El balance del cerebro se altera a nivel estructural y funcional por el consumo de alcohol y puede causar trastornos por consumo de alcohol (TCA). El objetivo de esta Tesis Doctoral fue investigar los efectos del consumo crónico y excesivo de alcohol en el cerebro desde una perspectiva funcional y estructural, mediante análisis de imágenes multimodales de resonancia magnética (RM). Realizamos tres estudios con objetivos específicos: i) Para entender cómo las neuroadaptaciones desencadenadas por el consumo de alcohol se ven reflejadas en la conectividad cerebral funcional entre redes cerebrales, así como en la actividad cerebral, realizamos estudios en ratas msP en condiciones de control y tras un mes con acceso a alcohol. Para cada sujeto se obtuvieron las señales específicas de sus redes cerebrales tras aplicar análisis probabilístico de componentes independientes y regresión espacial a las imágenes funcionales de RM en estado de reposo (RMf-er). Después, estimamos la conectividad cerebral en estado de reposo mediante correlación parcial regularizada. Para una lectura de la actividad neuronal realizamos un experimento con imágenes de RM realzadas con manganeso. En la condición de alcohol encontramos hipoconectividades entre la red visual y las redes estriatal y sensorial; todas con incrementos en actividad. Por el contrario, hubo hiperconectividades entre tres pares de redes cerebrales: 1) red prefrontal cingulada media y red estriatal, 2) red sensorial y red parietal de asociación y 3) red motora-retroesplenial y red sensorial, siendo la red parietal de asociación la única red sin incremento de actividad. Estos resultados indican que las redes cerebrales ya se alteran desde una fase temprana de consumo continuo y prolongado de alcohol, disminuyendo el control ejecutivo y la flexibilidad comportamental. ii) Para comparar el volumen de materia gris (MG) cortical entre 34 controles sanos y 35 pacientes con dependencia al alcohol, desintoxicados y en abstinencia de 1 a 5 semanas, realizamos un análisis de morfometría basado en vóxel. Las principales estructuras cuyo volumen de MG disminuyó en los sujetos en abstinencia fueron el giro precentral (GPreC), el giro postcentral (GPostC), la corteza motora suplementaria (CMS), el giro frontal medio (GFM), el precúneo (PCUN) y el lóbulo parietal superior (LPS). Disminuciones de MG en el volumen de esas áreas pueden dar lugar a cambios en el control de los movimientos (GPreC y CMS), en el procesamiento de información táctil y propioceptiva (GPostC), personalidad, previsión (GFM), reconocimiento sensorial, entendimiento del lenguaje, orientación (PCUN) y reconocimiento de objetos a través de su forma (LPS). iii) Caracterizar estados cerebrales dinámicos en señales de RMf mediante una metodología basada en un modelo oculto de Markov (HMM en inglés)-Gaussiano en un paradigma con diseño de bloques, junto con distintas señales temporales de múltiples redes: componentes independientes y modos funcionales probabilísticos (PFMs en inglés) en 14 sujetos sanos. Cuatro condiciones experimentales formaron el paradigma de bloques: reposo, visual, motora y visual-motora. Mediante la aplicación de HMM-Gaussiano a los PFMs pudimos caracterizar cuatro estados cerebrales a partir de la actividad media de cada PFM. Los cuatro mapas espaciales obtenidos fueron llamados HMM-reposo, HMM-visual, HMM-motor y HMM-RND (red neuronal por defecto). HMM-RND apareció una vez el estado de tarea se había estabilizado. En un futuro cercano se espera obtener estados cerebrales en nuestros datos de RMf-er en ratas, para comparar dinámicamente el comportamiento de las redes cerebrales como un biomarcador de TCA. En conclusión, las técnicas de neuroimagen aplicadas en imagen de RM multimodal para estimar la conectividad cerebral en estado de reposo, la actividad cerebral y el volumen de materia gris han permitido avanzar en el entendimiento de los mecanismos homeostático / La ingesta d'alcohol altera el balanç del cervell a nivell estructural i funcional i pot causar trastorns per consum d' alcohol (TCA). L'objectiu d'aquesta Tesi Doctoral fou estudiar els efectes en el cervell del consum crònic i excessiu d'alcohol, des d'un punt de vista funcional i estructural i per mitjà d'anàlisi d'imatges de ressonància magnètica (RM). Vam realitzar tres anàlisis amb objectius específics: i) Per a entendre com les neuroadaptacions desencadenades pel consum d'alcohol es veuen reflectides en la connectivitat cerebral funcional entre xarxes cerebrals, així com en l'activitat cerebral, vam realitzar estudis en rates msP en les condicions de control i després d'un mes amb accés a alcohol. Per a cada subjecte vam obtindre els senyals de les xarxes cerebrals tras aplicar a les imatges funcionals de RM en estat de repòs una anàlisi probabilística de components independents i regressió espacial. Després, estimàrem la connectivitat cerebral en estat de repòs per mitjà de correlació parcial regularitzada. Per a una lectura de l'activitat cerebral vam adquirir imatges de RM realçades amb manganés. En la condició d'alcohol vam trobar hipoconnectivitats entre la xarxa visual i les xarxes estriatal i sensorial, totes amb increments en activitat. Al contrari, va haver-hi hiperconnectivitats entre tres parells de xarxes cerebrals: 1) xarxa prefrontal cingulada mitja i xarxa estriatal, 2) xarxa sensorial i xarxa parietal d'associació i 3) xarxa motora-retroesplenial i xarxa sensorial, sent la xarxa parietal d'associació l'única xarxa sense increment d'activitat. Aquests resultats indiquen que les xarxes cerebrals ja s'alteren des d'una fase primerenca caracteritzada per consum continu i prolongat d'alcohol, disminuint el control executiu i la flexibilitat comportamental. ii) Per a comparar el volum de MG cortical entre 34 controls sans i 35 pacients amb dependència a l'alcohol, desintoxicats i en abstinència de 1 a 5 setmanes vam emprar