Objetivo: Caracterizar as respostas do Mismatch Negativity (MMN) em crianças com limiares auditivos dentro dos padrões de normalidades e sem queixas auditivas. Métodos: Estudo do tipo transversal. Participaram desta pesquisa crianças de cinco a onze anos, sem queixas auditivas. Todos os participantes realizaram avaliação audiológica periférica com medidas de imitância acústica, audiometria tonal e audiometria vocal previamente à realização do MMN. Para a execução do procedimento eletrofisiológico, MMN, foi utilizado o equipamento Masbe ATC Plus da marca Contronic. Os eletrodos foram fixados nas posições Fpz (eletrodo ativo), M1 e M2 (eletrodos referência) e na fronte (eletrodo terra). A intensidade utilizada para evocar o potencial foi de 80 dBNA, o estímulo frequente utilizado foi de 1.000 Hz e o estímulo raro de 2.000 Hz. Os estímulos foram apresentados em ambas as orelhas de modo monoaural. As crianças realizaram a avaliação sentadas e foram condicionadas a assistirem a um vídeo sem som, no tablet, enquanto o procedimento era realizado. Resultados: Para o grupo feminino, a média das latências e amplitudes foi de 177,3 ms e 5,01 μV na orelha direita e de 182,4 ms e 5,39 μV na orelha esquerda. Quanto ao grupo masculino, a média das latências foi de 194,4 ms na orelha direita e 183,6 ms na orelha esquerda, com amplitude de 5,11 μV na orelha direita e 5,83 μV na orelha esquerda. Não houve diferença estatisticamente significante nos valores de latência e amplitude entre orelhas (p=0,867 e p=0,178), idade (p>0,20) e sexo dos participantes (p>0,05). Conclusão: Os valores encontrados nas latências e amplitudes do potencial MMN são semelhantes aos observados na literatura científica compulsada, em crianças com desenvolvimento típico e sem queixas auditivas. / Aim: To characterize the answers of Mismatch Negativity (MMN) in children with hearing thresholds within the normality patterns and without auditory complaints. Methods: Transversal type study. Children between 5 and 11 years old without auditory complaints have participated in this research. All the participants have done peripheral audiological evaluation with acoustic immittance measures, tonal audiometry and vocal audiometry previously to MMN execution. To perform the electrophysiological procedure, MMN, it was used Masbe ATC Plus equipment from Contronic brand. The electrodes were fixed in Fpz (active electrode), M1 and M2 (reference electrodes) and front (earth electrode) positions. The intensity used to evoke the potential was 80 dBNA, the frequent stimulus used was 1.000 Hz and the rare stimulus was 2.000 Hz. The stimuli were presented in both ears monoaurally. Children performed the assessment sat and they were conditioned to watch a video without sound, on a tablet computer, while the procedure was performed. Results: For the female group, the average of the latencies and amplitudes was 177,3 ms and 5,01 μV for the right ear and 182,4 ms and 5,39 μV for the left ear. Regarding the male group, the average of latencies was 194,4 ms for the right ear and 183,6 ms for the left ear, with an amplitude of 5,11 μV for the right ear and 5,83 μV for the left ear. There was no significant statistically difference for the values of latency and amplitude among ears (p=0,867 and p=0,178), age (p>0,20) and gender of the participants (p>0,05). Conclusion: The values found in the latencies and amplitudes of MMN potential are similar to those observed in the scientific literature examined, in children with typical development and without auditory complaints.

