The serotonergic anatomy of the developing human medulla oblongata: Implications for pediatric disorders of homeostasis

► The caudal serotonergic system is part of a homeostatic network that regulates protective responses to asphyxial and other stressors. ► Its critical developmental period extends into the first postnatal year, corresponding to the fetal transition to self-sustaining homeostasis. ► Serotonergic-related disorders of early life can be unified under the rubric of “developmental serotonopathies”. ► Developmental serotonopathies affect the rostral and/or caudal domain of serotonergic brainstem neurons. ► Evidence is mounting that the sudden infant death syndrome is a developmental serotonopathy of the caudal domain.