anàlisi de morfometria basada en vòxel. Les principals estructures on el volum de MG va disminuir en els subjectes en abstinència van ser el gir precentral (GPreC), el gir postcentral (GPostC), la corteça motora suplementària (CMS), el gir frontal mig (GFM), el precuni (PCUN) i el lòbul parietal superior (LPS). Les disminucions de MG en eixes àrees poden donar lloc a canvis en el control dels moviments (GPreC i CMS), en el processament d'informació tàctil i propioceptiva (GPostC), personalitat, previsió (GFM), reconeixement sensorial, enteniment del llenguatge, orientació (PCUN) i reconeixement d'objectes a través de la seua forma (LPS). iii) Caracterització de les dinàmiques temporals del cervell com a diferents estats cerebrals, en senyals de RMf mitjançant una metodologia basada en un model ocult de Markov (HMM en anglès)-Gaussià en imatges de RMf, junt amb dos tipus de senyals temporals de múltiples xarxes cerebrals: components independents i modes funcionals probabilístics (PFMs en anglès) en 14 subjectes sans. Quatre condicions experimentals van formar el paradigma de blocs: repòs, visual, motora i visual-motora. HMM-Gaussià aplicat als PFMs (senyals de RM funcional de xarxes cerebrals) va permetre la millor caracterització dels quatre estats cerebrals a partir de l'activitat mitjana de cada PFM. Els quatre mapes espacials obtinguts van ser anomenats HMM-repòs, HMM-visual, HMM-motor i HMM-XND (xarxa neuronal per defecte). HMM-XND va aparèixer una vegada una tasca estava estabilitzada. En un futur pròxim s'espera obtindre estats cerebrals en les nostres dades de RMf-er en rates, per a comparar dinàmicament el comportament de les xarxes cerebrals com a biomarcador de TCA. En conclusió, s'han aplicat tècniques de neuroimatge per a estimar la connectivitat cerebral en estat de repòs, l'activitat cerebral i el volum de MG, aplicades a imatges multimodals de RM i s'han obtés resultats que han permés avançar en l'enteniment dels m / Alcohol intake alters brain balance, affecting its structure and function, and it may cause Alcohol Use Disorders (AUDs). We aimed to study the effects of chronic, excessive alcohol consumption on the brain from a functional and structural point of view, via analysis of multimodal magnetic resonance (MR) images. We conducted three studies with specific aims: i) To understand how the neuroadaptations triggered by alcohol intake are reflected in between-network resting-state functional connectivity (rs-FC) and brain activity in the onset of alcohol dependence, we performed studies in msP rats in control and alcohol conditions. Group probabilistic independent component analysis (group-PICA) and spatial regression were applied to resting-state functional magnetic resonance imaging (rs-fMRI) images to obtain subject-specific time courses of seven resting-state networks (RSNs). Then, we estimated rs-FC via L2-regularized partial correlation. We performed a manganese-enhanced (MEMRI) experiment as a readout of neuronal activity. In alcohol condition, we found hypoconnectivities between the visual network (VN), and striatal (StrN) and sensory-cortex (SCN) networks, all with increased brain activity. On the contrary, hyperconnectivities were found between three pairs of RSNs: 1) medial prefrontal-cingulate (mPRN) and StrN, 2) SCN and parietal association (PAN) and 3) motor-retrosplenial (MRN) and SCN networks, being PAN the only network without brain activity rise. Interestingly, the hypoconnectivities could be explained as control to alcohol transitions from direct to indirect connectivity, whereas the hyperconnectivities reflected an indirect to an even more indirect connection. These findings indicate that RSNs are early altered by prolonged and moderate alcohol exposure, diminishing the executive control and behavioral flexibility. ii) To compare cortical gray matter (GM) volume between 34 healthy controls and 35 alcohol-dependent patients who were detoxified and remained abstinent for 1-5 weeks before MRI acquisition, we performed a voxel-based morphometry analysis. The main structures whose GM volume decreased in abstinent subjects compared to controls were precentral gyrus (PreCG), postcentral gyrus (PostCG), supplementary motor cortex (SMC), middle frontal gyrus (MFG), precuneus (PCUN) and superior parietal lobule (SPL). Decreases in GM volume in these areas may lead to changes in control of movement (PreCG and SMC), in processing tactile and proprioceptive information (PostCG), personality, insight, prevision (MFG), sensory appreciation, language understanding, orientation (PCUN) and the recognition of objects by touch and shapes (SPL). iii) To characterize dynamic brain states in functional MRI (fMRI) signals by means of an approach based on the Hidden Markov model (HMM). Several parameter configurations of HMM-Gaussian in a block-design paradigm were considered, together with different time series: independent components (ICs) and probabilistic functional modes (PFMs) on 14 healthy subjects. The block-design fMRI paradigm consisted of four experimental conditions: rest, visual, motor and visual-motor. Characterizing brain states' dynamics in fMRI data was possible applying the HMM-Gaussian approach to PFMs, with mean activity driving the states. The four spatial maps obtained were named HMM-rest, HMM-visual, HMM-motor and HMM-DMN (default mode network). HMM-DMN appeared once a task state had stabilized. The ultimate goal will be to obtain brain states in our rs-fMRI rat data, to dynamically compare the behavior of brain RSNs as a biomarker of AUD. In conclusion, neuroimaging techniques to estimate rs-FC, brain activity and GM volume can be successfully applied to multimodal MRI in the advance of the understanding of brain homeostasis in AUDs. These functional and structural alterations are a biomarker of chronic alcoholism to explain impairments in executive control, reward evaluation and visuospatial processing. / Pérez Ramírez, MÚ. (2018). Characterizing functional and structural brain alterations driven by chronic alcohol drinking: a resting-state fMRI connectivity and voxel-based morphometry analysis [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/113164 / TESIS

