ŚFiNiA

Genkaku

Naukowiec Bill Newsome chce zaaplikować sobie implant do mózgu, by lepiej zrozumieć ludzką świadomość.

Naukowcy uczą się wciąż tego jak mózg dokonuje ułamkowosekundowych decyzji, jak uczy się na błędach, jak tłumaczy impulsy świetlne na złożone sceny wizualne. Odkodowanie 'języka' impulsów elektrycznych to tylko połowa historii. Drugą połową jest pytanie: jak mózg tłumaczy aktywność na świadomość - samoświadomość i percepcję świata wokół danej osoby.

Bill Newsome mam obsesję na punkcie pytania: W jaki sposób świadomość powstaje z funkcji mózgu ? Uważa on, że najlepszym sposobem na poznanie odpowiedzi jest umieszczenie elektrody w swoim mózgu - i obserwowanie jak elektryczność zmienia jego percepcję świata.

Bill Newsome twierdzi, iż jednym z nabardziej interesujących kwestii w neurobiologii jest właśnie problem powstawania świadomości z funkcjonowania mózgu.

Zbanowany Uczy

Czy znasz już jedną z moich ulubionych stron: [link widoczny dla zalogowanych]
? (jest również forum)

wujzboj

Bardzo ciekawe doswiadczenie. Ale zanim zacznie sie z niego wyciagac wnioski, warto przedtem zastanowic sie, czego ono dotyczy, a czego nie dotyczy. Patrz Śmierć nauki?

Genkaku

Zbanowany Uczy, tak znam tę stronkę. Mi także się podoba.

Wujzboj, ale co ma do rzeczy Twój artykuł Śmierć nauki ?

wujzboj

Tylko tyle, o czym wspomnialem: zeby nie mylic swiadomosci w roznym znaczeniu tego slowa. Jak wiesz, jest to powszechne, wiec warto przypominac, gdy sie zaczyna rozmowe o swiadomosci w naukowym znaczeniu tego slowa.

Genkaku

A jakie są znaczenia tego słowa ? Poza naukowym.

wujzboj

A widzisz. O tym wlasnie jest w artykule "Smierc nauki"

Bart · Wysłany: Czw 19:32, 02 Mar 2006 Temat postu:

W ostatnim "Świecie Nauki" jest artykuł właśnie na temat świadomości. Jeszcze nie przeczytałem ;) ale może ktoś by chciał wiedzieć.

wujzboj · Wysłany: Czw 20:34, 02 Mar 2006 Temat postu:

Jak przeczytasz to moze podzielisz sie wrazeniami?

Bart · Wysłany: Czw 20:51, 02 Mar 2006 Temat postu:

Zbanowany Uczy · Wysłany: Czw 20:58, 02 Mar 2006 Temat postu:

Nic nowego już nie napiszą. Mi świadomość już wychodzi uszami.
Macie i smacznego:

Science News Online

Week of Feb. 11, 2006; Vol. 169, No. 6

Self-Serve Brains

Personal identity veers to the right hemisphere

Bruce Bower

The concept of identity theft assumes an entirely new meaning for
people with brain injuries that rob them of their sense of
self—the unspoken certainty that one exists as a person in a
flesh—bounded body with a unique set of life experiences and
relationships. Consider the man who, after sustaining serious brain
damage, insisted that his parents, siblings, and friends had been
replaced by look-alikes whom he had never met. Everyone close to him
had become a familiar-looking stranger. Another brain-injured patient
asserted that his physicians, nurses, and physical therapists were
actually his sons, daughters-in-law, and coworkers. He identified
himself as an ice skater whom he had seen on a television program.

[IMAGE] Brain-damaged patients can experience strange alterations of
self-knowledge. Investigations of such cases and of brain activity
during normal self-recognition suggest that the right brain
orchestrates the sense of "I." But it's still unclear how the brain
fosters one's ability to distinguish oneself from others.
Artville

The sense of "I" can also go partially awry. After a stroke had left
one of her arms paralyzed, a woman reported that the limb was no
longer part of her body. She told a physician that she thought of the
arm as "my pet rock."

Other patients bequeath their physical infirmities to phantom
children. For instance, a woman blinded by a brain tumor became
convinced that it was her child who was sick and blind, although the
woman had no children.

