaliadas 20 crianças com diagnóstico de dislexia do desenvolvimento, com idade de 8 a 14 anos, sendo o grupo I (GI) composto por 10 escolares submetidos ao programa, e grupo II (GII), composto por 10 escolares não submetidos à remediação. Foram utilizados no processo de avaliação: Prova de Consciência Fonológica; Teste de Nomeação Automática Rápida; Prova de Leitura e Escrita de palavras reais e inventadas; Escrita temática; Prova de Memória de trabalho e teste do Potencial evocado auditivo cognitivo PEAC-P300. Após, foi aplicado o programa de remediação fonológica, de leitura e escrita, realizado em três etapas distintas, com 24 sessões, cumulativas, sendo cada etapa realizada duas vezes por semana, com duração de 30 minutos cada. Na pós-testagem do programa foram reaplicados todos os testes da pré-testagem. Houve diferença estatisticamente significante na pontuação dos testes de consciência fonológica, do acesso ao léxico mental, da memória de trabalho, escrita temática e escrita sob ditado, além da leitura de palavras e pseudopalavras, assim como na latência do componente P3 do PEAC-P300, para o grupo submetido à remediação fonológica, na comparação entre pós e pré testagem, enquanto o GII manteve o mesmo nível de dificuldades. Além disso, encontramos relação entre a alteração de desempenho obtido pelo grupo submetido ao programa entre o teste de consciência fonológica e a latência do componente LN2 do p300. A análise desses resultados revela que houve diferença no desempenho pós-intervenção terapêutica dos participantes do GI nas habilidades, mesmo em curto prazo. O programa de remediação fonológica mostrou-se um método terapêutico de efeitos benéficos e rápidos, proporcionando melhora não apenas quantitativa, mas principalmente qualitativa nos escolares com dislexia do desenvolvimento, quanto ao domínio de habilidades auditivas, fonológicas e de leitura e escrita, favorecida pelo uso do processamento fonológico da informação. Além disso, o PEAC-P300 mostrou-se uma ferramenta útil para o monitoramento da evolução terapêutica, podendo ser utilizado na prática clínica.Dyslexia is a learning disorder, being a specific disorder in learning of reading. Constitutional origin, characterized by difficulty in decode simple words, showing insufficiency in the phonological process, not expected for his chronological age, despite conventional instruction, adequate intelligence, socio-cultural opportunity, without cognitive disorders. The use of therapeutic activities of training of phonological skills leads to an improvement in phonological analysis with regard to written language, interfering directly in the ability to read and understand. It is important to seek the means to monitor the therapeutic evolution, especially as your cognitive ability. The goal of this study was to verify the performance in evaluation procedures of language in children with developmental dyslexia in pre and post phonological remediation program and reading and writing, prepared from phonological abilities, auditory and visual skills, reading and writing. Were evaluated 20 children diagnosed with developmental dyslexia, aged 8 to 14 years, with the Group I (GI) composed of school 10 submitted to the program, and group II (GII), composed of 10 schools not subject to remediation. Were used in the evaluation process: Phonological Awareness; Rapid Auto-naming test; Proof-reading and writing real words and invented; Thematic writing; Proof of working memory and cognitive auditory evoked potential CAEP-P300. After, was applied the phonological remediation program of reading and writing, in three distinct steps, with 24 sessions, cumulative, with each step performed twice a week, with a duration of 30 minutes each. In the post testing of the program were reapplied all the tests of pre testing.There was a statistically significant difference in score of phonological awareness tests, access to mental lexicon, working memory, thematic writing and written under dictation, and reading words and pseudo-words, as well as the latency of the P3 component of the CAEP-P300, the group submitted to the phonological remediation, in comparison between pre and post testing, while the GII has maintained the same level of difficulty. In addition, we find the relation between the change of performance achieved by the Group submitted to the program between the test of phonological awareness and the LN2 component of P300 latency. The analysis of the results reveals that there was difference in post-intervention performance of participants in the GI in therapy skills, even in the short term. The phonological remediation program proved to be an therapeutic method of beneficial effects and fast, providing improved not only quantitative, but qualitative mainly school development in with dyslexia, as to the field of auditory skills, phonological and reading and writing, favored by use of the phonological processing of information. In addition, the CAEP-P300 proved to be a useful tool for monitoring goal of evolution therapy, and can be used in clinical practice.
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Micali, Alberto. "Hacktivism and the heterogeneity of resistance in digital cultures." Thesis, University of Lincoln, 2016. http://eprints.lincoln.ac.uk/25324/.
