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Brain Activation Sequences Abstract INTRODUCTION: This research goes beyond the EEG source localization up to the field of brain connectivity in an attempt to create software tool that eases diagnostic procedures in selected nosologic units by discriminating between patients and healthy controls. METHODS: Experiment 1 - a group of 26 adult patients (14 male, 12 female) suffering from NC and 10 adult controls (5 male, 5 female) participated in the experiment. The experiment contained audio recordings designed to trigger laughter in participants during the EEG recording. Experiment 2 - twenty eight female inpatients diagnosed with ED and ten healthy controls were selected and presented with various stimuli while the EEG was recorded. The Brain Activation Sequences method, applied to all recordings, utilizes nonlinear differential model structure to calculate final output sequence of the brain locations involved substantially in the stimulus processing. RESULTS: Experiment 1 - the BAS results show statistically significant differences in activity between patients and controls namely in gyrus orbitalis, rectus, occipitalis inferior (right), occipitalis medius (right), paracentralis, cinguli, cuneus (right) and parahippocampalis (left). Experiment 2 - the results confirm significant differences in processing the...

Functional magnetic resonance imaging (fMRI) has been widely used to study cortical and subcortical mechanisms related to pain. The pathophysiology of burning mouth disorder (BMD) is not clearly understood. Central neuropathic mechanisms are thought to be main players in BMD. This study aimed to compare the location and extension of brain activation following thermal stimulation of the trigeminal nerve with fMRI blood oxygenation level dependent (BOLD) signal. This study included 8 female patients with BMD and 8 matched pain-free volunteers. Qualitative and quantitative differences in brain activation patterns between the two study groups were demonstrated. There were differences in the activation maps regarding the location of activation, with patients displaying greater BOLD signal changes in the right anterior cingulate cortex (ACC BA 32/24) and bilateral precuneus (pandlt;0.005). The control group showed larger BOLD signal changes in the bilateral thalamus, right middle frontal gyrus, right pre-central gyrus, left lingual gyrus and cerebellum (pandlt;0.005). It was also demonstrated that patients had far less volumetric activation throughout the entire brain compared to the control group. These data are discussed in light of recent findings suggesting brain hypofunction as a key player in chronic neuropathic pain conditions.

This dissertation establishes a novel data-driven method to identify language network activation patterns in pediatric epilepsy through the use of the Principal Component Analysis (PCA) on functional magnetic resonance imaging (fMRI). A total of 122 subjects’ data sets from five different hospitals were included in the study through a web-based repository site designed here at FIU. Research was conducted to evaluate different classification and clustering techniques in identifying hidden activation patterns and their associations with meaningful clinical variables. The results were assessed through agreement analysis with the conventional methods of lateralization index (LI) and visual rating. What is unique in this approach is the new mechanism designed for projecting language network patterns in the PCA-based decisional space. Synthetic activation maps were randomly generated from real data sets to uniquely establish nonlinear decision functions (NDF) which are then used to classify any new fMRI activation map into typical or atypical. The best nonlinear classifier was obtained on a 4D space with a complexity (nonlinearity) degree of 7. Based on the significant association of language dominance and intensities with the top eigenvectors of the PCA decisional space, a new algorithm was deployed to delineate primary cluster members without intensity normalization. In this case, three distinct activations patterns (groups) were identified (averaged kappa with rating 0.65, with LI 0.76) and were characterized by the regions of: 1) the left inferior frontal Gyrus (IFG) and left superior temporal gyrus (STG), considered typical for the language task; 2) the IFG, left mesial frontal lobe, right cerebellum regions, representing a variant left dominant pattern by higher activation; and 3) the right homologues of the first pattern in Broca's and Wernicke's language areas. Interestingly, group 2 was found to reflect a different language compensation mechanism than reorganization. Its high intensity activation suggests a possible remote effect on the right hemisphere focus on traditionally left-lateralized functions. In retrospect, this data-driven method provides new insights into mechanisms for brain compensation/reorganization and neural plasticity in pediatric epilepsy.

Both model-driven and data-driven approaches can be used to analyse fMRI data on group level but they have their respective advantages and disadvantages. A model-driven approach such as the GLM requires prior knowledge of the BOLD contrast while offering a simple way of performing inference. In contrast, ICA is a data-driven approach that instead takes full advantage of the data but in which it is harder to make meaningful inference. A method for combining GLM and ICA on group level utilising their respective strengths is therefore tested. The performance of the method highly relies on ICA’s ability to estimate accurate sources. Violation of ICA’s assumptions can potentially affect this ability and this aspect is investigated to get a broader understanding. The method is tested on both simulated and real fMRI data consisting of subjects with schizophrenia and healthy controls. The simulation shows high power but a higher false positive rate than expected. The method is able to find the brain regions that are typically active during a spatial working memory task, such as the posterior parietal cortex and the dorsolateral prefrontal cortex. It is further found that ICA performs especially poorly when the sources are uniformly distributed on the unit sphere.

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Cognitive function disorders have an enormous impact on the life quality of a patient, his or her family and close people. It influences the patient's job, social interaction and independence. This diploma thesis focuses on the possibility of improving cognitive functions concerning multiple sclerosis with the help of facilitation physiotherapy. Twelve disordered volunteers participated a two-month physiotherapeutic programme (motor programs activating therapy), for 1 hour, twice per week. Before the beginning and after the end of the therapeutic programme an examination by a clinic test PASAT and the monitoring of functional magnetic resonance was done. The results of functional magnetic resonance were further compared with the results of group of healthy volunteers. Concerning clinic test, the results of the disordered patients have improved after the therapy. In functional magnetic resonance statistics the earlier start and change of a curve progress of brain activation was discovered, which portrays improving speed of processing information at multiple sclerosis disordered.