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18872号 / 医博第3983号 / 新制||医||1008(附属図書館) / 31823 / 京都大学大学院医学研究科医学専攻 / (主査)教授 河野 憲二, 教授 古川 壽亮, 教授 髙橋 良輔 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DGAM

Succédant à une théorisation centrée sur le rôle des déficits des fonctions exécutives, les modèles contemporains du trouble déficit de l'attention / hyperactivité (TDAH) mettent en avant l’hétérogénéité d’une catégorie diagnostique impliquant des déficits neuropsychologiques, voies cérébrales et mécanismes étiopathogéniques multiples. En dépit de cette évolution, la majorité des études d'imagerie cérébrale des corrélats structurels du trouble menées à ce jour ont été conduites au niveau de la catégorie diagnostique, sans spécification supplémentaire. Cette approche comparant en moyenne un groupe de patients avec TDAH à un groupe de sujets sains a donné des résultats très variables d'une étude à l'autre, la comparaison inter-étude étant toutefois rendue difficile par la présence de facteurs confondants, tels que des différences en terme de régions d’intérêt examinées, de comorbidités acceptées chez les patients, de pourcentages de sujets masculins et féminins, de fenêtre d’âge sélectionnée, de méthodologie d'analyse ou encore de pourcentage de patients traités par méthylphénidate. Dans ce doctorat, nous nous sommes appuyés sur la morphométrie voxel-à-voxel pour isoler l’influence sur les volumes de matière grise de deux facteurs d’hétérogénéité intra-catégorielle dans le TDAH : le genre d’une part, et un polymorphisme génétique (Val158Met du gène Catéchol-O-méthyltransferase (COMT)) d’autre part ; ces deux facteurs présentant l’intérêt de moduler le risque associé de développer un trouble de type externalisé. Nous avons également comparé les volumes de matière grise d’enfants avec TDAH ayant reçu un traitement par méthylphénidate, de patients n'ayant jamais été exposé à la médication, et de sujet sains. Ces recherches expérimentales ont été inscrites dans une discussion plus générale de l’hétérogénéité des résultats de la littérature structurelle consacrée au TDAH et des sources neuropsychologiques de cette hétérogénéité. Dans notre étude des effets du genre sur les volumes de matière grise dans le TDAH, nous reportons pour la première fois une interaction entre genre et diagnostic, avec des corrélats structurels du trouble différents chez les garçons et les filles avec TDAH dans des régions de la ligne médiane du cerveau, impliquées à la fois dans la régulation émotionnelle et dans le fonctionnement du mode de réseau par défaut. Nous suggérons que ces différences structurelles pourraient contribuer aux différences de risque associé pour les troubles internalisés et externalisés présentées par les garçons et filles avec TDAH. Dans notre étude explorant l'influence du polymorphisme Val158Met sur les volumes de matière grise, nous mettons en évidence une modulation génétique des corrélats structurels du trouble : les sujets homozygotes pour l'allèle Val158, identifiés dans la littérature comme à risque pour le développement d'un trouble des conduites, présentent des volumes de matière grise supérieurs dans le noyau caudé comparativement aux sujets sains, tandis que les patients avec TDAH porteurs d'un allèle Met158 présentent des volumes de matière grise plus faibles dans le cortex préfrontal inférieur droit, une région cruciale pour les processus de contrôle attentionnel. Enfin, dans notre étude des corrélats structurels de l'exposition au méthylphénidate, nous reportons un effet potentiellement normalisateur du traitement sur les volumes de matière grise de l'insula et du pole temporal, des volumes de matière grise plus faibles chez les patients traités comparativement aux sujets sains dans le gyrus frontal moyen et dans le gyrus précentral, et une association entre volume de matière grise dans le nucleus accumbens gauche et durée d'exposition au méthylphénidate chez les sujets traités. (...) / Previous models of Attention Deficit / Hyperactivity Disorder (ADHD) such as Barkley’s or Brown’s conceptualized ADHD as essentially a developmental impairment of executive function. Against this view, it is now recognized that ADHD is a heterogeneous disorder, involving multiple deficits and multiple neuronal pathways. Despite this current theoretical framework, most structural brain imaging studies in ADHD have compared groups of children with ADHD with typically developing children, without trying to identify subgroups within the diagnostic category. This approach has yielded heterogeneous findings, possibly due to inter-studies variations in the type and number of comorbidities, the percentage of medicated participants included, the number of girls included, and/or methodological and statistical differences. Patients participating in these studies were also often exposed to methylphenidate, and potential medication effects on grey matter volumes are still unclear in certain brain regions such as the frontal lobe, despite a therapeutic action involving the preferential activation of catecholamine neurotransmission within the prefrontal cortex. In this thesis, we used voxel-based morphometry to study the influence of two important risk factors for the development of comorbid conditions in ADHD. The first of these two factors was gender, and the second a genetic polymorphism of the Catechol-O-methyltransferase gene known to put children with ADHD at risk for developing a conduct disorder (Val158Met). We also compared grey matter volumes in children with ADHD exposed to methylphenidate, never-medicated children