NMDA receptor‐mediated transmission contributes to network ‘hyperexcitability’ in the rat insular cortex
Bibliographic record
Abstract
The insular cortex (IC) plays distinct roles under physiological and pathological conditions. However, the mechanisms regulating excitability in this area remain unknown. By employing field potential and sharp-electrode intracellular recordings in horizontal rat brain slices comprising the IC and the perirhinal cortex, we studied here the intrinsic and network characteristics of neurons in the agranular IC. These cells generated regular action potential firing with weak adaptation during intracellular injection of depolarizing current pulses, and were pyramidal in shape when neurobiotin filled. Spontaneous, field events (duration = 2.3 +/- 0.25 s; intervals of occurrence = 44.9 +/- 6.3 s) were identified in 22/52 slices and corresponded in IC neurons to intracellular depolarizations with action potential firing. Similar field and intracellular discharges were elicited in all slices by electrical stimuli. Antagonizing N-methyl-d-aspartate (NMDA) receptors blocked the spontaneous activity and reduced or abolished the stimulus-induced discharges. In the latter cases, stimuli elicited depolarizing events that became hyperpolarizing at about -64 mV, suggesting the contribution of gamma-aminobutyric acid (GABA)(A) receptor-mediated conductances. Our findings identify for the first time some functional properties of agranular IC neurons and point at a powerful NMDA receptor-mediated mechanism implementing network hyperexcitability. This feature may contribute to the role of IC in neurological disorders.
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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) | 0.000 | 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".