Brain fuel uptake during aging and in Alzheimer's disease: A positron emission tomography and MRI study comparing glucose and a new ketone tracer – <sup>11</sup>C-acetoacetate
Bibliographic record
Abstract
Lower regional cerebral metabolic rate of glucose (CMR g ) is present during normal aging and may contribute to the development or progression of Alzheimer's disease (AD) (1) . However, with only [ 18 F]-fluorodeoxyglucose ( 18 F-FDG) available to measure brain energy metabolism by positron emission tomography (PET), it remains unclear whether lower CMR g in AD represents a global problem of brain energy substrate metabolism or is specific to glucose. The ketones, acetoacetate (AcAc) and beta-hydroxybutyrate, are the brain's main alternative energy substrates to glucose during prolonged fasting or in other forms of glucose deficit, so we compared brain glucose and AcAc metabolism in three groups: young healthy adults, healthy elderly and mild AD. Our objectives were to: (i) quantify CMR g and brain [ 11 C]-AcAc uptake (CMR a ) by PET, and (ii) compare regional brain volumes, CMR g and CMR a between healthy young and elderly persons, and between the healthy elderly and mild AD.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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) | 0.000 | 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 teacher head, 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".