Socioeconomic status (SES) is a key predictor of a multitude of health and functional outcomes, and growing up in low SES contexts is associated with poor neurocognitive outcomes and mental health problems across the lifespan. Recent studies of the links between SES and brain development suggest that associations between low SES and poor neurocognitive and health outcomes are likely accounted for by impacts on neurodevelopment. Low SES is associated with structural brain development, including reduced cortical thickness in frontal regions relevant to higher-level cognitive functions. However, understanding of how the impacts of SES on neurodevelopment contribute to developing psychopathology is limited. The study of how neurodevelopmental processes may contribute to depression is of particular interest given numerous neural correlates of depression, including reduced cortical thickness in frontal regions. Whereas both SES and depression independently have demonstrated associations with grey matter maturation, no studies to date have examined how the associations between SES, depression, and cortical structure interrelate. The current study addresses this gap in the literature by examining associations between SES at both household and neighborhood levels, depression symptoms, and cortical structure in adolescence. Furthermore, exploratory analyses investigated specific pathways of SES effects on depression symptoms and cortical structure through exposure to psychosocial stress. Data were drawn from an ongoing prospective longitudinal study of reward function development. Participants included 232 youth ages 9-13 (57.03% female; 46.59% White, 39.36% African American, 11.24% Multiracial, 2.81% Other; 11.24% Hispanic) and their primary caregivers who completed assessments of depression symptoms and stress at baseline and a 9-month follow-up, as well as an MRI assessment between baseline and follow up. Regression analyses examined associations between 1) SES to cortical structure, 2) SES to depression symptoms, 3) baseline depression symptoms and cortical structure, and 4) cortical structure to depression symptoms at follow-up. Structural equation models examined indirect effects of 1) SES on depression symptoms through cortical structure, 2) SES on cortical structure through depression symptoms, and 3) SES on cortical structure and depression symptoms through experiences of psychosocial stress. Neighborhood SES was positively associated with mean cortical thickness, and household SES was inversely associated with depression symptoms at follow up, controlling for baseline symptoms. No indirect effects were identified. Findings suggest that different aspects of SES may confer unique risks for neural and psychosocial development in early adolescence, such that SES of the neighborhood appears to have global effects on neurodevelopment that are not mediated by mood or proximal stress, whereas SES of the household appears to be associated with increasing mood symptoms and heightened stress experiences in early adolescence. / Psychology

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23776号 / 医博第4822号 / 新制||医||1057(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 花川 隆, 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 / DFAM

Individuals exposed to alcohol in utero have reduced cortical grey matter volumes. However, the underlying determinants of these reductions have not been investigated exclusively in alcohol-related neurodevelopmental disorder (ARND). Using magnetic resonance imaging scans from 121 participants (57 ARND and 64 controls) aged 8 to 16 years, cortical morphology was analyzed. Results revealed the ARND group had reduced cortical grey matter volumes, but did not differ from controls in cortical thickness. Rather, the cortical abnormalities reflected reductions in global surface area, local surface area reductions in the right occipital-temporal area and right superior temporal gyrus, as well as reduced gyrification. A significant interaction between sex and group was observed, with females showing greater reductions than males in cortical volume and surface area. Results suggest that ARND is characterized by global reductions in cortical surface area and gyrification and females are more vulnerable than males to the teratogenic effects of alcohol.

Individuals exposed to alcohol in utero have reduced cortical grey matter volumes. However, the underlying determinants of these reductions have not been investigated exclusively in alcohol-related neurodevelopmental disorder (ARND). Using magnetic resonance imaging scans from 121 participants (57 ARND and 64 controls) aged 8 to 16 years, cortical morphology was analyzed. Results revealed the ARND group had reduced cortical grey matter volumes, but did not differ from controls in cortical thickness. Rather, the cortical abnormalities reflected reductions in global surface area, local surface area reductions in the right occipital-temporal area and right superior temporal gyrus, as well as reduced gyrification. A significant interaction between sex and group was observed, with females showing greater reductions than males in cortical volume and surface area. Results suggest that ARND is characterized by global reductions in cortical surface area and gyrification and females are more vulnerable than males to the teratogenic effects of alcohol.

