Cardiorespiratory depression from brainstem seizure activity in freely moving rats
Bibliographic record
Abstract
Cardiorespiratory dysfunction during or after seizures may contribute to sudden unexpected death in epilepsy. Disruption of lower brainstem cardiorespiratory systems by seizures is postulated to impair respiratory and cardiac function. Here, we explore the effects of brainstem seizures and stimulation on cardiorespiratory function using a rat model of intrahippocampal 4-aminopyridine (4-AP)-induced acute recurrent seizures. Cardiac and respiratory monitoring together with local field potential recordings from hippocampus, contralateral parietal cortex and caudal dorsomedial brainstem, were conducted in freely moving adult male Wistar rats. Seizures were induced by intrahippocampal injection of 4-AP. Increased respiratory rate but unchanged heart rate occurred during hippocampal and secondarily generalized cortical seizures. Status epilepticus without brainstem seizures increased respiratory and heart rates, whereas status epilepticus with intermittent brainstem seizures induced repeated episodes of cardiorespiratory depression leading to death. Respiratory arrest occurred prior to asystole which was the terminal event. Phenytoin (100 mg/kg, intraperitoneal injection), administered after 4-AP intrahippocampal injection, terminated brainstem seizures and the associated cardiorespiratory depression, preventing death in five of six rats. Focal electrical stimulation of the caudal dorsomedial brainstem also suppressed cardiorespiratory rates. We conclude that in our model, brainstem seizures were associated with respiratory depression followed by cardiac arrest, and then death. We hypothesize this model shares mechanisms in common with the classic sudden unexpected death in epilepsy (SUDEP) syndrome associated with spontaneous seizures.
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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) | 0.001 | 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 | 0.001 |
| 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".