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Digital media and networks occupy an increasing central position within contemporary societies. This position does not simply involve communicational forms. From the turn of the millennium, phenomena of on- line activism have regularly emerged, bringing novel political forms of resistance to the fore. In academic literature, such phenomena are defined as ‘hacktivism’, putting hacker culture in contact with the politically motivated use of networked media by social movements. However, these scholarly perspectives often fail to deal sufficiently with the original forms of mediation that are at stake in hacktivist ‘deployments’ of media apparatuses. Finding inspiration especially in the work of Félix Guattari, I propose a ‘machinic’ methodology able to deal with the relations and processes with which the act of researching is inescapably involved, overcoming the distances that epistemologically separate the subject from its objects of research. Hence, I originate a ‘method assemblage’ by combining emergent theories in the field of media and culture, and advancing a critical questioning on the same researching procedures. Linking media ecologies and archaeologies, the resulting creative method allows an approach to the case study of ‘Anonymous’ through a novel critical compass. The original creation of the method aims to study without foreclosing the heterogeneous forms of active resistance actualised through media technologies. I suggest that the short-term, transient character of contemporary forms of resistance does not lack political efficacy. Rather hacktivism has to be reconsidered in vital terms beyond representation, within a field that is ‘micro-political’ and materially involves novel processes of subjectivation and disruptiveness.
24
Lombard, F. D. "An investigation of the P300 event related potential across gender." Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-01312006-110751.
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Erdogan, Hasan Balkar. "A Design And Implementation Of P300 Based Brain-computer Interface." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12611141/index.pdf.
Full textAbstract:
In this study, a P300 based Brain-Computer Interface (BCI) system design is
realized by the implementation of the Spelling Paradigm. The main challenge in
these systems is to improve the speed of the prediction mechanisms by the
application of different signal processing and pattern classification techniques in
BCI problems.
The thesis study includes the design and implementation of a 10 channel
Electroencephalographic (EEG) data acquisition system to be practically used in
BCI applications. The electrical measurements are realized with active electrodes
for continuous EEG recording. The data is transferred via USB so that the device
can be operated by any computer.
v
Wiener filtering is applied to P300 Speller as a signal enhancement tool for the
first time in the literature. With this method, the optimum temporal frequency
bands for user specific P300 responses are determined. The classification of the
responses is performed by using Support Vector Machines (SVM&rsquos) and Bayesian decision. These methods are independently applied to the row-column intensification groups of P300 speller to observe the differences in human perception to these two visual stimulation types. It is observed from the investigated datasets that the prediction accuracies in these two groups are different for each subject even for optimum classification parameters. Furthermore, in these datasets, the classification accuracy was improved when the signals are preprocessed with Wiener filtering. With this method, the test characters are predicted with 100% accuracy in 4 trial repetitions in P300 Speller dataset of BCI Competition II. Besides, only 8 trials are needed to predict the target character with the designed BCI system.
26
Valsecchi, Matteo, Olaf Dimigen, Reinhold Kliegl, Werner Sommer, and Massimo Turatto. "Microsaccadic Inhibition and P300 Enhancement in a Visual Oddball Task." Universität Potsdam, 2009. http://opus.kobv.de/ubp/volltexte/2011/5717/.
Full textAbstract:
It has recently been demonstrated that the presentation of a rare target in a visual oddball paradigm induces a prolonged inhibition of microsaccades. In the field of electrophysiology, the amplitude of the P300 component in event-related potentials (ERP) has been shown to be sensitive to the stimulus category (target vs. non target) of the eliciting stimulus, its overall probability, and the preceding stimulus sequence. In the present study we further specify the functional underpinnings of the prolonged microsaccadic inhibition in the visual oddball task, showing that the stimulus category, the frequency of a stimulus and the preceding stimulus sequence influence microsaccade rate. Furthermore, by co-recording ERPs and eye-movements, we were able to demonstrate that, despite being largely sensitive to the same experimental manipulation, the amplitude of P300 and the microsaccadic inhibition predict each other very weakly, and thus constitute two independent measures of the brain’s response to rare targets in the visual oddball paradigm.
27
Wintermute, Cody Lee. "Observing P300 Amplitudes in Multiple Sensory Channels using Cognitive Probing." Wright State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=wright1598375415421172.
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Kawamura, Teruhisa. "Expression of p300 protects cardiac myocytes from apoptosis in vivo." Kyoto University, 2004. http://hdl.handle.net/2433/147539.
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Martens, Joost Hendrik Adriaan. "P300 recruitment to DNA elements required for transcription regulation : Proefschrift /." Leiden : Universiteit Leiden, 2003. http://catalogue.bnf.fr/ark:/12148/cb399326180.
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Matthews, David. "Dissociation of P300 brain potentials evoked by rare visual stimuli." Thesis, University of St Andrews, 1995. http://hdl.handle.net/10023/14732.
