For years, scientists thought that neurons in the brain's suprachiasmatic nuclei, or SCN, regulated our body clocks by firing a lot during the day and less at night.

很多年来，科学家们认为大脑的视交叉上核（SCN）是生物钟中枢，具体机制是此处的神经元白天比夜间更兴奋。

And fatigue experts have weighed in to note that the evening hours when the incident occurred typically don't pose particular challenges for the internal body clocks of pilots.

疲劳问题研究专家也说，虽然晚间是事故多发时段，但对飞行员的生物钟并不构成特别的挑战。