Aberrant Gating of Photic Input to the Suprachiasmatic Circadian Pacemaker of Mice Lacking the VPAC<sub>2</sub>Receptor
Bibliographic record
Abstract
VIP acting via the VPAC(2) receptor is implicated as a key signaling pathway in the maintenance and resetting of the hypothalamic suprachiasmatic nuclei (SCN) circadian pacemaker; circadian rhythms in SCN clock gene expression and wheel-running behavior are abolished in mice lacking the VPAC(2) receptor (Vipr2(-/-)). Here, using immunohistochemical detection of pERK (phosphorylated extracellular signal-regulated kinases 1/2) and c-FOS, we tested whether the gating of photic input to the SCN is maintained in these apparently arrhythmic Vipr2(-/-) mice. Under light/dark and constant darkness, spontaneous expression of pERK and c-FOS in the wild-type mouse SCN was significantly elevated during subjective day compared with subjective night; no diurnal or circadian variation in pERK or c-FOS was detected in the SCN of Vipr2(-/-) mice. In constant darkness, light pulses given during the subjective night but not the subjective day significantly increased expression of pERK and c-FOS in the wild-type SCN. In contrast, light pulses given during both subjective day and subjective night robustly increased expression of pERK and c-FOS in the Vipr2(-/-) mouse SCN. Although photic stimuli activate intracellular pathways within the SCN of Vipr2(-/-) mice, they do not engage the core clock mechanisms. The absence of photic gating, together with the general lack of overt rhythms in circadian output, strongly suggests that the SCN circadian pacemaker is completely dysfunctional in the Vipr2(-/-) mouse.
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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 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".