京都大学 / 新制・課程博士 / 博士(医学) / 甲第23069号 / 医博第4696号 / 新制||医||1049(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 髙橋 良輔, 教授 林 康紀, 教授 渡邉 大 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

The objective of the thesis is to get familiar with the method of psychophysiological interactions and its common inplementation. It is explaining the usual methods of removing disruptive signals from the data processed in correlation analysis and presents the possibility of their implementation. In the practical part it is focused on cerating suggested program and its testing on the real data sets.

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Phonological processing, the ability to recognize and manipulate the sounds of one's native language, is an essential linguistic skill. Deficits in this skill may lead to decreased social, educational, and financial success (Kraus & White-Schwoch, 2019). Additionally, phonological disorders have been shown to be highly variable and individualized (Bellon-Harn & Cradeur-Pampolina, 2016) and therefore difficult to treat effectively. A better understanding of the neural underpinnings of phonological processing, including the underlying skill of phonemic discrimination, could lead to the development of more individualized and effective intervention. Several studies, some using quantitative electroencephalography (qEEG) and others using functional magnetic resonance imaging (fMRI), have been conducted to investigate these neural underpinnings. When considering the relative strengths and weaknesses of qEEG and fMRI, the scientific community has traditionally believed qEEG to be excellent at determining when brain activity occurs (temporal resolution), but to have limited abilities in determining where it occurs (spatial resolution). On the other hand, the reverse is believed to be true for fMRI. However, the spatial resolution of qEEG has improved over recent decades and some studies have reached levels of specificity comparable to fMRI. This thesis provides an abbreviated meta-analysis determining the accuracy and consistency of source references, or areas where brain activation is determined to originate from, in qEEG studies evaluating phonemic discrimination. Nineteen experiments were analyzed using the Comprehensive Meta-Analysis software. A study's event rate was defined as the number of times an anatomical area was coded as a source reference, divided by the participants in the study. Results show that each of these experiments had relatively low event rates, culminating into a summary event rate of 0.240. This indicates that qEEG does not provide source references that are as accurate or consistent as fMRI. This meta-analysis concludes that although there is research suggesting qEEG may have developed to be comparable to fMRI in spatial resolution, this is not supported in the analysis of qEEG studies focused on phonemic discrimination.

The dissertation discusses various node identification techniques as well as their downstream effects on network characteristics using task-activated fMRI data from two working memory paradigms: a verbal n-back task and a visual n-back task. The three node identification techniques examined within this work include: a group-aggregated approach, a subject-specific approach, and a voxel wise approach. The first chapters highlight crucial differences between group-aggregated and subject-specific methods of isolating nodes prior to undirected functional connectivity analysis. Results show that the two techniques yield significantly different network interactions and local network characteristics, despite having their network nodes restricted to the same anatomical regions. Prior to the introduction of the third technique, a chapter is dedicated to explaining the differences between a priori approaches (like the previously introduced group-aggregated and subject-specific techniques) and no a priori approaches (like the voxel wise approach). The chapter also discusses two ways to aggregate signal for node representation within a network: using the signal from a single voxel or aggregating signal across a group of neighboring voxels. Subsequently, a chapter is dedicated to introducing a novel processing pipeline which uses a data driven voxel wise approach to identify network nodes. The novel pipeline defines nodes using spatial temporal features generated by a deep learning algorithm and is validated by an analysis showing that the isolated nodes are condition and subject specific. The dissertation concludes by summarizing the main takeaways from each of the three analyses as well as highlighting the advantages and disadvantages of each of the three node identification techniques. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20967号 / 医博第4313号 / 新制||医||1026(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 村井 俊哉, 教授 松田 秀一, 教授 安達 泰治 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第21671号 / 医博第4477号 / 新制||医||1035(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 髙橋 良輔, 教授 溝脇 尚志, 教授 黒田 知宏 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

The ability to regulate emotions is essential for human well-being. Among posttraumatic stress disorder (PTSD) patients, the capability to control emotions is impaired. Trauma-focused cognitive behavioral therapy is a recommended treatment for patients diagnosed with PTSD. Usually, cognitive reappraisal is considered the primary regulation technique in cognitive behavioral therapy treatment. The strategy aims to decrease negative or increase positive emotions by changing the interpretation of an event to alter the meaning of the situation. The aim of this thesis was to conduct a systematic review of the neural correlates of cognitive reappraisal among post-traumatic stress disorder patients. Through a systematic search, screening, and selection process out of initial 545 articles, six studies were included for data extraction and discussion. Using functional magnetic resonance imaging, participants utilized the strategy of cognitive reappraisal during an emotion regulation task in the scanner. Using functional magnetic resonance imaging, the neural activity of the participants in the included studies was compared during a cognitive reappraisal task. The result revealed a tendency of decreased activity in prefrontal cortices in PTSD patients during reappraisal compared to controls, indicating deficient recruitment of prefrontal cortices in PTSD patients during reappraisal.

