P1‐102: Multi‐decade hippocampal and amygdala volume norms
Bibliographic record
Abstract
The variability and time course of hippocampal (HC) and amygdala (AG) volumes throughout asymptotic adulthood have not been often characterized. We investigated the effects of age, sex and hemisphere on HC/AG volumes from subjects in the Italian Brain Normative Archive (Galluzzi et al., 2009). We included data on manual segmentation of 422 HC and 228 AG from 422 subjects in the Archive aged 20 to 84 years. We conducted correlation analysis, hierarchical regression and ANOVA to determine interaction effects. Interactions: There was no significant difference in age between men and women (p = 0.4094) and no interaction between sex and hemisphere on HC/AG volumes (hemisphere: HC - p < .0001; AG - p =0.011 / sex: HC - p < .0001; AG - p =0.0098). Only AG volumes for women when both hemispheres were considered and right AG volumes when all genders were considered have a negative correlation with Age. When sex was considered as confounding variable in hierarchical regression, age was linearly associated only with right AG volumes (Bêta = −3.365; p = 0.0078). Age and Age have no significant effects on HC/AG volumes (p > 0.280 for both HC and AG) in a quadratic regression model. Yet, if sex was introduced as an independent variable in the above models, age kept a weak effect on rightAG volumes (Bêta = −3.438; p = 0.0960). Normative data: When the subjects were divided by decade into six different strata ,the difference between age groups was significant only for right AG volumes (p = 0.0212). A Tucky multiple comparison test showed that there was no significant difference in HC volumes between any strata. The distribution of HC/AG volumes showed homogeneity of volumes for HC but not for AG throughout all groups. Except for the rightAG, this study demonstrates that age has no discernable effects on HC/AG volumes and that there exists as wide a variability in early adulthood as in later years. The volumes from the Archive can be used as normative data for future research and clinical studies.
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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 | 0.002 | 0.005 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.010 | 0.005 |
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".