A significant portion of Dbx1 neurons in the intermediate reticular formation are XII inspiratory premotoneurons
Bibliographic record
Abstract
Reduced tonic and inspiratory drive to XII motoneurons (MNs) that innervate the genioglossus muscle (GG, a tongue protruder) is implicated in obstructive sleep apnea. Reduced excitability of glutamatergic inspiratory XII premotoneurons (preMNs) during sleep may contribute. Little is known about XII inspiratory preMNs due to their sparse distribution in the intermediate reticular formation (IRt). We hypothesized that ipsilaterally‐projecting XII inspiratory preMNs derive from Dbx1 progenitors, a transcription factor expressed in the IRt. Rhythmic, transverse medullary slices (550 μm) were produced from Dbx1 ERCreT2 ; R26 tdTomato neonatal mice (postnatal day 0‐5). Approximately 20% of the Dbx1 IRt neurons received inspiratory drive. In total we identified 29 inspiratory‐modulated Dbx1 IRt neurons via whole‐cell recording. 10 of 24 neurons were antidromically activated from the ipsilateral XII nucleus. Anatomical reconstruction of biocytin‐filled neurons revealed 10 commissural axons and 4 ipsilateral axons projecting to the XII nucleus. Using in situ hybridization, 57.3% (range 54.0‐58.9%) of Dbx1 IRt neurons were glutamatergic. Laser ablation of individual Dbx1 IRt neurons caused a significant (36 ± 3.6%) drop in ipsilateral, but not contralateral, XII inspiratory burst amplitude, and had no effect on inspiratory burst period. Thus, a subpopulation of Dbx1‐derived neurons in the IRt are XII inspiratory preMNs that contribute significantly to XII inspiratory output. This discovery will aid study of XII inspiratory preMNs. Funding: CIHR, NSERC, WCHRI, AIHS, CFI, NIH.
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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".