Color contribution to motion due to early expansive nonlinearities within the luminance pathway
Bibliographic record
Abstract
Adding an equiluminance color grating to a similar high contrast luminance grating drifting in the same direction increases the motion response (i.e. to null the perceived motion, an opposing luminance grating needs a higher contrast). Such color contribution to motion could either be due to nonlinearities within the luminance pathway or to a color-opponent pathway (L − M) distinct from the luminance pathway (L + M). The fact that nonlinearities following the summation of the L- and M-cone contrast responses (e.g., [L + M]2) would not be sufficient to explain the substantial color contribution to motion has been taken as evidence of a color-opponent motion pathway (L − M). However, our simulations showed that expansive nonlinearities preceding the summation of the L- and M-cone contrast responses (e.g., L2 + M2) would substantially increase the color contribution to motion especially when the color and luminance gratings are in phase (0 or 180 deg) compared to out of phase (90 or 270 deg). To investigate if the color contribution to motion is due to a color-opponent pathway (e.g., L − M) or to early expansive nonlinearities within the luminance pathway (e.g. L2 + M2), we measured the color contribution to motion when superimposing high contrast luminance and color gratings as a function of their relative phase. We found that the color contribution to motion was about two times greater when the luminance and color gratings were in phase compared to when they were out of phase. This color-luminance phase interaction cannot be explained by a color-opponent pathway (L − M) independent of the luminance pathway (L + M). We conclude that early expansive nonlinearities within the luminance pathway substantially increase the color contribution to motion and the fact that adding a color grating to a high contrast luminance grating increases the motion response cannot be taken as evidence of a color-opponent motion pathway distinct from the luminance motion pathway.
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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 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".