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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

SHORT AND LONG-TERM EFFECTS OF TOBACCO ABSTINENCE, BUPROPION AND NICOTINE ON BRAIN ACTIVITY DURING A VISUOSPATIAL TASK

Bruzadin Nunes, Ugo 01 August 2023 (has links) (PDF)
One of the main reasons smokers struggle to quit is the cognitive deficits caused by abstinence. Bupropion (BUP) and nicotine replacement therapy (NRT) are two of the three FDA-approved efficacious pharmacotherapies to assist in nicotine abstinence. Very little is known about the differences between the neurocognitive effects of NRT and BUP. This dissertation analyzed a dataset of electroencephalogram (EEG) collected while participants performed a visuospatial dot-localization task (DOTLOC). In the study, 119 smokers were randomly divided into 4 groups (BUP, NRT, placebo, and delayed-quit controls) for 6 sessions – one baseline experimental session, four treatment sessions and one post-treatment session after 67 days of abstinence. During the task, source-localized theta, alpha, and beta activity were obtained for the four groups (NRT and BUP, placebo, and delay-quit smokers) at three network-related regions of interest (ROIs). After 3 and 24 days of abstinence, NRT contrasted with placebo showed increases in high frequency current source density (CSD) and decrease in low-frequency CSD. After 3 days of abstinence, BUP contrasted with placebo showed increase in theta and beta CSD at parietal sites and decrease in spectral CSD at frontal and temporal sites. When contrasted with NRT, BUP showed an increase in low-frequency CSD at parietal regions, and decrease in low and high-frequency at temporal and frontal regions. A significant difference was also found in abstinent smokers at 66 days compared to pre-quit session and smoking controls, with a significant increase in parietal alpha activity and a significant decrease in beta CSD. This was the first research to look at the neurocognitive effects of bupropion compared to NRT, as well as the first to identify the long-term changes caused by tobacco abstinence on task-related cortical activity.
2

The Role of Cognitive Disposition in Re-examining the Privacy Paradox: A Neuroscience Study

Mohammed, Zareef 01 January 2017 (has links)
The privacy paradox is a phenomenon whereby individuals continue to disclose their personal information, contrary to their claim of concerns for the privacy of their personal information. This study investigated the privacy paradox to better understand individuals' decisions to disclose or withhold their personal information. The study argued that individuals’ decisions are based on a cognitive disposition, which involves both rational and emotional mental processes. While the extended privacy calculus model was used as the theoretical basis for the study, the findings of cognitive neuroscience was applied to it to address its limitation in assuming individuals are purely rational decision-makers. Three within-subjects experiments were conducted whereby each subject participated in all three experiments as if it were one. Experiment 1 captured the neural correlates of mental processes involved in privacy-related decisions, while experiment 2 and 3 were factorial-design experiments used for testing the relationship of neural correlates in predicting privacy concerns and personal information disclosure. The findings of this study indicated that at least one neural correlate of every mental process involved in privacy-related decisions significantly influenced personal information disclosure, except for uncertainty. However, there were no significant relationships between mental processes and privacy concerns, except Brodmann’s Area 13, a neural correlate of distrust. This relationship, however, had a positive relationship with privacy concerns, opposite to what was hypothesized. Furthermore, interaction effects indicated that individuals put more emphasis on negative perceptions in privacy-related situations. This study contributed to the information privacy field by supporting the argument that individuals’ privacy-related decisions are both rational and emotional. Specifically, the privacy paradox cannot be explained through solely rational cost-benefit analysis or through an examination of individuals’ emotions alone.
3

EEG analýza chůze na nestabilním povrchu / EEG analysis of gait on an unstable surface

Hons, Pavel January 2020 (has links)
1 Abstract Title: EEG analysis of gait on an unstable surface Objectives: The aim of the thesis was comparison of changes of electrical activity of intercerebral brain structures using the programme sLORETA between 1) the state of rest and walk on slackline, 2) the state of rest and walk on groundline and 3) between the state of rest and projection of first-person virtual reality of walking on slackline; to find out which intracerebral areas are activated during these activities. Methods: 10 healthy participants took part in the test, 6 males and 4 females, between 18 and 30 years of age, 24 years of age on average. The experiment consisted of EEG gauging at rest with open/closed eyes (5 minutes each) and three other consequent parts in random order: 1. walk on slackline (2 minutes), 2. walk on groundline imitating walk on slackline (2 minutes), 3. watching a video with the first-person virtual reality projection of walking on slackline in basic position (2 minutes). During the whole experiment the brain activity was monitored and recorded by Wireless EEG Nicolet, EEG hat Waveguard Connect with 19 electrodes was used for collecting data by scalp EEG. The record was consequently assessed by sLORETA programme which created projection of active brain parts in 3D Talairach atlas. Results: Statistically...
4

sLORETA-basierte Untersuchung niederamplitudiger Aktivität im Ruhe-EEG in Abhängigkeit vom Vorhandensein langsamer Augenbewegungen (SEM)

