<p> Relationships between dorsal hippocampal EEG and behavior were studied in the rat. Walking etc, and lever pressing were associated with significantly more hippocampal RSA than operant licking, normal drinking, polydipsic drinking, grooming, saliva spreading and holding still. The results suggested that hippocampal EEG is related to the form of response, rather than to perceptual or sensory processes or to central integrative processes. Furthermore, the results suggested that hippocampal EEG is not related to the operant role of response or to relative intensities of response. </p> / Thesis / Doctor of Philosophy (PhD)

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.

In this thesis, we consider a stochastic SIRS model of EEG data. The model is built over three different network structures: a random network, a scale-free network, and a small-world network. These models are then fit to an EEG signal from a control individual and an EEG signal from an individual experiencing an epileptic seizure. We are interested in determining whether these models can distinguish between the two data sets, and whether any of the network structures offer a significantly better fit to the data than others; there is also a broader interest in the effects of different network structures on the time series characteristics of an SIRS system. / Thesis / Master of Science (MSc)

Phase Synchrony (PS) and coherence analyses of stochastic time series - tools to discover brain tissue pathways traveled by electrical signals - are considered for the specific purpose of processing of the electroencephalogram (EEG). We propose the Phase Synchrony Processor (PSP), as a tool for implementing phase synchrony analysis, and examine its properties on the basis of known signals. Long observation times and wide filter bandwidths can decrease bias in PS estimates. The value of PS is affected by the difference in frequency of the sequences being analyzed and can be related to that frequency difference by the periodic sinc function. PS analysis of the EEG shows that the average PS is higher - for a number of electrode pairs - for non-ADHD than for ADHD participants. The difference is more pronounced in the δ rhythm (0-3 Hz) and in the γ rhythm (30-50 Hz) PS. The Euclidean classifier with electrode masking yields 66 % correct classification on average for ADHD and non-ADHD subjects using the δ and γ1 rhythms. We observed that the average γ1 rhythm PS is higher for the eyes closed condition than for the eyes open condition. The latter may potentially be used for vigilance monitoring. The Euclidean discriminator with electrode masking shows an average percentage of correct classification of 78 % between the eyes open and eyes closed subject conditions. We develop a model for a pair of EEG electrodes and a model-based MS coherence estimator aimed at processing short (i.e. 20 samples) EEG frames. We verify that EEG sequences can be modeled as AR(3) processes degraded by additive white noise with an average SNR of approximately 11-12 dB. Application of the MS coherence estimator to the EEG suggests that MS coherence is generally higher for non-ADHD individuals than for ADHD participants when evaluated for the θ rhythm of EEG. Also, MS coherence is consistently higher for ADHD subjects than for the majority of non-ADHD individuals when computed for the low end of the δ rhythm (i.e. below 1 Hz). ADHD produces more measurable effects in the frontal lobe EEG and for participants performing attention intensive tasks. / Ph. D.

The thesis deals with EEG signals, their description, methods of quantitative analysis and the processes in time-frequency domains, or power spectrums. The relationsheep between brain electrical activity and acustic stimuli (Mozart´s “Sonata K448”) was studied using EEG analysis in relation to sound impulses from replayed extracts of. The proposed experiment protocol included recording of EEG of volunteers. In order to visualize and analyze the data, the software with the graphic user interface was created, which enables topological mapping of brain activity and its vizualization in the time-frequency domain.

This thesis deals with analysis and processing of the Sleep Electroencephalogram (EEG) signals. The scope of this thesis can be split into several areas. The first area is application of the Independent Component Analysis (ICA) method for EEG signal analysis. A model of EEG signal formation is proposed and conditions under which this model is valid are examined. It is shown that ICA can be used to remove non-deterministic artifacts contained in the EEG signals. The second area of interest is analysis of stationarity of the Sleep EEG signal. Methods to identify stationary signal segments and to analyze statistical properties of these stationary segments are presented. The third area of interest focuses on spectral analysis of the Sleep EEG signals. Analyses are performed that shows the processes that form particular parts of EEG signals spectrum. Also, random signals that are an integral part of the EEG signals analysis are performed. The last area of interest focuses on elimination of the transition processes that are caused by the filtering of the short EEG signal segments.

