brain waves and the dreaming mind
Every night we go to sleep and, to all intents and purposes, we are ‘dead to the world’. We have to sleep in order to dream and each night, when we slip off into that unconscious state which would be frightening in the extreme if we were not so familiar with it, we visit another world – the world of dreams.
Although we now know a little about the condition scientifically, physiologically and psychologically, its real purpose is not fully understood. Until the twentieth century the only access we had to sleep came from remembered dreams but, with the advent of electronic monitoring of brain activity, certain information and discoveries have been made.
For centuries the purpose of going to sleep was thought to be solely to rest the physical body. Having worked hard during the day, it needed to relax, so we went to sleep. This reasoning fell into disrepute when it was realised that resting while awake rejuvenated muscles in much the same way as in sleep. Furthermore, the body did not lie still during sleep; a series of time-lapsed photographs revealed that the body makes frequent movements – turning over as often as twenty times in a night, and stretching continually – in order to exercise the muscles, not to relax them.
Having realised this, it was decided it was not physical rest we needed during sleep after all, but psychological rest. The brain, the most important and active organ in the body, had, so it was thought, to be ‘switched off’, during sleep. This assumption again proved wrong. When it was possible to measure electronic impulses from the brain, it was found to be more active during sleep than when awake. Experiments involving sleep deprivation revealed unexpected results. By waking sleeping subjects throughout two consecutive nights it was discovered that, through lack of sleep, they were mentally disturbed and disorientated. Some years ago a US disc jockey named Peter Tripp decided to stay awake for 200 hours to raise money for charity. At the beginning of this sleepathon he was in good spirits and broadcast daily from Time Square. Later, his speech became slurred and towards the end of this stint it was incoherent. He then became paranoic, believing someone was drugging his food to make him go to sleep. He completed his 200-hour sleepless marathon and the only treatment he needed to restore his balance was a good, long sleep.
From this, and other experiments, it was discovered that lack of sleep harms both the body and the mind. If, then, sleep rests neither the body nor the mind, what, indeed, is it for? The advent of space travel gave scientists further opportunities to investigate this thing called sleep. They proved once again that resting the body is not the specific function of sleep. They also found that prolonged periods of isolation decreased the need for sleep. In other words, the less interaction there is between people, and the less stimuli received from external contact, the less sleep is needed.
Older people who have difficulty in sleeping may well be suffering from nothing more than lack of contact with others and deprivation of external stimuli. Apparently, we have a sleep control centre in the brain stem, at the base of the brain, associated with activity during wakefulness. When it is overloaded, it produces feelings of fatigue and eventually sleep. Lack of stimuli from the outer world, while causing drowsiness and disinterest in life, is not always sufficient to trigger this mechanism into sleep. Hence the problem of insomnia in institutionalised geriatrics and the reason why 95% of them are given sleeping tablets. Boredom and lack of stimuli may also account for insomnia in younger people. The paradox, however, is that over-stimulation causing anxiety also produces insomnia.
brain waves and the dreaming mind
Falling asleep follows lying down and relaxing the body, then the mind. Once asleep, the heart and breathing rate slows down, blood pressure is lowered and the body temperature drops slightly. The exact moment of going off to sleep is impossible to determine, even with the help of an electroencephalogram. The difference between being awake and being asleep is loss of conscious awareness. An external noise, for example asking a question, does not evoke a response.
Dream laboratories may not discover the reason for sleep or even what it is but, nonetheless, investigations have revealed some very interesting discoveries. Using computer language some researchers, comparing the brain with a computer, say we are ‘off-line’ during sleep. This means that the brain, like some computers, is not idle or resting but is reassessing, filing and up-dating the day’s input. This would certainly seem to be the case, but it is taking the analogy too far when it is said that the brain, like the computer, jettisons all out-of-date data in the form of meaningless dreams. Since dreams are memories, no memory can be totally eradicated, so the jettison theory is too mechanical and simplistic. According to this reasoning our dreams are mere sittings worth nothing more than the rubbish bin. Such a notion, in the light of inventive, creative, prophetic and lucid dreaming, is nonsense.
To understand sleep we need to understand the brain. It was found earlier this century that the brain gives off electrical impulses and by the 1920s scientists could measure two different types of waves which they called Alpha and Beta. Later, as electrical devices improved, Delta, Theta, Mu, Gamma, Vertex, Spike and K waves have been found as well. To obtain these readings, electrodes are attached to various areas on the head and impulses are intensified and transformed into wave motions on graphs or into electroencephalograms on computer screens – EECs for short.
Interpreting what these waves mean is far from clear, and individual researchers each had their own names for them: ‘deep and light phases’; ‘active and quiet phases’; ‘desynchronised and synchronised phases’; ‘high and low phases’, and finally ‘paradoxical and orthodox phases’ were terms used to describe dreaming and non-dreaming brain waves.
In the 1960s it was clear that brain waves altered from Beta to Alpha when a subject closed his or her eyes. This was thought to be due to cutting off visual impulses from the outer world. It was further discovered that sleep, a stage beyond closing the eyes, could be divided into six levels which were labelled A, B, C, D, E and F. A represented light sleep and B, C, D, E and F levels represented progressively deeper sleep.
Associated with these levels are two distinct types of sleep. These have been called REM (Rapid Eye Movement) and NREM (non-REM) sleep. Early sleep, known as ‘quiet sleep’, is NREM sleep. There are several NREM phases throughout the night, the first lasting approximately 90 minutes, followed by a short REM phase which lasts about 10 minutes. Throughout the night NREM and REM phases alternate. Initially, the NREM stages are longer, then, as the night progresses, they become shorter and the REM phases take up the majority of sleeping time.
REM sleep is recognised by small twitches of facial muscles and slight movements of the hands. If snoring occurs during NREM sleep, this stops and breathing becomes laboured. Arms and legs are paralysed and the sleeper is unable to move. Blood pressure rises and the heartbeat increases as if the body is under physical exertion. Most significant of all, the eyes begin to move rapidly from side to side under closed eyelids, as if looking at a moving object. Researchers have discovered that when a sleeper within the REM stage is awakened, they invariably say