Title

Alzheimer's disease and aging: effects on perforant pathway perikarya and synapses

UMMS Affiliation

Department of Neurology

Date

5-1-1992

Document Type

Article

Subjects

Adult; Aged; Aged, 80 and over; Aging; Alzheimer Disease; Child, Preschool; Hippocampus; Humans; Image Processing, Computer-Assisted; Middle Aged; Neural Pathways; Synapses; Temporal Lobe

Disciplines

Neurology | Neuroscience and Neurobiology

Abstract

The hippocampal perforant pathway originates in the entorhinal cortex (ERC) and terminates in the outer molecular layer of the dentate gyrus (DG). To compare the effects of normal aging and Alzheimer's disease (AD) on the elements of the perforant pathway, we compared relative perikaryal numbers (determined by counting cell bodies and estimating volumes) in layer II of the ERC with synaptic quantities (estimated from immunoreactivity for the synaptic terminal protein synapsin I and DG volume) in the molecular layer of the DG. The brains of 5 young and 9 elderly cognitively normal individuals, and of 9 AD patients were studied. In normal aging we found a significant age-related decline in perikaryal numbers in the ERC without demonstrable synaptic loss in the DG. In AD there was marked and equivalent, (or proportional) reduction in both ERC perikaryal numbers and DG synapses. These data suggest that in normal aging remaining neurons may continue to support a full array of synapses, perhaps due to mechanisms such as axonal sprouting, synaptic enlargement, or synaptic ingrowth. In AD, however, the accelerated neuronal loss may overwhelm such compensatory mechanisms or alternatively, independent synaptic and perikaryal losses may occur.

Rights and Permissions

Citation: Neurobiol Aging. 1992 May-Jun;13(3):405-11.

Related Resources

Link to Article in PubMed

PubMed ID

1625770

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