Full textAbstract:
The P300 event related potential (ERP) has consistently been dissociated into separate components on the basis of scalp amplitude distribution within the auditory modality (for instance Squires et al. 1975). A parietally maximum P300 deflection being evoked in response to target stimuli in comparison with a more frontally maximum P300 deflection evoked in response to rare nontarget stimuli. Results obtained within experiment 1 and 6 demonstrated such a dissociation employing auditory stimuli within a three stimulus oddball paradigm. It did not prove possible to obtain such a dissociation of P300 deflections on the basis of scalp amplitude distribution within the visual modality. Across a number of experimental manipulations both target and rare nontarget stimuli evoked P300 deflections with similar amplitude distributions (centro-parietal maximum along the midline). Experiment 5 demonstrated that frequent stimuli similarly evoked a centro-parietal maximum amplitude distribution. It was demonstrated that both stimulus probability (Experiment 4) and the physical characteristics of the stimuli (Experiment 5) affected the mean amplitude of the evoked P300 deflection. However, the scalp amplitude distribution of the evoked deflections remained constant. Within Experiment 6 it was demonstrated that within both auditory and visual modalities P300 deflections, evoked in response to both target and rare nontarget stimuli, demonstrated an equipotential amplitude distribution within an elderly group of subjects. In addition across both modalities amplitude evoked in response to rare nontarget stimuli demonstrated an asymmetric distribution across lateral chains of electrodes. Amplitude evoked along the right chain was significantly reduced in comparison to that evoked along the left chain. It would appear that the same, or a similar combination of, underlying neural generators are responsible for the activity that may be recorded at the scalp as the P300 deflection within the visual modality.
31
Babini, Federico. "Il potenziale cerebrale P300 evocato da stimoli acustici: acquisizione e analisi." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18880/.
Full textAbstract:
Questo lavoro di tesi ha riguardato i Potenziali Evento Correlati (ERP) in risposta a stimoli uditivi, con particolare riferimento alla componente P300. Quest’ultima si manifesta maggiormente in risposta alla presentazione di uno stimolo raro immerso in una sequenza di stimoli più frequenti (paradigma di oddball). In primo luogo si è voluto sviluppare un protocollo sperimentale di oddball acustico che permettesse di acquisire segnali EEG sincronizzati con un trigger. Questo sistema doveva essere in grado di:
- generare una successione di due stimoli acustici con diversa caratteristica fisica, di cui uno frequente e uno raro, presentati in modo random;
- generare un trigger sincronizzato con l’inizio di ciascun stimolo;
- rendere il trigger adatto alla sua acquisizione da parte di un sistema EEG (OpenBCI) simultaneamente ai segnali elettroencefalografici;
- segmentare i segnali EEG in epoche sulla base del trigger, per l’estrapolazione degli ERP con la tecnica dell’averaging.
Il secondo obiettivo di questo lavoro di tesi è stato quello di testare il funzionamento del sistema, acquisendo i segnali EEG su alcuni soggetti sottoposti al paradigma di oddball acustico implementato, e calcolando i potenziali ERP in risposta allo stimolo standard e allo stimolo deviante. Questo è stato fatto usando due paradigmi di oddball: un paradigma di oddball passivo (in cui non è richiesta alcuna risposta comportamentale) e un paradigma di oddball attivo (in cui è richiesta una risposta comportamentale in corrispondenza allo stimolo deviante).
L’utilizzo dei due paradigmi di oddball ha permesso di valutare come la P300 si manifesti maggiormente in risposta allo stimolo deviante rispetto allo stimolo standard e come l’attenzione volontaria posta verso lo stimolo deviante (target) durante la prova attiva possa generare una componente P300 di ampiezza maggiore rispetto alla prova passiva.
32
Morhard, Dominik. "fMRT der P300: Modifikation der klassischen EEG-Untersuchung für die fMRT." Diss., lmu, 2004. http://nbn-resolving.de/urn:nbn:de:bvb:19-16959.
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Perrin, Margaux. "Coadaptation cerveau machine pour une interaction optimale : application au P300-Speller." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10329/document.
