O esquecimento intencional pode cumprir uma função estratégica no sistema cognitivo, que permite aos indivíduos não pensar sobre acontecimentos indesejados do passado, tais como eventos traumáticos, dolorosos e violentos, dos quais se prefere não recordar. Enquanto esquecer involuntariamente é uma falha da lembrança, por outro lado, esquecer intencionalmente parece ser uma função estratégica da memória. A presente dissertação teve por objetivo investigar os mecanismos neurocognitivos que contribuem para o esquecimento de memórias. A dissertação se organizou em dois estudos. O primeiro estudo consiste em uma revisão sistemática de artigos empíricos publicados nos últimos dez anos sobre a supressão de memórias indesejadas. O segundo estudo é um ensaio empírico, no qual foi executado um experimento adaptado do paradigma Think/No-Think com a utilização de marcadores eletrofisiológicos de eletroencefalograma. Participaram do experimento 22 sujeitos, alocados aleatoriamente em dois grupos com estratégias distintas de esquecimento: Supressão de memória e substituição de pensamentos. Durante toda a tarefa experimental, os participantes tiveram dados de EEG continuamente gravados. Os resultados decorrentes do ensaio empírico estão de acordo com os achados da literatura, indicando que a positividade parietal em torno de 400-800ms após a apresentação do estímulo é um marcador de lembrança consciente durante a recuperação de memória. Apenas na estratégia de supressão de memória houve uma redução da positividade centro-parietal durante o esquecimento, entre 450 e 700ms após apresentação do estímulo. Além disso, uma maior deflexão no componente N2 durante a supressão é um preditor de esquecimento induzido. Os achados indicam que é possível mapear o sistema neurocognitivo subjacente à supressão de memórias. / Intentional forgetting can be characterized as a strategic function of the cognitive system that allows us not to think about unwanted memories from our past, as for example emotional events or traumatic experiences that we would prefer not to remember. While forgetting involuntarily is a failure of recollection, on the other hand, forgetting intentionally seems to be a strategic function of memory. The aim of this dissertation was to investigate the neurocognitive mechanisms that contribute to forgetting memories. The dissertation was organized in two studies. The first study consists of a systematic review of empirical articles published in the last ten years on the suppression of unwanted memories. The second study is an empirical essay, in which an experiment adapted from the Think/No-Think paradigm was performed, with the use of electrophysiological markers of electroencephalogram. Twenty-two subjects participated in the experiment, randomly assigned to two groups with distinct strategies of forgetting: Memory suppression and thought substitution. Throughout the experimental task, participants had continuously recorded EEG data. The results of the empirical essay are in agreement with the literature findings, indicating that the parietal positivity around 400-800 ms after the presentation of the stimulus is a marker of conscious memory during memory recovery. Only direct memory suppression reduced centro-parietal positivity during forgetting, between 450 and 700 ms post-stimulus. Also, a greater deflection in the N2 component during suppression is an induced forgetting predictor. The findings indicate that it is possible to map the neurocognitive system underlying memory suppression.

Orientador: Prof. Dr. André Mascioli Cravo / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Neurociência e Cognição, 2016. / We constantly learn and update our predictions about when events we cause will occur. This flexibility is important to program motor actions and to estimate when errors have been made. However, the mechanisms that govern learning and updating in temporal domain are largely unknown. In order to clarify these mechanisms we had three mains objectives: 1. To describe how we learn a new temporal relation between two events and how expectation is updated based on new information; 2. To describe the neural correlates underlying temporal learning and temporal updating; 3. To investigate temporal learning in two different sensory modalities: vision and audition, in order to verify whether such processes occur independently of sensory modality. In order to achieve the objectives, we developed two different experiments with electroencephalography recordings. In the first experiment, we aimed to answer the first two objectives by developing a behavioral task in which participants had to monitor whether a temporal error had been made. Results evidenced a rapid temporal adjustment by the participants to a new temporal relation. Temporal errors evoked electrophysiological markers classically related to error coding as frontal theta oscillations and feedback-related negativity. Delta phase was modulated by behavioral adjustments, suggesting its importance in temporal prediction updating. In conclusion, low frequency oscillations appear to be modulated in error coding and temporal learning. The second experiment investigated temporal learning in two different sensory modalities. Results indicated that time perception is biased differently depending on temporal marker sensory modality. Besides, we found that intertrial phase coherence of theta oscillations was modulated by expectation on both sensory conditions. However, such result occurs on central electrodes analysis, but not on sensory electrodes analysis, indicating a supramodal mechanism of temporal prediction.