with ADHD and typically developing children. These experimental studies were part of a more general discussion of ADHD neuropsychological and neurobiological heterogeneity. In our study exploring the influence of gender on the structural correlates of ADHD, we report for the first time a gender-by-diagnosis interaction, with grey matter volume differences in boys and girls with ADHD in midline cortical structures, involved in emotional regulation and part of the default mode network. We propose that these differences may contribute to explain why girls with ADHD more often develop inattentive and internalizing symptoms, whereas externalizing symptoms are predominant in boys with ADHD. In our study investigating the effects of Val158Met in ADHD, we report the first evidence of a COMT-related genetic modulation of ADHD-related grey matter volume alterations. Indeed, children with ADHD at higher risk for developing a conduct disorder (children homozygotes for the Val158 allele) presented increased grey matter volumes in the caudate nucleus when compared with typically developing children, whereas children carrying a Met158 allele presented with decreased grey matter volumes in the right inferior frontal cortex, a region known for its key role in attention. Finally, we measured grey matter volumes in medicated children with ADHD, never-medicated children with ADHD and typically developing children using both whole-brain voxel-based morphometry and automated tracing procedures in chosen regions of interest. We document potential methylphenidate-related grey matter volume normalization and deviation in previously unexplored frontal and temporal regions, and report a positive association between treatment history and grey matter volume in the nucleus accumbens, a key region for reward processing. Our first two experimental studies therefore contribute to a better understanding of the influence of important sources of within-category heterogeneity, while the third helps clarifying the potential confounding effect of medication exposure in previous structural brain imaging studies in ADHD.

Succédant à une théorisation centrée sur le rôle des déficits des fonctions exécutives, les modèles contemporains du trouble déficit de l'attention / hyperactivité (TDAH) mettent en avant l’hétérogénéité d’une catégorie diagnostique impliquant des déficits neuropsychologiques, voies cérébrales et mécanismes étiopathogéniques multiples. En dépit de cette évolution, la majorité des études d'imagerie cérébrale des corrélats structurels du trouble menées à ce jour ont été conduites au niveau de la catégorie diagnostique, sans spécification supplémentaire. Cette approche comparant en moyenne un groupe de patients avec TDAH à un groupe de sujets sains a donné des résultats très variables d'une étude à l'autre, la comparaison inter-étude étant toutefois rendue difficile par la présence de facteurs confondants, tels que des différences en terme de régions d’intérêt examinées, de comorbidités acceptées chez les patients, de pourcentages de sujets masculins et féminins, de fenêtre d’âge sélectionnée, de méthodologie d'analyse ou encore de pourcentage de patients traités par méthylphénidate. Dans ce doctorat, nous nous sommes appuyés sur la morphométrie voxel-à-voxel pour isoler l’influence sur les volumes de matière grise de deux facteurs d’hétérogénéité intra-catégorielle dans le TDAH : le genre d’une part, et un polymorphisme génétique (Val158Met du gène Catéchol-O-méthyltransferase (COMT)) d’autre part ; ces deux facteurs présentant l’intérêt de moduler le risque associé de développer un trouble de type externalisé. Nous avons également comparé les volumes de matière grise d’enfants avec TDAH ayant reçu un traitement par méthylphénidate, de patients n'ayant jamais été exposé à la médication, et de sujet sains. Ces recherches expérimentales ont été inscrites dans une discussion plus générale de l’hétérogénéité des résultats de la littérature structurelle consacrée au TDAH et des sources neuropsychologiques de cette hétérogénéité. Dans notre étude des effets du genre sur les volumes de matière grise dans le TDAH, nous reportons pour la première fois une interaction entre genre et diagnostic, avec des corrélats structurels du trouble différents chez les garçons et les filles avec TDAH dans des régions de la ligne médiane du cerveau, impliquées à la fois dans la régulation émotionnelle et dans le fonctionnement du mode de réseau par défaut. Nous suggérons que ces différences structurelles pourraient contribuer aux différences de risque associé pour les troubles internalisés et externalisés présentées par les garçons et filles avec TDAH. Dans notre étude explorant l'influence du polymorphisme Val158Met sur les volumes de matière grise, nous mettons en évidence une modulation génétique des corrélats structurels du trouble : les sujets homozygotes pour l'allèle Val158, identifiés dans la littérature comme à risque pour le développement d'un trouble des conduites, présentent des volumes de matière grise supérieurs dans le noyau caudé comparativement aux sujets sains, tandis que les patients avec TDAH porteurs d'un allèle Met158 présentent des volumes de matière grise plus faibles dans le cortex préfrontal inférieur droit, une région cruciale pour les processus de contrôle attentionnel. Enfin, dans notre étude des corrélats structurels de l'exposition au méthylphénidate, nous reportons un effet potentiellement normalisateur du traitement sur les volumes de matière grise de l'insula et du pole temporal, des volumes de matière grise plus faibles chez les patients traités comparativement aux sujets sains dans le gyrus frontal moyen et dans le gyrus précentral, et une association entre volume de matière grise dans le nucleus accumbens gauche et durée d'exposition au méthylphénidate chez les sujets traités. (...) / Previous models of Attention Deficit / Hyperactivity Disorder (ADHD) such as Barkley’s or Brown’s conceptualized ADHD as essentially a developmental impairment of executive function. Against this view, it is now recognized that ADHD is a heterogeneous disorder, involving multiple deficits and multiple neuronal pathways. Despite this current theoretical framework, most structural brain imaging studies in ADHD have compared groups of children with ADHD with typically developing children, without trying to identify subgroups within the diagnostic category. This approach has yielded heterogeneous findings, possibly due to inter-studies variations in the type and number of comorbidities, the percentage of medicated participants included, the number of girls included, and/or methodological and statistical differences. Patients participating in these studies were also often exposed to methylphenidate, and potential medication effects on grey matter volumes are still unclear in certain brain regions such as the frontal lobe, despite a therapeutic action involving the preferential activation of catecholamine neurotransmission within the prefrontal cortex. In this thesis, we used voxel-based morphometry to study the influence of two important risk factors for the development of comorbid conditions in ADHD. The first of these two factors was gender, and the second a genetic polymorphism of the Catechol-O-methyltransferase gene known to put children with ADHD at risk for developing a conduct disorder (Val158Met). We also compared grey matter volumes in children with ADHD exposed to methylphenidate, never-medicated children with ADHD and typically developing children. These experimental studies were part of a more general discussion of ADHD neuropsychological and neurobiological heterogeneity. In our study exploring the influence of gender on the structural correlates of ADHD, we report for the first time a gender-by-diagnosis interaction, with grey matter volume differences in boys and girls with ADHD in midline cortical structures, involved in emotional regulation and part of the default mode network. We propose that these differences may contribute to explain why girls with ADHD more often develop inattentive and internalizing symptoms, whereas externalizing symptoms are predominant in boys with ADHD. In our study investigating the effects of Val158Met in ADHD, we report the first evidence of a COMT-related genetic modulation of ADHD-related grey matter volume alterations. Indeed, children with ADHD at higher risk for developing a conduct disorder (children homozygotes for the Val158 allele) presented increased grey matter volumes in the caudate nucleus when compared with typically developing children, whereas children carrying a Met158 allele presented with decreased grey matter volumes in the right inferior frontal cortex, a region known for its key role in attention. Finally, we measured grey matter volumes in medicated children with ADHD, never-medicated children with ADHD and typically developing children using both whole-brain voxel-based morphometry and automated tracing procedures in chosen regions of interest. We document potential methylphenidate-related grey matter volume normalization and deviation in previously unexplored frontal and temporal regions, and report a positive association between treatment history and grey matter volume in the nucleus accumbens, a key region for reward processing. Our first two experimental studies therefore contribute to a better understanding of the influence of important sources of within-category heterogeneity, while the third helps clarifying the potential confounding effect of medication exposure in previous structural brain imaging studies in ADHD.

The side-effects of chemotherapy treatment are an increasingly important research focus as more cancer patients are reaching survivorship. While treatment allows for survival, it can also lead to problems which can significantly affect quality of life. Cognitive impairments after chemotherapy treatment are one such factor. First presented as anecdotal patient reports, over the last decade empirical evidence for this cognitive concern has been obtained. Much attention has been focused on post-chemotherapy research, yet little attention has been granted to these same patients’ cognition before treatment commences. Breast cancer (BC) patients face many obstacles before chemotherapy treatment such as: surgery and side-effects of anesthesia, increased cytokine activity, stress of a new disease diagnosis and upcoming challenges, and emotional burdens such as depression and anxiety. Many of these factors have independently been shown to affect cognitive abilities in both healthy populations as well as other patient groups. Therefore, the pre-treatment (or baseline) BC patient status warrants systematic study. This would then reduce mistakenly attributing carried-over cognitive deficits to side effects of chemotherapy. As well, it is possible that certain confounding variables may have neural manifestations at baseline that could be exacerbated by chemotherapy agents. The following thesis first presents a review paper which critically describes the current literature examining chemotherapy-related cognitive impairments (CRCIs), as well as possible confound variables affecting this population. Subsequently, three original research papers present pre-chemotherapy data showing significant neuroanatomical and neurofunctional differences in BC patients compared to controls. In particular, these neural differences are present in brain regions that have been reported in post-chemotherapy papers. This, as well as the effects of variables such as the number of days since surgery, depression and anxiety scores and more, support the initiative that research attention should increase focus on these patients at baseline in order to better understand their post-chemotherapy results.

