Developmental psychobiology
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The magnitude and duration of the hormonal stress response change dramatically throughout an organism's lifespan. Although much is known about the factors that modulate stress reactivity during adulthood and how neonatal development and aging influence stress responsiveness, we know relatively little about how stress reactivity changes during the juvenile to adult transition. ⋯ A growing body of literature indicates that pubertal organisms react differentially, both physiologically and behaviorally, to a stressor compared to adults. The purpose of this review, therefore, is to discuss the recent findings regarding the pubertal maturation of stress reactivity, while also highlighting future research directions that will aid in our understanding of stress and adolescent mental health and development.
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Adult cognitive neuroscience employs a wide variety of techniques to investigate a broad range of behavioral and cognitive functions. One prominent area of study is that of executive control, complemented by a smaller but growing literature exploring the developmental cognitive neuroscience of executive control. To date this approach has often compared children with specific developmental disorders, such as ADHD and ASD, with typically developing controls. ⋯ Some very elegant investigations illustrate how seemingly common processes in adulthood present as separable in childhood, on the basis of their distinctive developmental trajectories. These demonstrations have implications not only for an understanding of changing behavior from infancy through childhood and adolescence into adulthood, but, moreover, for our grasp of the adult end-state per se. We contend that, if used appropriately, developmental cognitive neuroscience could enable us to construct a more mechanistic account of executive control.
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Tobacco smoke exposure affects the activity of both the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system (SNS). Statistics reveal 41 million children in the U. S. are regularly exposed to tobacco smoke, but we know little about the effects of environmental tobacco smoke exposure on HPA and SNS activity in early childhood. ⋯ Mothers who smoked had higher salivary cortisol levels and lower sAA activity compared to nonsmoking mothers. There were no associations between maternal smoking behavior, infant's salivary cotinine levels, or tobacco exposure group, and cortisol or sAA measured in infant's saliva. The findings are discussed in relation to the influence of smoking tobacco on the validity of salivary biomarkers of stress.
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Comparative Study
Maternal anesthesia via isoflurane or ether differentially affects pre-and postnatal behavior in rat offspring.
Our understanding of prenatal behavior has been significantly advanced by techniques for direct observation and manipulation of unanesthetized, behaving rodent fetuses with intact umbilical connections to the mother. These techniques involve brief administration of an inhalant anesthesic, enabling spinal transection of the rat or mouse dam, after which procedures can continue with unanesthetized dams and fetuses. Because anesthetics administered to the mother can cross the placental barrier, it is possible that fetuses are anesthetized to varying degrees. ⋯ Fewer spontaneous fetal movements and first postpartum nipple attachments were observed following maternal exposure to ether as compared to isoflurane. Neonatal breathing frequencies and oxygenation did not account for group differences in nipple attachment. Our results provide evidence that the particular inhalant anesthetic employed in prenatal manipulation studies determines frequencies of perinatal behavior.
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Newborn rats are capable of obtaining milk by attaching to a surrogate nipple. During this procedure pups show a gradual increase in head and forelimb movements oriented towards the artificial device that are similar to those observed during nipple attachment. In the present study the probability of execution of these behaviors was analyzed as a function of their contingency with intraoral milk infusion using brief training procedures (15 min). ⋯ In addition, it was observed that the rate of responding of Paired pups during the early phase of the extinction session significantly predicted subsequent levels of acceptance of the reinforcer. These results indicate that the frequency of suckling-related behaviors can be rapidly modified by means of associative operant processes. The operant procedure here described represents an alternative tool for the ontogenetic analysis of self-administration or behavior processes of seeking.