White matter matters: a multimodal approach to investigate white matter microstructure and metabolism

White matter connects different brain areas and applies electrical insulation to the neuron’s axons with myelin sheaths in order to enable quick signal transmission. Due to its modulatory properties in signal conduction, white matter plays an essential role in learning, cognition and psychiatric disorders (Fields, 2008a). In respect thereof, the non-invasive investigation of white matter anatomy and function in vivo provides the unique opportunity to explore the most complex organ of our body. Thus, the present thesis aimed to apply a multimodal neuroimaging approach to investigate different white matter properties in psychiatric and healthy populations. On the one hand, white matter microstructural properties were investigated in a psychiatric population; on the other hand, white matter metabolic properties were assessed in healthy adults providing basic information about the brain’s wiring entity. As a result, three research papers are presented here. The first paper assessed the microstructural properties of white matter in relation to a frequent epidemiologic finding in schizophrenia. As a result, reduced white matter integrity was observed in patients born in summer and autumn compared to patients born in winter and spring. Despite the large genetic basis of schizophrenia, accumulating evidence indicates that environmental exposures may be implicated in the development of schizophrenia (A. S. Brown, 2011). Notably, epidemiologic studies have shown a 5–8% excess of births during winter and spring for patients with schizophrenia on the Northern Hemisphere at higher latitudes (Torrey, Miller, Rawlings, & Yolken, 1997). Although the underlying mechanisms are unclear, the seasonal birth effect may indicate fluctuating environmental risk factors for schizophrenia. Thus, exposure to harmful factors during foetal development may result in the activation of pathologic neural circuits during adolescence or young adulthood, increasing the risk of schizophrenia (Fatemi & Folsom, 2009). While white matter development starts during the foetal period and continues until adulthood, its major development is accomplished by the age of two years (Brody, Kinney, Kloman, & Gilles, 1987; Huang et al., 2009). This indicates a vulnerability period of white matter that may coincide with the fluctuating environmental risk factors for schizophrenia. Since microstructural alterations of white matter in schizophrenia are frequently observed, the current study provided evidence for the neurodevelopmental hypothesis of schizophrenia. In the second research paper, the perfusion of white matter showed a positive correlation between white matter microstructure and its perfusion with blood across healthy adults. This finding was in line with clinical studies indicating a tight coupling between cerebral perfusion and WM health across subjects (Amann et al., 2012; Chen, Rosas, & Salat, 2013; Kitagawa et al., 2009). Although relatively little is known about the metabolic properties of white matter, different microstructural properties, such as axon diameter and myelination, might be coupled with the metabolic demand of white matter. Furthermore, the ability to detect perfusion signal in white matter was in accordance with a recent study showing that technical improvements, such as pseudo-continuous arterial spin labeling, enabled the reliable detection of white matter perfusion signal (van Osch et al., 2009). The third paper involved a collaboration within the same department to assess the interrelation between functional connectivity networks and their underlying structural connectivity.

The development of self-esteem

In this article, we review new insights gained from recent longitudinal studies examining the development of self-esteem and its influence on important life outcomes. The evidence supports the following three conclusions. First, self-esteem increases from adolescence to middle adulthood, peaks at about age 50 to 60 years, and then decreases at an accelerating pace into old age; moreover, there are no cohort differences in the self-esteem trajectory from adolescence to old age. Second, self-esteem is a relatively stable, but by no means immutable, trait; individuals with relatively high (or low) self-esteem at one stage of life are likely to have relatively high (or low) self-esteem decades later. Third, high self-esteem prospectively predicts success and well-being in life domains such as relationships, work, and health. Given the increasing evidence that self-esteem has important real-world consequences, the topic of self-esteem development is of considerable societal significance.

Trauma, developmental stages, and motivational abilities in indentured Swiss child laborers in old age

OBJECTIVES The study examined the relationship between potential traumatic events in childhood and motivational abilities in old adulthood according to developmental stage. METHODS The motivational abilities of self-efficacy, conscientiousness and impulsivity (self control) were investigated in a sample of 114 formerly indentured Swiss child laborers. Adversities were assessed by the Childhood Trauma Questionnaire (CTQ). The sample was split into four age groups according to the beginning of the potential trauma: infancy (0-2), preschool (3-5), early childhood (6-9), and early adolescence (≥ 10). RESULTS The strongest relationship was found between self-efficacy and CTQ in the group "early adolescence," followed by the relationship between conscientiousness and CTQ in the same group. Impulsivity and CTQ were most strongly associated in the "preschool" group. CONCLUSION Childhood adversities seem to have a negative impact on self-efficacy and conscientiousness after the age of ten. In contrast, self-control seems to be affected by the deleterious effect of trauma or adversity already at an earlier age.

Persistent and compartmentalised disruption of dendritic cell subpopulations in the lung following influenza A virus infection.

Immunological homeostasis in the respiratory tract is thought to require balanced interactions between networks of dendritic cell (DC) subsets in lung microenvironments in order to regulate tolerance or immunity to inhaled antigens and pathogens. Influenza A virus (IAV) poses a serious threat of long-term disruption to this balance through its potent pro-inflammatory activities. In this study, we have used a BALB/c mouse model of A/PR8/34 H1N1 Influenza Type A Virus infection to examine the effects of IAV on respiratory tissue DC subsets during the recovery phase following clearance of the virus. In adult mice, we found differences in the kinetics and activation states of DC residing in the airway mucosa (AMDC) compared to those in the parenchymal lung (PLDC) compartments. A significant depletion in the percentage of AMDC was observed at day 4 post-infection that was associated with a change in steady-state CD11b+ and CD11b- AMDC subset frequencies and significantly elevated CD40 and CD80 expression and that returned to baseline by day 14 post-infection. In contrast, percentages and total numbers of PLDC were significantly elevated at day 14 and remained so until day 21 post-infection. Accompanying this was a change in CD11b+and CD11b- PLDC subset frequencies and significant increase in CD40 and CD80 expression at these time points. Furthermore, mice infected with IAV at 4 weeks of age showed a significant increase in total numbers of PLDC, and increased CD40 expression on both AMDC and PLDC, when analysed as adults 35 days later. These data suggest that the rate of recovery of DC populations following IAV infection differs in the mucosal and parenchymal compartments of the lung and that DC populations can remain disrupted and activated for a prolonged period following viral clearance, into adulthood if infection occurred early in life.

