New Understandings of Neonatal Sleep-Wake States

Extremely high percentages of REM sleep and frequent nonvoluntary movements (jerks) are near-mythic phenomena in neonates. Understanding the molecular mechanism of neonatal REM sleep may be crucial in understanding why the amount of REM sleep is so high in neonates. 

CRF receptor mRNA abundance increases steadily between PN 2 and PN 9, to levels twice higher than those in the adult. In the cortex, CRF receptor mRNA levels are high on PN 2 and are decreased to adult levels by PN 12 (125). 

In summary, the above evidence supports my hypothesis that neonatal REM sleep may increase the release of 5-HT and neurotrophic factors and may facilitate the development of multiple brain systems through the increase of 5-HT and neurotrophic factors. However, this hypothesis needs to be empirically tested. 

Growth of frontal cortex, aminergic orexinergic neurons 

I thank Dr. Kingman R Strohl (Case Western Reserve University) and Dr. Jidong Fang (Pennsylvania State University) for their review of the manuscript and their extremely helpful comments. 

---