Failed Compensatory Dendritic Growth as a Pathophysiological Process in Alzheimer's Disease

In normal human aging the remaining neurons of two areas of the hippocampal region have been found to compensate for age-related neuronal loss by proliferating new dendrites. In Alzheimer's disease (AD) the layer II pyramidal neurons of the parahippocampal gyrus fail to show this compensatory response, in spite of a probable, exaggerated disease-related loss of neurons. In AD the dentate gyrus granule cells of the hippocampus also show a reduced amount of the compensatory response. This failure of the AD brain to show the normal compensatory plastic response, seen in normal aging as dendritic growth, may be viewed as one of the pathophysiological processes of the disease.