Dreams are tune-ups?
Lance
A Dream Interpretation: Tuneups for the Brain
By BENEDICT CAREY
It’s snowing heavily, and everyone in the backyard is in a swimsuit,
at some
kind of party: Mom, Dad, the high school principal, there’s even an
ex-girlfriend. And is that Elvis, over by the piñata?
Uh-oh.
Lou Beach
Dreams are so rich and have such an authentic feeling that scientists
have long
assumed they must have a crucial psychological purpose. To Freud,
dreaming
provided a playground for the unconscious mind; to Jung, it was a
stage where
the psyche’s archetypes acted out primal themes. Newer theories hold
that dreams
help the brain to consolidate emotional memories or to work through
current
problems, like divorce and work frustrations.
Yet what if the primary purpose of dreaming isn’t psychological at
all?
In a paper published last month in the journal Nature Reviews
Neuroscience, Dr.
J. Allan Hobson, a psychiatrist and longtime sleep researcher at
Harvard, argues
that the main function of rapid-eye-movement sleep, or REM, when most
dreaming
occurs, is physiological. The brain is warming its circuits,
anticipating the
sights and sounds and emotions of waking.
“It helps explain a lot of things, like why people forget so many
dreams,” Dr.
Hobson said in an interview. “It’s like jogging; the body doesn’t
remember every
step, but it knows it has exercised. It has been tuned up. It’s the
same idea
here: dreams are tuning the mind for conscious awareness.”
Drawing on work of his own and others, Dr. Hobson argues that dreaming
is a
parallel state of consciousness that is continually running but
normally
suppressed during waking. The idea is a prominent example of how
neuroscience is
altering assumptions about everyday (or every-night) brain functions.
“Most people who have studied dreams start out with some predetermined
psychological ideas and try to make dreaming fit those,” said Dr. Mark
Mahowald,
a neurologist who is director of the sleep disorders program at
Hennepin County
Medical Center, in Minneapolis. “What I like about this new paper is
that he
doesn’t make any assumptions about what dreaming is doing.”
The paper has already stirred controversy and discussion among
Freudians,
therapists and other researchers, including neuroscientists. Dr.
Rodolfo Llinás,
a neurologist and physiologist at New York University, called Dr.
Hobson’s
reasoning impressive but said it was not the only physiological
interpretation
of dreams.
“I argue that dreaming is not a parallel state but that it is
consciousness
itself, in the absence of input from the senses,” said Dr. Llinás, who
makes the
case in the book “I of the Vortex: From Neurons to Self” (M.I.T.,
2001). Once
people are awake, he argued, their brain essentially revises its dream
images to
match what it sees, hears and feels — the dreams are “corrected” by
the senses.
These novel ideas about dreaming are based partly on basic findings
about REM
sleep. In evolutionary terms, REM appears to be a recent development;
it is
detectable in humans and other warm-blooded mammals and birds. And
studies
suggest that REM makes its appearance very early in life — in the
third
trimester for humans, well before a developing child has experience or
imagery
to fill out a dream.
In studies, scientists have found evidence that REM activity helps the
brain
build neural connections, particularly in its visual areas. The
developing fetus
may be “seeing” something, in terms of brain activity, long before the
eyes ever
open — the developing brain drawing on innate, biological models of
space and
time, like an internal virtual-reality machine. Full-on dreams, in the
usual
sense of the word, come much later. Their content, in this view, is a
kind of
crude test run for what the coming day may hold.
None of this is to say that dreams are devoid of meaning. Anyone who
can
remember a vivid dream knows that at times the strange nighttime
scenes reflect
real hopes and anxieties: the young teacher who finds himself naked at
the
lectern; the new mother in front of an empty crib, frantic in her
imagined loss.
But people can read almost anything into the dreams that they
remember, and they
do exactly that. In a recent study of more than 1,000 people,
researchers at
Carnegie Mellon University and Harvard found strong biases in the
interpretations of dreams. For instance, the participants tended to
attach more
significance to a negative dream if it was about someone they
disliked, and more
to a positive dream if it was about a friend.
In fact, research suggests that only about 20 percent of dreams
contain people
or places that the dreamer has encountered. Most images appear to be
unique to a
single dream.
Scientists know this because some people have the ability to watch
their own
dreams as observers, without waking up. This state of consciousness,
called
lucid dreaming, is itself something of a mystery — and a staple of New
Age and
ancient mystics. But it is a real phenomenon, one in which Dr. Hobson
finds
strong support for his argument for dreams as a physiological warm-up
before
waking.
