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Quantitative synaptic alterations in the human neocortex during normal aging
Masliah E, Mallory M, Hansen L, DeTeresa R, Terry RD.. Neurology, 1993-01-01
Topic: Brain proteins, microglia and lab models
We quantified the synaptic population density in the frontal cortex of 25 individuals without dementia 16 to 98 years old, using sections double-immunolabeled for beta/A4 amyloid and for synaptophysin, and found a significant inverse correlation between the presynaptic terminal (PT) counts and age (r = -0.7, p < 0.001). Individuals older than 60 years had an average 20% decrease in PT density compared with individuals younger than 60 years. There were no significant correlations between the age and the number of beta/A4 amyloid-positive plaques or between synaptic density and the number of amyloid plaques. Further analysis of the digitized serial optical images showed focal areas of synapse loss and distended synaptophysin-containing boutons in the mature plaques of the normal aged cases. However, we found no microscopic changes in the synaptic content inside and outside the diffuse plaques. We suggest that a loss of synaptic input in the neocortex is an age-dependent factor that contributes to the overall synaptic loss in Alzheimer's disease, but that this might be largely independent of the beta/A4-amyloid deposition.
Key findings
- We quantified the synaptic population density in the frontal cortex of 25 individuals without dementia 16 to 98 years old, using sections double-immunolabeled for beta/A4 amyloid and for synaptophysin, and found a significant inverse correlation between the presynaptic terminal (PT) counts and age (r = -0.7, p < 0.001).
- Individuals older than 60 years had an average 20% decrease in PT density compared with individuals younger than 60 years.
- There were no significant correlations between the age and the number of beta/A4 amyloid-positive plaques or between synaptic density and the number of amyloid plaques.
- However, we found no microscopic changes in the synaptic content inside and outside the diffuse plaques.
- We suggest that a loss of synaptic input in the neocortex is an age-dependent factor that contributes to the overall synaptic loss in Alzheimer's disease, but that this might be largely independent of the beta/A4-amyloid deposition.
Study details
- Participants25
- Evidence strengthLow
How this study scored 47/100
Published in a leading specialty journal. Scored zero for study design, effect reported and randomised / blinded because the record does not state it. We have no data on journal's citation record, times cited, citations per year, impact for its field and year, cited by studies here, still being cited, senior author's track record, institution's track record and multi-centre collaboration, so those were left out: it earned 27 of the 58 points we could judge it on, which is 47 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (Neurology) |
| Journal's citation record | — / 4 | No journal record from OpenAlex — left out of this score |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 1993 — older than 20 years, still counted |
| Sample size | 1 / 4 | 25 participants |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | — / 7 | No citation count (not found in OpenAlex) — left out of this score |
| Citations per year | — / 5 | No citation count or no year — left out of this score |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | — / 6 | Not yet checked against this library's citation graph — left out of this score |
| Still being cited | — / 4 | No yearly citation counts — left out of this score |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | — / 3 | No institution listed in OpenAlex — left out of this score |
| Multi-centre collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 8423884) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Points | 27 / 58 | Scored on 11 of 20 parts. We have no data for the rest, so they are left out: 27 of the 58 points we could judge it on is 47 out of 100. |
| Total | 47 / 100 | — |
What each of these 20 components measures, and what this score is not →
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APA 7th
Masliah, E., Mallory, M., Hansen, L., DeTeresa, R., & Terry, R. D. (1993). Quantitative synaptic alterations in the human neocortex during normal aging. Neurology. https://doi.org/10.1212/wnl.43.1_part_1.192
Vancouver
Masliah E, Mallory M, Hansen L, DeTeresa R, Terry RD. Quantitative synaptic alterations in the human neocortex during normal aging. Neurology. 1993. doi:10.1212/wnl.43.1_part_1.192. PMID: 8423884.
BibTeX
@article{masliah1993-8423884,
author = {Masliah, E. and Mallory, M. and Hansen, L. and DeTeresa, R. and Terry, R. D.},
title = {{Quantitative synaptic alterations in the human neocortex during normal aging}},
journal = {Neurology},
year = {1993},
doi = {10.1212/wnl.43.1_part_1.192},
pmid = {8423884},
url = {https://doi.org/10.1212/wnl.43.1_part_1.192}
}