Received: by alpheratz.cpm.aca.mmu.ac.uk id SAA28466 (8.6.9/5.3[ref pg@gmsl.co.uk] for cpm.aca.mmu.ac.uk from fmb-majordomo@mmu.ac.uk); Fri, 13 Apr 2001 18:56:33 +0100 Subject: Fwd: Best place to locate the 'self' is in the brain Date: Fri, 13 Apr 2001 13:52:18 -0400 x-sender: wsmith1@camail2.harvard.edu x-mailer: Claris Emailer 2.0v3, Claritas Est Veritas From: "Wade T.Smith" <wade_smith@harvard.edu> To: "memetics list" <memetics@mmu.ac.uk> Content-Type: text/plain; charset="iso-8859-1" Content-transfer-encoding: quoted-printable Message-ID: <20010413175231.AAA26056@camailp.harvard.edu@[128.103.125.215]> Sender: fmb-majordomo@mmu.ac.uk Precedence: bulk Reply-To: memetics@mmu.ac.uk
Best place to locate the 'self' is in the brain
By William J. Cromie
Gazette Staff
http://www.hno.harvard.edu/gazette/2001/04.12/01-selfawareness.html
If you train a monkey to look in a mirror, then put a dab of odorless red
dye on its eyebrow, the monkey will try to rub the dye off the mirror. If
you do the same with a chimpanzee, this more advanced ape will wipe its
own eyebrow.
This simple test is an indicator of self-awareness.
"The chimp is aware of its own mental state; the monkey is not," says
Alvaro Pascual-Leone, associate professor of neurology at the Harvard
Medical School. "The ape can access a whole series of individual and
social behaviors that lie outside the mental reach of the monkey."
Psychologist Julian Keenan, Pascual-Leone, and their colleagues have
devised experiments to learn how self-awareness arises in humans. They
seek a scientific answer to a question posed by 16th century philosopher
René Descartes: "What is this 'I' that I know?"
Pascual-Leone works with epileptic patients at the Beth Israel Deacones
Medical Center, a Harvard teaching hospital in Boston. He carefully scans
the brains of these patients to find areas that control memory and
language. These places must be avoided during surgery that treats their
epilepsy.
Five such patients gave him permission to piggyback a self-awareness test
on this preoperative procedure. "In a sense," he says, "we borrowed their
illness. And we are very grateful that they let us use it."
A human brain consists of two hemispheres connected by thick cables of
nerves. The researchers administered an anesthetic first to the front of
one hemisphere, then to the front of the other. While one hemisphere
slept, the other was shown a composite picture of the brain's owner
morphed with that of a famous person like Marilyn Monroe or Bill Clinton.
When the anesthetic wore off, the experimenters showed the patients'
pictures of themselves and of the famous person, and asked which they saw
while one half of their brain slept. They hadn't, of course, seen either
one, but they had to make a choice. (Brain regions drugged by researchers
were not near areas where epileptic seizures occurred, so their illness
would have nothing to do with the outcome.)
All of those who saw the composite with the right side of their brain
awake chose their own picture. Those with the left hemisphere awake
overwhelmingly (four out of five) picked the celebrity.
Thus, the right hemisphere, usually considered the emotional side of the
brain, must be critical for seeing one's self in a picture, while the
left side, usually thought of as a seat of logic, is not so attuned to
the self. (All the subjects were right-handed; things might come out
different with lefties.)
Self centers
Does this mean that our self-awareness is centered on the right side of
our brains, behind the forehead and temple, at least in most right-handed
people? "The frontal part of the right hemisphere is critical for
recognizing ourselves," Pascual-Leone answers. "People with damage to
that area have problems remembering things that relate to themselves or
with being in touch with their own person. But this doesn't mean that's
where the self is."
He and Keenan think that answer is too simple. "I doubt if any one
function is centered in a particular part of the brain," Pascual-Leone
says. "We know it's not true for memory and language. Like those
functions, we believe 'self' arises from the interaction of different
areas in the brain. Although the right frontal area is essential for a
healthy 'self,' it's not the whole story."
One possibility would involve interplay with the limbic system,
substructures deep in the center of the brain that govern emotion.
There's a lot of scientific suggestion and some evidence, but no proof,
that this emotional part of the brain and the right frontal cortex act
together to generate self-consciousness. Descartes might have said, "I
feel what I think, therefore I know who I am."
A striking bit of evidence for a connection between the frontal cortex
and emotional behavior comes from the bizarre story of Phineas Gage. In
1848, during construction of a railroad in Vermont, an accident drove a
31/2-foot iron rod into Gage's face between his jaw and cheek. About an
inch in diameter, the rod passed through his face and the front of his
brain, exiting through the top of his skull.
Remarkably, Gage survived. He suffered no obvious impairment of sight,
movement, speech, learning, memory, or intelligence. But he became a
different man. Once responsible, intelligent, well-adjusted, and
well-liked, Gage became profane and capricious; he could not be trusted
and offended everyone around him. Gage lived another 13 years, wandering
about the country and never holding a responsible job.
In the words of his former friends, "Gage was no longer Gage." He had
lost his original sense of self.
Making virtual patients
To probe more deeply into how the self operates, Keenan, Pascual-Leone,
and their team briefly disrupted the brains of 10 normal volunteers. They
used strong but harmless magnetic fields to induce electrical changes in
precise areas of the brain. While the volunteers looked at composite
photographs of themselves and famous people, parts of their right or left
hemispheres were disorganized with magnetic stimulation for a half-second
or less. This setup revealed significantly more activity in the front of
the right hemispheres of people when pictures looked more like themselves
than when they looked like someone else.
Keenan then created movies showing a gradual transition from a famous or
familiar face to a self-face. At the point where a subject recognized his
or her own face, he or she pressed a stop button with the left or right
hand. To evaluate the result, you must know about a peculiarity of human
anatomy, namely that the right side of the brain controls the left hand
and vice versa. When the left hand of a right-handed person makes a move,
the right side of the brain guides that movement.
This neat little experiment showed that the right hemisphere is faster at
recognizing self than the left. It also showed that the left hemisphere
more quickly recognizes the self than a celebrity or a familiar friend.
In other words, everyone is faster at picking his or her face out of a
crowd than any other face.
It's nice to know how your brain finds yourself, but does it have any
practical value?
"Understanding the brain essence of self-awareness helps us come closer
to understanding what makes us conscious human beings," Pascual-Leone
answers. "We are able to reflect on ourselves and our actions. We are
able to project intentions into the actions of others. Without such
knowledge we have an impaired relationship with our social surroundings."
That happens in some mental illnesses, like autism and schizophrenia.
Autistic people, for example, lack an emotional response to self.
"Understanding more about what goes on in the brains of such people is a
first step to treating their illnesses, in bridging the gap between
abnormal and normal," Pascual-Leone says.
Experiments will continue in an effort to find out how the rest of the
brain interacts with the right frontal area to generate self-awareness.
Keenan now does this kind of probing at the Mt. Sinai Medical Center in
New York City. In Boston, Pascual-Leone continues to search for
connections between the thinking and emotional parts of the brain. He
believes that "the right frontal cortex provides a window to the
emotional or limbic area deep in the center of the brain. I see a bridge
between these two regions, between the cognitive and the emotional. I
think it is necessary to cross that bridge to gain a sense of self, to
find the 'I' that we know."
Copyright 2001 by the President and Fellows of Harvard College
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