Serotonergic neurons modulating locomotion and autonomic support for movement
Bibliographic record
Abstract
Much of the present-day research on brainstem and spinal cord control of locomotion is primarily focused on the neurotransmitter glutamate. However, evidence suggests that monoamines, such as serotonin, may initiate or modulate locomotion. This dissertation aimed to investigate the involvement of caudal brainstem serotonin neurons in locomotion. The results indicated that while selective stimulation of 5-HT neurons could occasionally initiate fictive locomotor episodes, it predominately led to increases in tonic electroneurogram activity. This suggests that 5-HT stimulation can enhance the excitability of locomotor central pattern generators, and sometimes elicit rhythmic activity. One unexpected outcome from this study was the strong correlation between locomotion and autonomic activity, specifically blood pressure increases with 5-HT neuron stimulation. This study provides evidence that a small subset of 5-HT neurons can have dual roles, regulating both locomotor and autonomic function. It has been proposed that the rostral ventrolateral medulla (RVLM) may serve as an integrator of locomotor and autonomic function. Chapter IV provides a proof-of-concept study highlighting the utility of the decerebrate rat preparation to study the RVLM as the final integrator for locomotion and autonomic support. Specifically, it provides a framework to study how the RVLM may be able to coordinate metabolic support with ongoing movement. The results of this dissertation suggest that future research on locomotor systems should also incorporate autonomic measures to better understand the interconnectedness between these two systems. Further, it has emphasized the need for more research on 5-HT’s ability to act within multifunctional neural circuits. This dissertation also explored the outputs of the CPG, specifically by using a broad-spectrum potassium (K+) channel blocker called 4-aminopyridine (4-AP). Systemic administration of 4-AP resulted in an increase in frequency and synchronized bursts in functionally different nerves, highlighting the adaptability of the locomotor central pattern generator. The observed frequency can reach up to 6-7 Hz. This study suggests a differential distribution of K+ channels on inhibitory interneurons due to the persistence of synchronous activity. In addition, there may be coupling with sympathetic preganglionic neurons as there were concurrent increases in blood pressure. Further dosing studies
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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) | 0.003 | 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".