This research project will examine whether experimental sleep extension in children alters the neural and behavioral mechanisms by which short sleep is a risk factor for emotional/behavioral problems. Children ages 5.0-5.9 years with chronic insufficient sleep (≤9 h/night for ≥6 months) will be randomized to either a sleep Extension or to an active Control group. Extension group parents will participate in a 1-month individualized behavioral sleep intervention to promote targeted sleep duration improvements before beginning a 2-week sleep Extension schedule (8 week protocol). Brain and behavioral assessments will occur at Baseline and post sleep Extension.

Research on processes influencing the development of affective brain circuits is critical to elucidating the neurobiological substrates of psychiatric disorders. Mechanistic evidence from adults showing a sleep-dependent functional "disconnect" between brain regions central to adaptive emotion processing (i.e., regulation and expression) suggests that sleep loss is a fundamental target. Similar data in young children, however, do not exist. Early childhood is a sensitive period in the maturation of sleep and emotion processing and also a time when disturbance in both domains is commonly first detected. Further, epidemiological findings reveal that insufficient sleep in childhood is prevalent, associated with concurrent emotional problems, and predicts later mood and attentional disorders. Although the investigator's recent experimental findings indicate that acute sleep loss results in non-adaptive emotion processing in young children, the neural systems underlying such sleep-dependent effects are not known. Also, the vast majority of basic research on sleep and affective substrates has utilized sleep deprivation or sleep restriction protocols. The investigators will instead employ sleep extension in chronically sleep-restricted children, a highly translatable approach with significant public health implications.

This research project will examine whether experimental sleep extension in children alters the neural and behavioral mechanisms by which short sleep is a risk factor for emotional/behavioral problems. Children ages 5.0-5.9 years with chronic insufficient sleep (≤9 h/night for ≥6 months) will be randomized to either a sleep Extension or to an active Control group. Extension group parents will participate in a 1-month individualized behavioral sleep intervention to promote targeted sleep duration improvements before beginning a 2-week sleep Extension schedule (8 week protocol). Brain and behavioral assessments will occur at Baseline and post sleep Extension.

Inclusion Criteria:

4.0-6.9 years Reportedly obtain ≤9 h of sleep/night for ≥6 months

Exclusion Criteria:

Nocturnal sleep disturbance determined by clinical cut-offs on the Children's Sleep Habits Questionnaire and the Pediatric Sleep Questionnaire Medications Developmental disabilities Chronic medical conditions Low-birth weight or pre-term term delivery Family history of psychiatric disorders Living at altitude <1 year Metal implants or Claustrophobia