These strange transformations and extensions of personal identity are
beginning to yield insights into how the brain contributes to a sense
of self, says neuroscientist Todd E. Feinberg of Beth Israel Medical
Center in New York City. Thanks to technology that literally gets
inside people's heads, researchers now are probing how the brain
contributes to a sense of self and to perceptions of one's body and
its control. Scientists expect that their efforts to shed light on
the vexing nature of consciousness, as well as on the roots of mental
disorders, such as schizophrenia, characterized by disturbed
self-perception.

I spy

Scholars have argued for more than 300 years about whether a unified
sense of self exists at all. A century ago, Sigmund Freud developed
his concept of ego, a mental mechanism for distinguishing one's body
and thoughts from those of other people. Around the same time,
psychologist William James disagreed, writing that each person's
"passing states of consciousness" create a false sense that an "I" or
an ego runs the mental show.

Researchers still debate whether the self is the internal engine of
willful behavior or simply a useful fiction that makes a person feel
responsible for his or her actions. Some investigators argue that
each person harbors many selves capable of emerging in different
situations and contexts.

Regardless of philosophical differences, Feinberg notes, evidence
suggests that the brain's right hemisphere often orchestrates basic
knowledge about one's self, just as the left hemisphere usually
assumes primary responsibility for language.

Disorders of the self caused by brain damage fall into two main
categories, Feinberg proposes. Some patients lose their personal
connection to significant individuals or entities, such as the man
who thought everyone he knew was a familiar stranger and the woman
who regarded her lifeless arm as a pet rock. Other patients perceive
personal connections where they don't exist, such as the man who saw
his medical caretakers as family and coworkers and the woman who
mentally conceived a phantom daughter.

In both categories, Feinberg says, "right brain damage is much more
likely than left brain damage to cause lasting disturbances of the
normal relationship between individuals and their environments."

Other neuroscientists take a similar view. According to brain-imaging
studies conducted by researchers including Jean Decety and Jessica A.
Sommerville, both of the University of Washington in Seattle, during
the past 3 years, a right brain network located mainly in the frontal
lobe organizes neural efforts aimed at discerning one's body and
thoughts. That network overlaps a brain circuit that plays a role in
identifying others, perhaps contributing to the two-sided nature of
the self as "special and social, unique and shared," Decety and
Sommerville said in a seminal 2003 article.

The right me

In order to coordinate the relationship between the self and the
world, the brain takes sides, according to work by Feinberg and
Julian Paul Keenan of Montclair State University in New Jersey. They
analyzed patterns of brain damage in 29 previously published cases of
disordered selves. Injury to the frontal region of the right
hemisphere occurred in 28 people, compared with left-frontal damage
in 14.

[IMAGE]
Alfred Gescheidt

Ten of the patients had also incurred injuries to other parts of the
right brain, compared with three individuals who displayed damage in
other left brain areas, Feinberg and Keenan report in the December
2005 Consciousness and Cognition.

Research in the past decade on the recognition of one's face reached
similar conclusions. In a study directed by Keenan, adults with no
known brain impairment viewed images that gradually transformed from
their own faces into the face of a famous person such as Marilyn
Monroe or Bill Clinton. Participants alternated using their left or
right hands to hit keys that indicated whether they saw themselves or
a famous person in each composite image.

When responding with their left hands, volunteers identified
themselves in composite images more often than when they used their
right hands. Since each side of the brain controls movement on the
opposite side of the body, the left-handed results implicated the
right brain in self-recognition.

Similar findings came from epileptic patients who underwent a medical
procedure in which one brain hemisphere at a time was anesthetized.
Keenan and his colleagues showed each patient an image that blended
features of his or her own face with facial features of a famous
person and later asked whose face the patient had seen. When tested
with only the right brain awake, most patients reported that they had
seen their own faces. When only the left brain was active, they
usually recalled having seen the famous face.

A brain-scan investigation of 10 healthy adults, published in the
April 15, 2005 NeuroImage, also implicates the right hemisphere in
self-recognition. A team led by Lucina Uddin of the University of
California, Los Angeles showed volunteers a series of images that, to
varying degrees, blended their own faces with those of same-sex
coworkers. Participants pressed keys indicating whether they saw
themselves or a coworker in each image.

