Book: Functional Anatomy of the Sleep-Wakefulness Cycle – Review

Functional Anatomy of the Sleep-Wakefulness Cycle

This book is mainly about the specific nerves, hormones and other body parts responsible for sleep. Of course I should have known from the title, which has ‘anatomy’ in it, but this particular book was not too helpful for me. In a big part due to the fact I could not really read about the various experiments without gagging. But I concentrated and read through at least one particularly creative experiment.

The Sleep-Wakefulness-Cycle (SWC) simplified, exists of three stages: wake, non-REM sleep, REM sleep. Rapid Eye Movement (REM) sleep, is when you dream. Apparently, the cycle becomes longer in time, later in the night, which could explain why most people remember more complex dreams in the morning compared with when they wake up in the middle of the night. Also REM sleep is diminished in older people.

An experiment is described to see whether input on the body, influences the SWC. Normally, darkness causes certain hormones to be released which is why people and many animals sleep at night and are awake at day. The brain gives the command to release the hormones. But does the animal ‘know’ that its night, through his body or brain?

The conclusion was, that influences on the spinal cord nerves, must be responsible for the circadian rhythm. In other words, our brain does not dictate when we sleep, our body does!

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