Ultima Thule

In ancient times the northernmost region of the habitable world - hence, any distant, unknown or mysterious land.

Friday, May 05, 2006

To sleep, perchance to dream -- ay -- there's the rub!!

By Aussiegirl

There's no question that man has always found the subject of his dreams to be a fascinating one. There are the recurring dreams, the nonsense dreams, the ones that seem to be a rehash of the day's events. Then there are the extremely vivid ones, the ones that sometimes even seem like visitations to or from another world. We've all had the scary ones -- and the seemingly universal dreams involving being unprepared for a test. I usually not only haven't studied or read the text, I have never attended one lecture and don't even know where the class meets. And I'm usually barefoot as well. Now that I'm blogging I frequently dream about that. Some of us dream in color (I do), and some of us dream of flying.

But I have had very meaningful dreams which helped me to solve some problem I was encountering at the moment. Dreams which seemed to point me to a resolution of a conflict.

William Shakespeare - To be, or not to be (from Hamlet 3/1)

To be, or not to be: that is the question:
Whether 'tis nobler in the mind to suffer
The slings and arrows of outrageous fortune,
Or to take arms against a sea of troubles,
And by opposing end them? To die: to sleep;
No more; and by a sleep to say we end
The heart-ache and the thousand natural shocks
That flesh is heir to, 'tis a consummation
Devoutly to be wish'd. To die, to sleep;
To sleep: perchance to dream: ay, there's the rub;
For in that sleep of death what dreams may come
When we have shuffled off this mortal coil,
Must give us pause: there's the respect
That makes calamity of so long life;
For who would bear the whips and scorns of time,
The oppressor's wrong, the proud man's contumely,
The pangs of despised love, the law's delay,
The insolence of office and the spurns
That patient merit of the unworthy takes,
When he himself might his quietus make
With a bare bodkin? who would fardels bear,
To grunt and sweat under a weary life,
But that the dread of something after death,
The undiscover'd country from whose bourn
No traveller returns, puzzles the will
And makes us rather bear those ills we have
Than fly to others that we know not of?
Thus conscience does make cowards of us all;
And thus the native hue of resolution
Is sicklied o'er with the pale cast of thought,
And enterprises of great pith and moment
With this regard their currents turn awry,
And lose the name of action.

Telegraph | Connected | To sleep, perchance to think
To sleep, perchance to think
(Filed: 02/05/2006)

The meaning and cause of dreams has fascinated scientists for centuries. The brain is never idle, says Jim Horne

Dreams can be delightful and inspirational. Leonardo da Vinci attributed many of his inventions to them and wrote: "why does the eye see a thing more clearly in dreams than the imagination when awake?"

Deep in thought: there is much more to REM than meets the eye

Friedrich Kekule, pioneer of organic chemistry, attributed his inspiration for the benzene ring to a dream in which a snake swallowed its tail. Robert Louis Stevenson frequently had vivid dreams, and his The Strange Case of Dr Jekyll and Mr Hyde came from one.

The link between eye movements and dreaming was first suggested a long time ago, with one of the earliest accounts appearing in 1892. We refer to this dream state as Rapid Eye Movement (REM) sleep.

But although dreaming is most vivid and intense during REM sleep, milder, more reflective and less fantastic forms of dreaming occur throughout much of the rest of sleep - and we don't always dream during REM sleep.

In fact, there is much more to REM sleep than meets the eye. It's more like wakefulness and maybe we should view REM sleep not as true sleep but as a type of wakefulness, or even non-wakefulness, rather like screen-saver mode on a computer. The brain is not really unconscious during REM sleep.

Whispering a familiar name or some other meaningful sound will usually produce an instant awakening. Whereas a fairly loud and meaningless noise, even a train thundering past (if you live beside a railway) will be ignored, providing that it's not annoying.

Annoyance or the emotional significance of the sound is particularly important in determining whether we wake up from REM sleep. Even in our enlightened age of the equality of the sexes, the crying baby is more likely to wake up mum rather than dad, and from REM sleep. Low-flying aircraft may well only wake up dad, who gets particularly annoyed by these flights, not mum, who may have other matters to worry about.