Pronounced blood flow, a sign of heightened neural activity, appeared
in certain parts of the right hemisphere only when the participants
recognized themselves, Uddin's group reports. Previous studies in
monkeys indicated that these areas of the brain contain so-called
mirror neurons, which respond similarly when an animal executes an
action or observes another animal perform the same action (SN:
12/10/05, p. 373: Available to subscribers at
[link widoczny dla zalogowanych]).

A right brain network of these mirror neurons maintains an internal
self-image for comparison with faces that one sees, Uddin and her
colleagues propose.

Still, not everyone regards the right brain as central to the self.
Todd F. Heatherton of Dartmouth College in Hanover, N.H., and his
coworkers reported in 2003 on a patient who had had surgery to
disconnect the bundle of nerve fibers that connects the neural
hemispheres. That split-brain patient recognized himself in images
that blended his features with those of one of the researchers only
when the images appeared in his right visual field and were thus
handled by his left brain.

"Recognition of the self is one of the most basic, yet poorly
understood, cognitive operations," Uddin says.

Losing control

Chris Frith, a neuroscientist at University College London, has long
wondered why people diagnosed with schizophrenia often experience
their own actions as being controlled by others. A person with this
severe mental disorder may report, for example, that space aliens
ordered him to behave destructively.

Fifteen years ago, Frith thought that schizophrenia robbed people of
the ability to monitor their intentions to act. If their behavior
came as a complete surprise, they might attribute it to external
forces.

Frith abandoned that idea after reading neurologists' reports of a
strange condition called anarchic-hand syndrome. Damage to motor
areas on one side of the brain leaves these patients unable to
control the actions of the hand on the opposite side of the body. For
example, when one patient tried to soap a washcloth with his right
hand, his left hand, much to his chagrin, kept putting the soap back
in its dish. Another patient used one hand to remove the other from
doorknobs, which it repeatedly grabbed as he walked by doors.

Despite being unaware of any intention to use a hand in these ways,
anarchic-hand patients don't experience their behavior as controlled
by space aliens or another outside entity—they just try to
correct their wayward hands.

Frith now suspects that anarchic-hand syndrome and schizophrenia's
delusions of being controlled by others share a neural defect that
makes it seem like one's movements occur passively. However, people
with schizophrenia mistakenly perceive the passive movements as
having been intentional.

In support of this possibility, Frith and his colleagues find that
when shown scenes of abstract shapes moving across a computer screen,
patients with schizophrenia, but not mentally healthy volunteers,
attribute good and bad intentions to these shapes. Patients with
schizophrenia may monitor their own actions in excruciating detail
for signs of external control, Frith suggests.

In general, people rarely think about their selves but act as if such
entities must exist. "The normal mark of the self in action is that
we have very little experience of it," Frith says.

Harvard University psychologist Daniel Wegner goes further. Expanding
the view of William James, Wegner argues that the average person's
sense of having a self that consciously controls his or her actions
is an illusion. This controversial proposal builds on an experiment
conducted more than 20 years ago by neurophysiologist Benjamin Libet
of the University of California, San Francisco.

Libet found that although volunteers' conscious decisions to perform
a simple action preceded the action itself, they occurred just after
a distinctive burst of electrical activity in the brain signaled the
person's readiness to move. In other words, people decided to act
only after their brains had unconsciously prepared them to do so.

Wegner has since performed experiments demonstrating the ease with
which people claim personal responsibility for actions that they have
not performed. In one study, participants looked in a mirror at the
movements of an experimenter's arms situated where their own arms
would be. When the arms moved according to another researcher's
instructions, volunteers reported that they had willed the movements.

Feinberg says that these findings offer no reason to write off the
self as a mental mirage.

Waist not

A young woman stands in neuroscientist J. Henrik Ehrsson's laboratory
at London's University College and places her palms on her waist.
Cuffs placed over her wrists begin to vibrate tendons just under the
skin, creating the sensation that her hands are bending inward. At
the same time, the woman feels her waist and hips shrink by several
inches to accommodate the imagined hand movements. Dr. Ehrsson's
illusory instant-waist-loss program lasts only about 30 seconds.

Ehrsson and his coworkers used a brain-imaging machine to measure
blood flow in the brains of 24 people as they experienced this
illusion. Parts of the left parietal cortex, located near the brain's
midpoint, displayed especially intense activity as volunteers felt
their waists contract, the scientists report in the December 2005
PloS Biology.

