Becoming a couple: the developing relationship between respiratory oscillators of the American Bullfrog
Bibliographic record
Abstract
Many vital mammalian behaviors, including locomotion, swallowing, and breathing, are dependent upon activity of, and coupling between, neural oscillators. In the mammal, multiple respiratory oscillators—chiefly the preBötzinger complex and parafacial respiratory group—are coordinated to generate muscular outputs driving inspiratory and expiratory activity. This multiple oscillator architecture, however, is not unique to mammals. Indeed, in the bullfrog, three spatially‐distinct burst generators driving different phases of the respiratory pattern have been identified, and at least two have oscillator‐like properties. Despite extensive study of these networks in both mammals and frogs, the mechanism and development of coupling between oscillators are not fully characterized. Over metamorphosis, the bullfrog transitions from water breathing in the tadpole to air breathing in the frog. Paralleling this shift in respiratory medium are radical changes to the underlying motor pattern produced by the brainstem, shifting from buccal ventilation in the tadpole to buccal and lung ventilation in the adult frog. To investigate the question of whether the bullfrog respiratory networks producing buccal and lung bursts ‘begin coupled’ (i.e., with tight synchronicity between oscillator rhythms upon the initial appearance of the lung pattern) or if this interaction arises over development, we employed the bullfrog isolated superfused brainstem preparation. We recorded burst‐triggered respiratory outputs in facial and hypoglossal rootlets from isolated brainstems from early tadpole to juvenile frog. By evaluating variance in the offset between the two primary rhythms, we established coupling coefficients to characterize the oscillators’ interactions. We found evidence to suggest that, in the tadpole, the rhythms of the gill‐ventilating and nascent lung oscillators are uncoupled. Over the course of metamorphosis, these rhythms become increasingly tightly coupled, paralleling the structural and behavioral changes in the animal. Specifically, coupling appears to reach adult levels in unison with the eruption of the forelimbs. Our results indicate that the expression of the lung oscillator is effectively knit into the larger respiratory network over metamorphosis. These findings further our understanding of amphibian respiratory development and may have implications for the origins of modern air‐breathing. Support or Funding Information National Science and Engineering Council of Canada (NSERC) and Alberta Innovates Health Solutions (AIHS) provided funding for this study
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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 | 0.001 |
| 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".