Cerebral cortex, classified as gray matter, is the superficial layer of the cerebrum. In recent years, many studies have shown the abnormality of cortical thickness is possibly correlated to the disease or disorder in central nervous system, such as Alzheimer¡¦s disease and lissencephaly. Therefore, this purpose of this work is to implement the measurement of the cortical thickness. In general, two approaches, surface-based and voxel-based methods, have been proposed to measure the cortical thickness. In this thesis, a procedure of the voxel-based method using Laplace¡¦s equation was developed on the basis of a 2008 publication reported by Chloe Hutton et al to obtain voxel-based cortical thickness (VBCT) map. The result of our home-made program was further compared with those calculated by Hutton¡¦s program, whic h was generously provided by the author. The difference between two implementations was consisted of four main parts. First of all, different strategies of the tissue classification were used to define boundary condition of Laplace¡¦s equation. When grey matter, white matter, and cerebrospinal fluid were classified by maximizing the tissue probability, Hutton¡¦s program tends to search more voxels of cerebrospinal fluid in sulci by skeletonizing the non-parenchyma area. Second, the algorithm of layer growing also differs. The single layer obtained by the 26-neighborhood algorithm in our program would be obviously thicker than that provided by Hutton¡¦s program using 6-neighborhood. Third, compared with a fixed step size (usually 0.5 mm) porposed in the main reference to track cortical streamline, we designed a variable step size, reducing the underestimation of cortical thickness. The last but not the least, the connecting points of the cortical streamline usually are not grid points, thus requiring interpolation to estimate the stepping gradient. We adapted the linear interpolation for better accuracy when Hutton et al searched for the closest grid point for replacement to achieve faster computation.

No description available.

Complex regional pain syndrome (CRPS) is a chronic neuropathic pain disorder characterized by both central and peripheral symptoms that can be debilitating in children. CRPS treatment typically consists of intensive physical, occupational, and psychological therapy with evidence supporting the efficacy of this approach. Among these outcomes, some patients report significant improvements in pain while others report no change. Identifying baseline predictors of treatment resistance would refine our treatment approach and provide additional targets for intervention. The current study examined baseline brain structure via cortical thickness and gray matter volume (GMV) in 29 pediatric CRPS patients enrolled in an intensive pain rehabilitation program. All participants underwent MRI using a high-resolution T1-weighted sequence. Patients were categorized as pain treatment “responders” (n=19) or “non-responders” (n=10) based on change in reported pain levels from admission to follow up. Compared to treatment responders, non-responders demonstrated significantly less GMV in the bilateral nucleus accumbens p<0.05 and right: putamen p<0.01, pallidum p<0.05, and amygdala p<0.05. Furthermore, treatment non-responders exhibited significant cortical thickening in the left anterior insular cortex and medial frontal gyrus, and cortical thinning in the bilateral precentral gyrus and superior frontal gyrus; right: middle frontal gyrus, fusiform gyrus, inferior temporal gyrus, middle temporal gyrus, and anterior prefrontal cortex; and left: parahippocampal gyrus. Though we did see significant thinning of the primary motor cortex in treatment non-responders compared to responders, the majority of our findings were localized to regions associated with reward, motivation, learning, and emotion. We, therefore, postulate that treatment non-responders, when compared to responders, likely have an intrinsically reduced reward responsiveness, diminished motivation, and impaired learning, overall contributing to their negative treatment outcomes and chronification of pain. In conclusion, these baseline differences overall suggest these regional morphometric alterations may potentially serve as predictors of treatment response in pediatric CRPS. Furthermore, these areas may also indicate possible targets for future treatment.

Despite extensive research in the field of aging neuroscience, it still remains unclear whether age related cortical changes can be detected in different functional networks of younger adults and whether these networks respond identically to healthy aging. We collected high-resolution brain anatomical data from 56 young healthy adults (mean age = 30.8 +/- 8.1 years, 29 males). We performed whole brain parcellation into seven functional networks, including visual, somatomotor, dorsal attention, ventral attention, limbic, frontoparietal and default mode networks. We estimated intracranial volume (ICV) and averaged cortical thickness (CT), cortical surface area (CSA) and cortical volume (CV) over each hemisphere as well as for each network. Averaged cortical measures over each hemisphere, especially CT and CV, were significantly lower in older individuals compared to younger ones (one-way ANOVA, p < 0.05, corrected for multiple comparisons). There were negative correlations between age and averaged CT and CV over each hemisphere (p < 0.05, corrected for multiple comparisons) as well as between age and ICV (p = 0.05). Network level analysis showed that age was negatively correlated with CT for all functional networks (p < 0.05, corrected for multiple comparisons), apart from the limbic network. While age was unrelated to CSA, it was negatively correlated with CV across several functional networks (p < 0.05, corrected for multiple comparisons). We also showed positive associations between CV and CT and between CV and CSA for all networks (p < 0.05, corrected for multiple comparisons). We interpret the lack of association between age and CT of the limbic network as evidence that the limbic system may be particularly resistant to age-related declines during this period of life, whereas the significant age-related declines in averaged CT over each hemisphere as well as in all other six networks suggests that CT may serve as a reliable biomarker to capture the effect of normal aging. Due to the simultaneous dependence of CV on CT and CSA, CV was unable to identify such effects of normal aging consistently for the other six networks, but there were negative associations observed between age and averaged CV over each hemisphere as well as between age and ICV. Our findings suggest that the identification of early cortical changes within various functional networks during normal aging might be useful for predicting the effect of aging on the efficiency of functional performance even during early adulthood.

