京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第22885号 / 医博第4679号 / 新制||医||1048(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 伊佐 正, 教授 古川 壽亮, 教授 高橋 淳 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

The bedroom community has become a prevalent and oft-criticized part of the modern architectural landscape. These suburban towns have continually grown radially outward from major cities across the nation since the end of the Second World War. While these suburbs have served to fulfill housing needs and wants of society, pressure to develop has often forced this growth to occur at a much more rapid rate than a traditional community. This rapid development has led to poorly implemented infrastructure, especially with regard to walkability and public transportation, which has fallen short of meeting the needs of users. These solutions in turn have contributed to the automotive dependence of society, despite the numerous detrimental effects this engenders, such as waste of natural resources, greenhouse gas emissions, and increased congestion of roadways. This has led many within the architectural community to push for a shift away from the suburbs due to their lack of sustainability, especially when compared to urban environments. However, the reality of the situation which our society faces does not enable us to simply abandon the suburbs in a mass exodus to city centers. Even if it did, there is a large percentage of the population which simply likes suburbia and its associated lifestyle. If this is the case, then, there needs to be a shift in the way transit is implemented within these communities. This thesis will examine how improving access to transit can revitalize bedroom communities and better serve their residents. Through examining the town of Beacon, NY, a bedroom community serving New York City and currently underutilizing its existing transit infrastructure, this thesis will explore how architecture can integrate mass transit into lives and daily activities of a community in order to better serve its residents and reduce automotive dependency.

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

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Decisions often require weighing the costs and benefits of available prospects. Value-based decision making depends on the coordination of multiple cognitive faculties, making it potentially susceptible to at least two forms of variability. First, there is heterogeneity in brain organization across individuals in areas of association cortex that exhibit decision-related activity. Second, a person’s preferences can fluctuate even for repetitive decision scenarios. Using functional magnetic resonance imaging (fMRI) and behavioral experiments in humans, this project explored how these distinct sources of variability impact choice evaluation, localization of valuation in the brain, and the links between valuation and other cognitive phenomena. Group-level findings suggest that valuation processes share a neural representation with the “default network” (DN) in medial prefrontal cortex (mPFC) and posterior cingulate cortex (PCC). Study 1 examined brain network variability in an open dataset of resting-state fMRI (n=100) by quantitatively testing the hypothesis that the spatial layout of the DN is unique to each person. Functional network topography was well-aligned across individuals in PCC, but highly idiosyncratic in mPFC. These results highlighted that the apparent overlap of cognitive functions in these areas should be evaluated within individuals. Study 2 examined variability in the integration of rewards with subjective costs of time and effort. Two computerized behavioral experiments (total n=132) tested how accept-or-reject foraging decisions were influenced by demands for physical effort, cognitive effort, and unfilled delay. The results showed that people’s willingness to incur the three types of costs differed when they experienced a single type of demand, but gradually converged when all three were interleaved. The results could be accounted for by a computational model in which contextual factors altered the perceived cost of temporal delay. Finally, Study 3 asked whether the apparent cortical overlap between valuation effects and the DN persisted after accounting for individual variability in brain topography and behavior. Using fMRI scans designed to evoke valuation and DN-like effects (n=18), we reproduced the idiosyncratic network topography from Study 1, and observed valuation-related effects in individually identified DN regions. Collectively, these findings advance our taxonomic understanding of higher-order cognitive processes, suggesting that seemingly dissimilar valuation and DN-related functions engage overlapping cortical mechanisms.

In addition to mood symptoms, major depressive disorder (MDD) is characterized by cognitive impairments that can have detrimental impacts on quality of life and daily function, and have been found to persist into remission. In particular, altered affective cognition (e.g. biased attention to negative stimuli) has been reported in MDD, and may continue into remission. Unfortunately, current pharmacotherapies do not adequately address cognitive dysfunction in acute or remitted MDD. Understanding the neurobiological underpinnings of affective cognitive dysfunction in remitted MDD may help inform the development of new interventions to address this lingering problem and the associated poorer functional outcomes. The triple network model posits that altered functioning of three key networks implicated in normal cognitive function – the default mode network (DMN), central executive network (CEN) and salience network (SN) – underlies cognitive dysfunction in a variety of psychiatric illnesses, including MDD. Though notable exceptions exist, work in acutely depressed MDD patients has found evidence of DMN hyperconnectivity, CEN hypoconnectivity and abberant SN connectivity both at rest and during the completion of various cognitive tasks. The evidence for triple network connectivity alterations persisting into remission is less robust, and warrants further investigation. Furthermore, there is a paucity of studies examining remitted MDD connectivity during affective tasks. As such, the primary objectives of this thesis were to: 1) compare resting-state and task triple network connectivity profiles in remitted MDD patients (rMDDs) and healthy volunteers (HVs) at rest, during an affective (emotional Stroop [eStroop]) task, and during rest vs. the task and, 2) assess the relationship between DMN and CEN connectivity and measures of daily functioning, quality of life and/or negative, self-relational rumination in the rMDD cohort. Behaviourally, there were findings of an affective attentional bias and impaired processing speed in the rMDD vs. HVs, as revealed by a computerized cognitive test battery. However, we found no evidence of DMN hyperconnectivity or CEN hyperconnectivity in the rMDD study sample. We did find evidence of altered intrinsic CEN and CEN-SN connectivity between the rest and task conditions that seemed driven by the rMDD sample, as well as positive CEN-DMN correlations across the entire sample both at rest and during the eStroop task. Suprisingly, we also found higher intrinsic DMN connectivity during the eStroop task vs. at rest across the whole sample. Finally, we found a positive relationship between task-based CEN connectivity and hopeless rumination, and a significant negative relationship between resting state and task-based DMN connectivity and psychosocial dysfunction in the rMDD sample. These findings contribute to our understanding of large-scale intrinsic network connectivity alterations during remitted depression, and their relationship to functional outcomes.

