Differential effects of aging on dendritic spines in visual cortex and prefrontal cortex of the rhesus monkey.
Aging decreases the density of spines and the proportion of thin spines in the non-human primate (NHP) dorsolateral prefrontal cortex (dlPFC). In this study, we used confocal imaging of dye-loaded neurons to expand upon previous results regarding the effects of aging on spine density and morphology in the NHP dlPFC and compared these results to the effects of aging on pyramidal neurons in the primary visual cortex (V1). We confirmed that spine density, and particularly the density of thin spines, decreased with age in the dlPFC of rhesus monkeys. Furthermore, the average head diameter of non-stubby spines in the dlPFC was a better predictor than chronological age of the number of trials required to reach criterion on both the delayed response test of visuospatial working memory and the delayed nonmatching-to-sample test of recognition memory. By contrast, total spine density was lower on neurons in V1 than in dlPFC, and neither total spine density, thin spine density, nor spine size in V1 was affected by aging. Our results highlight the importance and selective vulnerability of dlPFC thin spines for optimal prefrontal-mediated cognitive function. Understanding the nature of the selective vulnerability of dlPFC thin spines as compared to the resilience of thin spines in V1 may be a promising area of research in the quest to prevent or ameliorate age-related cognitive decline.
Fishberg Department of Neuroscience, The Friedman Brain Institute, Kastor Neurobiology of Aging Laboratory, and The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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Young
Fishberg Department of Neuroscience, The Friedman Brain Institute, Kastor Neurobiology of Aging Laboratory, and The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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Fishberg Department of Neuroscience, The Friedman Brain Institute, Kastor Neurobiology of Aging Laboratory, and The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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Dumitriu
Laboratory of Behavioral Neuroscience, National Institute on Aging, Baltimore, MD 21224, USA.
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Fishberg Department of Neuroscience, The Friedman Brain Institute, Kastor Neurobiology of Aging Laboratory, and The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Geriatrics and Palliative Care, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA. Electronic address: john.morrison@mssm.edu.
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Morrison
D000375:Aging; D000818:Animals; D049229:Dendritic Spines / Q000502:physiology*; D005260:Female; D008253:Macaca mulatta; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D017397:Prefrontal Cortex / Q000502:physiology* / Q000648:ultrastructure; D017966:Pyramidal Cells / Q000502:physiology / Q000648:ultrastructure; D014793:Visual Cortex / Q000502:physiology* / Q000648:ultrastructure
aging; dendritic spines; macaque; prefrontal cortex; visual cortex