This working paper is based on an analysis of data gathered and interviews conducted in 1986. The study examines the involvement of women in food production in Zambia, the constraints they face in increasing their productivity, and the measures which need to be taken in order to increase women's food production capacity. It shows the many difficulties female farmers have to face raising their agricultural output, so as lack of access to good quality land, extension services and credit. The paper points out that in order to increase employment and output in the agricultural sector, it is of utmost importance that women are included in agricultural programmes and provided with the necessary means to enhance their agricultural production
There is accumulating evidence for positive effects of green spaces on mental and brain health. Here we investigated whether differentiating the types of green spaces may be relevant. On longitudinal data of children ( N = 95) from the Netherlands, we quantified the link between green space exposure at home from birth onwards and MRI brain structure at 12.5 years. We differentiated between green space resulting from trees versus open green spaces and also associated visibility of sky (sky view factor) with brain structure (200 m buffer around home address). We observed a positive association between grey matter volume in different prefrontal clusters and green open space coverage as well as sky view, but a negative association within prefrontal clusters for tree cover density. Most importantly, in the medial prefrontal cortex, the only region in which all three analyses overlapped, the visibility of sky was the most important predictor. Our findings advance knowledge on health-promoting, evidence-based urban planning.
The aim of this longitudinal study was to investigate emerging adults' mental health before and during the COVID-19 pandemic, and whether social support from mothers, fathers, and best friends moderated the change in mental health. Participants were 98 emerging adults (46% men) who were assessed prior to COVID-19 ( Mage = 20.60 years) and during the first lockdown ( Mage = 22.67 years). Results indicated that the pandemic did not uniformly lead to elevated levels of mental health problems, but instead depended on level of mental health problems prior to COVID-19 and the source of support. For emerging adults who already experienced more problems prior to COVID-19, more maternal support was related to decreases in general psychological distress and depressive symptoms, whereas more paternal support was related to increases in general psychological distress and depressive symptoms. Support from best friends were not associated with (changes in) mental health.
AbstractA paradox of testosterone effects is seen in adolescents versus adults in social emotional approach‐avoidance behavior. During adolescence, high testosterone levels are associated with increased anterior prefrontal (aPFC) involvement in emotion control, whereas during adulthood this neuro‐endocrine relation is reversed. Rodent work shows that, during puberty, testosterone transitions from a neuro‐developmental to a social‐sexual activating hormone. In this study, we explored whether this functional transition is also present in human adolescents and young adults. Using a prospective longitudinal design, we investigated the role of testosterone on neural control of social emotional behavior during the transitions from middle to late adolescence and into young adulthood. Seventy‐one individuals (tested at ages 14, 17, and 20 years) performed an fMRI‐adapted approach‐avoidance (AA) task involving automatic and controlled actions in response to social emotional stimuli. In line with predictions from animal models, the effect of testosterone on aPFC engagement decreased between middle and late adolescence, and shifted into an activational role by young adulthood—impeding neural control of emotions. This change in testosterone function was accompanied by increased testosterone‐modulated amygdala reactivity. These findings qualify the testosterone‐dependent maturation of the prefrontal‐amygdala circuit supporting emotion control during the transition from middle adolescence into young adulthood.
Acutely challenging or threatening situations frequently require approach-avoidance decisions. Acute threat triggers fast autonomic changes that prepare the body to freeze, fight or flee. However, such autonomic changes may also influence subsequent instrumental approach-avoidance decisions. Since defensive bodily states are often not considered in value-based decision-making models, it remains unclear how they influence the decision-making process. Here, we aim to bridge this gap by discussing the existing literature on the potential role of threat-induced bodily states on decision making and provide a new neurocomputational framework explaining how these effects can facilitate or bias approach-avoid decisions under threat. Theoretical accounts have stated that threat-induced parasympathetic activity is involved in information gathering and decision making. Parasympathetic dominance over sympathetic activity is particularly seen during threat-anticipatory freezing, an evolutionarily conserved response to threat demonstrated across species and characterized by immobility and bradycardia. Although this state of freezing has been linked to altered information processing and action preparation, a full theoretical treatment of the interactions with value-based decision making has not yet been achieved. Our neural framework, which we term the Threat State/Value Integration (TSI) Model, will illustrate how threat-induced bodily states may impact valuation of competing incentives at three stages of the decision-making process, namely at threat evaluation, integration of rewards and threats, and action initiation. Additionally, because altered parasympathetic activity and decision biases have been shown in anxious populations, we will end with discussing how biases in this system can lead to characteristic patterns of avoidance seen in anxiety-related disorders, motivating future pre-clinical and clinical research.
AbstractGiven the long‐lasting detrimental effects of internalizing symptoms, there is great need for detecting early risk markers. One promising marker is freezing behavior. Whereas initial freezing reactions are essential for coping with threat, prolonged freezing has been associated with internalizing psychopathology. However, it remains unknown whether early life alterations in freezing reactions predict changes in internalizing symptoms during adolescent development. In a longitudinal study (N = 116), we tested prospectively whether observed freezing in infancy predicted the development of internalizing symptoms from childhood through late adolescence (until age 17). Both longer and absent infant freezing behavior during a standard challenge (robot‐confrontation task) were associated with internalizing symptoms in adolescence. Specifically, absent infant freezing predicted a relative increase in internalizing symptoms consistently across development from relatively low symptom levels in childhood to relatively high levels in late adolescence. Longer infant freezing also predicted a relative increase in internalizing symptoms, but only up until early adolescence. This latter effect was moderated by peer stress and was followed by a later decrease in internalizing symptoms. The findings suggest that early deviations in defensive freezing responses signal risk for internalizing symptoms and may constitute important markers in future stress vulnerability and resilience studies.