In dozens of studies, researchers have brought people into the
laboratory and
trained them to dream lucidly. They do this with a variety of
techniques,
including auto-suggestion as head meets pillow (“I will be aware when
I dream; I
will observe”) and teaching telltale signs of dreaming (the light
switches don’t
work; levitation is possible; it is often impossible to scream).
Lucid dreaming occurs during a mixed state of consciousness, sleep
researchers
say — a heavy dose of REM with a sprinkling of waking awareness. “This
is just
one kind of mixed state, but there are whole variety of them,” Dr.
Mahowald
said. Sleepwalking and night terrors, he said, represent mixtures of
muscle
activation and non-REM sleep. Attacks of narcolepsy reflect an
infringement of
REM on normal daytime alertness.
In study published in September in the journal Sleep, Ursula Voss of
J. W.
Goethe-University in Frankfurt led a team that analyzed brain waves
during REM
sleep, waking and lucid dreaming. It found that lucid dreaming had
elements of
REM and of waking — most notably in the frontal areas of the brain,
which are
quiet during normal dreaming. Dr. Hobson was a co-author on the paper.
“You are seeing this split brain in action,” he said. “This tells me
that there
are these two systems, and that in fact they can be running at the
same time.”
Researchers have a way to go before they can confirm or fill out this
working
hypothesis. But the payoffs could extend beyond a deeper understanding
of the
sleeping brain. People who strugglewith schizophrenia suffer delusions
of
unknown origin. Dr. Hobson suggests that these flights of imagination
may be
related to an abnormal activation of a dreaming consciousness. “Let
the dreamer
awake, and you will see psychosis,” Jung said.
For everyone else, the idea of dreams as a kind of sound check for the
brain may
bring some comfort, as well. That ominous dream of people gathered on
the lawn
for some strange party? Probably meaningless.
No reason to scream, even if it were possible.
Peter Brooks
>
>
> These novel ideas about dreaming are based partly on basic findings
> about REM
> sleep. In evolutionary terms, REM appears to be a recent development;
> it is
> detectable in humans and other warm-blooded mammals and birds.
>
and birds is pretty ancient. Or is the suggestion that it is recent
parallel evolution? If so, do octopuses dream? [google finds tons of
'interpretations' of octopus dreams, but not much about dreaming
octopuses]
>
> For everyone else, the idea of dreams as a kind of sound check for the
> brain may
> bring some comfort, as well. That ominous dream of people gathered on
> the lawn
> for some strange party? Probably meaningless.
>
> No reason to scream, even if it were possible.
>
large gathering - strange, and a party, but not, as far as I could
tell, the least bit ominous. Odd things about it were the presence of
my dead mother and brother, but no inclination on my part to chat to
them - and the most excellent smoked salmon on brown bread that the
waiter prepared for me despite my being late for supper - and the
peculiar thing of a large party being in the house, but supper only
for six of us.
The idea of schizophrenia being a leakage between dreaming and
conscious thought is also mentioned by David Horrobin as a source of
creativity, so long as the leakage is not too extreme.
Peter Brooks
"
Meanwhile, Anderson has been investigating another phenomenon little-
noted in invertebrates: sleep. Until recently, only vertebrates were
believed to sleep in the full metabolic sense. But Anderson has
observed that octopuses, ordinarily hypervigilant, may sleep deeply.
Their eyes glaze over, their breathing turns slow and shallow, they
don't respond to light taps, and a male will let his delicate ligula—
the sex organ at the tip of one arm—dangle perilously.
Stephen Duntley, a sleep specialist at Washington University Medical
School in St. Louis, has videotaped similar slumber in cuttlefish,
with a twist: Sleeping cuttlefish lie still, their skin a dull brown,
for 10- to 15-minute stretches, then flash bold colored patterns and
twitch their tentacles for briefer intervals. After viewing Duntley's
footage, Anderson suggests the cuttlefish might merely be waking to
check for threats. But Duntley says the cycling resembles the rapid
eye movement sleep of birds and mammals, when humans dream. If
invertebrates undergo a similar cycle, Duntley argues, it would affirm
"that REM sleep is very important to learning." Would it also suggest
that cuttlefish and octopuses dream? "That's the ultimate question,"
Duntley responds.
"
http://discovermagazine.com/2003/oct/feateye