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Are
Dreams as Vital as Sleep?
by Roger Louis
Can
dreams be controlled at our own will? Is dreaming the ability
of all animals? How do the deaf-mutes and the mentally disabled
dream? The following article discusses these issues.
Sooner or later biologists were bound to
investigate one of the brain's most mysterious functions,
probably the least tangible and the least comprehensible function
of the body, dreaming.
Just a few years ago we thought that ,
when he took the keys to the city of dreams away from the
philosophers and poets, had given them once and for all to
the psychologists and .
But now biologists, biochemists and
are invading what used to be thought an exclusive preserve.
One of these is a Frenchman, Dr. Michel Jouvet,
whose research at the medical school of Lyons is internationally
recognized as authoritative and on the same plane as that
of Professor Nathaniel Kleitman in the United States, which
has been continued since 1960 by one of his colleagues, Dr.
William Dement.
It was more or less by chance that Dr. Jouvet
became interested in dreams in 1958, or rather it was the
logic inherent in any experimental work that stimulated his
curiosity.
"I was interested at that time in confirming
s
theories of conditioning, using cats as test animals," he
told us. "We had put electrodes in the muscles of their paws
in order to check on certain movements."
"During their sleep we noted an unexpected
phenomenon that occurred sporadically—the complete disappearance
of muscular tone, sometimes lasting for several minutes, after
which muscular tone reappeared while the animal continued
to sleep.
"We thought of all possible theories to explain
this phenomenon. It
even occurred to us that it might be connected with the very
special role that whiskers play in the cat, and we actually
tried cutting them off to see whether this might have some
effect. Only after a long period of groping, did
we realize that there was a possible correlation with dreaming.
"From that moment our research was directed
towards the physiological study of sleep, especially towards
what we now call its paradoxical phase. This corresponds to
the period in which an animal or a person dreams.
"This
research was carried out in collaboration with Kleitman and
Dement in the United States, among others. In a
very short time we were able to collect an extraordinary amount
of information and numerous records.
"We might begin with the most basic points.
By mere physical examination of a person or an animal who
is sound asleep, we can now tell whether he is dreaming or
not; better yet, we
can identify, to within one second, the instant he begins
to dream and the instant his dream ends.
"We have three basic physiological criteria
for this finding, and they are now accepted by all neurophysiologists:
1. Virtually complete disappearance of muscle
tone.
2. Rapid eye movements (hence the term REM
sleep), which seem to be without purpose.
3. Characteristic brain waves on the ,
quite different from those recorded in deep sleep and very
similar to those recorded in the waking state. Discovery of
this tracing gave rise to the term "paradoxical phase," which
we apply to sleep in the dreaming state.
"We can also state that the average adult
dreams about twenty per cent of the time he is asleep, in
a number of separate dreams. Each dream episode, about twenty
minutes, is preceded by a period of deep sleep, indicated
on the encephalographic record by typical long waves.
"While we are talking statistics, we might
add that the newborn infant dreams much more than the adult—fifty percent of his sleeping time—and this applies to
all mammals.
"I might also point out that the capability for dreaming is
not an attribute of all animal species. In the evolutionary
scale it first appears with birds and with them only to a limited
degree—about point five percent of their sleeping time. All
studies in reptiles and amphibians (e.g. tortoises) give negative
results—there are no dreams in their sleep.
"This gives a
brief summary of recent findings, which will enable us to make
a detailed study of the problems still confronting neurophysiologists
in the phenomena of dreams as well as in the essential function
of dreaming. We are now convinced that dreams play an important
physiological role, although we are not yet in a position to
say just what that role is.
One solitary cat was crouched on
a brick in the middle of a miniature pool and sleeping peacefully
while an electroencephalograph recorded his brain waves. "We
keep him from dreaming," Dr. Jouvet said, "I just explained
that one of the recognized physiological criteria of the
dream phase in animals is disappearance of muscular tone.
This cat can sleep on his brick, but as soon as he begins to
dream his muscular tone disappears, and he falls into the
water. This at once wakes him up, he climbs back on his
brick, licks himself and goes back to sleep—but whenever he
dreams he falls into the water again.
"If we continue the experiment for a week and then put him
back in his cage, we observe that he has such a need to
dream that, instead of spending only twenty percent of his
sleep time dreaming, he will then spend forty percent of it
or more. A kind of compensatory mechanism exists somewhere
in his nervous system.
"For this reason we think that dreaming is not a pointless
phenomenon that occurs every time the nervous system goes
into free wheeling, but that it reflects a specific activity
of the brain and forms an essential part of a process. As to
what the process is, that is what we are trying to discover.
