Reduction in size of perforated postsynaptic densities in hippocampal axospinous synapses and age-related spatial learning impairments

Daniel A. Nicholson, Rie Yoshida, Robert W. Berry, Michela Gallagher, Yuri Geinisman

Research output: Contribution to journalArticle

Abstract

A central problem in the neurobiology of normal aging is why learning is preserved in some aged individuals yet impaired in others. To investigate this issue, we examined whether age-related deficits in spatial learning are associated with a reduction in postsynaptic density (PSD) area in hippocampal excitatory synapses (i.e., with a structural modification that is likely to have a deleterious effect on synaptic function). A hippocampus-dependent version of the Morris water maze task was used to separate Long-Evans male rats into young adult, aged learning-unimpaired, and equally aged learning-impaired groups. Axospinous synapses from the CA1 stratum radiatum were analyzed using systematic random sampling and serial section analyses. We report that aged learning-impaired rats exhibit a marked (∼30%) and significant reduction in PSD area, whereas aged learning-unimpaired rats do not. The observed structural alteration involves a substantial proportion of perforated synapses but is not observed in nonperforated synapses. These findings support the notion that many hippocampal perforated synapses become less efficient in aged learning-impaired rats, which may contribute to cognitive decline during normal aging.

Original languageEnglish (US)
Pages (from-to)7648-7653
Number of pages6
JournalJournal of Neuroscience
Volume24
Issue number35
DOIs
StatePublished - Sep 1 2004

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Keywords

  • CA1 stratum radiatum
  • Hippocampus
  • Learning deficits
  • Normal aging
  • Perforated synapses
  • Rat

ASJC Scopus subject areas

  • Neuroscience(all)

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