Painted Turtle Cortex is Resistant to an <i>in Vitro</i> Mimic of the Ischemic Mammalian Penumbra
Bibliographic record
Abstract
Anoxia or ischemia causes hyperexcitability and cell death in mammalian neurons. Conversely, in painted turtle brain anoxia increases γ-amino butyric acid (GABA)ergic suppression of spontaneous electrical activity, and cell death is prevented. To examine ischemia tolerance in turtle neurons, we treated cortical sheets with an in vitro mimic of the penumbral region of stroke-afflicted mammalian brain (ischemic solution, IS). We found that during IS perfusion, neuronal membrane potential (V(m)) and the GABA(A) receptor reversal potential depolarized to a similar steady state (-92 ± 2 to -28 ± 3 mV, and -75 ± 1 to -35 ± 3 mV, respectively), and whole-cell conductance (G(w)) increased >3-fold (from 4 ± 0.2 to 15 ± 1 nS). These neurons were electrically quiet and changes reversed after reperfusion. GABA receptor antagonism prevented the IS-mediated increase in G(w) and neurons exhibited enhanced electrical excitability and rapid and irreversible rundown of V(m) during reperfusion. These results suggest that inhibitory GABAergic mechanisms also suppress electrical activity in ischemic cortex. Indeed, after 4 hours of IS treatment neurons did not exhibit any apparent damage; while at 24 hours, only early indicators of apoptosis were present. We conclude that anoxia-tolerant turtle neurons are tolerant of exposure to a mammalian ischemic penumbral mimic solution.
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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".