TED-ED: How does your body know what time it is? - Marco A. Sotomayor

Michel Siffre's isolation experiments revealed the existence of circadian rhythms, which are internal cycles that regulate sleep and other bodily functions without external cues. These rhythms are part of chronobiology, a field studying time-related biological changes. The brain's timekeeping system involves proteins like CLK and PER, which regulate sleep cycles. External cues, or zeitgebers, such as light and temperature, help fine-tune these cycles. Neuronal communication in the brain also plays a role in our perception of time, as demonstrated by Siffre's altered time perception during his isolation.

What did Siffre's experiments reveal about the body's natural cycle?

• The body relies solely on food intake for its cycles.

• The body can maintain a regular sleep-wake cycle without external cues.

• The body cannot maintain any cycle without light.

• The body needs external cues to maintain a sleep-wake cycle.

What is the role of the suprachiasmatic nucleus (SCN) in the brain?

• It regulates the body's temperature.

• It controls the body's hunger signals.

• It is responsible for processing visual information.

• It acts as the primary timekeeper for the body's circadian rhythms.

How do proteins CLK and PER interact in the brain?

• CLK and PER work together to increase hunger.

• CLK activates genes for wakefulness, while PER deactivates CLK to induce sleep.

• PER activates genes for wakefulness, while CLK deactivates PER to induce sleep.

• CLK and PER have no interaction in the brain.

What are zeitgebers and their role in our daily behavior?

• They are internal cues that disrupt our sleep.

• They are hormones that induce sleep.

• They are external cues that help fine-tune our circadian rhythms.

• They are proteins that regulate hunger.

How does natural morning light affect our sleep-wake cycle?

• It has no effect on our sleep-wake cycle.

• It triggers the production of melatonin.

• It helps wake us up by halting melatonin production.

• It decreases energy levels.

What did Siffre discover about his perception of time in isolation?

• His perception of time remained unchanged.

• He lost all sense of time.

• He could count time more accurately.

• His perception of time slowed down significantly.

What question does Siffre's altered time perception raise?

• Is time perception linked to hunger?

• Does time perception affect sleep patterns?

• Can time be measured accurately?

• Is time perception the same for everyone?