The Huntington's Society of Canada wrote:
The website you sent me was the correct one for the article on the
brain, and our Director
of Communications is now going to try to get permission for us to use it with our HD families.
I
think that it's really good, and it will be helpful for kids as well as for adults who do not
have a medical background.
So thank you very much for all your help!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
From discussions, we've seen more "sensorary" functions such as
itching, hot and/cold,
noises/hearing. etc as directly related to HD symptoms.Others, such as Kelly in later stage, had occipital/vision changes or sensitivity
to light.
~~~~~~~~~~~
Mayo Clinic Scottsdale
13400 E. Shea Boulevard
Scottsdale, Arizona 85259
Why Do Certain Symptoms Occur In Huntington's Disease
(HD)
- A Tour Through the Brain.
John N. Caviness, M.D.
Medical Advisor to HDSA-AZ board
Mayo Clinic
Scottsdale
April 11, 2001
George Huntington described Huntington's disease (HD) is 1872.
He took note of the involuntary
movement (chorea) that occurred in families. Family members
seemed to inherit the disorder in a
certain pattern that we now call autosomal dominant. These
movements caused decreased
control of voluntary movements and balance. In addition, the
mental abilities of people with HD
changed.
Today, we know that HD comes from the abnormal genetic code in a certain location
on chromosome four. We hope that this knowledge will allow a cure for HD to be
found. Even so, why do certain symptoms occur in HD?
It is important to have an
understanding of why these symptoms occur in people with HD. Recognizing the
symptom allows one to better adapt and deal with it.
The brain sits in the skull and has a jelly-like consistency.
Over its surface, there are many folds
and crevices. Multiple folds are grouped together under the term,
"lobe." The lobes of the brain
have names and take on certain functions. These functions
are not completely understood and
often have more than one location, but some general statements can
be made:
LOBE NAME
BEHAVIORAL FUNCTION
Frontal lobe
Concentration, Judgement, Planning, Motor Coordination
Parietal lobe
Sensory function, perception, recognition of space relations
Temporal lobe
Memory, emotional control, language
Occipital lobe
Vision
In HD, there is a tendency for the frontal and temporal lobes to
be affected. Nothing is absolute
and each case is different. However, after realizing that
the frontal and temporal lobes experience
major problems with executing their function in HD, some common
symptoms in HD become
more understandable.
Some of the common symptoms
in HD are coordination problems, concentration difficulties, less
judgement, planning difficulties, decrease memory ability, emotional
withdrawal, and less
emotional control. These symptoms are at least partially tied
to dysfunction of the frontal and
temporal lobes.
Sensory function, perception
of touch and recognition of space relations are usually not affected
or minimally involved in HD.
Deeper in the brain, below the lobes, are places referred to subcortical
nuclei. These centers
have to do with motor execution and control, among other functions.
These are also affected in
HD and their dysfunction can create involuntary movements, abnormal
swallowing, balance
problems, and speech difficulty.
Of course, the best way to treat a disease is to treat its basic
cause. This is the approach being
taken by many researchers in HD. Studies, such as PHAROS which
is an observational study for
persons at-risk for the HD gene, is being performed at Mayo Clinic
Scottsdale as part of the
Huntington's Disease Study group, will help attain that goal.
NOTE: To find out more about the HD Study Group and on-going
____________________________________________________________________
Following is from the Blake Medical Center
On the left hand side, under "Family & Friends" click on "Virtual
Body"
The Human Brain
Skeleton
Human Heart
Digestive Tract
The Human Brain
The human brain controls every action, thought, and process of the
body; but what makes the brain function?
A network of nearly one hundred billion individual cells called
neurons, or nerve cells, allows the brain to think,
remember, hear a symphony, enjoy a sunset, love and imagine.
Neurons tell our bodies to move, breathe,
and create. The amazing network of neurons that forms the
human brain makes it the most complicated brain
on the planet.
This system is based on electrochemical impulses. Like a computer,
these impulses travel along circuits. Unlike
computers, these signals are created chemically. These chemical
transmissions are called neurotransmitters,
and they are responsible for the incredibly rapid communication
between neurons. The speed and accuracy
of these neurotransmissions are what let us react to the world around
us, and ultimately, to survive.
Faulty functioning of this communication between neurons may be
responsible for all sorts of illnesses, from
depression to Parkinson's disease. An overabundance of neurotransmitters
has been linked to schizophrenia.
Various medications that increase or decrease neurotransmitters
are now available and have been shown to
be effective in treating some of these conditions.
The basic nutrient employed by neurons is glucose,
a simple sugar. In order to metabolize the glucose, neurons
need lots of oxygen. While the brain is only two percent
of the body's weight, it uses twenty percent of its
oxygen. Because the liver actively makes
glucose from carbohydrates, fats and sugars, there is rarely any
shortages of glucose for the brain. However, the brain
needs Thiamine or vitamin B1 in order to process glucose.
