The presubicular region in Alzheimer's disease: topography of amyloid deposits and neurofibrillary changes.

Specific silver impregnation techniques for extracellular amyloid and intraneuronal neurofibrillary changes were used to examine the presubiculum in Alzheimer victims. Extended amyloid clouds in the absence of neurofibrillary changes were noted in the parvopyramidal layer of the presubiculum proper. The corresponding layer in the parasubiculum, in contrast, showed many neurofibrillary tangles and neuropil threads in the absence of amyloid. The transsubicular parvopyramidal layer contained both amyloid deposits and neurofibrillary changes. This severe involvement of all subdivisions of the presubicular region in Alzheimer's disease is considered to impair functions of the Papez circuit.