Alzheimer’s disease (AD) is a neurodegenerative disorder in which the death of brain cells causes memory loss and cognitive decline. As AD progresses, changes in the electrophysiological brain activity take place. Such changes can be recorded by the electroencephalography (EEG) and magnetoencephalography (MEG) techniques. These are the only two neurophysiologic approaches able to directly measure the activity of the brain cortex. Since EEGs and MEGs are considered as the outputs of a nonlinear system (i.e., brain), there has been an interest in nonlinear methods for the analysis of EEGs and MEGs. One of the most powerful nonlinear metrics used to assess the dynamical characteristics of signals is that of entropy. The aim of this thesis is to develop entropy-based approaches for characterization of EEGs and MEGs paying close attention to AD. Recent developments in the field of entropy for the characterization of physiological signals have tried: 1) to improve the stability and reliability of entropy-based results for short and long signals; and 2) to extend the univariate entropy methods to their multivariate cases to be able to reveal the patterns across channels. To enhance the stability of entropy-based values for short univariate signals, refined composite multiscale fuzzy entropy (MFE - RCMFE) is developed. To decrease the running time and increase the stability of the existing multivariate MFE (mvMFE) while keeping its benefits, the refined composite mvMFE (RCmvMFE) with a new fuzzy membership function is developed here as well. In spite of the interesting results obtained by these improvements, fuzzy entropy (FuzEn), RCMFE, and RCmvMFE may still lead to unreliable results for short signals and are not fast enough for real-time applications. To address these shortcomings, dispersion entropy (DispEn) and frequency-based DispEn (FDispEn), which are based on our introduced dispersion patterns and the Shannon’s definition of entropy, are developed. The computational cost of DispEn and FDispEn is O(N) – where N is the signal length –, compared with the O(N2) for popular sample entropy (SampEn) and FuzEn. DispEn and FDispEn also overcome the problem of equal values for embedded vectors and discarding some information with regard to the signal amplitudes encountered in permutation entropy (PerEn). Moreover, unlike PerEn, DispEn and FDispEn are relatively insensitive to noise. As extensions of our developed DispEn, multiscale DispEn (MDE) and multivariate MDE (mvMDE) are introduced to quantify the complexity of univariate and multivariate signals, respectively. MDE and mvMDE have the following advantages over the existing univariate and multivariate multiscale methods: 1) they are noticeably faster; 2) MDE and mvMDE result in smaller coefficient of variations for synthetic and real signals showing more stable profiles; 3) they better distinguish various states of biomedical signals; 4) MDE and mvMDE do not result in undefined values for short time series; and 5) mvMDE, compared with multivariate multiscale SampEn (mvMSE) and mvMFE, needs to store a considerably smaller number of elements. In this Thesis, two restating-state electrophysiological datasets related to AD are analyzed: 1) 148-channel MEGs recorded from 62 subjects (36 AD patients vs. 26 age-matched controls); and 2) 16-channel EEGs recorded from 22 subjects (11 AD patients vs. 11 age-matched controls). The results obtained by MDE and mvMDE suggest that the controls’ signals are more and less complex at respectively short (scales between 1 to 4) and longer (scales between 5 to 12) scale factors than AD patients’ recordings for both the EEG and MEG datasets. The p-values based on Mann-Whitney U-test for AD patients vs. controls show that the MDE and mvMDE, compared with the existing complexity techniques, significantly discriminate the controls from subjects with AD at a larger number of scale factors for both the EEG and MEG datasets. Moreover, the smallest p-values are achieved by MDE (e.g., 0.0010 and 0.0181 for respectively MDE and MFE using EEG dataset) and mvMDE (e.g., 0.0086 and 0.2372 for respectively mvMDE and mvMFE using EEG dataset) for both the EEG and MEG datasets, illustrating the superiority of these developed entropy-based techniques over the state-of-the-art univariate and multivariate entropy approaches. Overall, the introduced FDispEn, DispEn, MDE, and mvMDE methods are expected to be useful for the analysis of physiological signals due to their ability to distinguish different types of time series with a low computation time.

