Developmental brain-stem pathology in sudden infant death syndrome.

The brain-stems of control and sudden infant death syndrome (SIDS) infants were examined developmentally with Golgi and immunohistochemical methods. The development of dendritic spines changed dramatically from the prenatal to postnatal period in the ventrolateral medulla as well as in the reticular formation and vagal nuclei in controls, but persisted in SIDS infants. These observations suggest a delay in maturation of the meduallary respiratory neurons and transneuronal connection between the central chemoreceptor and neural respiratory center in SIDS. In addition, substance P (SP)-positive nerve fibers were increased in the pons of SIDS infants. An increased activity in the afferent SP neurons in SIDS may be due to chronic hypoxia as in brain-stem gliosis, and may be involved in cardiorespiratory regulation.