This chapter presents results from studies showing strong evidence for pronounced heritability of waking and rapid eye movement (REM) and non-REM sleep electroencephalographic (EEG) activity. Genes regulate the expression and function of the neurobiological systems that modulate sleep and wakefulness. The most commonly employed method for identifying genes involved in some aspect of physiological or behavioral regulation is the candidate gene approach. In this approach, individuals with genetic polymorphisms thought to be involved in sleep-wake regulation or neurobehavioral vulnerability to sleep loss are subjected to sleep loss in the laboratory, and neurobehavioral measures are assessed throughout. The chapter determines whether functional polymorphisms of the catechol-O-methyltransferase (COMT) gene moderate responsivity to other psychostimulants that also act via dopaminergic signaling. Genetic variations also appear to control individual responsivity to stimulants. Evidence indicates that the COMT Val158Met polymorphism controls individual responsivity to the stimulant modafinil during sleep loss.

This chapter concentrates on three areas of model development. First, it presents data showing how differential impacts to specific neural regulatory systems are associated with variations by the type of early life stress (ELS) experienced. Second, the chapter describes how studies of the severity of ELS are providing a new basis for understanding trajectories towards risk versus resilience among foster children and other populations who experience ELS. Third, it also describes a growing body of evidence documenting the plasticity of these neural systems in response to psychosocial, family-based therapeutic interventions. The chapter focuses on the neurobiological systems involved in the reaction and the regulation of physiological responses to stressors. Much work remains to be done across the spectrum of risk and resilience following ELS in order to improve the identification of individuals in need of services and to specify the techniques most likely to improve outcomes.

This chapter summarizes available findings on the neuroendocrine effects of exposure to trauma during early development, with a focus on a role for such alterations in the increased risk of mood and anxiety disorders in adulthood. The principal components of the stress system are the hypothalamic-pituitary-adrenal (HPA) axis, the locus ceruleus-norepinephrine (LC-NE) system and the extrahypothalamic corticotropin-releasing factor (CRF) systems. In addition, increased rates of major depression, post-traumatic stress disorder (PTSD) and attention-deficit hyperactivity disorder (ADHD) have been reported in maltreated children. The relationship between early adverse experiences and the development of adult psychopathology is likely mediated by alterations in neurobiological systems involved in the regulation of stress. Findings from the research would have important implications for the development of optimized treatment strategies that directly target different neurobiological pathways involved in depression and anxiety disorders in victims of early child maltreatment.

Early life stress (ELS) and abuse are the most commonly assessed environmental exposures in psychiatric genes and environment (GxE) interaction studies, partly because of the strength of evidence that ELS plays a role in risk for multiple psychiatric disorders. The research on GxE interactions is organized by the presumed underlying neurobiological systems and by the broader classification of psychiatric outcomes (mood/anxiety disorders and externalizing disorders). This chapter discusses the importance of clearly defining and measuring both the proposed environmental risk/resilience factors as well as the predicted diagnostic and behavioral outcomes. This allows investigators to conduct GxE studies that better inform the understanding of the role of ELS in predicting psychiatric risk/resilience. The chapter focuses on childhood physical, sexual and emotional abuse, which is currently among the most well-researched environmental risk variables in human psychopathology research.

This chapter discusses the importance of dynamics to understanding cognition. The author turns to the issue of how dynamics have been integrated into various theories of cognition. The author describes strengths and weaknesses of three main contenders in cognitive science, in relation to their incorporation of time into their methods of model construction. The neural engineering framework (NEF) is a general theory of neurobiological systems. Neural dynamics are characterized by considering neural representations as control theoretic state variables. Thus, the dynamics of neurobiological systems can be analyzed using control theory. The model employs biologically realistic neurons to learn the relevant structural transformations appropriate for a given context, and it generalizes such transformations to novel contents with the same syntactic structure. The intent of the NEF is to provide a suggestion as to how we might take seriously many of the important insights generated from cognitive science.