Esta tese apresenta uma revisão relativa às questões cognitivas de processamento de informações envolvidas na aprendizagem motora, para consolidar pesquisa empírica a esse respeito. Baseado em fontes bibliográficas, apresenta-se o contexto histórico da cultura educacional brasileira da pesquisa em movimento humano. Propõe-se metodologia de observação e quantificação de sinais bioelétricos-fisiológicos para identificação de aspectos relacionados a diferentes etapas da aprendizagem humana no âmbito da cognição e da motricidade. Descreve-se experimento dados originais para a área das Ciências do Movimento Humano, em que se monitora – com EEG e EMG – quantifica e interpreta a alteração de sinais de base em relação a modificações ocorridas durante vários momentos da aquisição da memória motora - aprendizagem - relativa à prática deliberada de partitura musical por violonista. Os dados reforçaram as hipóteses já comprovadas na literatura quanto ao maior esforço do sistema nervoso relacionada à exposição do violonista a uma tarefa específica e sua prática deliberada pelo sistema musculoesquelético, não servindo para generalizações, apenas como validação do desenho experimental e das análises estatísticas realizadas. O objetivo de monitorar, quantificar e descrever a dinâmica neural de freqüência eletrofisiológica durante o desenvolvimento de padrões musculoesqueléticos de coordenação e controle, foi alcançado. / This article presents a revision related to the cognitive questions of information processing involved in motor learning, to consolidate empirical research on the subject. The historical Brazilian educational background to culture of the human movement research is presented, based on bibliographical sources. Methodology of observation and quantification of bioelectrical physiological signals is proposed, which serves to identify the modifications occurred during the task-acquisition process. A experiment is described, along with data relevant for the Human Movement Sciences, in which the alteration of base signals in relation to various movements of the task are monitored, quantified and interpreted. The task consists of learning and performing a short musical excerpt by guitarists.

abstract: This dissertation proposes a new set of analytical methods for high dimensional physiological sensors. The methodologies developed in this work were motivated by problems in learning science, but also apply to numerous disciplines where high dimensional signals are present. In the education field, more data is now available from traditional sources and there is an important need for analytical methods to translate this data into improved learning. Affecting Computing which is the study of new techniques that develop systems to recognize and model human emotions is integrating different physiological signals such as electroencephalogram (EEG) and electromyogram (EMG) to detect and model emotions which later can be used to improve these learning systems. The first contribution proposes an event-crossover (ECO) methodology to analyze performance in learning environments. The methodology is relevant to studies where it is desired to evaluate the relationships between sentinel events in a learning environment and a physiological measurement which is provided in real time. The second contribution introduces analytical methods to study relationships between multi-dimensional physiological signals and sentinel events in a learning environment. The methodology proposed learns physiological patterns in the form of node activations near time of events using different statistical techniques. The third contribution addresses the challenge of performance prediction from physiological signals. Features from the sensors which could be computed early in the learning activity were developed for input to a machine learning model. The objective is to predict success or failure of the student in the learning environment early in the activity. EEG was used as the physiological signal to train a pattern recognition algorithm in order to derive meta affective states. The last contribution introduced a methodology to predict a learner's performance using Bayes Belief Networks (BBNs). Posterior probabilities of latent nodes were used as inputs to a predictive model in real-time as evidence was accumulated in the BBN. The methodology was applied to data streams from a video game and from a Damage Control Simulator which were used to predict and quantify performance. The proposed methods provide cognitive scientists with new tools to analyze subjects in learning environments. / Dissertation/Thesis / Doctoral Dissertation Industrial Engineering 2017