Full textAbstract:
Les interfaces cerveau-machine (ICM) permettent de contrôler une machine directement à partir de l'activité cérébrale. Le P300-Speller, en particulier, pourrait offrir à des patients complètement paralysés, la possibilité de communiquer sans l'aide de la parole ou du geste. Nous avons cherché à améliorer cette communication en étudiant la coadaptation entre cerveau et machine. Nous avons d'abord montré que l'adaptation d'un utilisateur peut être partiellement perçue, en temps-réel, à travers les modulations de sa réponse électrophysiologique aux feedbacks de la machine. Nous avons ensuite proposé, testé et évalué les effets sur l'utilisateur de plusieurs approches permettant d'améliorer l'interaction, notamment : la correction automatique des erreurs, grâce à la reconnaissance en temps-réel des réponses aux feedbacks ; une stimulation dynamique permettant de diminuer le risque d'erreur tout en réduisant l'inconfort lié aux stimulations ; un processus automatique de décision adaptative, en fonction de l'état de vigilance du sujet. Nos résultats montrent la présence de réponses aux feedbacks spécifiques des erreurs et modulées par l'attention ainsi que par la surprise du sujet face au résultat de l'interaction. Par ailleurs, si l'efficacité de la correction automatique est variable d'un sujet à l'autre, le nouveau mode de stimulation comme la décision adaptative apparaissent comme très avantageux et leur utilisation a un effet positif sur la motivation. Dans la perspective d'études cliniques pour évaluer l'utilité des ICM pour la communication, ces travaux soulignent et quantifient l'intérêt de développer des interfaces capables de s'adapter à chaque utilisateurBrain-computer interfaces (BCI) aim at enabling the brain to directly control an artificial device. In particular, the P300-Speller could offer patients who cannot speak and neither move, to communicate again. This work consisted in improving this communication by implementing and studying a coadaptation between the brain and the machine. First, on the user side, we showed that adaptation is reflected in real-time by modulations of the electrophysiological responses to the feedbacks from the machine. Then, on the computer side, we proposed, tested and evaluated the effect on the user, of several approaches that endow the machine with adaptive behavior, namely: Automatic correction of errors, based on real-time recognition of feedback responses; Dynamic stimulation to increase spelling accuracy as well as to reduce the discomfort associated with the traditional row/column stimulation paradigm; Adaptive decision making for optimal stopping, depending on the attentional state of the user. Our results show the presence of feedback responses which are error specific and modulated by attention as well as user's surprise with respect to the outcome of the interaction. Besides, while the interest of automatic correction is highly subject-dependant, the new stimulation mode and the adaptive decision method proved clearly beneficial and their use had a significant positive impact on subject's motivation. In the perspective of clinical studies to assess the usefulness of ICM for communication, this work highlights and quantifies the importance of developing adaptive interfaces that are tailored to each every individual
34
Al-Ghazawi, Feras. "Roles of bromodomain in the regulation of p300-dependent gene expression." Thesis, University of Ottawa (Canada), 2009. http://hdl.handle.net/10393/28045.
Full textAbstract:
The transcriptional coactivator p300 displays an intrinsic histone acetyltransferase activity. It contains an evolutionarily conserved bromodomain serving as a specific acelyl-lysine binding module for histones or transcription factors to facilitate chromatin remodeling and transcriptional activation. The function of p300 is required by a diverse set of promoters. However, roles of bromodomain in the function of p300 are yet to be fully determined. In this study, we utilize cell lines expressing either wild-type or bromodomain truncated p300 to examine the expression of several p300-dependent genes that are involved in cell cycle regulation. The effects of histone acetylation on the expression of these genes were also examined by utilizing histone deacetylase inhibitors. Our results suggest that p300 regulates genes through different mechanisms and that bromodomain has roles in the recruitment of p300 to target promoters, providing an indication that the role of bromodomain in p300-dependent transcription is determined by individual promoter context.
35
Fazikas, Wolf Angela. "P300 and target identification complexity using numerical and line segment stimuli." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ34361.pdf.
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36
Brown, Kerri J. "Beyond the P300 target and non-target ERP components in schizophrenia /." Access electronically, 2004. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20050218.140514/index.html.
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37
Margaux, Perrin. "Coadaptation cerveau machine pour une interaction optimale : application au P300-Speller." Phd thesis, Université Claude Bernard - Lyon I, 2012. http://tel.archives-ouvertes.fr/tel-00870395.
Full textAbstract:
Les interfaces cerveau-machine (ICM) permettent de contrôler une machine directement à partir de l'activité cérébrale. Le P300-Speller, en particulier, pourrait offrir à des patients complètement paralysés, la possibilité de communiquer sans l'aide de la parole ou du geste. Nous avons cherché à améliorer cette communication en étudiant la coadaptation entre cerveau et machine. Nous avons d'abord montré que l'adaptation d'un utilisateur peut être partiellement perçue, en temps-réel, à travers les modulations de sa réponse électrophysiologique aux feedbacks de la machine. Nous avons ensuite proposé, testé et évalué les effets sur l'utilisateur de plusieurs approches permettant d'améliorer l'interaction, notamment : - la correction automatique des erreurs, grâce à la reconnaissance en temps-réel des réponses aux feedbacks ; - une stimulation dynamique permettant de diminuer le risque d'erreur tout en réduisant l'inconfort lié aux stimulations ; - un processus automatique de décision adaptative, en fonction de l'état de vigilance du sujet. Nos résultats montrent la présence de réponses aux feedbacks spécifiques des erreurs et modulées par l'attention ainsi que par la surprise du sujet face au résultat de l'interaction. Par ailleurs, si l'efficacité de la correction automatique est variable d'un sujet à l'autre, le nouveau mode de stimulation comme la décision adaptative apparaissent comme très avantageux et leur utilisation a un effet positif sur la motivation. Dans la perspective d'études cliniques pour évaluer l'utilité des ICM pour la communication, ces travaux soulignent et quantifient l'intérêt de développer des interfaces capables de s'adapter à chaque utilisateur.
38
Obeidat, Qasem Turki. "Towards Improving P300-based Brain-Computer Interfaces: From Desktop to Mobile." Diss., North Dakota State University, 2014. https://hdl.handle.net/10365/27367.
