[Hippocampal pathology as one of the possible factors in the pathogenesis of several dementias of old age].

In the light of comtemporary concepts concerning the functional significance of the limbic system, the author reports of some results in the subiculum in young and old individuals (39 cases) with different forms of dementia of old age (senile and vascular dementia, Pick's and Alzheimer's disease). The authors assessed the thickness of the subicular cortical stratum, the relative and absolute amount of nervous and glial cells and capillaries. In old age the thickness of the subicular cortical stratum is decreased by 28%, while the absolute amount of neurons by 29%. In old age dementia the thickness of the subicular cortical stratum decreased by 47--71% and the absolute amount of neurons becomes 2--3 times less. In old age in general and in dementia of old age in particular there was no "substitutional" gliosis because the absolute amount of glial cells in the cortical stratum is reduced in this group of individuals by 20--50%.