Modulatory Effect of Substance P to the Brain Stem Locomotor Command in Lampreys
Bibliographic record
Abstract
Substance P initiates locomotion when injected in the brain stem of mammals. This study examined the possible role of this peptide on the supraspinal locomotor command system in lampreys. Substance P was bath applied or locally injected into an in vitro isolated brain stem, and the effects of the drug were examined on reticulospinal cells and on the occurrence of swimming in a semi-intact preparation. Bath applications of substance P induced sustained depolarizations occurring rhythmically in intracellularly recorded reticulospinal cells. Spiking activity was superimposed on the depolarizations and swimming was induced. The sustained depolarizations were abolished by tetrodotoxin, and substance P did not affect the membrane resistance of reticulospinal cells nor their firing properties, suggesting that it did not directly effect reticulospinal cells. To establish where the effects were exerted, successive lesions of the brain stem were made as well as local applications of the drug in the brain stem. Removing the mesencephalon abolished the sustained depolarizations, whereas large ejections of the drug in the mesencephalon excited reticulospinal cells and elicited bouts of swimming. More local injections into the mesencephalic locomotor region (MLR) also elicited swimming. After an injection of substance P, the current threshold needed to induce locomotion by MLR stimulation was decreased, and the size of the postsynaptic responses of reticulospinal cells to MLR stimulation was increased. Substance P also reduced the frequency of miniature spontaneous postsynaptic currents in reticulospinal cells. Taken together, these results suggest that substance P plays a neuromodulatory role on the brain stem locomotor networks of lampreys.
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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".