The greater the parietal response, the more waist shrinkage the
individual reported.

The scientists suspect that the activated parietal areas integrate
sensory information from different body parts, a key step in
constructing an internal image of one's body size and shape. When the
brain receives a message that the hands are bending into the waist,
it adjusts the internal body image accordingly, Ehrsson's team
hypothesizes.

The brain can adjust its internal body map in a matter of minutes,
the experiment demonstrates. Researchers who similarly induced
illusions of expanding fingers came to that same conclusion (SN:
7/30/05, p. 69: Available to subscribers at
[link widoczny dla zalogowanych]).

The possibility that the brain can redraw body image in dramatic ways
resonates with neuroscientist Miguel A.L. Nicolelis of Duke
University Medical Center in Durham, N.C., and his colleagues.
They've found that after monkeys learn to alter their brain activity
to control a robotic arm, the animals' brains show the same activity
pattern as when they move their own limbs.

Nicolelis' team reported in 2003 that the researchers had implanted
electrodes in the frontal and parietal lobes of the brains of two
female rhesus monkeys that used a joystick to control a cursor on a
computer screen. That action maneuvered a robotic arm in another
room. The animals gradually learned to modulate their brain signals
to reposition the cursor, without moving a muscle.

Electrode data show that, after training, many neurons that formerly
emitted synchronized signals as the monkeys manually manipulated the
joystick to control the robotic arm also did so when the animals
performed the same task mentally. Those results appeared in the May
11, 2005 Journal of Neuroscience.

The monkeys assimilated into their neural self-images a tool that
they had learned to use proficiently, Nicolelis suggests. Apes and
people possess an even stronger capacity for integrating tools into
the brain's definition of self, in his view. This process may
underlie the acquisition of expertise (SN: 4/12/03, p. 234: Available
to subscribers at
[link widoczny dla zalogowanych]).

"Our brains' representations of our bodies are adaptable enough to
incorporate any tools that we create to interact with the
environment, from a robot appendage to a computer keyboard or a
tennis racket," Nicolelis says.

Self doubts

Despite the proliferation of such studies, the self's special status
in the brain is far from assured. After reviewing relevant brain
imaging and psychology studies, neuroscientists Seth J. Gillihan and
Martha J. Farah, both of the University of Pennsylvania in
Philadelphia, found little compelling evidence for brain networks
devoted solely to physical or psychological aspects of the self.

At most, work such as Feinberg's with brain-damaged patients
indicates that singular brain networks distinguish between one's
limbs and those of other people, the researchers say. There are also
suggestions that other brain areas foster a sense of control over
one's limb movements, Gillihan and Farah reported in the January 2005
Psychological Bulletin.

Still, much of what we typically think of as "the self" may not be
assignable to brain states or structures, in their view.

Feinberg argues that each of the increasingly complex levels of the
brain—including the brain stem, the limbic system, and the
cortex—contributes to intentional actions and to perceiving
meaning in the world, the main ingredients of an "inner I."

Brain-damaged patients vividly illustrate the self's resiliency,
Feinberg adds. While injury to the right frontal brain transforms
some patients' identities in odd ways, other comparably injured
patients somehow maintain their old selves.

A person's coping style and emotional resources usually influence
responses to right brain damage, according to Feinberg's clinical
observations. For example, one patient, a young man living half a
world away from his family, referred to his paralyzed left arm as his
brother's arm.

Feinberg asked the man what it meant to him to possess his sibling's
arm rather than his own. "It makes me feel good," the man responded,
in a voice choked with emotion. "Having my brother's arm makes me
feel closer to my family."

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References:

Ehrsson, H.H., et al. 2005. Neural substrate of body size: Illusory
feeling of shrinking of the waist. PLoS Biology 3(December):e412.
Available at [link widoczny dla zalogowanych]

Feinberg, T.D., and J.P. Keenan. 2005. Where in the brain is the
self? Consciousness and Cognition 14(December):647-790. Abstract
available at [link widoczny dla zalogowanych]

Feinberg, T.E. 2001. Altered Egos: How the Brain Creates the Self.
New York: Oxford University Press.