Autistic children demonstrate a constellation of traits with varying degrees of severity in areas including language differences, restrictive and repetitive behaviors, and sensory processing differences. However, the relationship between sensory processing and these other behaviors are not well understood especially their neurobiological underpinnings. Therefore, this research examined behavioral measures of semantic language, sensory traits, and associated brain networks in 20 autistic children (ages 6-11) and 22 typically developing (TD) age matched peers. Mann-Whitney U tests revealed a strong correlation between sensory traits and general composite and semantic language in both groups of participants. Sensory seeking traits were most significantly correlated with overall and semantic language scores in our autistic participants. Resting state functional network connectivity was also examined and correlated with behavioral measures. The autistic participants demonstrated three networks of interest that were correlated with semantic language scores. These networks demonstrated both over and underconnectivity, and the brain regions involved provided functions in multisensory integration, language, somatosensory processing, and prediction (among other functions). These findings point to an association between sensory integration and language, especially semantics in both the neurotypical population and autistic individuals. Furthermore, for the autistic population it presents novel information about brain regions and connectivity patterns that may contribute to the relationships between semantic language and sensory differences in the autism.

With the fast development of 5G networks and the advancement in networking technologies, more and more new technologies such as internet of vehicles (IoV) is catching our eyes. With technologies of artificial intelligence and automatic control, IoV is transformed into an intelligent transportation system (ITS). The object of this thesis is to analyze the connectivity probability issues in vehicle ad hoc networks (VANETs), which is a subset of ITS. This will be achieved by a platoon-based two dimensional model. In order to make the results more accurate and more close to real scenario, different situations will be analyzed separately, and different types of platoon will be included. In addition, other system parameters are also discussed and stimulated. The results show that many parameters like the increases of traffic density, ratio of platoon, and lane numbers will improve connectivity probability. No-leader based platoons are easier to connect to the base stations compared to leader based platoons.

Childhood maltreatment can have detrimental consequences on individual well-being and cognitive functioning. One type of childhood maltreatment that remains stigmatized and under-researched among men is child sexual abuse (CSA). Research examining the neurophysiological consequences of CSA in males is limited even further. This dissertation presents three original research articles which provide preliminary evidence of the lasting neurophysiological impact of CSA in men. We recruited all male participants, of those who experienced CSA, some had PTSD (CSA+PTSD) others did not have PTSD (CSA-PTSD) allowing for the examination of differences in males with histories of CSA (but no PTSD) versus those who have CSA histories and PTSD. We also recruited control males with no CSA histories nor PTSD. Three functional MRI tasks and one resting state functional scan were obtained. The letter n-back, and an emotional picture n-back task were used in the first study as a measure of working memory and emotional processing. The first study highlights the lasting impact CSA can have on men, regarding brain activity during working memory, and working memory when negative emotional stimuli are involved. The second study examined how negative/traumatic memories are re-experienced. Results from the second study demonstrate that CSA impacts the neurophysiology of autobiographical memory for traumatic experiences. In the final study, resting state functional connectivity was examined within the default mode, salience and limbic networks, and differences in functional connectivity within the networks were observed. Together, these findings highlight the long-term neural impact of CSA and can validate the experience of men who have lived through CSA. They can also guide researchers and clinicians to potential avenues of support for the well-being of these men. These studies highlight the need for more research with men who have experienced CSA so we can fully understand their altered neurophysiological responses, and how this knowledge can be used to support their mental health and continued wellness throughout their lives.

BACKGROUND: Cognitive deficits are a core component of schizophrenia and among the strongest determinants of functional disability in psychotic illnesses. In particular, impairment in information processing speed has been demonstrated to be among the most significant in patients. Poor processing speed not only frequently occurs prior to psychosis onset during the prodromal or clinical high risk phase of psychotic illness, it has also been found to be a strong predictor of conversion to psychosis. However, the neurobiological basis of impaired processing speed in the clinical high risk population is not well understood. Functional connectivity during resting state fMRI provides useful insights into the organization and communication between brain regions that may elucidate the brain circuit basis underlying processing speed. OBJECTIVE: To identify the strongest link between brain functional connectivity and a measure of information processing speed in individuals at clinical high risk for conversion to psychosis by utilizing a data-driven analysis. METHODS: Cognitive and resting state fMRI data were collected from 198 clinical high risk participants and 123 neurotypical controls in the second phase of the North American Prodromal Longitudinal Study. Processing speed was measured by the Brief Assessment of Cognition in Schizophrenia Symbol Coding task. A multivariate pattern analysis was used to identify, at the individual voxel level, how functional connectivity correlates with information processing speed. RESULTS: Clinical high risk participants demonstrated significantly reduced processing speed, relative to neurotypical controls. Similarly, at risk patients who later converted to psychosis (n=17) also showed poorer performance on the BACS Symbol Coding task compared to non-converters. The strongest whole-brain link between connectivity and processing speed within the clinical high risk population was the bilateral amygdala. Specifically, connectivity between the bilateral amygdala and a functional brain network known as the salience network correlated with processing speed. CONCLUSIONS: Functional connectivity between the bilateral amygdala and the salience network was linked to individual variation in processing speed in the clinical high risk population. This affirmed a growing literature that implicates amygdala involvement in cognitive function and provides a potential biomarker for psychosis risk prior to diagnosis.