Evidence suggesting three respiratory oscillators in frogs (Rana catasbeiana): implications for the Oscillator Homology Hypothesis and the evolution of breathing.
Bibliographic record
Abstract
Recent data in mammals and frogs suggest at least two separate respiratory oscillators, one who's activity coincides with the powerstroke of lung inflation (the preBötzinger Complex and the lung oscillator, respectively) and a second priming oscillator, who's activity appears to precede the powerstroke (the PreI and buccal oscillators, respectively). According to the Oscillator Homology Hypothesis, the oscillators in mammals evolved from the same ancestors as those in lower vertebrates. However, the priming oscillator in mammals and frogs maybe located in different rhombomeric segments and their rostral‐caudal location relative to the powerstroke oscillator may be reversed. Using the “sheep‐dip” technique, a new method for systematically surveying respiratory rhythm promoting sites in lower vertebrates, we provide evidence suggesting that the lung oscillator in late‐stage metamorphic frogs can, itself, be subdivided into a powerstroke and a novel priming component. As in mammals, the novel lung‐priming component in frogs appears to extend more rostrally than the powerstroke component. These data suggest the Oscillator Homology Hypothesis has to be revised: the mammalian PreI and PreBötzinger Complex oscillators may have evolved from the same two components that gave rise to the frog lung oscillator and not from the buccal oscillator as previously thought. Work funded by NSERC.
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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 | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".