No processo de indicação e adaptação do Aparelho de Amplificação Sonora Individual, as informações obtidas por meio dos Potenciais Evocados Auditivos de Longa Latência, geralmente pesquisado em campo livre, têm sido utilizadas para a avaliação dos benefícios e limitações dos dispositivos eletrônicos aplicados à surdez. O objetivo foi o de analisar de forma comparativa, a influência do transdutor no registro dos componentes P1, N1 e P2 eliciados por estímulo de fala, quanto à latência e amplitude, em crianças ouvintes. A casuística foi formada por 30 crianças ouvintes de quatro a 12 anos de idade de ambos os sexos. Os potenciais evocados auditivos de longa latência foram pesquisados por meio dos transdutores, fone de inserção e caixa acústica, eliciados por estímulo de fala /da/ apresentado com 526ms de intervalo interestímulos, na intensidade de 70dBNA e taxa de apresentação de 1,9 estímulos por segundo. A estimulação foi definida aleatoriamente, ora na orelha direita ora na esquerda, assim como a ordem do tipo do transdutor, iniciando ora pelo fone de inserção ora pela caixa acústica. Foram analisados os componentes P1, N1 e P2 quando presentes, quanto à latência e amplitude. Para verificar a reprodutibilidade dos registros, realizou-se uma análise de concordância entre a pesquisadora e um juiz, que mostrou um nível de concordância forte. Não houve diferença estatisticamente significante ao comparar os valores de latência e amplitude dos componentes P1, N1 e P2, para cada tipo de transdutor, considerando o sexo e orelha, assim como entre os tipos de transdutores utilizados ao comparar os valores de latências dos componentes do potencial evocado auditivo de longa latência. Entretanto, houve diferença estatisticamente significante na amplitude dos componentes P1 e N1 obtidos com os transdutores caixa acústica e fone de inserção, com maior amplitude para o transdutor caixa acústica. Os valores de latência dos componentes P1, N1 e P2 e amplitude de P2 obtidos com fone de inserção podem ser utilizados como referência para análise do registro obtido com o transdutor caixa acústica. / In the process of indication and fitting of Hearing Aids, the data obtained through Long Latency Auditory Evoked Potentials, generally researched in free field, have been utilized to assess the benefits and limitations of electronic devices applied to deafness. The goal was to analyze, in a comparative manner, the influence of the transducer on the recordings of components P1, N1 and P2, elicited through speech stimulus, as to the latency and amplitude, in hearing children. The sample was comprised of 30 hearing children aged 4-12 yrs, of both genders. The long latency auditory evoked potentials were researched by means of transducers, insertion phone and speakers, elicited through speech stimulus /da/ presented with 526ms of interstimuli interval, in the intensity of 70dBNA and presentation rate of 1.9 stimuli per second. The stimulation was randomly defined, sometimes on the right ear, sometimes on the left one, as well as the order of the type of transducer, beginning, sometimes, with the insertion phone, and sometimes, with the speaker. Whenever present, components P1, N1 and P2 were analyzed as to latency and amplitude. In order to verify the reproducibility of the recordings, an agreement analysis was carried out between the researcher and a referee, showing a strong agreement level. No statistically significant difference was seen when comparing the latency and amplitude values of components P1, N1 and P2, for each type of transducer, taking into account the gender and ear, as well as among the types of transducers utilized when comparing the latency values of the components of long latency auditory evoked potential. Nevertheless, there was a statistically significant difference in the amplitude of components P1 and N1, obtained with the speaker and insertion phone transducers, with greater amplitude for the speaker transducer. The latency values of components P1, N1 and P2 and amplitude of P2 obtained with the insertion phone may be utilized as a reference for the analysis of the recording obtained with the speaker transducer.

L'empathie nous permet de comprendre et de réagir aux sensations des autres individus. Regarder une situation douloureuse peut induire des comportements de type prosociaux orientés vers les autres ou des réponses d'évitement comme celles enregistrées en réponse à une menace. Le but principal de cette thèse était d'étudier les comportements d'approche/évitement et freezing qui se produisent soit en observant la douleur des autres, soit pendant l'anticipation de la douleur. Deux tâches manipulant la prise de perspective ont permis d'enregistrer des cotations supérieures concernant le niveau de douleur, des temps de réaction inférieurs (expérience 1) et des index de réponses d'évitement plus grands (expérience 2) pour la perspective consistant à imaginer que le sujet représenté dans une condition douloureuse était la personne la plus aimée. Dans la troisième expérience, nous avons analysé le comportement du freezing au niveau du système corticospinal du participant : un effet du freezing spécifique fut rapporté uniquement lorsque de la présentation des stimuli douloureux en perspective du première personne. Dans une quatrième expérience, l'effet du freezing, normalement présent en réponse aux stimuli douloureux fut aussi rapporté dans le cadre de l'anticipation de la douleur pour soi-même. Nos études suggèrent que ce sont principalement les mécanismes cognitifs de prise de perspective qui modulent la réponse empathique et que la perspective de la personne la plus aimée induise la réponse empathique la plus forte. Au contraire les réponses du freezing des modulations corticospinales sont principalement observées lorsque le sujet adopte une perspective en première personne / Empathy allows us to understand and react to other people feelings. Regarding empathy for pain, a witness looking at a painful situation may react to other-oriented and prosocial-altruistic behaviors or self-oriented withdrawal responses. The main aim of this thesis was to study approach/avoidance and freezing behavioral manifestations that co-occurring along with both others’ pain observation and during the anticipation of pain. In two perspective-taking tasks, we investigated the influence of the type of relationship between the witness and the target in pain. Results showed that higher pain ratings, lower reactions times (experiment 1) and greater withdrawal avoidance postural responses (experiment 2) were attributed when participants adopted their most loved person perspective. In experiment 3, we analyzed the freezing behavior in the observer’s corticospinal system while subject was observing painful stimuli in first-and third-person perspectives. Results showed the pain-specific freezing effect only pertained to the first-person perspective condition. An empathy for pain interpretation suggests empathy might represent the anticipation of painful stimulation in oneself. In experiment 4 results, we found that the freezing effect present during a painful electrical stimulation was also present in the anticipation of pain. In conclusion, our studies suggest that cognitive perspective-taking mechanisms mainly modulate the empathic response and the most loved person perspective seems to be prevalent. In addition, more basic pain-specific corticospinal modulations are mainly present in the first-person perspective and it seems to not be referred to the empathy components

