College College Biology and Chemistry College Mind, Brain, and Behavior

The Science of Sleep (Part 1)

I'm sure we've all wondered where our mind wanders off to when we're unconscious, or more specifically asleep. Here is a rundown of the various stages our mind goes through when we're not even conscious.

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No, I’m not referencing Charlie Kaufman’s hit film The Science of Sleep. Rather, I’m sure we’ve all wondered where our mind wanders off to when we’re unconscious, or more specifically asleep. Here is a rundown of the various stages our mind goes through when we’re not even conscious.

We know that the brain is still active during sleep because of psychologist Eugene Aserinsky’s experiment on his son, where he used an EEG to record his son’s brain’s electrical activity during sleep. (1) The lines depicting brain wave patterns on the machine went crazy, signaling activity. This may seem farfetched, as humans seem to not do anything during sleep. After all, humans are mostly still. This example is an instance of the paradoxical sleep in REM sleep (more on that later). Otherwise, besides the twists and turns in humans’ sleep, it’s mainly the body that sleeps, not the brain.

To prepare for sleep, your body’s endocrine system switches from releasing “awake” cortisol hormones via the adrenal glands to “sleepy” melatonin hormones via the pineal gland.

First, humans linger between a state of consciousness and unconsciousness before sleep finally hits, like that period when you pretend to sleep for a few minutes and suddenly wake up the next day, wondering about the exact time of the breaking point between wakefulness and unconsciousness. This kicks off the first stage: non-REM sleep stage 1. Alpha waves predominate and your breathing slows until you’re suddenly asleep. n-REM 1 may also bring strange sensations like bodily jerks or feelings that you’re about to fall. This light sleep is common in the first few minutes you fall asleep, like waking up to your head dropping in a boring lecture.

Next is n-REM 2, where sleep spindles or bursts of heightened brain activity occur. After that, n-REM 3 presents slower brain delta waves. (2)

Finally, the phenomenon that sleep is most famous for: REM sleep. This final stage involves Rapid Eye Movement, where one sees, hears, and feels vivid imagery, like a simulation. Dreams are often bizarre like a dreaming that a clown is chasing you or may be mundane, like a simulation of a lecture in class. This is an instance of the information-processing theory, where your brain brings up imagery relating to the day’s event in an effort to process each day. Freudians believe that dreams hint hidden desires or signify unresolved conscious conflicts, such as how dreaming of scary clowns may point to your phobia of clowns.

You may have several dreams a night, as each dream only lasts from a few minutes to around a half-hour. One would expect wild physical activity if such crazy brain activity occurs during REM, but as stated before, REM is also known as paradoxical sleep, for the brain’s motor cortex is super active, but the brain stem blocks these signals, resulting in bodily paralysis. Afterward, the cycle repeats every 90 minutes, going back to light non-REM sleep and then back to longer REM dreams.

Well, now you have a clearer understanding of what your mind is up to when you aren’t even consciously using your mind. Start recording your dreams in a journal when you wake up, as I discuss more dream analysis techniques and sleep disorders!

References and Footnotes:



1 comment on “The Science of Sleep (Part 1)

  1. Thanks, I found this post really elucidated the stages of sleep to me! I can’t wait for Part 2…


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