The side-effects of chemotherapy treatment are an increasingly important research focus as more cancer patients are reaching survivorship. While treatment allows for survival, it can also lead to problems which can significantly affect quality of life. Cognitive impairments after chemotherapy treatment are one such factor. First presented as anecdotal patient reports, over the last decade empirical evidence for this cognitive concern has been obtained. Much attention has been focused on post-chemotherapy research, yet little attention has been granted to these same patients’ cognition before treatment commences. Breast cancer (BC) patients face many obstacles before chemotherapy treatment such as: surgery and side-effects of anesthesia, increased cytokine activity, stress of a new disease diagnosis and upcoming challenges, and emotional burdens such as depression and anxiety. Many of these factors have independently been shown to affect cognitive abilities in both healthy populations as well as other patient groups. Therefore, the pre-treatment (or baseline) BC patient status warrants systematic study. This would then reduce mistakenly attributing carried-over cognitive deficits to side effects of chemotherapy. As well, it is possible that certain confounding variables may have neural manifestations at baseline that could be exacerbated by chemotherapy agents. The following thesis first presents a review paper which critically describes the current literature examining chemotherapy-related cognitive impairments (CRCIs), as well as possible confound variables affecting this population. Subsequently, three original research papers present pre-chemotherapy data showing significant neuroanatomical and neurofunctional differences in BC patients compared to controls. In particular, these neural differences are present in brain regions that have been reported in post-chemotherapy papers. This, as well as the effects of variables such as the number of days since surgery, depression and anxiety scores and more, support the initiative that research attention should increase focus on these patients at baseline in order to better understand their post-chemotherapy results.

Succédant à une théorisation centrée sur le rôle des déficits des fonctions exécutives, les modèles contemporains du trouble déficit de l'attention / hyperactivité (TDAH) mettent en avant l’hétérogénéité d’une catégorie diagnostique impliquant des déficits neuropsychologiques, voies cérébrales et mécanismes étiopathogéniques multiples. En dépit de cette évolution, la majorité des études d'imagerie cérébrale des corrélats structurels du trouble menées à ce jour ont été conduites au niveau de la catégorie diagnostique, sans spécification supplémentaire. Cette approche comparant en moyenne un groupe de patients avec TDAH à un groupe de sujets sains a donné des résultats très variables d'une étude à l'autre, la comparaison inter-étude étant toutefois rendue difficile par la présence de facteurs confondants, tels que des différences en terme de régions d’intérêt examinées, de comorbidités acceptées chez les patients, de pourcentages de sujets masculins et féminins, de fenêtre d’âge sélectionnée, de méthodologie d'analyse ou encore de pourcentage de patients traités par méthylphénidate. Dans ce doctorat, nous nous sommes appuyés sur la morphométrie voxel-à-voxel pour isoler l’influence sur les volumes de matière grise de deux facteurs d’hétérogénéité intra-catégorielle dans le TDAH : le genre d’une part, et un polymorphisme génétique (Val158Met du gène Catéchol-O-méthyltransferase (COMT)) d’autre part ; ces deux facteurs présentant l’intérêt de moduler le risque associé de développer un trouble de type externalisé. Nous avons également comparé les volumes de matière grise d’enfants avec TDAH ayant reçu un traitement par méthylphénidate, de patients n'ayant jamais été exposé à la médication, et de sujet sains. Ces recherches expérimentales ont été inscrites dans une discussion plus générale de l’hétérogénéité des résultats de la littérature structurelle consacrée au TDAH et des sources neuropsychologiques de cette hétérogénéité. Dans notre étude des effets du genre sur les volumes de matière grise dans le TDAH, nous reportons pour la première fois une interaction entre genre et diagnostic, avec des corrélats structurels du trouble différents chez les garçons et les filles avec TDAH dans des régions de la ligne médiane du cerveau, impliquées à la fois dans la régulation émotionnelle et dans le fonctionnement du mode de réseau par défaut. Nous suggérons que ces différences structurelles pourraient contribuer aux différences de risque associé pour les troubles internalisés et externalisés présentées par les garçons et filles avec TDAH. Dans notre étude explorant l'influence du polymorphisme Val158Met sur les volumes de matière grise, nous mettons en évidence une modulation génétique des corrélats structurels du trouble : les sujets homozygotes pour l'allèle Val158, identifiés dans la littérature comme à risque pour le développement d'un trouble des conduites, présentent des volumes de matière grise supérieurs dans le noyau caudé comparativement aux sujets sains, tandis que les patients avec TDAH porteurs d'un allèle Met158 présentent des volumes de matière grise plus faibles dans le cortex préfrontal inférieur droit, une région cruciale pour les processus de contrôle attentionnel. Enfin, dans notre étude des corrélats structurels de l'exposition au méthylphénidate, nous reportons un effet potentiellement normalisateur du traitement sur les volumes de matière grise de l'insula et du pole temporal, des volumes de matière grise plus faibles chez les patients traités comparativement aux sujets sains dans le gyrus frontal moyen et dans le gyrus précentral, et une association entre volume de matière grise dans le nucleus accumbens gauche et durée d'exposition au méthylphénidate chez les sujets traités. (...) / Previous models of