Biology 202
2002 Third Paper
On Serendip

If we accept that the brain's ability to "fill in the blanks" about each experience we have, then we can conclude that our past is indeed partially our own brain's creature. However, there are still some norms created by people that define certain experiences as normal and others as not. What happens when a person starts to behave ab-normally? How is his/her brain filling the blanks in a different manner? To discuss this subject we would discuss the most common form of dementia among old people, the Alzheimer's disease.

Dementia is a brain disorder, a loss of intellectual function (thinking, remembering, reasoning), which substantially affects a person's ability to carry out daily activities. Alzheimer's disease (AD), a form of progressive, irreversible dementia with no known cause or cure, first described in 1906 by Dr. Alois Alzheimer, causes damage to the parts of the brain that control thought, memory and language. The consequences of the disease in terms of the patient's lifestyle are often times confused with the natural syndromes of aging. However, AD is not a normal part of aging.

The processes which occur in an AD patient are still extensively researched. Nerve cells in the regions controlling the above mentioned faculties are lost and certain neurotransmitters' performance is damaged. The two most affected types of brain cells by AD are neuritic plaques and neurofibrillary tangles. While some neuritic plaques are commonly found in brains of elderly people, they appear in excessive numbers in the cerebral cortex of Alzheimer patients. Neurofibrillary tangles are twisted remnants of a protein called tau, found inside brain cells and crucial for maintaining proper cell structure and function (5)

As a result normal thinking and memory is harmed due to the disrupted communication between the different neuron cells. Thus, the ability of the person to participate in normal interaction with other people is severely damaged. (3)
The experiencing of the world and the way the patient reacts to it is radically influenced by this unhealthy interaction within the brain. The initial symptoms involve mild forgetfulness of recent events, activities or familiar people/things. In the process of development of the disease, skills acquired throughout the life of the patients such as brushing the teeth, easting with a fork and a knife are forgotten; thoughts are very unclear, and behavior becomes unable to be subordinated to normal human life norms. All the clues the brain has learned so as to be able to fill in the blank in everyday life have been forgotten. (3)

The symptoms of the disease are predominantly behavioral – agitation, anxiety, depression or sleeplessness, in general mood swings a feeling of withdrawnness. (1)
Main characteristics are personality changes, impairment of judgment (4)
Plaques and tangles develop in the brain, leading to the death of brain cells. The rate of progression can vary from 3 to 20 years with the final stage being common to all – a complete incapability of taking care of oneself. There is a list of warning signs developed by researchers that are used as base for judgment of resemblance of a medical condition to AD and the potential further examination this could prompt. Among the major signs, as formulated by researchers, are memory loss affecting job skills, difficulty performing familiar tasks, problems with language, disorientation to time and place, problems with abstract thinking, misplacing things, changes in mood and behavior, and subsequent changes in personality, loss of initiative. All this signals pertain to the essence of a personal identity and thus show the

Age is one of the greatest risk factors for dementia, affecting one in twenty people over the age of 65, and one in five over the age of 80. Another equally debated cause might be with genetic origin, genetic predisposition or abnormal protein build-up in the brain, as well as environmental toxins. (4)
However, the effect of inheritance seems to be very small, so that the possibility of developing Alzheimer if a parent or a relative has the dementia, is slightly higher than if you had no cases of the disease in your immediate family. (1)
After extensive investigation it has been found that people with Down's syndrome who succeed in surviving until their 50s are likely to develop AD. (2)
Other similar coincidences have been examined about people who have experienced severe head injuries, such as boxers, have a greater chance of developing AD.

Similar to Parkinson's disease, there has not been found yet a cure for Alzheimer's. The treatments that could ameliorate the condition have been acting upon delaying the onset of the symptoms. Another direction of treatment has been maintaining the level of acetylcholine, a neurotransmitter essential for processing memory and learning, in the brain which seems to decrease in patients with AD. However, all of these attempts only try to stabilize the symptoms for a limited period of time. (1)

What is one of the most intriguing aspects of studying the Alzheimer's disease is the effect it has upon a person's memory, experience and behavior. We talked a lot about the relationship between brain and behavior, whether they mean the same thing, and if not what is their mutual relationship. Looking at the specific symptoms and results of Alzheimer, we witness a complete eradication of prior learning experience, inability to perform or understand activities which have used to be essential for the person's existence, personally confusion, impaired judgment. And the processes that have harmed the normal functioning of the brain with no doubt, affect this outcome. So if your identity, your personality, your soul even, is argued to be something external to the biological processes happening in the body, how would such a theory or approach account for effects of diseases as this one. An argument is that memory loss is a natural part of aging. However, the symptoms of Alzheimer's disease have consequences different than just simple lapses of memory. Patients have difficulty executing all processes which they have learned throughout their life - communication, learning, thinking, reasoning. It involves destruction of brain cells as supposed to pure aging. This provokes the question of the extent to which yourself, everything you associate as being your personality, your memories, your knowledge, is vulnerable and how everything that defines a "self" could be destroyed.

References

1) Alzheimer's Society information sheet
2) About Alzheimer's Disease – Symptoms, Risk factors, etc.
3) Alzheimer's Disease Fact Sheet.
4) Alzheimer's Association
5) Neurology Forum


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