My lab has shown that neurons in some of the brain areas involved in the control of breathing are inherently sensitive to low oxygen. This sensitivity increases over developmental time.
Newborn animals have far fewer neurons that respond to hypoxia than do adults.
Maturation of these cells may be at lower levels in these babies. Such a reaction, however, was not seen in rats less than 12 days old, suggesting that the brain pathway in neonatal rats may not be sufficiently developed to respond. Dr. Terrence Sejnowski suggests that we sleep, at least in part, so that we can remember. He argues that links between brain cells are formed during deep sleep. In recent years, researchers have found that groups of brain cells involved in memory formation signal each other during the quieter phases of sleep.