SLEEP AND DREAMS - Your brain is never at rest
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The
study of sleep has always been neglected over the centuries
and in the past the only scientific interest shown in our
nocturnal lives has been the interpretation of our dreams.
It was only in the 1950s that the roles were inverted. Sleep
began to command more interest from researchers compared
to dreaming, now seen as a neuro-physiological manifestation
of man during sleep, while the actual dream content was
no longer taken into consideration by the new experimental
and clinical research carried out. |
Indeed
Freud himself only knew sleeping man through accounts of his dreams
while the "New" type of physician began to directly observe the
sleeper using laboratory experiments aimed at investigating the
biological rather than the psychological aspects.
The first research carried out into sleep made use of a mechanical
device, the ectograph which, when placed under the bed, monitored
the sleeper's body movements throughout the night. Nowadays the
electroencephalograph is used instead, a machine which amplifies
the slightest variations in the brain's electrical potential.
The brain has its own natural pulsation caused by the passage
of electrical charges between the cells and this generates potential
differences which become transferred into values on paper by needles
that trace the oscillations of these electrical charges. For this
type of experiment the subject is wired up to the encephalograph
by means of electrodes which, when applied to the cranial surface,
detect the impulses that create the lines on the graph.
These lines give a graphic representation of the cerebral wave
forms and one night's sleep can produce enough information to
cover a full six hundred metres of graph paper. Brain waves, like
electrical waves, are made up of an amplitude or height of oscillation,
giving an indication of which potential difference comes from
which particular area of the brain, and also of a frequency that
represents the number of oscillations made in a given unit of
time; these oscillations indicate the speed with which the potential
differences are produced by the brain.
Interpretation of the graphs deriving from the different cerebral
regions will show whether the brain waves have been emitted regularly,
with which amplitude (something the sleep trace shows clearly),
and whether these emissions are irregular (indicating a probable
waking status).
As well as the electroencephalograph, other means may be used
to examine the sleeping state such as cameras to observe the sleeper,
wire-recorders to monitor the dreams and equipment for measuring
the body temperature.
It may be also helpful to monitor the changes in breathing rhythms,
arterial pressure, pulse and skin resistance.
All this is necessary to obtain a picture of the alterations that
take place in the individual's organism.
Sleep is therefore a periodical biological phenomenon, characterised
by the loss of consciousness and, thanks to the electroencephalograph
it has been possible to demonstrate that one night's sleep consists
of the periodic succession of cycles lasting over one hour each,
that repeat four or five times during the night.
Each cycle comprises four synchronised sleep phases together with
a percentage of non-synchronised nocturnal sleep or REM (Rapid
Eye Movement). During synchronised sleep, or slow sleep, various
phenomena can be observed such as a reduction in the sleeper's
movements, muscle relaxation, slower reflexes, and the movement
of the eyeballs with restricted pupils.
In terms of bodily metabolism however other important changes
take place like a slowing down of the heart rate, a reduction
in blood pressure, slower breathing, and a fall in body temperature.
The characteristics of non-synchronised sleep either reverse or
modify the symptoms of synchronised sleep: the loss of muscle
potential is more marked than in the synchronised sleep phase,
there are fluctuations in the heart rate, variations in the intensity
of blood pressure from one minute to the next, and irregular breathing.
Besides this, the brain temperature, cerebral energy and oxygen
consumption all increase. REM activity, or rather rapid, irregular,
eyeball movements from left to right and up and down take place
periodically at this stage.
Sporadic
contraction of the small muscles can also be noted during this
phase.
It is during these REM periods that dreaming takes place, bringing
fantastic images of events taken from real life situations but
which are often exaggerated or which follow an illogical sequence.
Everybody dreams for two or three hours per night but not all
of us remember having dreamed and, generally, only few aspects
of the dream can be recalled.
The
difference between those who can remember their dreams and
those who cannot has nothing to do with the number of dreams
or their content but rather the nearness of the dream to
the moment of waking.
The quicker we awaken, the more chance there is of remembering
the dream: it is said that awakening more than 10 minutes
after the end of the dream gives little hope of recall.
Lengthy dreams are remembered more easily as are those which
charge the senses and emotions more intensely. |
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This is due to the fact that stimulation of the cerebral cortex
increases their number and frequency. In the same way noise, light,
states of over tiredness or acute physical illness increase the
ability to remember dreams.
It should also be stated however that, just like any other psychic
activity, our dream memory can be developed with effort. How much
of our dreams we remember is an indication of the individual's
personality:
efficient dreamers will be more introspective and interested in
their own psychological problems
Dreams have three common factors: length, colour and sensations.
As regards the first characteristic, thanks to the electroencephalograph,
it has been seen that dreams take a certain amount of time to
run their course.
The time it takes for each event (image sequence) to take place
in the dream is roughly the same as it takes to carry out that
event in the waking state. On average, dreams vary from about
five to ten minutes.
Regarding the second aspect of dreams, colour, it has been found
that between 20% to 75% of dreamers remember the colours of their
dreams, but no one (0%) has been able to state with certainty
that they dream in black and white.
It seems that everybody dreams in colour. The difficulty in remembering
this derives from the fact that little attention is paid to this
particular detail. Proof of this is that artists report coloured
dreams more often than other people.
Turning now to the third characteristic concerning the senses,
it is noted that visual sensations are reported in 100% of cases.
Sounds, language or aural elements are less frequent. The senses
of taste and touch come last of all. Nevertheless, in dreams the
tactile impressions are in fact more frequent than the memory
we retain of them and this can be put down to the amount of importance
our culture gives to the eye and images compared to touch.
Dreams are therefore a combination of images, shapes, colours,
and movements which have always been a source of inspiration for
our poetic imaginations. Dream visions have always inspired artists
of every kind and will go on doing so. The dream, whether pleasant
or otherwise has always been surrounded by wonder and might be
seen as a moment of communication between the unconscious and
one's own conscious state which listens in, constructing our inner
self from this complete and well balanced relationship.
Links
La cura del sonno www.espressonline.kataweb.it/ESW_articolo/0,2393,6883,00.html
Intelligenza emotiva e Cervello Emotivo
www.sicap.it/merciai/psicosomatica/students/taylor.htm
A che serve sognare www.mondadori.com/panorama/capeco/economist/economist_8_11.html
Il portale dei sogni
www.sognando.com
Il segreto dei sogni
cubo.newton.rcs.it:8666/archivio/articolo.php3?IdArticolo=260
Psicoanalisi on line
www.psicoanalisi.it
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