Full textAbstract:
A brain-computer interface (BCI) enables a paralyzed user to interact with an
external device through brain signals. A BCI measures identi es patterns within
these measured signals, translating such patterns into commands. The P300 is a
pattern of a scalp potentials elicited by a luminance increment of an attended target
rather than a non-target character of an alphanumeric matrix. The Row-Column
Paradigm (RCP) can utilize responses to series of illuminations of matrix target
and non-target characters to spell out alphanumeric strings of P300-eliciting target
characters, yet this popular RCP speller faces three challenges. The adjacent problem
concerns the proximity of neighboring characters, the crowding problem concerns their
number. Both adjacent and crowding problems concern how these factors impede BCI
performance. The fatigue problem concerns how RCP use is tiring. This dissertation
addressed these challenges for both desktop and mobile platforms. A new P300 speller interface, the Zigzag Paradigm (ZP), reduced the adjacent problem by increasing the distance between adjacent characters, as well as the crowding
problem, by reducing the number neighboring characters. In desktop study, the
classi cation accuracy was signi cantly improved 91% with the ZP VS 80.6% with
the RCP. Since the ZP is not suitable for mobile P300 spellers with a small screen size, a
new P300 speller interface was developed in this study, the Edges Paradigm (EP). The
EP reduced the adjacent and crowding problems by adding
ashing squares located upon the outer edges of the character matrix in the EP. The classi cation accuracy of
the EP (i.e., 93.3%) was signi cantly higher than the RCP (i.e., 82.1%). We further
compared three speller paradigms (i.e., RCP, ZP, and EP), and the result indicated
that the EP produced the highest accuracy and caused less fatigue. Later, the EP
is implemented in a simulator of a Samsung galaxy smart phone on the Microsoft
Surface Pro 2. The mobile EP was compared with the RCP under the mobility
situation when a user is moving on a wheelchair. The results showed that the EP
signi cantly improved the online classi cation accuracy and user experience over the
RCP.
39
Trempler, Niklas Ruben [Verfasser]. "Spezifität reduzierter Amplitudenmodulation der visuellen P300 bei Schizophrenie / Niklas Ruben Trempler." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2021. http://d-nb.info/1234982420/34.
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Ryan, David B. "Improving Brain-Computer Interface Performance: Giving the P300 Speller Some Color." Digital Commons @ East Tennessee State University, 2011. https://dc.etsu.edu/etd/1328.
Full textAbstract:
Individuals who suffer from severe motor disabilities face the possibility of the loss of speech. A Brain-Computer Interface (BCI) can provide a means for communication through non-muscular control. Current BCI systems use characters that flash from gray to white (GW), making adjacent character difficult to distinguish from the target. The current study implements two types of color stimulus (grey to color [GC] and color intensification [CI]) and I hypotheses that color stimuli will; (1) reduce distraction of nontargets (2) enhance target response (3) reduce eye strain. Online results (n=21) show that GC has increased information transfer rate over CI. Mean amplitude revealed that GC had earlier positive latency than GW and greater negative amplitude than CI, suggesting a faster perceptual process for GC. Offline performance of individual optimal channels revealed significant improvement over online standardized channels. Results suggest the importance of a color stimulus for enhanced response and ease of use.
41
Wheeler, Katie, Kelsey N. Shubert, Marissa R. Kellicut, David B. Ryan, and Eric W. Dr Sellers. "Simulating random eye-movement in a P300- based brain-computer interface." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/asrf/2018/schedule/9.
Full textAbstract:
People who suffer from amyotrophic lateral sclerosis (ALS) eventually lose all voluntary muscle control. In the late stages of the disease, traditional augmentative and alternative communication (AAC) devices fail to provide adequate levels of communication. Brain-computer interface (BCI) technology has provided effective communication after all other AAC devices have failed. Nonetheless, EEG-based BCI devices may also fail for people with late-stage ALS due to loss of voluntary eye movement. Specifically, some people may suffer from random eye movement (nystagmus) and/or drooping of the eyelids (ptosis). Presently, it is unclear in the literature whether BCI operation requires voluntary control of eye movement. The current study attempts to simulate involuntary random eye movement in able-bodied individuals employing the P300-based BCI. To simulate involuntary random eye movement, the stimuli shift in the X and Y dimensions. Stimulus movement ‘Jitter’ occurs between each stimulus presentation in increments of 1-5 pixels (Jitter 1), 5-10 pixels (Jitter 2), 10-15 pixels-(Jitter 3), or a no movement control condition. Data collected from a previous study using 22 participants compared the control condition to Jitter 1 and Jitter 2 indicated higher accuracy for control and Jitter 1 than Jitter 2. No significant differences were found in accuracy, selections per minute, or bitrate. Waveform analysis indicated significantly higher P300 amplitude for the control condition and Jitter 1 than Jitter 2. Preference survey scores showed a preference for Jitter 1 as compared to control and Jitter 2. This finding was unexpected and may be due to the slight movement of Jitter 1 forcing participants to be vigilant, but not distracted. Based on our finding in this study, the current study examines the amount of pixel movement that could lead to reductions in performance. Participants completed a control condition and the three levels of Jitter in a counter-balanced design. Preliminary data for the current study was collected from 15 participants. No significant differences were observed between the three conditions in measures of BCI accuracy, selections per minute, and bitrate. Furthermore, preference survey scores indicated no significant difference in condition preference. Based on the findings of the first study, as well as the data collected so far in the current study, it appears that random movement does not have a significant impact on the ability of healthy participants to operate the BCI system. This could indicate that individuals with random eye movement should be able to operate the system with high rates of accuracy.
