Fun Reading!!!!
Primary cause of age-associated cognitive deterioration:
First, cognitive decline occurs due to significant decrease of neurotransmitter, especially acetylcholine. Even if a memory trace is still intact, the cognitive deterioration may occur due to lack of acetylcholine. There is also a decrease of other neurotransmitters such as serotonin, dopamine and norepinephrine. Acetylcholine is primary carrier of memory; serotonin and norepinephrine is very important for maintenance of good mood. Also, the decrease in neuropeptides such as endorphin will affect the mood of an individual and is very likely to harm the immunity.
Second, impaired blood circulation. The brain uses about 25% of all blood; therefore, it is very vulnerable to blood deficiency. Approximately 20% of all cognitive declines occur due to poor circulation.
Third, the increased level of cortisol. Cortisol harms brain in three ways: it interferes with brain's supply of glucose; it also interferes with function of neurotransmitters; and it causes influx of calcium into brain cells. Calcium creates free-radical molecules; therefore, directly killing and damaging brain cells. When the brain is damaged by cortisol, the patient has difficulty paying attention, which prevents adequate storage of memory; therefore, interferes with general intelligence. It hence hurts the cognitive function that leads to the damage in creativity. Also, when the brain is damaged by cortisol, it suppresses long-term potentiation by interfering with neuronal receptors that "catch" memories. Therefore, it lowers the ability to absorb information quickly by reviewing. When there is an increase in the level of cortisol, it is very predictable that a person will experience loss/decline in cognitive function as well as the memory. Past tests show that older people with lower cortisol level perform as well as young on cognitive test.
Cortisol Analysis
In response to stress, hypothalamus secretes corticotropin-releasing factor, which activates pituitary gland to secrete corticotropin (ACTH). ACTH then activates adrenals to secrete cortisol. In reaching the "set point", hypothalamus will stop the production of coricotropin-releasing factor, which will stop the production of cortisol. As one ages, hippocampus in the limbic system of the brain is damaged from 20 - 25%. Hippocampus acts as a feedback mechanism for hypothalamus and therefore controls the production of cortisol. Damage in this area of the limbic system will lead to continual production of cortisol; however, hippocampus is most damaged by the production of the cortisol. Hence the "degenerative cascade" begins. Some of the effects of overproduction of cortisol would be irritability, inability to relax and difficulty in sleeping. Also, memory and concentration impairment may occur. There is a theory that psychological nurturing can greatly inhibit the feedforward mechanism; however, it is still under intense investigation.
Free-Radical Molecules
Free-radical molecules are molecules that have lost one of the electrons from a pair on its valence shell. Therefore, free-radical molecules are very reactive trying to strip another electron from other molecule to reach its molecular stability. Hence, it has the ability to directly kill brain cells, and it often contributes to the formation of cancer cells. It causes skin to harden and wrinkle, bones to soften and shrink, muscle to weaken and brain to degenerate over a long period of time. Brain damages can be prevented by taking antioxidants such as Vitamins C and E, coenzyme Q-10, Zinc and Selenium, Glutathione, L-methionine and L-taurine. For more information, see Diet.
References
http://library.thinkquest.org/C0126536/main.php?currentchap=6¤tsect=deterio.htm
Khalsa,Dharma Singh & Cameron Stauth. Brain Longevity. New York: Warner Books,1997.
Silverstein, Alvin & Virginia Silverstein. World of the Brain. New York: William Morrow and Co., 1986.
Sat 15 May 2010 - 10:14
.... If I managed to find out who some of you were, then really, am I that simple afterall?