The regulation of sleep and arousal: Development and psychopathology

Throughout early development, a child spends more time asleep than in any waking activity. Yet, the specific role of sleep in brain maturation is a complete mystery. In this article, the developmental psychobiology of sleep regulation is conceptualized within the context of close links to the control of arousal, affect, and attention. The interactions among these systems are considered from an ontogenetic and evolutionary biological perspective. A model is proposed for the development of sleep and arousal regulation with the following major tenets: 1. Sleep and vigilance represent opponent processes in a larger system of arousal regulation. 2. The regulation of sleep, arousal, affect, and attention overlap in physiological, neuroanatomical, clinical, and developmental domains. 3. Complex interactions among these regulatory systems are modulated and integrated in regions of the prefrontal cortex (PFC). 4. Changes at the level of PFC underlie maturational shifts in the relative balance across these regulatory systems (such as decreases in the depth/length of sleep and increased capacity for vigilance and attention), which occur with normal development. 5. The effects of sleep deprivation (including alterations in attention, emotions, and goal-directed behaviors) also involve changes at the level of PFC integration across regulatory systems. This model is then discussed in the context of developmental pathology in the control of affect and attention, with an emphasis on sleep changes in depression.