Deformation‐based morphometry analysis shows early degeneration in Nucleus basalis of Meynert in Alzheimer’s disease
Bibliographic record
Abstract
Abstract Background Nucleus basalis of Meynert (NbM) is the main source of cholinergic projection to the cerebral cortex, including entorhinal cortex (EC). Both cholinergic cells of NbM and their receptive targets in EC show degeneration during early stages of Alzheimer’s disease (AD). While precise delineation of NbM region on T1w scans is difficult due to limited spatial resolution and contrast, we sought to quantify the degeneration of NbM along the disease trajectory and confirm recent studies suggesting that NbM degeneration happens before degeneration in the EC using deformation‐based morphometry (DBM). Method Data included MRI scans of 1473 subjects from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) dataset. Resolution was increased to 0.5 mm isotropic voxel‐size before non‐linear registration to an ADNI‐based unbiased symmetric template. The resulting deformation fields were used to compute the Jacobian determinant map for each subject as a proxy for local volume. NbM and EC masks were mapped to our high‐resolution template and mean determinant values inside these masks were calculated for groups with different baseline diagnosis, and sex‐ and age‐corrected z‐scores were calculated. Two‐sample t‐tests were then used to compare the scores between different groups. Result Figure 1 shows the mean DBM score of both NbM and EC regions for Normal Controls (CN), subjects with early‐ and late‐stage mild cognitive impairment (EMCI and LMCI) and subjects with probable AD dementia. Results corrected for multiple comparisons showed a significant difference between CN and both EMCI and LMCI for left and right NbM. A significant difference was also observed between EMCI and LMCI in left NbM (p‐value = 0.0024). Z‐scored EC volumes did not show a significant difference between CN and EMCI groups; However, results from EMCI and LMCI differ significantly in both hemispheres. We also observed the expected differences between each group with AD in both NbM and EC (P<0.001). Conclusion Our results show that while macroscopic changes in EC emerge as MCI subjects advance toward the later stages, NbM degeneration starts sooner, as early as preliminary stages of MCI. This points to MRI‐based measurements of NbM as potential biomarkers for early detection of AD and as a marker of disease burden.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".