Neuronal and morphological bases of cognitive decline in aged rhesus monkeys

Yuko Hara, Peter R. Rapp, John Morrison

Research output: Contribution to journalReview article

54 Scopus citations

Abstract

Rhesus monkeys provide a valuable model for studying the basis of cognitive aging because they are vulnerable to age-related decline in executive function and memory in a manner similar to humans. Some of the behavioral tasks sensitive to the effects of aging are the delayed response working memory test, recognition memory tests including the delayed nonmatching-to-sample and the delayed recognition span task, and tests of executive function including reversal learning and conceptual set-shifting task. Much effort has been directed toward discovering the neurobiological parameters that are coupled to individual differences in age-related cognitive decline. Area 46 of the dorsolateral prefrontal cortex (dlPFC) has been extensively studied for its critical role in executive function while the hippocampus and related cortical regions have been a major target of research for memory function. Some of the key age-related changes in area 46 include decreases in volume, microcolumn strength, synapse density, and α1- and α2-adrenergic receptor binding densities. All of these measures significantly correlate with cognitive scores. Interestingly, the critical synaptic subtypes associated with cognitive function appear to be different between the dlPFC and the hippocampus. For example, the dendritic spine subtype most critical to task acquisition and vulnerable to aging in area 46 is the thin spine, whereas in the dentate gyrus, the density of large mushroom spines with perforated synapses correlates with memory performance. This review summarizes age-related changes in anatomical, neuronal, and synaptic parameters within brain areas implicated in cognition and whether these changes are associated with cognitive decline.

Original languageEnglish (US)
Pages (from-to)1051-1073
Number of pages23
JournalAge
Volume34
Issue number5
DOIs
StatePublished - Oct 1 2012
Externally publishedYes

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Keywords

  • Aging
  • Area 46
  • Dentate gyrus
  • Executive function
  • Perforated synapse
  • Recognition memory

ASJC Scopus subject areas

  • Aging
  • Geriatrics and Gerontology

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