Neocortical Capillary Flow Pulsatility is Not Elevated in Experimental Communicating Hydrocephalus
Bibliographic record
Abstract
While communicating hydrocephalus (CH) is often characterized by increased pulsatile flow of cerebrospinal fluid (CSF) in the cerebral aqueduct, a clear-cut explanation for this phenomenon is lacking. Increased pulsatility of the entire cerebral vasculature including the cortical capillaries has been suggested as a causative mechanism. To test this theory, we used two-photon microscopy to measure flow pulsatility in neocortical capillaries 40 to 500 μm below the pial surface in adult rats with CH at 5 to 7 days (acute, n=8) and 3 to 5 weeks (chronic, n=5) after induction compared with intact controls (n=9). Averaging over all cortical depths, no increase in capillary pulsatility occurred in acute (pulsatility index (PI): 0.15±0.06) or chronic (0.14±0.05) CH animals compared with controls (0.18±0.07; P=0.07). More specifically, PI increased significantly with cortical depth in controls (r=0.35, P<0.001), but no such increase occurred in acute (r=0.06, P=0.3) or chronic (r=0.05, P=0.5) CH. Pulsatile CSF aqueductal flow, in contrast, was elevated 10- to 500-fold compared with controls. We conclude that even in the presence of markedly elevated pulsatile CSF flow in the aqueduct, there is no concurrent increase in microvascular pulsatile flow.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 teacher head, 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".