Serotonin is a neurotransmitter best known for its influence on depression and sexual function. But it also plays less famous roles: serotonin-releasing neurons in the brain stem regulate our body temperature and how we breathe. Henry Krous, a professor of pathology and pediatrics at the University of California, San Diego, and his colleagues have found that a failure of this system may be responsible for sudden infant death syndrome, or SIDS.
SIDS is diagnosed when a sleeping baby dies without obvious cause. An infant who is sleeping face down or who is too warm is more likely to die of SIDS. But this new research suggests some babies may be particularly at risk.