Sex differences in the relationship between pain and autonomic outflow during a cold pressor test
Bibliographic record
Abstract
BACKGROUND: Chronic pain is partly maintained by the sympathetic nervous system, whose activity is best measured by muscle sympathetic nerve activity (MSNA). MSNA responses to acute pain have been thoroughly investigated, whereas MSNA responses to longer-lasting pain are poorly understood. Therefore, this study examined the relationship between pain ratings and peroneal MSNA during a tonic cold pressor test (CPT) in male and female participants. METHODS: We obtained MSNA measures during a 6 min CPT in 18 young adult (20-33 years) men and women. Verbal pain ratings (0-10) and autonomic outcomes (heart rate [HR], mean arterial blood pressure [MAP], and MSNA) were assessed simultaneously at multiple time points across the CPT. RESULTS: Pain, HR, and MAP increased in the initial 30s in both sexes. Females increased their MSNA burst frequency (BF) to a greater extent than males. Across the full CPT we observed a positive relationship between pain and HR in males, a positive relationship between pain and MSNA BF in females, and a negative relationship between pain and MSNA burst amplitude in females. CONCLUSIONS: Overall, males displayed a strong relationship between tonic pain and HR, an index of parasympathetic activity, whereas females displayed strong and offsetting relationships between tonic pain and purely sympathetic MSNA variables. These observations suggest sex differences in autonomic mechanisms during tonic pain, which may have relevance to ongoing efforts to modulate pain via manipulations of the autonomic nervous system, as well as sex/gender disparities in chronic pain prevalence.
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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 | 0.000 | 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) | 0.004 | 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".