42
Winston, Brian Norman. "How does technological development and adoption occur in the media? : a cultural determinist model." Thesis, University of Lincoln, 2006. http://eprints.lincoln.ac.uk/12623/.
Full textAbstract:
The thesis hereby submitted, ‘How Does Technological Development And Adoption Occur In The Media? A Cultural Determinist Model’ was originally published in Media Technology and Society A History: from the telegraph to the Internet (London: Routledge 1998) and Technologies of Seeing: Photography, Cinematography and Television (London: British Film Institute 1996). The argument outlined in those two books is further supported and updated by six other texts published between 1995 and 2005 on the same topic. Media Technology and Society A History: from the telegraph to the Internet deals with the development of electrical and electronic mass media proposing a model for the nature of such developments. It is a final iteration of an approach to this history which has its origins in work first begun in the 1970s. Technologies of Seeing: Photography, Cinematography and Television applies the same model to photographic and cinematographic technologies. The thesis argues that all these media developments can only be understood in a social context; that they are to be understood as examples of what has become known as ‘socially shaped technology’ (or, in terms of the thesis, ‘cultural determinism’). This is contrary to the received dominant view that technology itself is the driver determining social formation – termed the ‘technological determinist’, ‘technicist’ or ‘diffusion theory’ approach. In rejecting technicism, ‘How Does Technological Development And Adoption Occur In The Media? A Cultural Determinist Model’ proposes instead an original, pioneering contribution to a revisionist cultural determinist/SST historiography as well as outlining a model to explicate at a theoretical level how such innovations and adoptions occur.
43
Cóser, Maria José Santos. "O EFEITO DA IDADE SOBRE A LATÊNCIA DO POTENCIAL EVOCADO AUDITIVO P300." Universidade Federal de Santa Maria, 2007. http://repositorio.ufsm.br/handle/1/6428.
Full textAbstract:
This study aimed to estimate age related effects over the latency of P300 auditory potential within an elderly group. P300 latencies were measured in 62 healthy elderly subjects with pure tone thresholds of 1000 and 2000Hz equal or smaller than 40 dBNA, from both genders, 19 with ages between 60 e 64 years old (Group 60), 22 with ages between 65 and 69 years old (Group 65) and 21 with ages between 70 e 74 years old (Group 70). P300 latencies in response to rare 2000 Hz, 80 dBHL tone bursts randomly presented in 1/5 relationship with a frequent 80 dBHL, 1000 Hz tone burst were measured in all of them. Statistic analysis was made using with Variance Analysis (ANOVA) test, with its minimal significant differences Duncan test. In order to estimate the effect of age upon the latency of P300 was used the Linear Regression Coefficient. Data were submitted to the SAS 8.02 test and 5% significance level was adopted. Group 60 presented P300 latency of 337, 26 ms (SD 11, 31), Group 65 presented P300 latency of 351, 86 ms (SD 29,05) and Group 70 presented latency of 370, 19 ms (SD 23, 40). The linear regression of the all 62 elderly subjects P300 latencies showed a 2, 85 ms/year growth in the 60 - 74 years range. Statistics analysis showed that these were significant findings so P300 latency differs in the three studied groups and present tendency to growth with the age growing. In conclusion, the present study showed that P300 latency grows with aging in a significant way; this growing was of 2, 85 ms/year in the 60 74 years range.Esta pesquisa teve por objetivo estimar o efeito da idade sobre a latência do Potencial Evocado Auditivo P300 em um grupo de idosos. Foram estudados 62 idosos saudáveis, com limiares tonais iguais ou menores do que 40 dBNA nas freqüências de 1000 e 2000 Hz, de ambos os gêneros, 19 com idades entre 60 e 64 anos( Grupo 60), 22 com idades entre 65 e 69 anos (Grupo 65) e 21 com idades entre 70 e 74 anos (Grupo 70). Todos foram avaliados pela pesquisa da latência do P300 em resposta ao estímulo raro de 2000 Hz apresentado aleatoriamente em meio ao estímulo freqüente de 1000 Hz, ambos na intensidade de 80 dBNA, na proporção de 01 raro para cada 05 freqüentes. Para análise estatística, foi utilizado a análise de Variância (ANOVA), com o seu respectivo teste para diferenças mínimas significativas (d. m. s.), Teste de Duncan. Para estimar o efeito da idade sobre a latência do P300 foi utilizado Coeficiente de Regressão Linear. Os dados foram submetidos ao software SAS 8.02 sendo que o nível de significância adotado foi de 5%. O Grupo 60 apresentou latência média do P300 de 337,26 ms (DP 11,31), o Grupo 65 apresentou latência média de 351,86 ms (DP 29,05) e o Grupo 70 apresentou latência média de 370,19 (DP 23,40). A regressão linear dos valores de latência do P300 obtidos em todos os idosos analisados como um grupo único mostrou um aumento de 2,85 ms por ano de idade no intervalo de idade entre 60 e 74 anos. A análise estatística mostrou que os resultados obtidos foram significativos, ou seja, a latência do P300 difere nos três grupos estudados e tende a aumentar com o aumento da faixa etária. Conclui-se, dessa forma, que a idade aumenta a latência do P300 de forma significativa e que este aumento foi de 2,85 ms por ano entre a idade de 60 e 74 anos.