Within neurophysiology, there is need for improvements to functional brain imaging devices. Neural processing within the brain occurs on milli-second through to second timescales. Currently there are no systems with the sufficient temporal resolution and depth sensitivity. Electrical impedance tomography (EIT) is a technique that offers milli-second imaging, depth sensitivity, portability and low cost. It is already applied routinely in other medical applications such as lung function monitoring and breast imaging. The research presented in this thesis has contributed to the design and development of a 32-electrode EIT system, known as fEITER (functional Electrical Impedance Tomography of Evoked Responses). fEITER has been designed to be a brain imaging device that has a temporal resolution of 100 fps with an overall SNR of greater than 70 dB operating at 10 kHz. In order to carry out human tests using fEITER, the system required applications to the local and national ethics (NRES) as well as safety standards regulation (MHRA). These processes were successfully completed, receiving a 'notice of no objection' for a clinical trial using fEITER at The University of Manchester and Manchester Royal Infirmary. A series of tank tests were analysed as a method of understanding the system performance. The data obtained from human tests showed unique results. The reference data showed a repeating 'saw tooth' that is time-locked to the heart beat of the volunteer, which is a novel observation in medical EIT. Furthermore, the auditory stimuli data showed topographical differences across the scalp with respect to the startle and controlled auditory stimuli. These observations are based on single-event evoked responses, which is unique within the field of evoked potential studies. From the observations reported in this thesis it is plausible that fEITER is measuring voltages changes that are due to the neural processing.

Psychopathy is a complex personality disorder denned by a constellation of affective and behavioral characteristics. There is accumulating behavioral evidence suggesting that the condition is associated with impairments in affective, cognitive, and language functions. However, relatively little is known regarding the neural systems underlying these abnormalities. The present thesis is comprised of five experiments designed to elucidate and characterize the abnormal functional architecture underlying these abnormalities in psychopathic criminals. In Experiments 1 and 2, functional magnetic resonance imaging (fMRI) was used to elucidate the neural systems underling abnormal semantic and affective processes in these individuals. In Experiments 3, 4 and 5, event-related potentials (ERPs) were used to characterize the temporal features of cognitive and language functions in psychopaths. The results from Experiment 1 revealed that compared to control participants, psychopaths performed more poorly and failed to showed the appropriate neural differentiation between abstract and concrete stimuli during a lexical decision task. These deficits were located in the right anterior superior temporal gyrus. The results from Experiment 2 indicated that psychopaths, relative to control participants, showed less activation for processing affective stimuli than for neutral stimuli in several neural regions, including the right amygdala/hippocampal formation, left parahippocampal gyrus, ventral striatum, and in the anterior and posterior cingulate. Psychopaths did show greater activation for processing affective than for neutral stimuli in regions located outside the limbic system, including bilateral inferior frontal gyrus. These latter data suggesting that psychopaths used different neural systems than did controls for performing the task. The results from Experiments 3 and 4 indicated that psychopathy is associated with abnormalities in the P3 ERP component elicited by target stimuli during visual and auditory oddball tasks. In addition, the psychopaths' ERPs to visual and auditory target stimuli were characterized by large fronto-central negativities in the 350-600 millisecond time window. These fronto-central ERP negativities are similar to those observed for patients with temporal lobe damage. In Experiment 5, using a standard sentence processing paradigm, no group differences were observed between psychopaths and nonpsychopaths in the amplitude of the N400 potential elicited by terminal words of sentences that were either congruent or incongruent with the previous sentence context. These results indicate that the abnormal fronto-central ERP negativities observed in previous studies of language function in psychopaths are not related to processes involved in the generation of the N400. Taken together, these data suggest that one of the cardinal abnormalities in psychopathy is abnormal semantic processing of conceptually abstract information and affective information and that these abnormalities are related to the function of neural circuits in the anterior temporal lobes and lateral frontal cortex. / Arts, Faculty of / Psychology, Department of / Graduate