Jödicke, Johannes 30 July 2014 (has links) (PDF)
Im unter Ruhebedingungen abgeleiteten Elektroenzephalogramm (Ruhe-EEG) können Episoden niedergespannter EEG-Aktivität sowohl mit Schläfrigkeit, als auch mit geistiger Aktivität assoziiert sein. Aus diesem Grunde stellt niedergespannte EEG-Aktivität eine potentielle Fehlerquelle bei der Interpretation des Ruhe-EEGs dar. Wird niedergespannte EEG-Aktivität jedoch von für das Einschlafen charakteristischen, langsamen Augenbewegungen (Slow horizontal eye movements, SEM) begleitet, ist eine Assoziation mit geistiger Aktivität ausgeschlossen. Ziel dieser Dissertation ist die Untersuchung der Frage, ob niedergespannte EEG-Aktivität im Ruhe-EEG, welche von SEM begleitet wird (B1+), sich von solcher ohne begleitende SEM (B1-) hinsichtlich ihrer spektralen und räumlichen Zusammensetzung unterscheidet. Hierzu wurden 35 Ruhe-EEGs gesunder Probanden analysiert, welche jeweils mindestens 10s B1-, B1+ sowie 10s niedergespannter EEG-Aktivität während der Bearbeitung einer Kopfrechenaufgabe (calc) präsentierten. Unter Verwendung der Methode der standardized low resolution brain electromagnetic tomography (sLORETA) wurden für calc, B1- und B1+ die kortikalen Stromdichteverteilungen in vier verschiedenen, individuell angepassten Frequenzbändern berechnet. Die statistische Auswertung ergab signifikante Unterschiede zwischen B1- und B1+: Es zeigte bei B1- sowohl im Delta- als auch im Theta-Band eine geringere Aktivität im Bereich des Cingulums sowie benachbarten Teilen der Frontal-, Parietal- und Okzipiallappen. Zusätzlich zeigte sich eine erhöhte Aktivität im Frequenzbereich des Beta-Bandes in den Temporallappen für B1- verglichen mit B1+. Der Vergleich von calc mit B1+ erbrachte ähnliche Resultate. Die Befunde lassen eine Zugehörigkeit von B1- zu einem, verglichen mit B1+ höheren Vigilanzniveau vermuten und liefern Evidenz für die Einteilung niedergespannter Episoden im Ruhe-EEG in solche mit und ohne begleitende SEM.
5

sLORETA-basierte Untersuchung niederamplitudiger Aktivität im Ruhe-EEG in Abhängigkeit vom Vorhandensein langsamer Augenbewegungen (SEM)

Jödicke, Johannes 07 July 2014 (has links)
Im unter Ruhebedingungen abgeleiteten Elektroenzephalogramm (Ruhe-EEG) können Episoden niedergespannter EEG-Aktivität sowohl mit Schläfrigkeit, als auch mit geistiger Aktivität assoziiert sein. Aus diesem Grunde stellt niedergespannte EEG-Aktivität eine potentielle Fehlerquelle bei der Interpretation des Ruhe-EEGs dar. Wird niedergespannte EEG-Aktivität jedoch von für das Einschlafen charakteristischen, langsamen Augenbewegungen (Slow horizontal eye movements, SEM) begleitet, ist eine Assoziation mit geistiger Aktivität ausgeschlossen. Ziel dieser Dissertation ist die Untersuchung der Frage, ob niedergespannte EEG-Aktivität im Ruhe-EEG, welche von SEM begleitet wird (B1+), sich von solcher ohne begleitende SEM (B1-) hinsichtlich ihrer spektralen und räumlichen Zusammensetzung unterscheidet. Hierzu wurden 35 Ruhe-EEGs gesunder Probanden analysiert, welche jeweils mindestens 10s B1-, B1+ sowie 10s niedergespannter EEG-Aktivität während der Bearbeitung einer Kopfrechenaufgabe (calc) präsentierten. Unter Verwendung der Methode der standardized low resolution brain electromagnetic tomography (sLORETA) wurden für calc, B1- und B1+ die kortikalen Stromdichteverteilungen in vier verschiedenen, individuell angepassten Frequenzbändern berechnet. Die statistische Auswertung ergab signifikante Unterschiede zwischen B1- und B1+: Es zeigte bei B1- sowohl im Delta- als auch im Theta-Band eine geringere Aktivität im Bereich des Cingulums sowie benachbarten Teilen der Frontal-, Parietal- und Okzipiallappen. Zusätzlich zeigte sich eine erhöhte Aktivität im Frequenzbereich des Beta-Bandes in den Temporallappen für B1- verglichen mit B1+. Der Vergleich von calc mit B1+ erbrachte ähnliche Resultate. Die Befunde lassen eine Zugehörigkeit von B1- zu einem, verglichen mit B1+ höheren Vigilanzniveau vermuten und liefern Evidenz für die Einteilung niedergespannter Episoden im Ruhe-EEG in solche mit und ohne begleitende SEM.
6

Hodnocení zdrojové aktivity mozku pomocí sLORETA zobrazení v průběhu modulované a fyzické aktivity. / Brain activity assessment using sLORETA during modulated and physical activity.