Consumers' attitudes towards established brands were tested using implicit and explicit measures. In particular, late positive potential (LPP) effects were assessed as an implicit physiological measure of motivational significance. The implicit Association Test (IAT) was used as an implicit behavioural measure of valence-related aspects (affective content) of brand attitude. We constructed individualised stimulus lists of liked and disliked brand types from participants' subjective pre-assessment. Participants then re-rated these visually presented brands whilst brain potential changes were recorded via electroencephalography (EEG). First, self-report measures during the test confirmed pre-assessed attitudes underlining consistent explicit rating performance. Second, liked brands elicited significantly more positive going waveforms (LPPs) than disliked brands over right parietal cortical areas starting at about 800 ms post stimulus onset (reaching statistical significance at around 1000 ms) and lasting until the end of the recording epoch (2000 ms). In accordance to the literature this finding is interpreted as reflecting positive affect-related motivational aspects of liked brands. Finally, the IAT revealed that both liked and disliked brands indeed are associated with affect-related valence. The increased levels of motivation associated with liked brands is interpreted as potentially reflecting increased purchasing intention, but this is of course only speculation at this stage. (authors' abstract)

One of the techniques used to induce trance state in shamanic ceremonies is monotonous drumming. According to previous EEG research, certain patterns of drumming cause an increase in power of alpha and theta frequencies of the listener. Present study aimed to determine, if suggestion to experience trance state could increase the relative alpha and theta amplitude and the intensity of experienced state. A group of twenty-four subjects participated in the study. Suggestion to experience trance state decreased alpha frequency power during the drumming condition. No other significant effects of suggestion or drumming were found.

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.

O stress pode ser definido como uma reação complexa, necessária e benéfica ao organismo, porém quando permanece por um período prolongado cria-se um desequilíbrio no funcionamento global orgânico, enfraquecendo o sistema imunológico e deixando o indivíduo exposto a infecções e doenças oportunistas. Diversos tratamentos são propostos para o controle do stress dentre eles está à acupuntura, uma técnica milenar que consiste na inserção de agulhas em pontos específicos da pele. O eletroencefalograma (EEG) é um instrumento de registro gráfico das variações do potencial de membrana dos neurônios corticais, seu registro e sua interpretação é um processo rotineiro de diagnóstico neurológico e neste caso foi utilizado para verificar se existe alguma alteração no espectro de frequência do EEG imediatamente após a aplicação da acupuntura. Foram selecionados 38 sujeitos randomizados em grupo controle (n= 13), grupo acupuntura (n=13) e grupo eletroacupuntura (n=12). Antes das intervenções os sujeitos foram submetidos ao Inventário de Sintomas de Stress para adultos de Lipp (ISSL), a escala visual analógica (EVA) de stress, mensurados frequência cardíaca (FC) e pressão arterial (PA). As intervenções ocorreram durante vinte minutos e vinte minutos antes e depois das intervenções foram realizados os registros de EEG. Após o término do EEG os sujeitos novamente responderam ao EVA e foram mensurados FC e PA. Para análise dos dados foram utilizados ANOVA, correlação, BOOTSTRAP e teste t-student. Não foram encontradas diferenças significativas em relação ao espectro de frequência do EEG e a EVA antes e depois das intervenções, houve uma diminuição significante da FC após as intervenções. Não houve alteração da PA durante todo o processo. A acupuntura e a eletroacupuntura não apresentaram efeitos imediatos significativos após sua realização no espectro de frequência do EEG, embora tenha apresentado uma tendência a alterações. Não houve relação do espectro do EEG e os quesitos questionário de Lipp e EVA / Stress can be defined as a complex, necessary and beneficial response by the body, but when it remains for a prolonged period creates an imbalance in the overall organ function, by weakening the immune system, leaving exposed the individual opportunistic infections and diseases. Several treatments are proposed for the control of stress among them is acupuncture, an ancient technique that involves inserting fine needles into specific points on the skin. The electroencephalogram (EEG) is a tool of graphic record of the variations of the membrane potential of cortical neurons registration and its interpretation is a routine process of neurological diagnosis and this case was used to verify if there is any change in the frequency spectrum of the EEG immediately after application of acupuncture. 38 subjects randomized into control group (n = 13), acupuncture group (n = 13) and electroacupuncture group (n = 12) were selected. Before the intervention the subjects were submitted to the Inventory of Stress Symptoms for adults Lipp (ISSL), a visual analog scale (VAS) of stress, measured heart rate (HR) and blood pressure (BP). The interventions occurred for twenty minutes and twenty minutes before and after interventions EEG records were performed. After the end of the EEG subjects again responded to the EVA and HR and BP were measured. For data analysis, ANOVA, correlation, BOOTSTRAP and student t test were used. No significant differences were found in relation to the frequency of the EEG spectrum and VAS before and after the interventions, there was a significant decrease in HR after the interventions. There was no change in BP during the entire process. Acupuncture and electroacupuncture showed no significant immediate effect after its completion in the EEG frequency spectrum, although it had a tendency to change. There was no relation of the EEG spectrum and the questions questionnaire Lipp and EVA