Siffre, stuck in his dark cave, relied on the most primitive clock in the suprachiasmatic nucleus, or SCN of the hypothalamus.
Siffre 困在他的黑暗洞穴中,依靠视交叉上核或下丘脑 SCN 中最原始的时钟。
英语百科
Suprachiasmatic nucleus
The suprachiasmatic nucleus or nuclei (SCN) is a tiny region of the brain in the hypothalamus, situated directly above the optic chiasm. It is responsible for controlling circadian rhythms. The neuronal and hormonal activities it generates regulate many different body functions in a 24-hour cycle, using around 20,000 neurons.