Changes in S-cone increment and decrement sensitivity as a function of age and eccentricity
Bibliographic record
Abstract
Introduction: There is emerging evidence that the “blue” and “yellow” responses of S-cone opponent color vision are mediated by distinct neural cell types in the subcortical visual pathway, but so far there is little psychophysical evidence for any functional distinctions between them. Here we explore the effects of visual eccentricity on the sensitivity on the two types of S-cone opponent response across a range of different ages. Methods: We measured cone contrast sensitivity of human vision to S-cone increments (S+, blue) and decrements (S−, yellow) for calibrated S-cone isolating stimuli presented in the fovea or at 11 degrees of eccentricity (nasal field, horizontal meridian) with corrections for the presence of macular pigment in the fovea but not periphery. Stimuli were Gaussian blobs (sigma=1deg) in a temporal Gaussian envelope (sigma=125ms). Thresholds were obtained for 55 subjects ranging from 20–79 years. Results: Contrast detection thresholds to blue (S-cone increments) and yellow (S-cone decrements) remain stable with age until subjects reach their 50s, when both types of threshold show a significant and progressive increase with age. Comparing across age groups, we find significantly higher thresholds for S+ (blue) than for S− (yellow) in the periphery, whereas in the fovea these thresholds are no different. Thus the blue thresholds (S+) show a greater rise between fovea and periphery than yellow (S−). Conclusions: 1. The progressive deterioration with age in lens and optic media has little impact on blue-yellow color vision until around 50 years of age. 2. Our results indicate that there is an intrinsically poorer sensitivity to S-cone increments than decrements in the periphery thus supporting the idea that these two processes are physiologically distinct. 3. We speculate that this may reflect a chromatic normalization that compensates for the disappearance of macular pigment in the periphery by selectively reducing blue sensitivity over yellow.
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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 | 0.001 |
| 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".