Topography of neurofibrillary tangles and granulovacuoles in hippocampi of patients with Down's syndrome: quantitative comparison with normal ageing and Alzheimer's disease.

An XY pen recorder linked potentiometrically to a sampling stage microscope permitted the plotting of topographic "scattergrams" to determine the precise cytoarchitectonic localization of neurofibrillary tangles and granulovacuolar degeneration in hippocampal neurones of Down's syndrome adult brains. The area (and hence volume) of six cortical "zones" surveyed was measured with a digitizer and programmable calculator. In decreasing magnitude of affliction, the rank order for neurofibrillary tangles was: entorhinal greater than subiculum greater than H1 greater than endplate greater than H2 greater than presubiculum. That for granulovacuolar change was: subiculum greater than H2 greater than H2 greater than endplate greater than entorhinal greater than presubiculum. These striking regional predispositions suggest that a common neurotransmitter deficit may underlie the local selectivity of such lesions in Down's syndrome brains; and the predilections' marked similarities to ranking orders, already noted both in normal aged subjects and especially in senile dements of the Alzheimer type, enhance the importance of the Down's syndrome neuraxis as a key to the puzzle of Alzheimer's dementia.