CoChat
Sign Up
Cited by 268Neuroscience and Neuropharmacology ResearchMemory and Neural MechanismsDementia and Cognitive Impairment Research

Synapses are lost during aging in the primate prefrontal cortex

Open access
Peters, A., Sethares, C., Luebke, J.I.·2008·Neuroscience
DOI 10.1016/j.neuroscience.2007.07.014PMC PMC2441531
Open this paper in CoChat — free account

Abstract

An electron microscopic analysis has been carried out on the effects of age on the numerical density of both excitatory (asymmetric) and inhibitory (symmetric) synapses in the neuropil of layers 2/3 and of layer 5 in area 46 from the frontal cortex of behaviorally tested rhesus monkeys. There is no change in the lengths of synaptic junctions with age or in the percentage distribution of synapses relative to the postsynaptic spines and dendritic shafts. However, in layers 2/3 there is an overall loss of about 30% of synapses from 5 to 30 years of age, and both asymmetric and symmetric synapses are lost at the same rate. In layer 5 the situation is different; the overall loss of synapses is only 20% and this is almost entirely due to a loss of asymmetric synapses, since there is no significant loss of symmetric synapses from this layer with age. When the synapse data are correlated with the overall cognitive impairment shown by the monkeys, it is found that there is a strong correlation between the numerical density of asymmetric synapses in layers 2/3 and cognitive impairment, with a weaker correlation between symmetric synapse loss and cognitive impairment. In layer 5 on the other hand there is no correlation between synapse loss and cognitive impairment. However synapse loss is not the only factor causing cognitive impairment, since in previous studies of area 46 we have found that age-related alteration in myelin in this frontal area also significantly contributes to cognitive decline. The synapse loss is also considered in light of earlier studies, which show that the frequency of spontaneous excitatory synaptic responses is reduced with age in layers 2/3 neurons.

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1016/j.neuroscience.2007.07.014

Cites

48 of 48 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Quantitative analyses of synapses in the neuropil have shown that most synapses on dendritic shafts are AS (~80%), with relatively few being SS (~20%).

    “In fact, quantitative analyses of synapses in the neuropil have shown that most synapses on dendritic shafts are AS (∼80%), with relatively few being SS (∼20%) (Beaulieu et al., 1992; Peters et al., 2008; Hsu et al., 2017; Calì et al., 2018; Santuy et al., 2018b; Domínguez-Álvaro et al., 2019, 2021a,b; Yakoubi et al., 2019b; Montero-Crespo et al., 2020, 2021; Cano-Astorga et al., 2021, 2023;”

    From Unambiguous identification of asymmetric and symmetric synapses using volume electron microscopy (2024) · cites this paper as Peters et al., 2008

    Table 1 and the Results section on postsynaptic components give the percentage of each synapse type that contacts a shaft—not the percentage of shaft synapses that is each type. Combining the reported 87% asymmetric and 13% symmetric overall with the young layer 2/3 shaft-contact percentages (16.5% and 78.5%) gives approximately 58% asymmetric and 42% symmetric synapses on shafts, rather than the claimed 80% and 20%. (LLM, conf=0.87)

    Checked by a reasoning model — may be wrong.

    Experimental — accuracy not yet measured

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The self-check needs the paper’s full text.

Cites

Flagged first, then by citations

2 of the 50 references couldn’t be matched to a known paper.

Research works printed but not linked: 2

  1. [27]27. Moss MB, Moore TL, Schettler SP, Killiany R, Rosene DL. Successful v unsuccessful aging in the rhesus monkey. In: Riddle DR, editor. In: Brain aging. Models, methods and mechanisms. Baton Rouge: CRC Press; 2007. pp. 21–38. [[PubMed](https://pubmed.ncbi.nlm.nih.gov/21204342/)] [[Google Scholar](https://scholar.google.com/scholar_lookup?title=In:%20Brain%20aging.%20Models,%20methods%20and%20mechanisms&author=MB%20Moss&author=TL%20Moore&author=SP%20Schettler&author=R%20Killiany&author=DL%20Rosene&publication_year=2007&)]
  2. [41]41. Rosene DL, Nicholson TJ. Some neurotransmitter receptor changes in the hippocampus and cerebral cortex in normal aging. In: Peters A, Morrison JH, editors. Cerebral cortex Vol. 14. Neurodegenerative and age-related changes in cerebral cortex. New York: Kluwer Academic/Plenum Publishers; 1999. pp. 111–128. [[Google Scholar](https://scholar.google.com/scholar_lookup?title=Cerebral%20cortex%20Vol.%2014.%20Neurodegenerative%20and%20age-related%20changes%20in%20cerebral%20cortex&author=DL%20Rosene&author=TJ%20Nicholson&publication_year=1999&)]

Cited by

Sorted by citations

Related

Authors
Peters, A., Sethares, C., & Luebke, J. I.
Affiliations
Boston University (US)
ORCID
Venue
Neuroscience
Publisher
Elsevier BV
Published
2008-04
Volume
152
Issue
4
Pages
970-981
ISSN
0306-4522 (ISSN-L)
DOI
10.1016/j.neuroscience.2007.07.014
PMC
PMC2441531
OpenAlex
W2021005581
Cited by
268
References
50
Citations by year
2026: 10 · 2025: 18 · 2024: 16 · 2023: 23 · 2022: 10 · 2021: 20 · 2020: 14 · 2019: 13 · 2018: 17 · 2017: 11 · 2016: 17 · 2015: 8 · 2014: 13 · 2013: 22 · 2012: 21
FWCI
2.26
Type
journal article
Language
en
Open access
Licence
www.elsevier.com/tdm/userlicense/1.0/ (tdm)
Locations
  • Neuroscience (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
Funders
National Institute on Aging (R01AG025062, P01AG000001, P01-AG-00001)
Topics
  • Life Sciences › Neuroscience › Cellular and Molecular Neuroscience › Neuroscience and Neuropharmacology Research
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Memory and Neural Mechanisms
  • Health Sciences › Medicine › Psychiatry and Mental health › Dementia and Cognitive Impairment Research
Keywords
synaptic loss, aging, prefrontal cortex, rhesus monkeys, area 46, asymmetric synapses, symmetric synapses, cognitive impairment, layer 2/3, layer 5, myelin, postsynaptic spines
MeSH terms
Age Factors, Aging, Animals, Behavior, Animal, Female, Macaca mulatta, Male, Neurons, Synapses, Prefrontal Cortex, Microscopy, Electron, Transmission

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review