Emotive external sounds will quickly awaken us from REM sleep, so how is it that dreams, with all their emotional content, do not normally wake us up, except from the more frightening nightmares?

The dreamer seems to be emotionally numbed and protected from the emotional content of the dream. There are little or no increases in heart and breathing rates, or in blood pressure (although these do become more irregular) during REM sleep. Moreover, blood levels of the fight-or-flight and stress hormones, adrenaline and cortisol remain unchanged.

How all this is achieved is not clear, although important regions of the brain controlling emotional behaviour, such as the amygdala, almond-shaped structures, are very active in REM sleep, which may, in part, be due to their blocking of these emotions. The amygdala is probably the guardian of REM sleep as here is where the sleeping brain's main watchkeeper resides, keeping us vigilant to external threats.

Other evidence that suggests vigilance during dream sleep comes from electrical activity accompanying each burst of rapid eye movements. Initiated from deep in the brain, PGO waves (so named because they are from three brain areas: the Pons, Geniculate thalamus and Occiput areas) vary in intensity just as do the eye-movement bursts. Both are accompanied by small, almost unnoticeable twitches of the fingers and toes.

These waves are largely absent from the rest of (non-REM) sleep, but something very similar occurs in wakefulness whenever an animal is alerted to a new stimulus, when it will prick up it ears and look towards whatever is causing the interest (in humans, though, the waves are difficult to detect without the aid of electrodes implanted in the brain).

In REM sleep, PGO waves are not usually in response to some external stimulation, such as noise, but are spontaneous, unlike those in wakefulness. Nevertheless, they bombard the cortex as if it was being stimulated externally, and as REM sleep is so prolific in the baby before birth, these waves probably help mature its developing cortex, to make up for the dull confines of the mother's uterus. Something similar continues to happen during adult REM sleep.

Our cortex, the rind of the brain where consciousness resides, probably tries to make some sense of all these weird pseudo-sensations, by creating imagined events around them, through dreaming. The disjointed nature of dreams, leaping from one unexpected theme to another, reflects this.

Not all of the cortex is involved in dreaming, though, as the frontal cortex, which in wakefulness helps us sustain attention to a particular event and ignore distractions, either can't cope with all this distraction during REM sleep and shuts down, or purposely switches off so that it can continue to rest and recover.

For whatever reason, it means that the rest of the cortex is freed from the frontal region's usual constraints, to go off and play, so to speak. Hence the unfettered distractions and leaps of imagination in dreams, which makes them so unpredictable and fascinating.

What is fairly clear is that we dream as we think - dreams are a surreal pastiche of what we have recently encountered and thought about while awake. Why people want to place some meaning into dreams or interpret them is beyond the comprehension of many scientists, and probably those who write about the meaning of dreams. There is usually greater fantasy in the mind of the dream interpreter than the dream to be interpreted.

Viewing dreams as portents of the future has been a popular activity. In ancient Egypt, priests would conduct their interpretations as part of sleep therapy conducted in sleep temples. An ancient papyrus, the Dream Book, from the era of Ramses the Second (1275 BP), exists in the British Museum, providing numerous dream examples and interpretations. People with troubled minds would spend the night in these special temples, where priests would try to influence sleep with suggestions, in the hope of provoking special dreams sent by the gods. In fact, Imhotep, the architect of the first step pyramid and a famous physician, advocated this practice. After his death, he was worshipped as a god, in sleep temples built in his honour.

Maybe, in certain situations, dreams can be of help in understanding the pressures confronting patients with severe mental problems, and, to some extent, Freud may have been correct in saying that dreams are the "royal road to the unconscious". But it is crucial to know the patient before any interpretation can begin, and there is no evidence to support the notion of universal symbols in dream imagery, common to everyone. Dream dictionaries and schemes for dream analyses by mail, where there is no rapport between the dreamer and interpreter, must be treated with the greatest of suspicion.

Prof Jim Horne is director of the Sleep Research Centre, Loughborough University. This is an edited extract from his new book, 'Sleepfaring: A Journey through the Science of Sleep' (Oxford University Press)


Post a Comment

<< Home