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-03-10T22:53:04Z No. of bitstreams: 1 DanielGomesDaSilvaMachado_DISSERT.pdf: 1013287 bytes, checksum: 76ea33e872dcb51199db57697b11915f (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-03-18T00:10:10Z (GMT) No. of bitstreams: 1 DanielGomesDaSilvaMachado_DISSERT.pdf: 1013287 bytes, checksum: 76ea33e872dcb51199db57697b11915f (MD5) / Made available in DSpace on 2016-03-18T00:10:10Z (GMT). No. of bitstreams: 1 DanielGomesDaSilvaMachado_DISSERT.pdf: 1013287 bytes, checksum: 76ea33e872dcb51199db57697b11915f (MD5) Previous issue date: 2015-02-13 / Introdu??o: A respira??o abdominal lenta (RAL) estimula o barorreflexo e gera a arritmia respirat?ria sinusal, causando mudan?a positiva cardiovascular, emocional e cerebral aguda e cr?nica. Entretanto, embora as pr?ticas meditativas recebam aten??o crescente nos ?ltimos anos, n?o h? consenso acerca das mudan?as neurofisiol?gicas subjacentes a elas, principalmente pela falta de informa??o topogr?fica suficiente. Objetivo: Objetivamos analisar o efeito agudo da RAL sobre a atividade cerebral, respostas emocionais e cardiovasculares em sujeitos inexperientes em t?cnicas de medita??o. M?todos: Dezessete homens adultos saud?veis foram avaliados em duas sess?es diferentes de modo rand?mico e cruzado. Na condi??o experimental realizaram a RAL em 6 ciclos/minuto e na ix controle mantiveram sua taxa respirat?ria normal, ambas por 20 minutos. Avaliouse antes e ap?s as respectivas sess?es a atividade cerebral com o eletroencefalograma (EEG), ansiedade, humor, variabilidade da frequ?ncia card?aca (VFC) e press?o arterial. O EEG foi analisado pelo sLORETA para localiza??o das regi?es cerebrais que sofreram mudan?a. Resultados: O sLORETA evidenciou uma redu??o na banda de frequ?ncia beta no giro frontal (P<0,01) e c?rtex cingulado anterior (P<0,05) tanto durante quanto e ap?s a RAL (P<0,05) comparada ao repouso, sem mudan?a na condi??o controle. Adicionalmente, a ANOVA two-way com medidas repetidas mostrou que n?o houve efeito na ansiedade (P>0,8) nem no humor (P>0,08). Houve uma melhora na VFC (P<0,03), aumento do intervalo RR e redu??o da frequ?ncia card?aca ap?s RAL, assim como aumento no SDNN, RMSSD, pNN50, no componente de baixa frequ?ncia, raz?o LF/HF e pot?ncia total durante a mesma, sem altera??es na PAS e PAD. Conclus?o: Conclu?mos que a RAL, mesmo sem altera??es comportamentais, ? capaz de modificar a atividade cerebral em regi?es associadas ao processamento emocional. Al?m disso, melhora a VFC sem modificar a press?o arterial. / Introduction: Slow abdominal breathing (SAB) stimulates baroreflex and generates respiratory sinus arrhythmia, changing cardiovascular, emotional and cerebral systems acute and chronically. However, although meditative practices have been receiving increasingly attention in the last years, there is no agreement on the neurophysiological changes underlying them, mainly because of the lack of topographical pieces of information. Purpose: We aimed to analyze the acute effect of SAB on brain activity, emotional and cardiovascular responses in untrained subjects in meditative techniques. Methods: Seventeen healthy adults? men were assessed into two different sessions in a random and crossed order. Into experimental session, they breathed in 6 cycles/minute and in control session they kept breathing in normal rate, both for 20 minutes. xi Before, during, and after each session we assessed brain activity using electroencephalography (EEG), anxiety, mood, heart rate variability (HRV) and blood pressure. The sLORETA software was used to analyze EEG data for source localization of brain areas in which activity was changed. Results: The sLORETA showed that beta band frequency was reduced in frontal gyrus (P<0.01) and anterior cingulate cortex (P<0.05) both during and after SAB (P<0.05) compared to the moment before it. There was no change in brain activity in control session. Additionally, a two-way repeated measures ANOVA showed that there was no effect on anxiety (P>0.8) and mood (P>0.08). There were improvements in HRV (P<0.03), with increased RR interval and decreased HR after SAB, as well as increased SDNN, RMSSD, pNN50, low frequency, LF/HF ratio, and total power during it, with no changes in SBP and DBP. Conclusions: We conclude that SAB is able to change brain activity in areas responsible for emotional processing, even without behavioral changes. Furthermore, SAB improves HRV and does not change blood pressure in normotensive.