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I'll try and explain; which parts in particular?

This is a very interesting article because although they are not
mentioned explicitly, a wealth of research implicates not only dopamine,
but certain areas of the basal ganglia in these reward phenomena

-----Original Message-----
From: Parkinson's Information Exchange Network
[mailto:[log in to unmask]] On Behalf Of (Tony Su)
Sent: 20 February 2002 14:24
To: [log in to unmask]
Subject: Re: NYT article: starring...dddopamine

Hi:

Thank Kathleen for this info but would anyone of medical professionals
explain more.....I don't quite understand but I believe some of the
activities mentioned I have had overdone....

I was recently diagnosis of PD but still not sure...coz it seems too
early (only 43) and don't have any family history with PD.

Looking forward to enlighten me.



Tony from Taipei



Kathleen Cochran <[log in to unmask]> wrote:

>This from today's NY Times...I am not sure I follow it all, but it
>underscores that dopamine (and lack thereof) is complicated and potent.
>
>Kathleen
>
>
>February 19, 2002
>
>
>Hijacking the Brain Circuits With a Nickel Slot Machine
>
>
>By SANDRA BLAKESLEE
>
>
>Compulsive gambling, attendance at sporting events, vulnerability to
>telephone scams and exuberant investing in the stock market may not
seem to
>have much in common. But neuroscientists have uncovered a common
thread.
>Such behaviors, they say, rely on brain circuits that evolved to help
animals
>assess rewards important to their survival, like food and sex.
Researchers
>have found that those same circuits are used by the human brain to
assess
>social rewards as diverse as investment income and surprise home runs
at the
>bottom of the ninth.
>And, in a finding that astonishes many people, they found that the
brain
>systems that detect and evaluate such rewards generally operate outside
of
>conscious awareness. In navigating the world and deciding what is
rewarding,
>humans are closer to zombies than sentient beings much of the time.
>
>The findings, which are gaining wide adherence among neuroscientists,
>challenge the notion that people always make conscious choices about
what
>they want and how to obtain it. In fact, the neuroscientists say, much
of
>what happens in the brain goes on outside of conscious awareness.
>
>The idea has been around since Freud, said Dr. Gregory Berns, a
psychiatrist
>at Emory University School of Medicine in Atlanta. Psychologists have
studied
>unconscious processing of information in terms of subliminal effects,
memory
>and learning, he said, and they have started to map out what parts of
the
>brain are involved in such processing. But only now are they learning
how
>these different circuits interact, he said.
>
>"My hunch is that most decisions are made subconsciously with many
gradations
>of awareness," Dr. Berns said. "For example, I'm vaguely aware of how I
got
>to work this morning. But consciousness seems reserved for more
important
>things."
>
>Dr. P. Read Montague, a neuroscientist at Baylor College of Medicine in
>Houston, says the idea that people can get themselves to work on
automatic
>pilot raises two questions: how does the brain know what it must pay
>conscious attention to? And how did evolution create a brain that could
make
>such distinctions?
>The answer emerging from experiments on animals and people is that the
brain
>has evolved to shape itself, starting in infancy, according to what it
>encounters in the external world.
>
>As Dr. Montague explained it, much of the world is predictable:
buildings
>usually stay in one place, gravity makes objects fall, light falling at
an
>oblique angle makes long shadows and so forth. As children grow, their
brains
>build internal models of everything they encounter, gradually learning
to
>identify objects and to predict how they move through space and time.
>
>As new information flows into it from the outside world, the brain
>automatically compares it to what it already knows. If things match up
as
>when people drive to work every day along the same route  events,
objects
>and the passage of time may not reach conscious awareness.
>
>But if there is a surprise  a car suddenly runs a red light  the
mismatch
>between what is expected and what is happening instantly shifts the
brain i
>nto a new state. A brain circuit involved in decision making is
activated,
>again out of conscious awareness. Drawing on past experience held in
memory
>banks, a decision is made: hit the brake, swerve the wheel or keep
going.
>Only a second or so later, after hands and feet have initiated the
chosen
>action, does the sense of having made a conscious decision arise.
>
>Dr. Montague estimates that 90 percent of what people do every day is
carried
>out by this kind of automatic, unconscious system that evolved to help
>creatures survive.
>
>Animals use these circuits to know what to attend to, what to ignore
and what
>is worth learning about. People use them for the same purposes which,
as a
>result of their bigger brains and culture, include listening to music,
eating
>chocolate, assessing beauty, gambling, investing in stocks and
experimenting
>with drugs  all topics that have been studied this past year with brain
>imaging machines that directly measure the activity of human brain
circuits.
>The two circuits that have been studied most extensively involve how
animals
>and people assess rewards. Both involve a chemical called dopamine. The
first
>circuit, which is in a middle region of the brain, helps animals and
