Infants who die of sudden infant death syndrome have abnormalities in the brainstem, a part of the brain that helps control heart rate, breathing, blood pressure, temperature and arousal, report researchers funded by the National Institutes of Health. The finding is the strongest evidence to date suggesting that innate differences in a specific part of the brain may place some infants at increased risk for SIDS.
The abnormalities appeared to affect the brainstem’s ability to use and recycle serotonin, a brain chemical which also is used in a number of other brain areas and plays a role in communications between brain cells. Serotonin is most well known for its role in regulating mood, but it also plays a role in regulating vital functions like breathing and blood pressure.
SIDS is the sudden and unexpected death of an infant under 1 year of age, which cannot be explained after a complete autopsy, an investigation of the scene and circumstances of the death, and a review of the medical history of the infant and his or her family. Typically, the infant is found dead after having been put to sleep and shows no signs of having suffered.
In previous studies, researchers have hypothesized that abnormalities in the brainstem may make an infant susceptible to situations in which they re-breathe their own exhaled breath, depriving them of oxygen. This hypothesis holds that certain infants may not be able to detect high carbon dioxide or low oxygen levels during sleep, and do not wake up.
The study appears in the November 1st issue of Journal of the American Medical Association and was conducted by researchers in the laboratory of Hannah Kinney, M.D., at Children’s Hospital Boston and Harvard Medical School as well as other institutions.
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