Postnatal Development of Sleep-Wake Cycle in Wild-Type Mice

Many neurological disorders affecting considerably the population, such as attention deficit hyperactivity disorder (ADHD), epilepsy, or Alzheimer’s disease concern a nucleus of the brainstem: the locus coeruleus. This fact motivates the study of the early development of the noradrenergic system, its normal functions, and how different lesions are involved in diverse diseases. In fact, neuronal connections are still forming in the brain of the neonate, while brainstem neurons project rostrally to the developing cortex. Lesions affecting the maturation of the noradrenergic system at first may go unnoticed. In this chapter we present how the respiratory, circulatory, and sleep parameters, all controlled by the noradrenergic system, evolve during early postnatal development in two mice strains (CD-1 and C57). Oxygen consumption and heart rate increase from P7 to P14 in both strains. C57 mice reduce strongly time spent in REM sleep and increase time spent in NREM sleep from P7 to P14.