Microelectrode recordings from the human cervical vagus nerve during maximal breath‐holds
Bibliographic record
Abstract
Voluntary breath-holds can be sustained for a long time following training, but ultimately, regardless of duration, the asphyxic break-point is reached and the apnoea terminated. The physiological changes occurring during the apnoea include a marked increase in sympathetically-mediated vasoconstriction in non-essential organs, such as skeletal muscle, spleen and kidney, while the brain is protected by a marked increase in perfusion. What is not understood is what happens to cardiac vagal activity. Here, we performed microelectrode recordings from the right cervical vagus nerve in healthy participants [both trained breath-hold divers (n = 10) and untrained controls (n = 10)] during tidal breathing, slow-deep breathing, an inspiratory-capacity apnoea and an end-expiratory apnoea. Using cross-correlation analysis of multi-unit neural activity, we tested the hypothesis that breath-hold divers would have greater cardiac modulation of vagal activity, which primarily reflects the discharge of cardiac afferents, particularly during a maximal apnoea. We showed that there were no differences in cardiac modulation of vagus nerve activity either during tidal breathing or during any of the respiratory manoeuvres, nor was there a difference in cardiac modulation during the static phase of a maximal apnoea or when involuntary breathing movements occurred before reaching the asphyxic break-point. We conclude that changes in vagal sensory inputs from the heart are not responsible for the marked tolerance to asphyxia shown by breath-hold divers.
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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) | 0.001 | 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 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".