Investigation of endocannabinoids in plasma and their correlation with physical fitness and resting state functional connectivity of the periaqueductal grey in women with fibromyalgia: An exploratory secondary study
Bibliographic record
Abstract
Abstract Objectives The endocannabinoid system is a neuromodulatory system linked to pain, distress, and physical activity. The endocannabinoids (eCBs) arachidonoylethanolamide (AEA) and 2-arachidonoylglycerol are known to activate the cannabinoid receptors. The eCB system has been reported to be acutely affected by physical activity. Altered connectivity related to pain intensity in patients with fibromyalgia (FM) has been reported. However, how the peripheral eCBs, including eCB-like N -acylethanolamines (NAEs) concentrations, associate with pain-related regions of the brain and physical activity in FM, is not known. This study aimed to investigate eCBs and eCB-like NAEs in plasma and the association with functional connectivity in brain regions relevant for pain and with physical fitness. Methods The plasma concentrations of eCBs and eCB-like NAEs were measured in 31 women with FM and 29 healthy controls (HC). Functional magnetic resonance imaging, measurement of physical fitness and questionnaire regarding pain and depression/anxiety were included. Results Significantly higher concentrations of AEA were found in FM compared to HC. The AEA level correlated positively with pain intensity and was inversely associated with physical fitness, which in turn were inversely correlated with pain intensity and psychological distress in FM. Periaqueductal gray (PAG)-thalamus connectivity was not associated with circulating eCB and eCB-like NAEs. Stronger PAG-thalamus connectivity was related to a higher level of physical activity. Conclusions These results confirm that impaired physical fitness is an important aspect of FM, which can be reflected in the increased eCB levels and in PAG-thalamus connectivity. Further studies are necessary to establish a causal relationship between physical fitness, eCBs, eCB-like NAEs, and brain connectivity.
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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 | 0.001 | 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".