Neurotransmitters, the chemical messengers of the brain are produced
by the various nutrients in our food.
These neurotransmitters include serotonin, epinephrine, norepinephrine,
dopamine and acetylcholine. The
brain can continue processing these even if a person does not eat
for a while, but nutrition contributes greatly
to one's brain functions.
Milk and cauliflower contain choline, which helps produce
acetylcholine, which aids in the transmission of impulses.
Lecithin, the substance that helps to make choline, can
be found in soybeans, peanuts, egg yolks, butter and liver.
Proteins contain amino acids such as phenylaianine and
tyrosine, which help form such neurotransmitters as
epinephrine, norepinephrine and dopamine. These influence
our emotions, and too much epinephrine can cause
excitability, irritability and anxiety.
Tryptophan, the amino acid responsible for the production
of serotonin, is abundant in turkey, as well as in
other meats and fish. Serotonin is thought to be the neurotransmitter
responsible for perception and sleep
function. In order to increase the amount of tryptophan received
by the brain, one must combine carbohydrates
and proteins. This is because carbohydrates increase the body's
release of insulin, which transports other
amino acids from the blood into cells, leaving a higher concentration
of tryptophan in the blood for the brain.
Voluntary & Involuntary Brain Functions
Medulla
In addition to allowing us to make deliberate decisions, the brain
controls those body functions over which we
have no control. The lower area of the brain known as the
medulla controls heart rate, breathing, vomiting,
salivation, coughing and other automatic functions.
These automatic functions are a great advantage. Imagine
having to tell yourself to breathe, or tell your heart to beat!
Because of the importance of these functions,
damage to this area of the brain and spinal chord is very dangerous.
Cerebral Cortex
Contains about 85% of the nerve cells in the brain and the human
cortex has become increasingly complex in
comparison to other species. It is divided into Temporal,
Frontal, Parietal and Occipital lobes. The cerebral
cortex contains the gray matter of the brain and the prefrontal
area of the cerebral cortex comprises a larger
portion of the human brain then the brains of other species.
Yet, the prefrontal cortex develops more slowly
in humans than it does in monkeys. Large numbers of neuronal
connections develop in the human brain
between 7 and 12 months.
Frontal Lobe
The frontal lobe controls planning of movements and some aspects
of memory.
Parietal Lobe
Controls body sensations like the sense of touch.
Occipital Lobe
Controls visual functions.
Temporal Lobe
Controls hearing and some advanced visual processing.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"suggests that the right frontal lobe "is the glue holding together
a sense of self."
Hence damages to that area of the brain in HD could contribute to personality changes?
============================================
Brain
area holding 'sense of self' found
NEW YORK, Sep 24 2001 (Reuters Health) - "I think, therefore I am" may
be a sound philosophy.
But if a certain part of the brain isn't working right, you might not be sure who you are,
scientists
have found.
They say the right frontal lobe appears to be key in holding on to a sense of self--from political
persuasions
to fashion sense. In a study of men and women with damage to that brain area,
they found that six out of seven went through
profound personality and lifestyle changes.
University of California researchers studied 72 patients with frontotemporal
dementia (FTD),
a type of mental decline that affects the brain's frontal and temporal lobes. When the left side
of
the brain is more affected than the right, patients have trouble with language. When the
problem is predominantly on the
right, patients' behavior is often disturbed.
"Remarkably," the authors write in the September 11th issue of Neurology,
"we have observed that
patients with predominantly right frontal FTD often evolve dramatic changes in well-established
patterns
of religion, political philosophy, dress and style."
In this study, seven of the 72 patients had predominantly right
frontal FTD. Six of these patients
--but only one of the remaining patients--showed a strong "change in self."
Religious
conversions, shifts in morals, wardrobe makeovers and turnarounds in temperament were
among the changes, according to Dr.
Bruce L. Miller, of the University of California, San Francisco,
and his colleagues.
One woman in her 50s developed
an alternate personality she called "Jenny"--a person she described
as "irritable, aggressive and domineering." Another
woman shifted her political inclinations in her
60s, adopting an animal-rights, anti-conservative stance.
Another
woman who had always been "meticulously health conscious" took to sodas and junk food and
starting smoking. And a conservative
businessman sold his business at age 40, took odd jobs from
which he was repeatedly fired, and shed his "puritanical" views
on sex for more "experimental" ones.
All of this, according to Miller's team, suggests that the right frontal lobe
"is the glue holding together
a sense of self."
They note that patients with FTD on the left side tend to lose their
comprehension of words like
"Catholic" or "Republican," but they do not shed such identities.
While knowledge of
who we are is stored throughout the brain, the report indicates, the right frontal
lobe appears to contain the "activator"
for using and maintaining that knowledge.
SOURCE: Neurology 2001 September.
http://www.reutershealth.com/archive/2001/09/24/eline/links/20010924elin008.html
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