We already know that cell death - including nerve cells in the brain - is a process that is a normal manifestation of the body's aging. In this process of physiological aging in every human being, the ability to absorb new information, process it, and memory becomes less accurate. And all these changes indicate gradual aging of the brain. In addition, changes include: reduced speech fluency and the ability to name new subjects, impaired attention, and difficulty in solving problems. In people over 50 years old, symptoms appear which are defined as age-related memory impairment (AAMI). Patients reporting to the doctor themselves inform him about the occurrence of memory disorders that interfere with everyday functioning. Age-related cognitive decline (ARCD) includes changes in memory, thinking, concentration, language and visual-spatial functions. In the performed neuropsychological tests, patients get results lower by 1 standard deviation than young adults. The lack of progression of reported disorders is the most important feature that differentiates dementia.
Pathomechanism of the aging of the nervous system
The brain of an aging person loses about 10,000 a day neurons (in the so-called optimistic version, this process begins at the age of 65, but may also affect 30-year-olds - the medical service writes. The results of the latest scientific research prove, however, that this is not the so-called final loss of neurons, because the brain has the ability to regenerate them is a process of partial loss of these important cells, but the facts are quite clear to us: the brain of a man who is about 50 years old weighs about 1.3 kg Fifteen years later only about 1.17 kg The loss of mass is mainly caused by a decrease in the amount of water in the brain cells.
The biggest losses occur in the so-called front panels that are responsible for thinking. It is believed that starts can reach up to 0.55% of the weight of cells yearly - this process begins most often when the patient's age exceeds 50 years. In the next part of the brain, called the hippocampus, losses can reach up to 20% of the volume. This occurs between 50 and 90 years of age.
The general rule is as follows: the older the brain, the more slowly the pulses are transferred. This causes a general slowdown in mental reactions. It is more difficult to solve tasks and problems that require more information to be considered. The information processing process is also slower. Of lesser significance is the actual loss of nerve cells, because it determines that the quality of connections between them is also worse.
The Los Angeles team even developed a prototype of an artificial hippocampus. It is to be tested first on tissue taken from the rat brain, and then on live animals - rats and monkeys. It is believed that if these attempts are successful, the artificial hippocampus will be tested on people whose brains have been damaged as a result of stroke, epilepsy or Alzheimer's disease. If the device works, they can regain the ability to remember. The creation of an artificial hippocampus required the development of a mathematical model of its operation in various conditions, the implementation of an appropriate electronic system and its connection to the brain.Placed on the skull, the electronic system (whose development lasted 10 years) is to communicate with the brain via two electrode systems - one receives signals from the brain, and the other sends in response such signals as the real hippocampus would react to similar stimulation. There are a number of ethical concerns associated with this type of experiment. Future science will have to answer it.
We managed to determine the pattern of memory gene activity in the rat hippocampus, which learned to recognize the route in the water maze. Genetic engineering, so-called DNA microarrays, or DNA chips. It allows you to analyze the activity of thousands of genes at a time. Previous studies on the genetic basis of learning and memorizing processes usually included a small group of genes and biochemical processes. This prevented the assessment of how many genes actually participate in these processes and how they cooperate with each other during the formation of memories. Tissue fragments taken from the rat hippocampus within 1 hour after completing the labyrinth as well as after 6 and 24 hours were analyzed. It turned out that the learning processes were associated with periodic characteristic activation in the hippocampal nerve cells of about 140 different genes whose functions are known. The largest group of genes active in learning and memory processes were genes related to mutual communication of cells through chemical signals and intracellular communication. This group includes, among others genes encoding growth factors, such as fibroblast growth factor, FGF-18, whose activity was elevated at each time point examined after completing the task in the maze.
The second group included genes coding for synaptic connections proteins. The next were the genes coding for the so-called cytoskeleton (i.e., internal protein scaffolding of cells) and proteins regulating direct cellular contacts. These molecules can regulate, for example, the processes of adapting the shapes of neurons during the formation of memories. A group of genes regulating the processes of programmed cell death was also isolated, which determines the plasticity of memory processes, such as forgetting and perpetuating memories.
