Topographic distribution of neurofibrillary tangles and granulovacuolar degeneration in hippocampal cortex of aging and demented patients. A quantitative study.

Topographic analysis was performed of the distribution of Alzheimer's neurofibrillary tangles and the granulovacuolar degeneration of Simchowicz in the hippocampal cortex of patients with Alzheimer's dementia and mentally normal aged controls. A semiautomated scanning stage microscope was linked potentiometrically to an XY pen recorder in order to plot cytoarchitectonic "scattergrams" from the sequentially screened hippocampal formations. The density of both lesions per cubic mm of pyramidal cortex was quantified by measuring the area of each of six "zones", using a digitizer and programmable calculator. In elderly normal brains as well as those of Alzheimer's disease, the statistically most representative ranking order of predilection for neurofibrillary tangles (in decreasing severity) was: entorhinal cortex greater than subiculum greater than H1 greater than end-plate greater than presubiculum greater than H2. For granulovacuolar degeneration the best rank order was: subiculum greater than H1 greater than H2 greater than end-plate greater than entorhinal cortex greater than presubiculum. The notable similarities of both such orders of predilection to the well-recognized "selective vulnerability" of certain hippocampal neurones in clinical conditions of hypoxia, ischemia and epilepsy suggest some common, focally accentuated cytotoxic mechanism may underlie all these regional predispositions.