Increased hippocampal activation in mild cognitive impairment compared to normal aging and AD
Dickerson BC, Salat DH, Greve DN, Chua EF, Rand-Giovannetti E, Rentz DM, Bertram L, Mullin K et al.. Neurology, 2005-08-01
Topic: Risk, prevention and care in population studies
Objective To use fMRI to investigate whether hippocampal and entorhinal activation during learning is altered in the earliest phase of mild cognitive impairment (MCI). Methods Three groups of older individuals were studied: 10 cognitively intact controls, 9 individuals at the mild end of the spectrum of MCI, and 10 patients with probable Alzheimer disease (AD). Subjects performed a face-name associative encoding task during fMRI scanning, and were tested for recognition of stimuli afterward. Data were analyzed using a functional-anatomic method in which medial temporal lobe (MTL) regions of interest were identified from each individual's structural MRI, and fMRI activation was quantified within each region. Results Significantly greater hippocampal activation was present in the MCI group compared to controls; there were no differences between these two groups in hippocampal or entorhinal volumes. In contrast, the AD group showed hippocampal and entorhinal hypoactivation and atrophy in comparison to controls. The subjects with MCI performed similarly to controls on the fMRI recognition memory task; patients with AD exhibited poorer performance. Across all 29 subjects, greater mean entorhinal activation was found in the subgroup of 13 carriers of the APOE epsilon4 allele than in the 16 noncarriers. Conclusions The authors hypothesize that there is a phase of increased medial temporal lobe activation early in the course of prodromal Alzheimer disease followed by a subsequent decrease as the disease progresses.
Key findings
- Results Significantly greater hippocampal activation was present in the MCI group compared to controls; there were no differences between these two groups in hippocampal or entorhinal volumes.
Why it matters
This small imaging study found that people with mild cognitive impairment had greater hippocampal activation during a learning task than healthy controls, while those with Alzheimer's disease had reduced activation and shrinkage. The authors suggest a phase of increased brain activity may occur early in the disease, but this does not offer a treatment, cure or prevention.
New to this subject? Start with our plain-English guide: Genetics →
Study details
- Evidence strengthLow
How this study scored 55/100
Published in a leading specialty 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 | 9 / 10 | Tier 2 — leading specialty journal (Neurology) |
| Journal's citation record | 4 / 4 | Neurology: journal h-index 525 (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 | 2005 — 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 | 6 / 7 | Cited 919 times (OpenAlex, 2026-10-10) |
| Citations per year | 4 / 5 | 40.0 citations a year over 23 year(s) since 2005 |
| Impact for its field and year | 5 / 6 | Cited 21.3× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 3 / 6 | Cited by 23 other studies in this library |
| Still being cited | 3 / 4 | Cited 132 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 4 / 4 | Last-listed author Reisa Anne Sperling: h-index 157 (OpenAlex, whole career) |
| Institution's track record | 2 / 3 | Massachusetts General Hospital: institution h-index 2,057 (OpenAlex) |
| Multi-centre collaboration | 1 / 3 | OpenAlex lists 2 institution(s) in 1 country |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 16087905) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 55 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
- DOI: 10.1212/01.wnl.0000171450.97464.49
- PubMed: 16087905
- Original source →
- Free full text: PubMed Central →
Full text: free to read — PubMed Central lists this copy as free to read: the link above (checked 10 Oct 2026).
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. The record's author list ends in “et al.”, so not every author is named. Check the citation against the original before you use it.
APA 7th
Dickerson, B. C., Salat, D. H., Greve, D. N., Chua, E. F., Rand-Giovannetti, E., Rentz, D. M., et al. (2005). Increased hippocampal activation in mild cognitive impairment compared to normal aging and AD. Neurology. https://doi.org/10.1212/01.wnl.0000171450.97464.49
Vancouver
Dickerson BC, Salat DH, Greve DN, Chua EF, Rand-Giovannetti E, Rentz DM, et al. Increased hippocampal activation in mild cognitive impairment compared to normal aging and AD. Neurology. 2005. doi:10.1212/01.wnl.0000171450.97464.49. PMID: 16087905.
BibTeX
@article{dickerson2005-16087905,
author = {Dickerson, B. C. and Salat, D. H. and Greve, D. N. and Chua, E. F. and Rand-Giovannetti, E. and Rentz, D. M. and Bertram, L. and Mullin, K. and others},
title = {{Increased hippocampal activation in mild cognitive impairment compared to normal aging and AD}},
journal = {Neurology},
year = {2005},
doi = {10.1212/01.wnl.0000171450.97464.49},
pmid = {16087905},
url = {https://doi.org/10.1212/01.wnl.0000171450.97464.49}
}
Studies this one cites
Referenced by this study and also in the alzhub library, so you can read them here. Showing 12 of 14.
Later studies that cite this one
23 studies in the alzhub library list this one in their references. Showing the 8 highest-scoring.
Related studies in Genetics
Also tagged “disorder”
492 studies in the library carry the topic tag “disorder”; these are this study's neighbours in a fixed, alphabetical-by-hash tour of them, not the closest in content. All 492 tagged studies.