Dendritic sprouting in Alzheimer's presenile dementia

Abstract

The use of Golgi techniques on brain tissue from aging and senescent human individuals has shown a series of progressive deteriorative changes in neurons at a number of sites in cortical structures. These include loss of dendritic spines, irregular swelling of cell body and dendrites, and progressive loss of the dendritic domain, culminating in cell death. These changes which characterize the senile dementias have now been seen also in two cases of Alzheimer presenile dementia. This material is additionally characterized by the presence of clusters of new dendritic growth, developing at one or more sites along the dendritic or somal surface. The dendritic branchlets are densely spine-covered at a time when the original dendritic systems of the neuron may be partially or totally devoid of their spine complements. Because these dendrite clusters appear haphazard in placement and orientation and do not coincide with any known presynaptic terminal fields, we provisionally refer to them as “lawless.” The mechanisms which trigger their development in presenile, but not senile, dementing disease are unknown at present.