"But a baby who has a defect in those brain stem circuits that use serotonin can't do that when challenged and they go on to die."

VOA: standard.2010.02.08

And so, it could be the problem is the baby's brain doesn't develop yet.

所以婴儿大脑并未发育成熟也就成了问题

耶鲁公开课 - 心理学导论课程节选

At present,doctors cannot measure the amount of serotonin in a living baby's brain.

VOA: standard.2010.02.08