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-03-12T19:37:12Z No. of bitstreams: 1 KimMansurYano_DISSERT.pdf: 4966584 bytes, checksum: 9dce6dbaeb9a570211bb48744f4f8f62 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-03-16T15:11:02Z (GMT) No. of bitstreams: 1 KimMansurYano_DISSERT.pdf: 4966584 bytes, checksum: 9dce6dbaeb9a570211bb48744f4f8f62 (MD5) / Made available in DSpace on 2018-03-16T15:11:02Z (GMT). No. of bitstreams: 1 KimMansurYano_DISSERT.pdf: 4966584 bytes, checksum: 9dce6dbaeb9a570211bb48744f4f8f62 (MD5) Previous issue date: 2017-02-17 / Introdu??o ? Durante o processo de envelhecimento, ocorrem altera??es fisiol?gicas que levam uma diminui??o na velocidade de processamento cerebral. Nos ?ltimos anos a realidade virtual (RV), vem se ampliando cada vez mais aplicada nos centros de reabilita??o, portanto conhecer a influ?ncia da RV sob a atividade cerebral, nessas popula??es se faz necess?rio. Dentro desse contexto, a Eletroencefalografia ? considerada como um dos principais meios de capta??o da atividade cerebral. Atrav?s da obten??o da atividade cerebral, podemos estud?-la de diversas formas, uma delas ? o estudo de coer?ncia entre pares de eletrodos, permitindo analisar as rela??es de diferentes ?reas cerebrais e como estas trocam informa??es. Objetivo: Este estudo teve por objetivo, investigar a influ?ncia imediata da exposi??o a uma sess?o de treino de equil?brio em ambiente virtual sobre a coer?ncia entre os lobos frontais de adultos jovens e idosos, mensurada atrav?s do Emotiv EPOC. Metodologia: Estudo comparativo, envolvendo 20 indiv?duos divididos nos grupos: jovem (GJ) e idoso (GI). Ap?s passarem por uma avalia??o do estado geral, do suporte necess?rio para a marcha (FAC) e do estado cognitivo (MEEM), os participantes realizaram durante 4 minutos, o jogo penguin slide da categoria de equil?brio do Nintendo Wii, cujos efeitos sobre a atividade cortical foram observados por meio da coleta realizada pelo EPOC. Resultados: O GJ apresentou valores de coer?ncia inter-hemisf?rica semelhantes na banda alfa e na banda beta em compara??o ao GI. Quanto a coer?ncia de fase o GI apresentou uma antecipa??o do hemisf?rio direito enquanto, o GJ apresentou do hemisf?rio esquerdo. Conclus?o: A realidade virtual parece estimular igualmente o GJ e o GI. Entretanto o GJ, apresentou padr?es de ativa??o e de coer?ncia de fase, que sugerem compatibilidade com aprendizado pr?vio ? RV, justificando as diferen?as encontradas na coer?ncia de fase entre os grupos. / Introduction: During the aging process, physiological changes occur that lead to a decrease in brain processing speed. In recent years virtual reality (VR) has been increasingly applied in rehabilitation centers, so knowing the influence of VR under brain activity, in these populations is necessary. Within this context, Electroencephalography is considered as one of the main means of capturing brain activity. By obtaining the brain activity, we can study it in several ways, one of them is the study of coherence between pairs of electrodes, allowing to analyze the relations of different brain areas and how they exchange information. Objective: This study aims to investigate the immediate influence of exposure to a balance session in a virtual environment on the coherence between the frontal lobes of young and old adults, measured using Emotiv EPOC. Methodology: A comparative study involving 20 individuals divided into the groups: young (GJ) and elderly (GI). After undergoing an evaluation of the general condition, the necessary support for the gait (FAC) and the cognitive state (MEEM), the participants performed during 4 minutes, the penguin slide game of the balancing category of Nintendo Wii, whose effects on the activity Were collected through COPD. Results: The GJ presented similar inter-hemispheric coherence values in the alpha band and in the beta band in comparison to the GI. Regarding phase coherence, the GI presented an anticipation of the right hemisphere while, the GJ presented of the left hemisphere. Conclusion: Virtual reality seems to stimulate both GJ and GI. However, the GJ presented patterns of activation and phase coherence, which suggest compatibility with prior learning to VR, justifying the differences found in phase coherence between the groups.