44
Dapšys, Kastytis. "Psichikos sutrikimų tyrimas ir jų gydymo įvertinimas klausos sukelto potencialo P300 metodu." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20111003_114604-77038.
Full textAbstract:
Kognityvieji sukeltieji potencialai arba su įvykiu susiję potencialai (SĮSP) leidžia įvertinti kai kurias kognityviąsias funkcijas. Jie nuo pat sukūrimo pradžios yra sėkmingai taikomi ir psichikos sutrikimų tyrimuose. SĮSP neinvaziškumas, objektyvumas, saugumas leidžia juos taikyti kognityviųjų funkcijų pokyčių, sukeltų medikamentinio gydymo ar kitos nemedikamentinės terapinės procedūros, įvertinimui. Pagrindinis darbo tikslas buvo įvertinti informacijos apdorojimo klausos sistemoje kitimą atipinių antipsichotikų risperidono ir kvetiapino poveikyje ir nemedikamentinių terapijos metodų - elektros impulsų terapijos bei metaglosoterapijos - poveikyje taikant su įvykiu susijusio potencialo P300 skaitmeninio registravimo ir kiekybinės analizės metodus. Klausos sukeltas P300 potencialas buvo registruojamas taikant „atsitiktinio įvykio“ principą trimis elektrodais (Fz, Cz ir Pz). Buvo matuojami 4 sukeltojo potencialo P300 parametrai: N2 latencija, P300 latencija, P300 amplitudė ir reikšmingo dirgiklio atpažinimo laikas. Darbo rezultatai parodė, kad SĮSP parametrai yra jautrūs informacijos apdorojimo klausos sistemoje procesų pažeidimo šizofrenijos spektro sutrikimų atveju rodikliai. Didesnę teigiamą įtaką klausos sukeltajam potencialui P300 turėjo atipinis antipsichotikas kvetiapinas. Nemedikamentiniai psichikos sutrikimų gydymo metodai nenusileidžia efektyvumu gerinant pacientų kognityviąsias funkcijas medikamentinei terapijai atipiniais antipsichotikais.Recording and analysis of event-related potentials is safe and harmless method of evaluation of cognition and is suitable to follow the changes of cognitive processes induced by psychoactive drugs or other therapeutic procedures. The main aim of the work was to evaluate the influence of atypical antipsychotics risperidone and quetiapine and such nonpharmacological methods as electroconvulsive therapy and metaglossotherapy on the changes of information processing in the auditory system using event-related potential P300 recording and analysis method. Auditory P300 potential was elicited applying “odd-ball” paradigm and recorded at 3 electrode sites (Fz, Cz, Pz). 4 parameters of P300 potential were measured: N2 latency, P300 latency, P300 amplitude and recognition time of target stimulus. Total number of 85 patients with schizophrenia spectrum disorders and mood disorders were studied. Results of this work showed that the parameters of P300 potential are sensitive indicators of abnormalities of information processing in auditory system in the case of schizophrenia spectrum disorders. More considerable positive influence on the event-related potential P300 had atypical antipsychotic quetiapine and that nonpharmacological methods of treatment of psychiatric disorders are as effective as drug therapy with atypical antipsychotics in remediation of cognitive functions.
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Bicu, Monica. "Trait and state aspects of P300 in schizophrenia : a prospective longitudinal study." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=78246.
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This study investigated trait and state aspects of the reduction of the P300 event-related potential component in schizophrenia in a prospective longitudinal design. Twelve patients and 12 healthy subjects underwent auditory and visual P300 tests on consecutive sessions at two month intervals. Patients had also PANSS symptom quantifications. The comparison between patients and healthy subjects revealed that the P300 reduction in patients is stable across sessions in the auditory modality thus representing a trait marker. The analysis of the relationships between symptoms and P300 showed that the frontal auditory P300 is negatively related to negative symptoms, whereas the posterior visual P300 positively correlates with positive symptoms. Consistent with clinical and pathophysiological models of schizophrenia, our study suggests that P300 assessment taking into account its frontal/posterior topography and visual/auditory modality could provide a simple tool to understand and follow changes in the brain activity involved in both trait and state expressions of schizophrenia.
