Heterogeneous Electrotonic Coupling and Synchronization of Rhythmic Bursting Activity in Mouse Hb9 Interneurons
Bibliographic record
Abstract
The neurons and mechanisms involved in mammalian spinal cord networks that produce rhythmic locomotor activity remain largely undefined. Hb9 interneurons, a small population of discretely localized interneurons in the mouse spinal cord, are conditionally bursting neurons. Here we applied potassium channel blockers with the aim of increasing neuronal excitability and observed that under these conditions, postnatal Hb9 interneurons exhibited bursts of action potentials with underlying voltage-independent spikelets. The bursts were insensitive to antagonists to fast chemical synaptic transmission, and the bursting and spikelets were blocked by tetrodotoxin. Calcium imaging studies using 2-photon excitation in spinal cord slices revealed that clustered Hb9 interneurons exhibited synchronous and occasional asynchronous, calcium transients that were also insensitive to fast synaptic transmission blockade. All transients were blocked by the gap junction blocker carbenoxolone. Paired whole cell patch-clamp recordings of Hb9 interneurons in the late postnatal mouse revealed common chemical synaptic inputs but no evidence of current transfer (i.e., electrotonic coupling) between the neurons. However, Hb9 and a previously defined population of non-Hb9 interneurons were electrotonically coupled. In the absence of fast chemical transmission in the whole spinal cord preparation, 2-photon excitation calcium imaging revealed bursting activity of Hb9 interneurons synchronous with rhythmic ventral root output. Thus Hb9 interneurons are both endogenous bursters and rhythmically active within a heterogeneous electrotonically coupled network. A network with these properties could produce the wide range of stable rhythms necessary for locomotor activity.
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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".