Frith, C. 2005. The self in action: Lessons from delusions of
control. Consciousness and Cognition 14(December):752-770. Abstract
available at [link widoczny dla zalogowanych]

Gillihan, S.J., and M.J. Farah. 2005. Is self special? A critical
review of evidence from experimental psychology and cognitive
neuroscience. Psychological Bulletin 131(January):76-97. Abstract
available at [link widoczny dla zalogowanych]

Heatherton, T.F., C.N. Macrae, and W.M. Kelley. 2004. What the social
brain sciences can tell us about the self. Current Directions in
Psychological Science 13(October):190-193. Abstract available at
[link widoczny dla zalogowanych]

Lebedev, M.A.... and M.A.L. Nicolelis. 2005. Cortical ensemble
adaptation to represent velocity of an artificial actuator controlled
by a brain-machine interface. Journal of Neuroscience 25(May
11):4681-4693. Available at
[link widoczny dla zalogowanych]

Uddin, L.Q., et al. 2005. Self-face recognition activates a
frontoparietal "mirror" network in the right hemisphere: an
event-related fMRI study. NeuroImage 25(April 15):926-935. Abstract
available at [link widoczny dla zalogowanych]

Wegner, D.M. 2003. The mind's best trick: How we experience conscious
will. Trends in Cognitive Sciences 7(February):65-69. Abstract
available at [link widoczny dla zalogowanych](03)00002-0.

Further Readings:

Bower, B. 2005. Mirror cells' fading spark: Empathy-related neurons
may turn off in autism. Science News 168(Dec. 10):373. Available to
subscribers at [link widoczny dla zalogowanych]

______. 2005. Fickle finger's funny feel: Digit illusion modifies
touch perception. Science News 168(July 30):69. Available to
subscribers at [link widoczny dla zalogowanych]

______. 2003. The stone masters. Science News 163(April 12):234-236.
Available to subscribers at
[link widoczny dla zalogowanych]

Sources:

H. Henrik Ehrsson
Functional Imaging Lab
Wellcome Department of Imaging Neuroscience
12 Queen Square
London WC1N 3BG
United Kingdom

Martha J. Farah
University of Pennsylvania
Center for Cognitive Neuroscience
3720 Walnut Street
Philadelphia, PA 19104

Todd E. Feinberg
Albert Einstein College of Medicine
Beth Israel Medical Center
New York, NY 10003

Chris Frith
Institute of Neurology
Wellcome Department of Imaging Neuroscience
University College London
12 Queen Square
London WC1N 3BG
United Kingdom

Seth J. Gillihan
University of Pennsylvania
Center for Cognitive Neuroscience
3720 Walnut Street
Philadelphia, PA 19104

Todd F. Heatherton
Department of Psychological and Brain Sciences
6207 Moore Hall
Dartmouth College
Hanover, NH 03755

Miguel A.L. Nicolelis
Department of Neurobiology
Duke University Medical Center
Bryan Research Building
Box 3209
Durham, NC 27710

Lucina Q. Uddin
Department of Psychology
University of California, Los Angeles
Box 951563
B627 Franz Hall
Los Angeles, CA 90095

Daniel M. Wegner
Department of Psychology
Harvard University
1470 William James Hall
33 Kirkland Street
Cambridge, MA 02138

[link widoczny dla zalogowanych]

From Science News, Vol. 169, No. 6, Feb. 11, 2006, p. 90.

Copyright (c) 2006 Science Service. All rights reserved.

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wujzboj · Wysłany: Czw 21:15, 02 Mar 2006 Temat postu:

Rzeczywiscie.

Ale temat podnieca czytelnikow, bo wyobrazaja sobie, ze mowa jest o tym, skad sie bierze i pochodzi ich swiadomosc, a nie o tym, jakie zwiazki zachodza miedzy elementami wplywajacymi na doswiadczane przez nich tresci.

Maniana

Śiadomość metafizyki, percepcja myśli, docieranie do głębi, w celu pozytywnych relacji, impulsów; wysyłania i odbierania czynników określających jednostkę.
Jak to nazwiecie ?

Maniana

Mając za sobą bagaż doświadczeń interpersonalnych powiedzcie czy demagogią jest przeproszenie Kardynała Dziwisza, a to : wszystkich którzy uważają, że zostali skrzywdzeni przez ksizęzy przepraszm czy tak ?

Drizzt

Maniano - ja tępy moderator jestem - czy możesz po krótce wyjaśnić związek swojego pytania z tematem?