Assessing central and peripheral respiratory chemoreceptor interaction in humans
Bibliographic record
Abstract
New Findings What is the central question of this study? We investigated the interaction between central and peripheral respiratory chemoreceptors in healthy, awake human participants by using a background of step increases in steady‐state normoxic fraction of inspired carbon dioxide to alter central chemoreceptor activation and by using the transient hypoxia test to target the peripheral chemoreceptors. What is the main finding and its importance? Our data suggest that the interaction between central and peripheral respiratory chemoreceptors is additive in minute ventilation and respiratory rate, but hypo‐additive in tidal volume. Our study adds important new data in reconciling chemoreceptor interaction in awake healthy humans and is consistent with previous reports of simple addition in intact rodents and humans. Abstract Arterial blood gas levels are maintained through respiratory chemoreflexes, mediated by central chemoreceptors in the CNS and peripheral chemoreceptors located in the carotid bodies. The interaction between central and peripheral chemoreceptors is controversial, and few studies have investigated this interaction in awake, healthy humans, owing, in part, to methodological challenges. We investigated the interaction between the central and peripheral chemoreceptors in healthy humans using a transient hypoxia test (three consecutive breaths of 100% N 2 ; TT‐HVR), which targets the temporal domain and stimulus specificity of the peripheral chemoreceptors. The TT‐HVRs were superimposed upon three randomized background levels of steady‐state inspired fraction of normoxic CO 2 (; 0, 0.02 and 0.04). Chemostimuli [calculated oxygen saturation ()] and respiratory variable responses [respiratory rate (R R ), inspired tidal volume ( V TI ) and ventilation ()] were averaged from all three TT‐HVR trials at each level. Responses were assessed as: (1) a change (∆) from baseline; and (2) indexed against . Aside from a significantly lower ∆ V TI response in 0.04 ( P = 0.01), the hypoxic rate responses (∆R R or ∆R R /; P = 0.46 and P = 0.81), hypoxic tidal volume response (; P = 0.08) and the hypoxic ventilatory responses ( and ; P = 0.09 and P = 0.31) were not significantly different across trials. Our data suggest simple addition between central and peripheral chemoreceptors in , which is mediated through simple addition in R R responses, but hypo‐addition in V TI responses. Our study adds important new data in reconciling chemoreceptor interaction in awake, healthy humans and is consistent with previous reports of simple addition in intact rodents and humans.
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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".