Parasternal intercostal and diaphragm function during sleep
Bibliographic record
Abstract
Action of the uppermost medial internal intercostal muscles-the parasternals-during rapid eye movement (REM) is uncertain; no direct recordings exist of shortening of these muscles during sleep. Historically, motor inhibition of skeletal muscles during REM sleep is thought to cause global loss of chest wall muscle function, REM "atonia," with preservation of only diaphragm function. However, recent evidence during wakefulness shows parasternals as distinctive obligatory inspiratory muscles. Therefore we hypothesized that attenuation of chest wall function during sleep may spare the parasternals along with the diaphragm, as essential muscles of inspiration during REM. We studied seven canines, comparing costal and crural diaphragm and parasternal intercostal muscle function during wakefulness and non-REM (NREM) and REM sleep, during normal spontaneous sleep, continuously recording ventilation and simultaneous muscle electromyogram (EMG) and length from sonomicrometry microtransducers. Ventilation during sleep declined significantly from wakefulness. From wakefulness to NREM and REM, costal and crural tidal EMG increased, while parasternal tidal EMG was preserved unchanged. Costal and crural shortening per breath during NREM and REM did not change significantly from wakefulness. Concurrently, parasternal shortening decreased equally in both NREM and REM despite preservation of the parasternal EMG. We conclude that diaphragm and parasternals are not inhibited, and both remain active together as essential inspiratory muscles, during REM sleep. The lesser contraction of parasternal intercostals compared with diaphragm may be attributed to net changes in mechanics affecting the chest wall during sleep.
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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".