NEW WAYS TO RISE

摘要

In the modern world many of us need an alarm clock to rouse us. Left to our own devices, however, we eventually wake up. The signal to do so is generated in a region of the brain called the suprachiasmatic nucleus (SCN) in the hypothalamus. This plays a central role in sleep-wake timing by regulating the rhythms of hormones such as melatonin, as well as neurotransmitters and neuromodulatorssuch as orexins. Because the internal wake-up call is gentle, it is easy to oversleep. Furthermore, the call often arrives a bit late because most of us have a body clock that naturally runs for longer than 24 hours. Exposure to light from cellphones, TVs and computers in the evening may also shift the clock to a later hour, making matters worse.