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-10-26T22:41:13Z No. of bitstreams: 1 ThaianaBarbosaFerreiraPacheco_DISSERT.pdf: 1254638 bytes, checksum: ab9fa4652ad82cfd16537ef9c0b943a7 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-12-26T18:29:32Z (GMT) No. of bitstreams: 1 ThaianaBarbosaFerreiraPacheco_DISSERT.pdf: 1254638 bytes, checksum: ab9fa4652ad82cfd16537ef9c0b943a7 (MD5) / Made available in DSpace on 2016-12-26T18:29:33Z (GMT). No. of bitstreams: 1 ThaianaBarbosaFerreiraPacheco_DISSERT.pdf: 1254638 bytes, checksum: ab9fa4652ad82cfd16537ef9c0b943a7 (MD5) Previous issue date: 2016-01-29 / Introdu??o: A ativa??o cerebral ? caracterizada como a propaga??o de impulsos el?tricos que promovem integra??o funcional do c?rebro. Na atualidade, uma das t?cnicas que tem permitido o monitoramento da atividade cerebral ? a eletroencefalografia a partir de interfaces n?o-invasivas e wireless. Estudos envolvendo EEG t?m investigado a rela??o entre altera??es nos padr?es de ativa??o cerebral e mudan?as no comportamento do indiv?duo. No entanto, pouco se sabe acerca do comportamento da ativa??o cerebral durante tarefas motoras e de que forma esta ativa??o ? caracterizada em ambientes virtuais ou reais.Objetivo: Investigar o comportamento do potencial de ativa??o das ondas theta, alpha, beta e gamma de adultos jovens saud?veis durante uma tarefa motora para membros inferiores em um ambiente virtual e em um ambiente real. Metodologia: Estudo cross-over, no qual 10 jovens saud?veis foram submetidos a uma avalia??o eletroencefalogr?fica durante a execu??o de tarefa de subir e descer um degrau no ambiente virtual (jogo basic step do Nintendo Wii) e em ambiente real, ambas com dura??o de 1 minuto. Os dados foram analisados atrav?s dos testes de Wilcoxon e o teste t?Student de amostras dependentes.Resultados: Descritivamente, a atividade de theta e alpha foi maior em ambiente real e a atividade de beta e gamma foi maior em ambiente virtual. O ambiente virtual promoveu maior ativa??o do hemisf?rio direito e de canais ?ntero-frontais bilateralmente. Al?m disso, na frequ?ncia theta, a regi?o occipital direita foi mais ativada em ambiente real do que virtual (p<0,05). Conclus?o: O comportamento do potencial de ativa??o das ondas theta, alpha, beta e gamma observado durante a execu??o de uma tarefa motora apresenta-se de forma vari?vel em fun??o do ambiente que o indiv?duo est? sendo exposto - real ou virtual. Dessa forma, ressalta-se a implementa??o de estudos futuros que promovam embasamento para tomada de decis?o cl?nica de forma que a escolha do ambiente terap?utico (real ou virtual) seja de acordo com as ?reas cerebrais que se objetiva ativar. / Introduction: Brain activity is defined as the propagation of electrical impulses in order to promote a functional integration of the brain. Electroencephalography is one of the techniques that allows brain activity?s monitoring by using non-invasive and wireless interfaces. Studies involving EEG have investigated the relationship between changes in patterns of brain activity and in individual behavior. However, knowledge about brain activity during motor tasks and how this activity is characterized in virtual or real environments is still unclear. Objective: Compare theta, alpha, beta and gamma power in healthy young adults during a lower limb motor task performed in a virtual and real environment. Methodology: Cross-over study in which 10 healthy young adults were subjected to an EEG assessment while performing a one-minute task consisted of going up and down a step in a virtual environment (performed by the virtual game ?Basic step?) and real environment. Wilcoxon and t'Student tests were executed to analyze data. Results: Descriptively, theta and alpha power were higher in real environment while beta and gamma power were higher in virtual environment. Virtual environment caused greater activation of the right hemisphere and anterior-frontal channels bilaterally. Furthermore, in theta frequency, the right occipital region?s activity in real environment was higher than in virtual environment (p <0.05). Conclusion: Theta, alpha, beta and gamma power observed while performing a motor task present variation according to environment in which the individual is being exposed - real or virtual. Thus, we emphasize the implementation of future studies in order to promote basis for clinical decision-making so that the choice of the therapeutic environment (real or virtual) would be according to the brain areas that are in need for activation.