Attention Deficit / Hyperactivity Disorder (ADHD) such as Barkley’s or Brown’s conceptualized ADHD as essentially a developmental impairment of executive function. Against this view, it is now recognized that ADHD is a heterogeneous disorder, involving multiple deficits and multiple neuronal pathways. Despite this current theoretical framework, most structural brain imaging studies in ADHD have compared groups of children with ADHD with typically developing children, without trying to identify subgroups within the diagnostic category. This approach has yielded heterogeneous findings, possibly due to inter-studies variations in the type and number of comorbidities, the percentage of medicated participants included, the number of girls included, and/or methodological and statistical differences. Patients participating in these studies were also often exposed to methylphenidate, and potential medication effects on grey matter volumes are still unclear in certain brain regions such as the frontal lobe, despite a therapeutic action involving the preferential activation of catecholamine neurotransmission within the prefrontal cortex. In this thesis, we used voxel-based morphometry to study the influence of two important risk factors for the development of comorbid conditions in ADHD. The first of these two factors was gender, and the second a genetic polymorphism of the Catechol-O-methyltransferase gene known to put children with ADHD at risk for developing a conduct disorder (Val158Met). We also compared grey matter volumes in children with ADHD exposed to methylphenidate, never-medicated children with ADHD and typically developing children. These experimental studies were part of a more general discussion of ADHD neuropsychological and neurobiological heterogeneity. In our study exploring the influence of gender on the structural correlates of ADHD, we report for the first time a gender-by-diagnosis interaction, with grey matter volume differences in boys and girls with ADHD in midline cortical structures, involved in emotional regulation and part of the default mode network. We propose that these differences may contribute to explain why girls with ADHD more often develop inattentive and internalizing symptoms, whereas externalizing symptoms are predominant in boys with ADHD. In our study investigating the effects of Val158Met in ADHD, we report the first evidence of a COMT-related genetic modulation of ADHD-related grey matter volume alterations. Indeed, children with ADHD at higher risk for developing a conduct disorder (children homozygotes for the Val158 allele) presented increased grey matter volumes in the caudate nucleus when compared with typically developing children, whereas children carrying a Met158 allele presented with decreased grey matter volumes in the right inferior frontal cortex, a region known for its key role in attention. Finally, we measured grey matter volumes in medicated children with ADHD, never-medicated children with ADHD and typically developing children using both whole-brain voxel-based morphometry and automated tracing procedures in chosen regions of interest. We document potential methylphenidate-related grey matter volume normalization and deviation in previously unexplored frontal and temporal regions, and report a positive association between treatment history and grey matter volume in the nucleus accumbens, a key region for reward processing. Our first two experimental studies therefore contribute to a better understanding of the influence of important sources of within-category heterogeneity, while the third helps clarifying the potential confounding effect of medication exposure in previous structural brain imaging studies in ADHD.

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The side-effects of chemotherapy treatment are an increasingly important research focus as more cancer patients are reaching survivorship. While treatment allows for survival, it can also lead to problems which can significantly affect quality of life. Cognitive impairments after chemotherapy treatment are one such factor. First presented as anecdotal patient reports, over the last decade empirical evidence for this cognitive concern has been obtained. Much attention has been focused on post-chemotherapy research, yet little attention has been granted to these same patients’ cognition before treatment commences. Breast cancer (BC) patients face many obstacles before chemotherapy treatment such as: surgery and side-effects of anesthesia, increased cytokine activity, stress of a new disease diagnosis and upcoming challenges, and emotional burdens such as depression and anxiety. Many of these factors have independently been shown to affect cognitive abilities in both healthy populations as well as other patient groups. Therefore, the pre-treatment (or baseline) BC patient status warrants systematic study. This would then reduce mistakenly attributing carried-over cognitive deficits to side effects of chemotherapy. As well, it is possible that certain confounding variables may have neural manifestations at baseline that could be exacerbated by chemotherapy agents. The following thesis first presents a review paper which critically describes the current literature examining chemotherapy-related cognitive impairments (CRCIs), as well as possible confound variables affecting this population. Subsequently, three original research papers present pre-chemotherapy data showing significant neuroanatomical and neurofunctional differences in BC patients compared to controls. In particular, these neural differences are present in brain regions that have been reported in post-chemotherapy papers. This, as well as the effects of variables such as the number of days since surgery, depression and anxiety scores and more, support the initiative that research attention should increase focus on these patients at baseline in order to better understand their post-chemotherapy results.

