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What is the amygdala?
Swanson LW, Petrovich GD.. Trends in neurosciences, 1998-08-01
Topic: Amyloid, tau and blood-test diagnosis
'Amygdala' and 'amygdalar complex' are terms that now refer to a highly differentiated region near the temporal pole of the mammalian cerebral hemisphere. Cell groups within it appear to be differentiated parts of the traditional cortex, the claustrum, or the striatum, and these parts belong to four obvious functional systems--accessory olfactory, main olfactory, autonomic and frontotemporal cortical. In rats, the central nucleus is a specialized autonomic-projecting motor region of the striatum, whereas the lateral and anterior basolateral nuclei together are a ventromedial extension of the claustrum for major regions of the temporal and frontal lobes. The rest of the amygdala forms association parts of the olfactory system (accessory and main), with cortical, claustral and striatal parts. Terms such as 'amygdala' and 'lenticular nucleus' combine cell groups arbitrarily rather than according to the structural and functional units to which they now seem to belong. The amygdala is neither a structural nor a functional unit.
Key findings
- Cell groups within it appear to be differentiated parts of the traditional cortex, the claustrum, or the striatum, and these parts belong to four obvious functional systems--accessory olfactory, main olfactory, autonomic and frontotemporal cortical.
- In rats, the central nucleus is a specialized autonomic-projecting motor region of the striatum, whereas the lateral and anterior basolateral nuclei together are a ventromedial extension of the claustrum for major regions of the temporal and frontal lobes.
- The rest of the amygdala forms association parts of the olfactory system (accessory and main), with cortical, claustral and striatal parts.
- Terms such as 'amygdala' and 'lenticular nucleus' combine cell groups arbitrarily rather than according to the structural and functional units to which they now seem to belong.
- The amygdala is neither a structural nor a functional unit.
Why it matters
This paper argues that the amygdala is not a single structural or functional unit but a set of cell groups belonging to several functional systems. It is a basic anatomy paper with no findings on treating, curing or preventing Alzheimer's disease.
Study details
- Evidence strengthLow
How this study scored 47/100
Published in a peer-reviewed journal. Scored zero for study design, sample size, effect reported, studied in people and randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Trends in neurosciences) |
| Journal's citation record | 3 / 4 | Trends in Neurosciences: journal h-index 439 (OpenAlex, 2026-10-29) |
| 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 | 1998 — older than 20 years, still counted |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 7 / 7 | Cited 1,350 times (OpenAlex, 2026-10-10) |
| Citations per year | 4 / 5 | 45.0 citations a year over 30 year(s) since 1998 |
| Impact for its field and year | 3 / 6 | Cited 5.1× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 2 / 6 | Cited by 3 other studies in this library |
| Still being cited | 3 / 4 | Cited 89 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 2 / 4 | Last-listed author Gorica D. Petrovich: h-index 33 (OpenAlex, whole career) |
| Institution's track record | 2 / 3 | University of Southern California: institution h-index 1,521 (OpenAlex) |
| Multi-centre collaboration | 0 / 3 | OpenAlex lists 1 institution(s) in 1 country — scores zero (affiliation lists can be incomplete) |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 9720596) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 47 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
May need a subscription OpenAlex found no free copy of the full text (checked 6 Feb 1020), so the publisher may charge for it. The PubMed abstract is free.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. Check the citation against the original before you use it.
APA 7th
Swanson, L. W., & Petrovich, G. D. (1998). What is the amygdala? Trends in neurosciences. https://doi.org/10.1016/s0166-2236(98)01265-x
Vancouver
Swanson LW, Petrovich GD. What is the amygdala? Trends in neurosciences. 1998. doi:10.1016/s0166-2236(98)01265-x. PMID: 9720596.
BibTeX
@article{swanson1998-9720596,
author = {Swanson, L. W. and Petrovich, G. D.},
title = {{What is the amygdala?}},
journal = {Trends in neurosciences},
year = {1998},
doi = {10.1016/s0166-2236(98)01265-x},
pmid = {9720596},
url = {https://doi.org/10.1016/s0166-2236(98)01265-x}
}
Later studies that cite this one
3 studies in the alzhub library list this one in their references.