[Brain aging and dementia]

It is common knowledge that the base of the demographic pyramide is turning upwards as a consequence of the constant growing of the elderly population. This phenomenon worries everybody from families to government agencies. As a consequence, neuroscientists have been asked to cooperate for a better understanding of the problem related with the aging of the nervous system. Essentially they try to better grasp the mechanism of aging and their deleterious effects on the brain and how to fight the diseases of the nervous system with particular affinity for the aged people. We know that brain goes through morphological and biochemical changes with the passing of the years; it loses weight, microscopic changes occur and the activity of many neurotransmitters diminishes. In this context it is strange that some people still argue against the enfeeblement of the mental faculties with aging. Of all diseases of the nervous system tormenting the aged, the most common are depression and dementia. Most cases of depression and some forms of dementia are treatable but Alzheimer's disease, which afflicts a considerable percentage of old people, leading to greater psychological decline and leaving doctors helpless to halt it's unavoidable progress, is certainly the most dreaded old age mental sickness. The etiology of Alzheimer's disease is unknown. Under these circumstances several possibilities are investigated: genetic, infectious and toxic. Lately, investigators have focused their attention on amyloid, constitutive substance of the senile plaques one of the characteristic structural changes of the diseased brain. Nowadays there are studies on the relation between amyloid and a protein considered to be its precursor which has been found outside the nervous system.(ABSTRACT TRUNCATED AT 250 WORDS)