The Brain - How it Functions (in understandable language)
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.
This article is from the HDSA Arizona Chapter website: http://www.hdsa-az.org/
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.
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
13400 E. Shea Boulevard
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
clinical trials, go to http://www.huntington-study-group.org
Transcribed from the Dimensions section of the Park Forest Star, March 14, 1996, with permission from the author. Dr. Kathleen Shannon, a neurologist with a genetic testing center for Huntington's disease, lists the range of symptoms the disease commonly causes. Victims, who span all races and ethnicities, may show any combination of symptoms,complicating diagnoses and symptomatic treatments.
Common symptoms fall into three categories.
Motor problems include clumsiness, decrease in coordination, slurred speech, difficulty in swallowing, chorea (involuntary movements), poor balance, problems walking, intoxicated appearance, and twitchy and fidgety spasms.
Personality changes -- irritability, temper tantrums, sometimes violent outbursts, depression, paranoia and obsessive compulsive behavior.
Cognitive difficulties, which tend to show up later on in the disease, can involve memory, mental flexibility, fluency of thought, organization, an inability to make a mental strategy, and poor communication. The latter can be especially frustrating to the patients exacerbating other areas. "They can feed off each other a lot," Shannon notes.
There are now 25,000 to 30,000 people afflicted with the disease in the United States. An additional 150,000 are at risk. Research on the disease, Shannon explains, involves several areas of study. One is better treatment of symptoms. "This doesn't affect the long-term degenerative nature of the disease," she notes, "but it vastly improves the quality of life for the patients."
Other research is now focusing on blocking the chemicals that may be damaging the brain cells, on strengthening the cells to resist damage, and on cell regeneration by either helping cells repair themselves or replacing dead or damaged cells.
Following is from the Blake Medical Center
On the left hand side, under "Family & Friends" click on "Virtual Body"
The Human Brain
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 brainon 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 betweenneurons. 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
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.
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.
The frontal lobe controls planning of movements and some aspects of memory.
Controls body sensations like the sense of touch.
Controls visual functions.
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.