"In recent times we have made great progress in localizing
the centers responsible for the phenomena that accompany
dreaming activity. At first we had to proceed by surgical
guesswork, successively removing various parts of the brain
stem of our experimental animals in order to observe any
disturbance in their sleeping behavior.
"Sleep itself is a highly complex phenomenon, and it had not
yet been decided whether there is a brain center responsible
for sleep or whether simple inhibition of the waking centers
is what causes it.
"However, we have succeeded in precisely
pinpointing the centers responsible for the two principal characteristics
of dreaming activity: first, rapid eye movement, which we call
phase phenomenon and second, the blocking of muscular tone,
which is called a tonic phenomenon.
Cats in a state of hallucination
"Taken together, these two centers are about the size of a pea.
They are located very close to one another, but we can influence
either one at will by different techniques. The
center controlling muscular tone, which is no bigger than a
grape seed, lives his dreams. The powerful blockade
of muscular tone is no longer effective, so that the sleeping
and dreaming animal carries out all the movements that correspond
to the action of his dream. An innocent bystander would get
the impression that he was wide awake and perhaps dangerous,
but in actual fact none of his actions or gestures corresponds
to the outside world in which he is moving. He is asleep and
he acts only in accordance with the fantasies that are passing
through his brain. He is living in an imaginary world—he is
hallucinating.
"As soon as he wakes up, his behavior will become
quite normal.
"In this experiment you can appreciate the importance
of this center: its role in dreaming is primordial. Work is
now in progress to study a possible correlation between these
hallucinatory states and certain mental illnesses.
You might
think that sleepwalking would be due to improper functioning
of this center, but recent experiments have shown that this
phenomenon occurs not during dream periods but in the half awake.
People may also talk at this level of sleep—not during
dreams.
"Another
related question is whether the weightlessness experienced in
cosmic flights may not have unexpected and undesirable effects
upon the astronauts insofar as it creates a state equivalent
to the absence of muscular tone. It
is not a coincidence that the physician chosen to participate
in the first trip to the moon planned by the Americans is a
specialist in sleep.
Dreaming can be regulated at will
"But study of the biochemistry of the phenomenon
associated with dreams will probably lead to the most fascinating
results, and gives us scope to formulate the boldest hypotheses.
In the past few years, chemistry has occupied a solid position
in the study of biologic phenomena.
"
processes of the brain are immensely intriguing to present-day
research men, who expect to find in them the key to the most
complex phenomena.
"Hyden's studies, to cite one example, convincingly
show that biochemistry can open a new point of view on biologic
phenomena as complicated as memory. This is also true of our
studies on dreaming. The REMs, which appear to be at the origin
of the dream stage of sleep, can be blocked or amplified by
chemical inhibitors or precursors. In other words, it is possible,
by means of specific drugs, to deprive an animal of dreams
entirely or to increase them to sixty percent of the time
he sleeps.
"I can offer only one hypothesis, which is
directing our study. It is difficult to verify in the present
state of our knowledge, but so far nothing contradicts it.
Here it is: dreaming activity is inseparable from other activities
of the nervous system. There are not separate states of waking,
sleeping, dreaming; these phenomena make up a continuum that
is characteristic of certain creatures. In the waking state
our nervous system, particularly the brain, perceives a certain
number of sensations and records or memorizes them in chemical
form by synthesizing molecules of specific proteins. This
synthesis takes place through a highly complex process.
"This conversion of incoming information into
a coded chemical schema is not instantaneous. The chemical
factory of our brain needs time to store, select and classify
information according to a code that is still to be defined.
We might say that the waking state is equivalent to recording
information on a dictaphone; during deep sleep this information
is typed out; and in the course of dreaming, each page or
each sentence, or even each word is classified in a file cabinet
along with previous information that is stored away in terms
of a careful, previously-established code.
"This would explain why our dreams contain
numerous images corresponding to impressions received in the
waking state, and also why some of this information is completely
deformed or symbolized. This synthesis of events of the day
in dreams would imply a "trituration" of information, together
with a review of previous information already classified and
coded.
"This hypothesis would also explain why newborn
infants and young animals have a high percentage of dreaming
time—more than twice as much as adults.
"I must admit that this hypothesis, although
it links dreams to learning and memory, encounters a number
of obstacles, it fails to explain why this function suddenly
appears in the evolution of species with the bird, to be magnified
in a kind of explosion with the mammals.
"We must wait some years for the neurophysiologists
to carry out further experiments and to interpret them; but
it seems to be already well-established that dreams have once
and for all left the world of unreality for the world of the
laboratory."
(1 894 words)
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