Résumé : Le trouble de l’acquisition de la coordination (TAC), d’étiologie encore indéterminée, est une anomalie neurologique affectant environ 6% des enfants de l'âge scolaire. Le TAC se manifeste essentiellement par un déficit au niveau des exécutions motrices. Le présent travail de recherche comporte deux volets portant sur le TAC. Premièrement, une étude clinique sur 129 sujets âgés de 4 à 18 ans a permis de classifier les caractéristiques du TAC en sous-groupes cliniques. Trente-trois caractéristiques du TAC, les plus fréquemment rapportées dans la littérature, ont été recensées chez nos sujets. L'application d'évaluations statistiques a permis de faire ressortir trois classes essentielles. Le deuxième volet consistait à identifier les régions cérébrales impliquées dans une tâche motrice à l'aide de l'imagerie par la tomographie d'émission par positrons (TEP). Deux sujets avec TAC et deux sujets normaux ont été étudiés en deux séances d'imagerie TEP dont l'une au repos et l'autre en tapotant du pouce sur les doigts de la main gauche non-dominante. Les analyses du premier volet ont montré, entre autres, que le TAC touchait 3.17 garçons pour une fille, que tous les sujets étaient lents, que 47% des sujets étaient gauchers ou ambidextres alors que seulement 10% sont gauchers dans la population générale, que 26% avaient une dyspraxie verbale, et que 83% avaient été diagnostiqués anxieux. Les sujets ont été classés en trois sous-groupes: 1- maladroits et autres caractéristiques, sans problème de langage; 2- trouble de l’estime de soi et relation avec les pairs; 3- difficulté de langage. En imagerie, les structures cérébrales ont été classées selon leur captation du 18F-fluorodesoxyglucose (FDG) dans les hémisphères droit et gauche, avant et après l'activation, et en comparaison avec les sujets normaux. Trois types de structures cérébrales sont ressortis avec les statistiques: des structures activées, celles relativement non sollicitées et des structures désactivées. Il y avait plus de variations dans la captation du FDG chez les sujets avec TAC que chez les normaux. En conclusion, la caractérisation des sujets avec TAC par le diagnostic clinique et par l'imagerie peut procurer un plan de thérapie adéquat et ciblé étant donné que le TAC a un large spectre et pourrait coexister avec d'autres déficits cérébraux. / Abstract : Developmental Coordination Disorder (DCD) is a neurological abnormality affecting approximately 6% of children of school age. DCD is essentially manifested by deficit in motor executions. The present research aims two parts of DCD. First, a clinical study on 129 subjects aged 4 to 18 years old allowed to classify DCD characteristics (subtyping) in three classes. Thirty-three features of DCD, the most frequently reported in literature, have been identified in our subjects. The application of statistical clustering produced three essential classes. The second part was to identify the brain regions involved in a motor task using positron emission tomography (PET) imaging. Subjects with DCD and control subjects were studied in two PET imaging sessions at rest and then by tapping the thumb on each finger of the left non-dominant hand. The results showed, that DCD concerned 3.17 boys for one girl, all subjects were slow, 47% of the subjects were left-handed or ambidextrous while only 10% are left-handed in general population, 26% had a verbal dyspraxia, and 83% had been diagnosed with anxiety. Subjects were classified into three groups: 1- clumsy and other features without language problem; 2- self-esteem and peer relationships concern; 3- difficulty of spoken language. With PET imaging, the brain structures were classified according to their uptake of 18F-fluorodeoxyglucose (FDG) in the right and left hemispheres before and after activation, and compared with normal subjects. Three types of brain structures statistically emerged: activated structures, those relatively unsolicited and those disabled. There was more variation in uptake of FDG in patients with DCD than in control subjects. In conclusion, the characterization of subjects with DCD for clinical diagnostic and imaging can provide adequate and focused treatment plan since DCD has a broad spectrum and could coexist with other brain deficits.

Several lines of evidence suggest that asymmetric anterior brain activation is related to affective style, linking left hemisphere activation to positive affect and right hemisphere activation to negative affect. However, previous reports of left frontal hypoactivation in depressed patients were not confirmed in recent studies. This study evaluated additional characteristics of resting EEG alpha (8–13 Hz) asymmetry in 15 clinically depressed patients and 22 healthy adults by recording EEG activity on two separate occasions, 2–4 weeks apart. Across both sessions, group differences in anterior EEG asymmetry were compatible with the original hypothesis. However, groups differed in temporal stability of anterior EEG asymmetry, which was retest reliable in controls but not depressed patients. In contrast, temporal stability of posterior EEG asymmetry was acceptable in both groups. Increased variability of anterior EEG asymmetry may be a characteristic feature for depression, and, if so, this would challenge the notion that anterior EEG alpha asymmetry is a trait marker for depression. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Several lines of evidence suggest that asymmetric anterior brain activation is related to affective style, linking left hemisphere activation to positive affect and right hemisphere activation to negative affect. However, previous reports of left frontal hypoactivation in depressed patients were not confirmed in recent studies. This study evaluated additional characteristics of resting EEG alpha (8–13 Hz) asymmetry in 15 clinically depressed patients and 22 healthy adults by recording EEG activity on two separate occasions, 2–4 weeks apart. Across both sessions, group differences in anterior EEG asymmetry were compatible with the original hypothesis. However, groups differed in temporal stability of anterior EEG asymmetry, which was retest reliable in controls but not depressed patients. In contrast, temporal stability of posterior EEG asymmetry was acceptable in both groups. Increased variability of anterior EEG asymmetry may be a characteristic feature for depression, and, if so, this would challenge the notion that anterior EEG alpha asymmetry is a trait marker for depression. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.