Vestibular inputs elicit patterned changes in limb blood flow in conscious cats
Bibliographic record
Abstract
Previous experiments have demonstrated that the vestibular system contributes to regulating sympathetic nervous system activity, particularly the discharges of vasoconstrictor fibres. In the present study, we examined the physiological significance of vestibulosympathetic responses by comparing blood flow and vascular resistance in the forelimb and hindlimb during head-up tilt from the prone position before and after the removal of vestibular inputs through a bilateral vestibular neurectomy. Experiments were performed on conscious cats that were trained to remain sedentary on a tilt table during rotations up to 60 deg in amplitude. Blood flow through the femoral and brachial arteries was recorded during whole-body tilt using perivascular probes; blood pressure was recorded using a telemetry system and vascular resistance was calculated from blood pressure and blood flow measurements. In vestibular-intact animals, 60 deg head-up tilt produced approximately 20% decrease in femoral blood flow and approximately 37% increase in femoral vascular resistance relative to baseline levels before tilt; similar effects were also observed for the brachial artery ( approximately 25% decrease in blood flow and approximately 38% increase in resistance). Following the removal of vestibular inputs, brachial blood flow and vascular resistance during head-up tilt were almost unchanged. In contrast, femoral vascular resistance increased only approximately 6% from baseline during 60 deg head-up rotation delivered in the first week after elimination of vestibular signals and approximately 16% in the subsequent 3-week period (as opposed to the approximately 37% increase in resistance that occurred before lesion). These data demonstrate that vestibular inputs associated with postural alterations elicit regionally specific increases in vascular resistance that direct blood flow away from the region of the body where blood pooling may occur. Thus, the data support the hypothesis that vestibular influences on the cardiovascular system serve to protect against the occurrence of orthostatic hypotension.
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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 | 0.001 |
| 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".