Košťálová, Johana January 2017 (has links)
Title: Brain activity assessment using sLORETA during modulated and physical activity. Objectives: The aim of this thesis was to compare changes in the electrical activity of cortical and deep brain structures using sLORETA program between the resting state, active movement and passive observation of identical motion performed by the author of this thesis and the same one shown in the video. Methods: In this research participated 12 university students (8 women, 4 men). Age of subjects was between 23 and 25 years. The whole experiment consisted of five parts: 1. electroencephalography in supinated lying position with opened eyes, 2. watching a video, where the selected movement was performed by a woman, 3. watching a video, where this movement was performed by a man, 4. watching the author performing the same movement, 5. performing this movement by subjects themselves. Each of this parts lasted two minutes. The tested movement was 1. diagonal (flexion and extension pattern) of PNF method for right upper extremity. During the whole experiment was registered electric activity of the brain using a scalp EEG. Obtained EEG signal was afterwards exported to sLORETA program, which enabled us to see the collected data in 3D Talairach system and also to make a statistical assessment using a Student's...
7

Změny zdrojové aktivity mozku v sLORETA zobrazení při chůzi ovlivněné cueingem u pacientů s Parkinsonovou nemocí / Brain Activity Changes During Walking Affected by Cueing in Parkinson's Disease Patients Viewed by sLORETA Imaging

Dvořáčková, Dominika January 2019 (has links)
Title: Brain Activity Changes During Walking Affected by Cuieng in Parkinson's Disease Patients Viewed by sLORETA Imaging. Objectives: The aim of this diploma thesis is to acertain changes in electrical activity of the brain, evaluated by sLORETA program, between gait affected by visual and auditory cueing and normal comfortable gait in patients with Parkinson's disease. Methods: This experiment was conducted on 11 patients with Parkinson's Disease aged between 60-78 years. The electrical activity of the brain was registred by scalp EEG during the whole experiment. The experiment consisted of 4 parts. In the beginning we measured resting EEG with closed and then opened eyes (5 + 5 minutes), after that we measured EEG during normal comfortable gait on 3 meters long track (3 minutes). Subsequently we measured EEG during walking affected by cueing, again on the 3 meters long track (3 + 3 minutes). The order of visual and auditory cueing was randomized. Visual cueing was mediated by white lines (tapes) stuck to the floor within 50 centimetres of each other. Auditory cueing was mediated by a metronome. The basic rhythm of the metronome was set on the 70 BPM. Next, the data from the experiment were transferred into the sLORETA program, which enabled statistical proccessing and also imaging of the active...
8

Efeito agudo da respira??o abdominal lenta sobre a atividade cerebral, respostas emocionais e cardiovasculares / Effect of slow abdominal breathing on brain activity emotional and cardiovascular responses

Machado, Daniel Gomes da Silva 13 February 2015 (has links)
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.
9

Měření elektrické aktivity mozku v průběhu stimulace spouštěcích zón z konceptu Vojtova principu / Measuring electrical brain activity during stimulation of trigger zones from concept of Vojta principle

Martínek, Milan January 2018 (has links)
Title: Measuring electrical brain activity during stimulation of trigger zones from concept of Vojta principle Objectives: The aim of this study is to clarify whether there is a change in the electrical brain activity evaluated by the sLORETA program during the stimulation of trigger zones according to the Vojta concept. The source activity during stimulation of trigger zones was scanned from the scalp EEG and compared with the sLORETA program with the source activity measured at rest, before and after the stimulation of the trigger zones. Methods: The research was conducted on 11 healthy adult subjects. The entire research group is consisted of women aged in range 19-32. The data was obtained from the scalp EEG before, during and after stimulation of trigger zones according to Vojta concept. For each proband the measurement of resting EEG with both open and closed eyes (2 x 10 minutes) was first performed, then the measurements were taken during the stimulation of trigger zones with open and closed eyes (2 x 15 minutes). Finally, a resting EEG was measured, alternating open and closed eyes after five minutes (4 x 5 minutes). There was a pause of at least 15 minutes between each stimulation of trigger zones. The order of open and closed eyes during resting EEG and during stimulation of trigger...
10

Cortical Representation of Frequency Changes in Cochlear Implant Users

Liang, Chun, Ph.D. 12 December 2017 (has links)
No description available.

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