The authors hope that their results may in the future be used to create therapies for people with cognitive impairments, including learning and memory processes (eg Alzheimer's disease).
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Doctor of Medicine Janusz Krzyżowski
Psychiatrist
Private office tel. 22 833 18 68 00-774Warszawa, Dolna 4 lok. 15
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Aging factors in the brain - GABA bio deficiency
Leventhal and colleagues believe that an important factor that is associated with brain aging is the decline in the organ of the level of an important biochemical compound - gamma-aminobutyric acid GABA and at the same time an increase in neuronal reactions to non-specific stimuli. Therefore, drugs that increase GABA levels may be able to reverse the effects of brain aging.
The main role of gamma-aminobutyric acid (GABA) molecules is to inhibit the activity of neurons in the brain and then neurons can react selectively only to specific stimuli, and the brain is not overloaded with information. The Leventhal team examined the activity of single neurons in the area of the visual cortex responsible for field orientation and shape recognition in old and young monkeys. The weakening of the function of this cortex is in monkeys, as in humans, associated with deterioration of vision.
The oldest studied monkeys were about 30 years old, and in human terms - 90. The researchers recorded the activity of neurons, while the monkeys received various visual signals. After administration of GABA-increasing drugs, researchers observed that after a few minutes neurons of older monkeys in a more selective manner reacted to the presented stimuli. In younger monkeys, the researchers did not notice the clear influence of the drugs administered on the selectivity of neuronal work. According to the authors, their results are the first to suggest that a decrease in GABA may be an important factor influencing brain aging and decline in mental abilities.
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Other causes of aging of the brain .
Another researcher - Tuszynski said that brain cells normally lost in the body's aging process can be renewed thanks to the transplantation of genetically modified nerve cells. The author and the team tried to show that it is possible to reverse the process of losing nerve cells associated with the aging process by providing nerve growth factor to the brain structures. He warns, however, that this experiment should not be thought to be a reversal of the normal aging process of nerve cells. The results of these tests may be helpful in the treatment of Alzheimer's disease.
Nevertheless, the death of nerve cells in the brain is a normal manifestation of the body's aging, but it can also be the result of a simple deficiency of iron ions. Among the processes that accompany brain neuronal aging as well as changes associated with Alzheimer's disease, mention is made of disorders of mitochondrial function, increase of free radicals level, decreased cell metabolism, disturbances of their growth and changes in the balance of iron ions. It has been known for a long time that iron deficiency can cause mental disorders of children, but there was little data on the relationship between these deficiencies and the impairment of mental functions in older people.
Weight gain due to the degeneration of nerve cells?
It was shown that in the brain of rats, which were cultivated for a long time on a diet of 40% poorer in calories than traditional ones, nerve cell death processes were much less frequent than in rats with unlimited access to food. It was also observed that in the brains of animals receiving less caloric food, the concentration of proteins with neuronal protection activity increased twice, while in rats that had unlimited access to food, it decreased by 60%. Moreover, the old rats on a low-calorie diet had a 40% higher level of neuronal-protecting proteins than young rats on a regular diet. The author of this publication believes that their results will be helpful in developing medical strategies to slow down the memory loss and other mental abilities that accompany aging.
The accumulation of these deposits is one of the main features of aging and many disabilities associated with advanced age. Overfeeding greatly increases the production of harmful metabolites (gout!), Which accelerate the process of senile degeneration of vital nucleic acid molecules and structural proteins, and impair the function of specific organs. Therefore, consuming an excessive amount of calories is tantamount to accelerating aging. Physiological is the reduction of the basic transformation of the figure, which between 25 and 75 years decreases by about 30%, and the increase in body weight results from overeating and entails a number of pathological phenomena. Premature infirmity, dementia and even premature death of obese people is most often caused by obesity accompanying diseases such as circulatory insufficiency, hypertension, diabetes and atherosclerotic complications (infarcts, strokes) and all these "plagues" are usually the result of normal gluttony. Why not be surprised, since from time immemorial, food was one of the most important human pleasures.
Doctor of Medicine Janusz Krzyżowski
Psychiatrist
Private office tel. 22 833 18 68
00-774Warszawa, Dolna 4 lok. 15 .