The effect of age and time perspective on implicit motives

People differ in how open-ended or limited they perceive their future. We argue that individual differences in future time perspective affect the activation of implicit motives. Perceiving the time remaining for the satisfaction of one’s motives as limited should be associated with a higher activation of these motives than perceiving one’s future as more open-ended. Given that future time perspective decreases across adulthood, older adults should score higher on implicit motives than younger adults. This hypothesis was supported in a study with young (n = 53, age M = 25.60 years) and older adults (n = 55, age M = 68.05 years). Additionally, an experimental manipulation of future time perspective showed that age-related differences in implicit motives are influenced by future time perspective. These findings demonstrate that future time perspective is an important factor to explain the strength of motives.

A Longitudinal Study of Mental Health in Emerging Adults

Emerging adulthood is a time of instability. This longitudinal study investigated the relationship between mental health and need satisfaction among emerging adults over a period of five years and focused on gender-specific differences. Two possible causal models were examined: (1) the mental health model, which predicts that incongruence is due to the presence of impaired mental health at an earlier point in time; (2) the consistency model, which predicts that impaired mental health is due to a higher level of incongruence reported at an earlier point in time. Emerging adults (N = 1,017) aged 18–24 completed computer-assisted telephone interviews in 2003 (T1), 2005 (T2), and 2008 (T3). The results indicate that better mental health at T1 predicts a lower level of incongruence two years later (T2), when prior level of incongruence is controlled for. The same cross-lagged effect is shown for T3. However, the cross-lagged paths from incongruence to mental health are marginally associated when prior mental health is controlled for. No gender differences were found in the cross-lagged model. The results support the mental health model and show that incongruence does not have a long-lasting negative effect on mental health. The results highlight the importance of identifying emerging adults with poor mental health early to provide support regarding need satisfaction.

Wanting to Get More or Protecting One's Assets: Age-Differential Effects of Gain Versus Loss Perceptions on the Willingness to Engage in Collective Action

OBJECTIVES: The present research examined motivational differences across adulthood that might contribute to age-related differences in the willingness to engage in collective action. Two experiments addressed the role of gain and loss orientation for age-related differences in the willingness to engage in collective action across adulthood. METHOD: In Experiment 1, N = 169 adults (20-85 years) were confronted with a hypothetical scenario that involved either an impending increase or decrease of health insurance costs for their respective age group. In Experiment 2, N = 231 adults (18-83 years) were asked to list an advantage or disadvantage they perceived in being a member of their age group. Subsequently, participants indicated their willingness to engage in collective action on behalf of their age group. RESULTS: Both experiments suggest that, with increasing age, people are more willing to engage in collective action when they are confronted with the prospect of loss or a disadvantage. DISCUSSION: The findings highlight the role of motivational processes for involvement in collective action across adulthood. With increasing age, (anticipated) loss or perceived disadvantages become more important for the willingness to participate in collective action.

IgA-Nephropathie und Purpura Schönlein-Henoch - ein breites Spektrum

IgA nephropathy is the most common glomerulonephritis in Europe. The disease has been discovered in 1968 in Paris by Jean Berger at the Necker-Children's Hospital. Diagnosis is made by kidney biopsy and requires the presence of mesangial deposits of IgA. This form of glomerulonephritis can be seen in children and adults. In childhood, it most frequently presents within the context of Schoenlein-Henoch purpura. In adulthood, the most common form is limited to the kidney. Schoenlein-Henoch purpura can be seen in adults and manifests as a very aggressive vasculitis, usually in the context of a specific drug intake. The underlying pathophysiological concept today is an insufficient glycosylation of the IgA1 hinge region triggering the formation of autoantibodies against this site. Therapeutic options for the disease are limited. Important is optimal blood pressure control. Selected patients will profit from steroid therapy.

Horn Growth and Reproduction in a Long-Lived Male Mammal: No Compensation for Poor Early-Life Horn Growth

Secondary sexual traits in males of polygynous species are important determinants of reproductive success. It is, however, unknown if and how the development of continuously growing traits at different life-stages is related to reproduction in long-lived male mammals. In this study, we evaluated the relationship of early and late horn growth on social status and reproduction in long-lived male Alpine ibex (Capra ibex). For this, we analysed individual horn growth and assessed its effect on dominance and reproduction. No evidence was detected for compensatory horn growth, as late-life horn growth positively depended on early-life horn growth in males. Still, individuals with longer horn segments grown during early adulthood experienced a stronger age-dependent length decline in annual horn growth during the late development. Accordingly, a divergence between individual growth potential and realized horn growth late in life has to be assumed. Residual age-specific horn length and length of early grown horn segments both positively affected dominance and reproductive success, whereas, contrary to our expectation, no significant effect of the length of horn segments grown during the late development was detected. Suspected higher somatic costs incurred by high-quality males during their late development might at least partly be responsible for this finding. Overall, our study suggests that the total length of horns and their early development in long-lived male Alpine ibex is a reliable indicator of reproductive success and that individuals may be unable to compensate for poor early-life growth performance at a later point in life.