Neurovascular coupling during nociceptive processing in the primary somatosensory cortex of the rat
Bibliographic record
Abstract
Neuroimaging methods such as functional magnetic resonance imaging (fMRI) have been used extensively to investigate pain-related cerebral mechanisms. However, these methods rely on a tight coupling of neuronal activity to hemodynamic changes. Because pain may be associated with hemodynamic changes unrelated to local neuronal activity (eg, increased mean arterial pressure [MAP]), it is essential to determine whether the neurovascular coupling is maintained during nociceptive processing. In this study, local field potentials (LFP) and cortical blood flow (CBF) changes evoked by electrical stimulation of the left hind paw were recorded concomitantly in the right primary somatosensory cortex (SI) in 15 rats. LFP, CBF, and MAP changes were examined in response to stimulus intensities ranging from 3 to 30 mA. In addition, LFP, CBF, and MAP changes evoked by a 10-mA stimulation were examined during immersion of the tail in non-nociceptive or nociceptive hot water (counter-stimulation). SI neurovascular coupling was altered for stimuli of nociceptive intensities (P<0.001). This alteration was intensity-dependent and was strongly associated with MAP changes (r=0.98, P<0.001). However, when the stimulus intensity was kept constant, SI neurovascular coupling was not significantly affected by nociceptive counter-stimulation (P=0.4), which similarly affected the amplitude of shock-evoked LFP and CBF changes. It remains to be determined whether such neurovascular uncoupling occurs in humans, and whether it also affects other regions usually activated by painful stimuli. These results should be taken into account for accurate interpretation of fMRI studies that involve nociceptive stimuli associated with MAP changes.
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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 | 0.000 |
| 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 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".