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-02-03T15:12:16Z No. of bitstreams: 1 JacildaOliveiraDosPassos_DISSERT.pdf: 7063552 bytes, checksum: 5d67388b2aad04059e63c3383ce0521f (MD5) / Approved for entry into archive by Monica Paiva (monicalpaiva@hotmail.com) on 2017-02-03T15:21:10Z (GMT) No. of bitstreams: 1 JacildaOliveiraDosPassos_DISSERT.pdf: 7063552 bytes, checksum: 5d67388b2aad04059e63c3383ce0521f (MD5) / Made available in DSpace on 2017-02-03T15:21:10Z (GMT). No. of bitstreams: 1 JacildaOliveiraDosPassos_DISSERT.pdf: 7063552 bytes, checksum: 5d67388b2aad04059e63c3383ce0521f (MD5) Previous issue date: 2014-12-05 / Os conceitos de aprendizagem motora e de neuroplasticidade est?o sendo cada vez mais inseridos na pr?tica cl?nica, principalmente no que concerne ? reabilita??o das sequelas motoras causadas por um Acidente Vascular Cerebral (AVC). Por isso, diversas t?cnicas t?m sido propostas para representar na pr?tica a aplicabilidade desses conceitos e promover a reorganiza??o neural e funcional dos pacientes. Nesse ?mbito, est? a Realidade Virtual, que simula o ambiente do mundo real e que baseia-se no pressuposto de que o conhecimento ou habilidade adquirida em um mundo virtual ser? transferida para o mundo real. Contudo, sabe-se pouco sobre o grau de fidelidade dos padr?es de movimento e ativa??o neural entre uma habilidade realizada em ambiente real e virtual. Logo, este estudo teve como objetivo comparar uma habilidade motora realizada em ambiente real e virtual por paciente com AVC. Este ? um estudo comparativo, do qual participaram 2 pacientes com AVC unilateral, com idade igual ou menor que 70 anos, sendo 1 com les?o cerebral ? direita e 1 com les?o cerebral ? esquerda e 2 indiv?duos saud?veis pareados com os pacientes de acordo com sexo, idade, escolaridade e membro superior que realizou a habilidade. O estudo foi realizado em sess?o ?nica, compreendendo avalia??o inicial (MEEM, NIHSS, Ashworth e Fugl-Meyer) seguida da realiza??o da habilidade motora de lan?ar dardos em ambiente virtual (XBOX Kinect) e real (jogo de dardo profissional), cuja ordem foi escolhida de forma aleat?ria. O lan?amento de dardos constou de 15 repeti??es, divididas em 3 blocos de 5, e o lan?amento foi realizado pelo MS par?tico do paciente e o membro pareado do saud?vel. Durante a execu??o da tarefa foram realizadas a an?lise cinem?tica, por meio do Qualisys Motion Capture System e a an?lise da ativa??o neural, por meio do Emotiv EPOC?. Os resultados preliminares apontaram diferen?a no mapeamento de ativa??o cerebral e no desempenho motor quanto ao percentual de acertos, entre pacientes e saud?veis, e de acordo com o tipo de jogo realizado e com o lado da les?o cerebral. / Os conceitos de aprendizagem motora e de neuroplasticidade est?o sendo cada vez mais inseridos na pr?tica cl?nica, principalmente no que concerne ? reabilita??o das sequelas motoras causadas por um Acidente Vascular Cerebral (AVC). Por isso, diversas t?cnicas t?m sido propostas para representar na pr?tica a aplicabilidade desses conceitos e promover a reorganiza??o neural e funcional dos pacientes. Nesse ?mbito, est? a Realidade Virtual, que simula o ambiente do mundo real e que baseia-se no pressuposto de que o conhecimento ou habilidade adquirida em um mundo virtual ser? transferida para o mundo real. Contudo, sabe-se pouco sobre o grau de fidelidade dos padr?es de movimento e ativa??o neural entre uma habilidade realizada em ambiente real e virtual. Logo, este estudo teve como objetivo comparar uma habilidade motora realizada em ambiente real e virtual por paciente com AVC. Este ? um estudo comparativo, do qual participaram 2 pacientes com AVC unilateral, com idade igual ou menor que 70 anos, sendo 1 com les?o cerebral ? direita e 1 com les?o cerebral ? esquerda e 2 indiv?duos saud?veis pareados com os pacientes de acordo com sexo, idade, escolaridade e membro superior que realizou a habilidade. O estudo foi realizado em sess?o ?nica, compreendendo avalia??o inicial (MEEM, NIHSS, Ashworth e Fugl-Meyer) seguida da realiza??o da habilidade motora de lan?ar dardos em ambiente virtual (XBOX Kinect) e real (jogo de dardo profissional), cuja ordem foi escolhida de forma aleat?ria. O lan?amento de dardos constou de 15 repeti??es, divididas em 3 blocos de 5, e o lan?amento foi realizado pelo MS par?tico do paciente e o membro pareado do saud?vel. Durante a execu??o da tarefa foram realizadas a an?lise cinem?tica, por meio do Qualisys Motion Capture System e a an?lise da ativa??o neural, por meio do Emotiv EPOC?. Os resultados preliminares apontaram diferen?a no mapeamento de ativa??o cerebral e no desempenho motor quanto ao percentual de acertos, entre pacientes e saud?veis, e de acordo com o tipo de jogo realizado e com o lado da les?o cerebral.