Bipolar spectrum disorders (BSDs) and substance use disorders (SUDs) are highly co-occurring and both are associated with dysfunction in neural networks that mediate reward processing and motivated behavior. Furthermore, despite their high comorbidity rate, limited research into their shared neural mechanisms or potential prospective risk factors exists. This study attempted to elucidate common neural pathways for these disorders, and adds to the small but growing literature on possible prospective predictors of these disorders. We employed a task-based functional magnetic resonance imaging (fMRI) study to examine regions-of-interest (ventral striatum [VS], orbitofrontal cortex [OFC], ventromedial prefrontal cortex [vmPFC], dorsolateral prefrontal cortex [dlPFC]) and connectivity (VS-OFC, VS-vmPFC, vmPFC-dlPFC) analyses to examine neural reward processing as potential predictors of future substance and mood symptoms, and to explore differences among groups of participants with and without BSDs and SUDs. Results from this study provided evidence that blunted activation in the VS and dlPFC and greater negative connectivity between the vmPFC and dlPFC, key reward and control circuits, is implicated in prospective substance use. However, we did not find evidence to support our hypothesis that reward-related neural responses predict BSD symptoms or could differentiate individuals with co-occurring BSDs and SUDs from healthy volunteers. The study highlights the importance of larger, longitudinal studies to more fully probe neurodevelopmental trajectories in mood, substance, and related disorders. We also conducted an extensive review of the neural reward literature in BSDs and SUDs to understand possible pre-existent mechanisms. Results of the review provided support for an equifinality/multifinality perspective in that similar neural reward processing dysfunctions can lead to both BSDs and SUDs and different neural reward processing abnormalities can lead to a single outcome (e.g., SUDs). Taken together, results from the dissertation address an important gap in the literature on BSD-SUD comorbidity, suggest possible shared mechanisms that predispose to both disorders, and provide a backdrop for future work in this area to inform more theoretically-targeted interventions and prevention. / Psychology

Non-suicidal self-injury (NSSI), defined as the deliberate damaging or destruction of body tissue without intent to die, are common behaviors amongst youth. Although prior work has shown heightened response to negative outcomes and dampened response to positive outcomes across multiple methods, including behavioral and physiological measures, little is known about the neural processes involved in NSSI. This study examined associations between NSSI engagement and responsivity to rewards and losses in youth with and without a lifetime engagement in NSSI. We employed a task-based functional magnetic resonance imaging (fMRI) study to examine differences between regions of interest (ROIs; ventral and dorsal striatum [VS, DS], anterior cingulate cortex [ACC], orbitofrontal cortex [OFC], ventrolateral and ventromedial prefrontal cortex [vlPFC; vmPFC], and insula) and whole-brain connectivity (utilizing bilateral DS, mPFC, and insula seed ROIs) in youth with and without NSSI. We used two reward tasks, in order to examine differences between groups across domains of reward (i.e., monetary and social). Additionally, we examined the specificity of the associations by controlling for dimensional levels of related psychopathology (i.e., aggression and depression). Results from the current study found that NSSI was associated with decreased activation following monetary gains in all ROIs. Further, these differences remained significant when controlling for comorbid psychopathology, including symptoms of aggression and depression. Finally, exploratory connectivity analyses found that NSSI was associated with differential connectivity between regions including the DS, vmPFC, insula, parietal operculum cortex, supramarginal gyrus, cerebellum, and central opercular cortex. Weakened connectivity between these regions could suggest deficits in inhibitory control of emotions in individuals with NSSI, as well as dysfunction in pain processing in individuals with NSSI, whereby these individuals experience pain as more salient or rewarding than individuals without NSSI. Although results did not support our hypotheses, findings suggest disrupted reward processes in youth with NSSI, contributing to our understanding of the role that reward processes may play in NSSI, in the engagement and reinforcement of these behaviors. We also conducted an extensive systematic review of the studies indexing neural structure and function in NSSI, summarizing the literature on the neurobiological correlates of several psychological processes implicated in NSSI engagement, including emotion processes, pain processes, executive processes, social processes, and reward processes. Results of the review highlighted the neural regions most consistently associated with NSSI, including the amygdala, insula, frontal, prefrontal, and orbitofrontal cortices, and the anterior cingulate, dorsal striatum, and ventral striatum. Additionally, data showed that NSSI is associated with greater emotional responses in negative situations, poorer down-regulation of negative emotions, and poorer inhibitory control over impulsive behaviors. Overall, findings suggest that NSSI is associated with maladaptive coping, and that this down-regulation of negative emotion resulting from NSSI may be experienced as rewarding and may serve to reinforce engagement in these behaviors. Finally, this review highlighted the importance of standardizing the methods of indexing neural structure and function in NSSI, specifically in terms of how NSSI is categorized, which comorbid disorders are examined, and how neuroimaging data are collected and analyzed, so that research in this area is comparable and reproducible. / Psychology