Читать книгу Counting Sheep: The Science and Pleasures of Sleep and Dreams - Paul Martin - Страница 38

Sleep rock thy brain.

William Shakespeare, Hamlet (1601)

Now it is time to peer beneath the surface at the strange state of existence known as sleep – or, to be more precise, the two strange states of existence known as sleep.

All of human life is spent in one of three states. You are very familiar with one of them: it is called the waking state, or consciousness, and it forms the subject matter for almost everything that has ever been said, written, acted, painted or composed about humanity. When scientists analyse the mind, when novelists dissect the human condition and when biographers portray the lives of eminent individuals, it is the waking state they almost invariably describe. However, there are two other distinct states of existence that together account for at least a third of each life. They labour under the workaday names of Rapid Eye Movement (REM) sleep and Non-Rapid Eye Movement (NREM) sleep, and we are about to take a closer look at them.

A night’s sleep is a complex and cyclic process, comprising several distinct patterns of brain activity and behaviour, with alternating episodes of NREM sleep and REM sleep. We will follow the sleep cycle from the beginning, starting with the transition from the waking state. But before we do that, a quick word about how scientists know what is going on when we are asleep.