Changes occur to the mandible with dental loss and senescence. However, the influence that these changes have on sex and ancestry estimations remains unclear. The purpose of this study was to investigate the influence of dental loss and senescence on changes in mandibular morphology. The outcome has implications for both forensic anthropology and restorative dentistry. The study sample consisted of 717 mandibles consisting of both male and female South Africans of African (SAA) and European ancestry (SAE). To minimise the effects of variation in dentition amongst sex-ancestry groups, the sample included individuals with a spectrum of tooth loss patterns, namely efficient and inefficient occlusions as well as no occlusions. Dentition was considered efficient when the remaining teeth in occlusion were evenly distributed between the sides. Linear measurements as well as geometric morphometric shape analyses were performed. Shape analyses of the complete mandible were performed on models from digitised landmarks by using a MicroScribe G2. Detailed shape analyses of the ramus and chin area as well as measurements of the cortical thickness at specific sites were executed on images generated by cone beam computed tomography (CBCT). A comprehensive assessment of changes in shape, size and cortical thickness of the mandible with age and dental loss were made. Shape and size differences of the mandible were evaluated for discriminant abilities between sex and ancestry groups. Although most dimensions decreased with tooth loss, the greatest impact was noted in the loss of alveolar bone. The mandibular angle increased minimally in size when a few teeth were lost, but recovered to some extent with further tooth loss. The cortical thicknesses at the mental foramen lingually as well as in the midline in females, were relatively spared with tooth loss. Male individuals of SAA were often the most resilient to tooth loss. In general external linear dimensions were maintained with age despite tooth loss. Conversely, measurements of cortical bone thickness decreased slightly, but could have been influenced by dental loss. The shape of the chin and gonial area was more affected by aging in SAE. The sex and ancestry discriminant ability of the linear dimensions when considered collectively approximated 90%, in general improving further when tooth loss was taken into account. All linear measurements were smaller in females and in general tooth loss accentuated sex differences. SAA exhibited greater dimensions, apart from maximum ramus height, bigonial breadth and cortical thickness at the gonion. The mental tubercles were more prominent than the pogonion in SAE (square chin) and vice versa in individuals of SAA (pointed chin). The gonial area in individuals of African ancestry was broad and more convex and the gonial eversion more prominent with a more upright ramus. Discriminant qualities of the gonial shape for sex in individuals of African ancestry reached 90% within dentition groups. Ramus flexure and chin shape were not found to be useful in sex estimation. In conclusion, this research elucidated the effects of tooth loss and senescence on the morphology of the mandible for the forensic anthropological setting. / Thesis (PhD)--University of Pretoria, 2015. / tm2015 / Anatomy / PhD / Unrestricted

Second language acquisition has proven to impact the brain in many ways. Studies have shown a distinct difference between the monolingual and the bilingual brain. These structural differences have included an observable increase in cortical thickness in bilingual individuals when compared to monolinguals. This is a significant observation since many neurological diseases and impairments have been connected to a decrease in cortical thickness. However, previous studies have focused solely on bilinguals who had acquired their second language early on in life. These studies have failed to focus on the potential impact that could be observed on the cortical thickness of individuals who acquire a language after the age of 40. This study focused on monolingual students 40 years and older, who participated in an entry level university level Spanish course and examined how their brains structurally changed after a three-month course. These results were compared to a group of adults not participating in a language course who acted as a control group. This was achieved through MRI imaging of all the participants' brains and measuring any changes in their cortical thickness. Upon completing the second round of MRI imaging, the comparison of the pre and post MRI scans yielded an observable difference between the experimental group who had participated in the Spanish course and the control group. However, these differences did not prove to be significant and should be viewed as exploratory. Future research opportunities should entail studies with a longer duration combined with a curriculum better suited to this age group.