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Furuhashi, Takeshi, Tomohiro Yoshikawa, and Takanori Yokoi. "Incremental learning to reduce the burden of machine learning for P300 speller." IEEE, 2012. http://hdl.handle.net/2237/20854.
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2012 Joint 6th International Conference on Soft Computing and Intelligent Systems (SCIS) and 13th International Symposium on Advanced Intelligent Systems (ISIS) (SCIS-ISIS 2012). November 20-24, 2012, Kobe, Japan
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Furuhashi, Takeshi, Tomohiro Yoshikawa, and Eri Samizo. "Improvement of spelling speed in P300 speller using transition probability of letters." IEEE, 2012. http://hdl.handle.net/2237/20856.
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2012 Joint 6th International Conference on Soft Computing and Intelligent Systems (SCIS) and 13th International Symposium on Advanced Intelligent Systems (ISIS) (SCIS-ISIS 2012). November 20-24, 2012, Kobe, Japan
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Godói, Antônio Carlos Bastos de. "Detecção de potenciais evocados P300 para ativação de uma interface cérebro-máquina." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3142/tde-19112010-115232/.
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Interfaces cérebro-computador ou Interfaces cérebro-máquina (BCIs/BMIs do inglês Brain-computer interface/Brain-machine interface) são dispositivos que permitem ao usuário interagir com o ambiente ao seu redor sem que seja necessário ativar seus músculos esqueléticos. Estes dispositivos são de extrema valia para indivíduos portadores de deficiências motoras. Esta dissertação ambiciona revisar a literatura acerca de BMIs e expor diferentes técnicas de pré-processamento, extração de características e classificação de sinais neurofisiológicos. Em particular, uma maior ênfase será dada à Máquina de vetor de suporte (SVM do inglês Support-Vector machine), método de classificação baseado no princípio da minimização do risco estrutural. Será apresentado um estudo de caso, que ilustra o funcionamento de uma BMI, a qual permite ao usuário escolher um dentre seis objetos mostrados em uma tela de computador. Esta capacidade da BMI é conseqüência da implementação, através da SVM de um sistema capaz de detectar o potencial evocado P300 nos sinais de eletroencefalograma (EEG). A simulação será realizada em Matlab usando, como sinais de entrada, amostras de EEG de quatro indivíduos saudáveis e quatro deficientes. A análise estatística mostrou que o bom desempenho obtido pela BMI (80,73% de acerto em média) foi promovido pela aplicação da média coerente aos sinais, o que melhorou a relação sinal-ruído do EEG.Brain-computer interfaces (BCIs) or Brain-machine interfaces (BMIs) technology provide users with the ability to communicate and control their environment without employing normal output pathway of peripheral nerves and muscles. This technology can be especially valuable for highly paralyzed patients. This thesis reviews BMI research, techniques for preprocessing, feature extracting and classifying neurophysiological signals. In particular, emphasis will be given to Support-Vector Machine (SVM), a classification technique, which is based on structural risk minimization. Additionally, a case study will illustrate the working principles of a BMI which analyzes electroencephalographic signals in the time domain as means to decide which one of the six images shown on a computer screen the user chose. The images were selected according to a scenario where users can control six electrical appliances via a BMI system. This was done by exploiting the Support-Vector Machine ability to recognize a specific EEG pattern (the so-called P300). The study was conducted offline within the Matlab environment and used EEG datasets recorded from four disabled and four able-bodied subjects. A statistical survey of the results has shown that the good performance attained (80,73%) was due to signal averaging method, which enhanced EEG signal-to-noise ratio.
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Sellers, Eric William. "A P300-based brain-computer interface testing an alternative method of communication /." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000536.
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Jones, Marissa R. "Faces, Locations, and Tools: A Proposed Two-Stimulus P300 Brain Computer Interface." Digital Commons @ East Tennessee State University, 2017. https://dc.etsu.edu/etd/3268.
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Brain Computer Interface (BCI) technology can be important for those unable to communicate due loss of muscle control. The P300 Speller allows communication at a rate up to eight selections per minute. Given this relatively slow rate of communication highly accurate classification is of great importance. Previous studies have shown that alternative stimuli (e.g., faces) can improve BCI speed and accuracy. The present study uses two new alternative stimuli, locations and graspable tools in a two-stimulus paradigm. Functional MRI studies have shown that images of familiar locations produce brain responses in the parahippocampal place area and graspable tools produce brain responses in premotor cortex.The current study shows that location and tool stimuli produce unique brain responses that can be used for classification in the two-stimulus paradigm. This study shows proof of concept for using two unique stimuli to improve speed and accuracy of the P300 Speller.