Orientadora: Ana Cláudia Figueiredo Frizzo / Banca: Ana Cláudia Mirândola Barbosa Reis / Banca: Ana Cláudia Vieira Cardoso / Resumo: Introdução: O aumento da expectativa de vida da população requer um manejo diferente das necessidades dos idosos. No envelhecimento ocorre a degeneração dos aspectos fisiológicos, funcionais e comportamentais, bem como mudanças estruturais nas vias auditivas centrais e déficits em habilidades binaurais, muitas vezes responsáveis por dificuldades de comunicação. O Potencial Evocado Auditivo de Média Latência mostra-se um instrumento útil para avaliação auditiva central em idosos e permite uma análise da função auditiva binaural ao nível cortical. Objetivo: Investigar os potenciais evocados auditivos de média latência, analisar e comparar as respostas obtidas com a estimulação unilateral e bilateral e a interação binaural em idosos. Metodologia: Estudo descritivo e analítico de corte transversal. Em um primeiro momento a avaliação audiológica básica foi realizada para determinação dos limiares audiométricos e dividir os sujeitos em 2 grupos. Grupo 1 (G1) composto por 20 indivíduos de ambos os sexos, a partir de 60 anos, saudáveis, sem perda auditiva e o grupo 2 (G2) composto por 20 indivíduos de ambos os sexos, a partir de 60 anos, saudáveis, com limiares entre 30 e 70 dBNA nas frequências de 4 a 8kHz. O registro do potencial foi realizado utilizando o equipamento Biologic's Evoked Potential System (EP) de dois canais, com estimulação unilateral (orelha direita, depois orelha esquerda) e bilateral (estimulação simultânea nas duas orelhas) e posteriormente foi calculado o Compon... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Introduction: The increase in life expectancy of the population requires a different management of the needs of the elderly. In aging, degeneration of the physiological, functional and behavioral aspects occurs, as well as structural changes in the central pathways and deficits in binaural abilities, often responsible for communication difficulties. The Auditory Middle Latency Response is shown to be a useful auditory tool for central assessment in the elderly and allows an analysis of binaural hearing function at the cortical level. Objective: To investigate the auditory middle latency response, to analyze and to compare the unilateral and bilateral stimulation and binaural interaction in the elderly. Methodology: Descriptive and analytical cross-sectional study. In the first moment, the audiological assessment was performed to determine the hearing thresholds and to divide the subjects into 2 groups. Group 1 (G1): 20 individuals of both genders, from 60 years, healthy, without hearing loss and group 2 (G2) consisted of 20 individuals of both genders, from 60 years of age, healthy, with thresholds between 30 and 70 dBHL in frequencies of 4 to 8 kHz. Potential recording was performed using two-channel Bio-logic Evoked Potential System (EP) equipment, with unilateral stimulation (right ear, then left ear) and bilateral stimulation (simultaneous stimulation in both ears) and then calculated the Binaural Interaction Component. Descriptive analysis (average and standard deviation... (Complete abstract click electronic access below) / Mestre

As neural interfaces continue to progress toward practical applications, there is increased demand for smaller, more efficient and cost effective devices. Event related potentials (ERPs) have recently been demonstrated to be reliable for practical communication in disabled individuals using the P300 Speller paradigm. With the objective of simplifying the processing of ERPs in order to minimize the hardware/computational requirements, and therefore the power consumption (for increased battery life for wireless, etc.), this study examines the effects of the analog-to-digital converter amplitude quantization on the ERP classification accuracy for the P300 Speller.

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