title: Synaptic density in the inner molecular layer of the hippocampal dentate gyrus in Alzheimer disease.
abstract: We examined the inner molecular layer (IML) of the hippocampal dentate gyrus for possible changes in synaptic density. Material was obtained from 9 individuals with Alzheimer disease (AD) and compared to samples obtained from 10 age-matched, postmortem-matched neurologically normal controls, employing standard ultrastructural techniques. Statistical analyses demonstrated a significant decline in synaptic numbers between controls and AD subjects. This decline was accompanied by a significant increase in apposition length and resulted in a significant correlation with the synaptic density. As the number of synapses declined, the apposition length increased. Assessment was also made of the granule cells density and the analyses showed a significant decline in the synapse to granule cell ratio in the AD group. This decline in the density of synaptic contacts in the IML reflects a more widespread decline in plasticity in AD and may be related to the memory problems associated with the disease.
authors.affiliation: Sanders-Brown Center on Aging, University of Kentucky, Lexington 40536, USA.
authors.forename: S W
authors.initials: SW
authors.lastname: Scheff
authors.forename: D A
authors.initials: DA
authors.lastname: Price
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000473:pathology*; D016022:Case-Control Studies; D018891:Dentate Gyrus / Q000648:ultrastructure*; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D016874:Neurofibrillary Tangles / Q000473:pathology; D013569:Synapses / Q000648:ultrastructure*