people
>instantly assess rewards or lack of rewards.
>
>The circuit was described in greater detail several years ago by Dr.
Wolfram
>Schultz, a neuroscientist at Cambridge University in England, who
tracked
>dopamine production in a monkey's midbrain and experimented with
various
>types of rewards, usually squirts of apple juice that the animal liked.
>
>Dr. Schultz found that when the monkey got more juice than it expected,
>dopamine neurons fired vigorously. When the monkey got an amount of
juice
>that it expected to get, based on previous squirts, dopamine neurons
did
>nothing. And when the monkey expected to get juice but got none, the
dopamine
>neurons decreased their firing rate, as if to signal a lack of reward.
>
>Scientists believe that this midbrain dopamine system is constantly
making
>predictions about what to expect in terms of rewards. Learning takes
place
>only when something unexpected happens and dopamine firing rates
increase or
>decrease. When nothing unexpected happens, as when the same amount of
>delicious apple juice keeps coming, the dopamine system is quiet.
>
>In animals, Dr. Montague said, these midbrain dopamine signals are sent
>directly to brain areas that initiate movements and behavior. These
brain
>areas figure out how to get more apple juice or sit back and do
nothing. In
>humans, though, the dopamine signal is also sent to a higher brain
region
>called the frontal cortex for more elaborate processing.
>
>Dr. Jonathan Cohen, a neuroscientist at Princeton, studies a part of
the
>frontal cortex called the anterior cingulate, located in back of the
>forehead. This part of the brain has several functions, Dr. Cohen said,
>including the task of detecting errors and conflict in the flow of
>information being processed automatically.
>
>Brain imaging experiments are beginning to show that when a person gets
an
>unexpected reward  the equivalent of a huge shot of delicious apple
juice
>more dopamine reaches the anterior cingulate. When a person expects a
reward
>and does not get it, less dopamine reaches the region. And when a
person
>expects a reward and gets it, the anterior cingulate is silent.
>
>When people expect a reward and do not receive it, their brains need a
way to
>register the fact that something is amiss so it can recalibrate
expectations
>for future events, Dr. Cohen said. As in monkeys, human dopamine
neurons
>project to areas that plan and control movements, he said. Fluctuating
levels
>of dopamine make people get up and do things, outside their conscious
>awareness. The number of things people do to increase their dopamine
firing
>rates is unlimited, neuroscientists are discovering. Several studies
were
>published last year looking at monetary rewards and dopamine. Money is
>abstract but to the brain it looks like cocaine, food, sex or anything
a
>person expects is rewarding, said Dr. Hans Breiter, a neuroscientist at
>Harvard. People crave it.
>
>Some people seem to be born with vulnerable dopamine systems that get
>hijacked by social rewards. The same neural circuitry involved in the
highs
>and lows of abusing drugs is activated by winning or losing money,
>anticipating a good meal or seeking beautiful faces to look at, Dr.
Breiter
>said.
>
>For example, dopamine circuits are activated by cocaine; people become
>addicted when their reward circuits have been hijacked by the drug, Dr.
>Montague said.
>
>Winning in gambling can also hijack the dopamine system, Dr. Berns
said. Many
>people visit a casino, lose money and are not tempted to go back. But
>compulsive gamblers seem to have vulnerable dopamine systems, he said.
The
>first time they win, they get a huge dopamine rush that gets embedded
in
>their memory. They keep gambling and the occasional dopamine rush of
winning
>overrides their conscious knowledge that they will lose in the long
run.
>
>Other experiments show that reward circuits are activated when young
men look
>at photos of beautiful women and that these circuits are defective in
women
>with eating disorders like bulimia. Bulimics say they are addicted to
>vomiting because it gives them a warm, positive feeling.
>
>Music activates neural systems of reward and emotion. Older people with
>age-related impairments to the frontal cortex do poorly on gambling
tasks
>and, experiments show, are prone to believe misleading advertising.
>Neuroscientists say that part of the appeal of live sporting events is
their
>inherent unpredictability. When a baseball player with two outs at the
bottom
>of the ninth inning hits a home run to win the game, thousands of
spectators
>simultaneously experience a huge surge of dopamine. People keep coming
back,
>as if addicted to the euphoria of experiencing unexpected rewards.
>
>One of the most promising areas for looking at unconscious reward
circuits in
>human behavior concerns the stock market, Dr. Montague said. Economists
do
>not study people, they study collective neural systems in people who
form
>mass expectations. For example, when the Federal Reserve unexpectedly
lowered
>interest rates twice last year, the market went up, he said. When it
lowered
>interest rates on other occasions and investors knew the move was
coming,
>markets did not respond.
>
>Economists and neuroscientists use the same mathematical equations for
>modeling market behavior and dopamine behavior, Dr. Montague said.
>Neuroscience may provide an entirely new set of constructs for
understanding
>economic decision making.
>
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