Location of central respiratory chemoreceptors in the developing tadpole
Bibliographic record
Abstract
The location of central respiratory chemoreceptors in amphibian larvae may change as the central chemoreceptive function shifts from driving gill to driving lung ventilation during metamorphosis. We examined this possibility in the in vitro brain stem of the pre- and postmetamorphic Rana catesbeiana tadpole by microinjecting hypercapnic artificial cerebrospinal fluid (aCSF) while recording fictive lung ventilation. The rostral and caudal brain stem were separately explored systematically using injections of 11 nl of aCSF equilibrated with 100% CO2 that transiently acidified a 500-microm region, producing a maximum reduction in pH of 0.23 +/- 0.06 at the site of injection. In postmetamorphic tadpoles, chemoreceptive sites were concentrated in the rostral compared with the caudal brain stem. No such segregation was observed in the premetamorphic tadpole. We conclude that, as in lung rhythmogenic function, respiratory chemosensitivity emerges rostrally in the amphibian brain stem during development.
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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 | 0.000 |
| 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 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".