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Agradecemos a compreensão. on 2016-04-27T16:55:50Z (GMT) / Submitted by ALINE MARQUES DA SILVA BRAGA null (aline.sms@gmail.com) on 2016-05-16T12:39:41Z No. of bitstreams: 1 Tese Aline.pdf: 9957836 bytes, checksum: 6bc924ddc7c437583c8bda4fb0a99ab3 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-05-16T14:36:42Z (GMT) No. of bitstreams: 1 braga_ams_dr_bot.pdf: 9957836 bytes, checksum: 6bc924ddc7c437583c8bda4fb0a99ab3 (MD5) / Made available in DSpace on 2016-05-16T14:36:42Z (GMT). No. of bitstreams: 1 braga_ams_dr_bot.pdf: 9957836 bytes, checksum: 6bc924ddc7c437583c8bda4fb0a99ab3 (MD5) Previous issue date: 2016-02-18 / Fundação de Amparo à Pesquisa do Estado de Mato Grosso (FAPEMAT) / Fundamento: Evidências experimentais de modelos animais de crises de ausência sugerem focalidades no início das descargas generalizadas. Estudos clínicos indicam que pacientes com o diagnóstico de epilepsia generalizada idiopática (EGI) exibem anormalidades focais que envolvem o circuito tálamo-cortical no eletroencefalograma (EEG) e na neuroimagem. Objetivos: Investigar a presença de características focais nas descargas generalizadas interictais usando análise quantitativa do EEG (EEGq) e avaliar o córtex do giro do cíngulo usando múltiplas abordagens quantitativas de neuroimagem. Métodos: 75 EEGs de 64 pacientes foram analisados. A primeira espícula generalizada inequívoca foi marcada para cada descarga. Três métodos de análise de fonte geradora da atividade observada foram aplicados: transformação do dipolo em imagem (dipole source imaging-DSI), abordagem LORETA aplicada iterativamente (CLARA), e análise de dipolo equivalente de componentes independentes com análise de agrupamentos. Após processamento do EEG, 32 pacientes (18 mulheres, 32 ± 11) fizeram ressonância magnética. Foram utilizados três métodos para comparar o giro do cíngulo de pacientes e controles: morfometria baseada em voxel (VBM), análise cortical e análise de formato. Resultados: 753 descargas generalizadas foram analisadas. Usando as três técnicas, o lobo frontal foi a principal fonte das descargas (70%), seguido pelos lobos parietal e occipital (14%) e, por fim, os núcleos da base (12%). As principais fontes anatômicas das descargas generalizadas foram o córtex da porção anterior do giro do cíngulo (36%) e giro frontal medial (23%). A VBM mostrou atrofia de substância cinzenta na porção anterior do giro do cíngulo (972 mm3) e no istmo (168 mm3). Análises individuais do córtex do giro do cíngulo mostraram resultados semelhantes. Comparações de superfície mostraram anormalidades principalmente na porção posterior do giro do cíngulo (718.12 mm2). A análise de formato demonstrou uma predominância de anormalidades nas porções anterior e posterior do giro do cíngulo. Discussão: A análise de fonte não mostrou uma fonte única comum a todas as descargas generalizadas mas indicou predominância do giro do cíngulo e lobo frontal. Além disso, o estudo sugere a existência de anormalidades estruturais sutis no giro do cíngulo, principalmente nas porções anterior e posterior. / Background: Experimental evidence from animal models of absence seizures suggests a focal source for the initiation of generalized spike-and-wave (GSW) discharges. Clinical studies indicate that patients diagnosed with idiopathic generalized epilepsy (IGE) exhibit focal electroencephalographic and subtle structural abnormalities, which involve the thalamo-cortical circuitry. Aims: The objectives of the current investigation were to investigate whether interictal generalized discharges exhibit focal characteristics using qEEG analysis and to perform a comprehensive analysis of the cingulate cortex using multiple quantitative structural neuroimaging techniques. Methods: 75 EEG recordings from 64 patients were analyzed. The first unequivocally confirmed generalized spike was marked for each discharge. Three methods of source imaging analysis were applied: dipole source imaging (DSI), classical LORETA analysis recursively applied (CLARA), and equivalent dipole of independent components with cluster analysis. After EEG analysis, 32 patients (18 women, 30± 10 years) and 36 controls (18 women, 32 ±11 years) were imaged by 3 Tesla magnetic resonance (MRI). We used three models to compare cingulate gyrus of patients and the control group: voxel-based morphometry (VBM), cortical analyses and shape analyses. Results: A total of 753 GSW discharges were spatiotemporally analyzed. Source analysis using all three techniques revealed that the frontal lobe was the principal source of GSW discharges (70%), followed by the parietal and occipital lobes (14%), and the basal ganglia (12%). The main anatomical sources of the generalized discharges were the anterior cingulate cortex (36%) and the medial frontal gyrus (23%). VBM analyses of cingulate gyrus showed areas of gray matter atrophy, mainly in the anterior cingulate gyrus (972 mm3) and the isthmus (168 mm3). Individual analyses of the cingulate cortex were similar between patients with IGE and controls. Surface- based comparisons revealed abnormalities located mainly in the posterior cingulate cortex (718.12 mm2). Shape analyses demonstrated a predominance of abnormalities in the anterior and posterior portions of cingulate gyrus abnormalities. Discussion: Source analysis did not reveal a common focal source of generalized discharges. However, there was a predominance of GSW discharges originating from the cingulate gyrus and the frontal lobe. Furthermore, this study suggests that patients with IGE have structural abnormalities in the cingulate gyrus mainly localized at the anterior and posterior portions. This finding is subtle and variable among patients. / FAPEMAT: 11/16452-2