O esquecimento intencional pode cumprir uma função estratégica no sistema cognitivo, que permite aos indivíduos não pensar sobre acontecimentos indesejados do passado, tais como eventos traumáticos, dolorosos e violentos, dos quais se prefere não recordar. Enquanto esquecer involuntariamente é uma falha da lembrança, por outro lado, esquecer intencionalmente parece ser uma função estratégica da memória. A presente dissertação teve por objetivo investigar os mecanismos neurocognitivos que contribuem para o esquecimento de memórias. A dissertação se organizou em dois estudos. O primeiro estudo consiste em uma revisão sistemática de artigos empíricos publicados nos últimos dez anos sobre a supressão de memórias indesejadas. O segundo estudo é um ensaio empírico, no qual foi executado um experimento adaptado do paradigma Think/No-Think com a utilização de marcadores eletrofisiológicos de eletroencefalograma. Participaram do experimento 22 sujeitos, alocados aleatoriamente em dois grupos com estratégias distintas de esquecimento: Supressão de memória e substituição de pensamentos. Durante toda a tarefa experimental, os participantes tiveram dados de EEG continuamente gravados. Os resultados decorrentes do ensaio empírico estão de acordo com os achados da literatura, indicando que a positividade parietal em torno de 400-800ms após a apresentação do estímulo é um marcador de lembrança consciente durante a recuperação de memória. Apenas na estratégia de supressão de memória houve uma redução da positividade centro-parietal durante o esquecimento, entre 450 e 700ms após apresentação do estímulo. Além disso, uma maior deflexão no componente N2 durante a supressão é um preditor de esquecimento induzido. Os achados indicam que é possível mapear o sistema neurocognitivo subjacente à supressão de memórias. / Intentional forgetting can be characterized as a strategic function of the cognitive system that allows us not to think about unwanted memories from our past, as for example emotional events or traumatic experiences that we would prefer not to remember. While forgetting involuntarily is a failure of recollection, on the other hand, forgetting intentionally seems to be a strategic function of memory. The aim of this dissertation was to investigate the neurocognitive mechanisms that contribute to forgetting memories. The dissertation was organized in two studies. The first study consists of a systematic review of empirical articles published in the last ten years on the suppression of unwanted memories. The second study is an empirical essay, in which an experiment adapted from the Think/No-Think paradigm was performed, with the use of electrophysiological markers of electroencephalogram. Twenty-two subjects participated in the experiment, randomly assigned to two groups with distinct strategies of forgetting: Memory suppression and thought substitution. Throughout the experimental task, participants had continuously recorded EEG data. The results of the empirical essay are in agreement with the literature findings, indicating that the parietal positivity around 400-800 ms after the presentation of the stimulus is a marker of conscious memory during memory recovery. Only direct memory suppression reduced centro-parietal positivity during forgetting, between 450 and 700 ms post-stimulus. Also, a greater deflection in the N2 component during suppression is an induced forgetting predictor. The findings indicate that it is possible to map the neurocognitive system underlying memory suppression.