Stronger responses to darks along the ventral pathway of the cat visual cortex
Bibliographic record
Abstract
Light increments (brights) and decrements (darks) are differently processed throughout the early visual system. It is well known that a bias towards faster and stronger responses to darks is present in the retina, lateral geniculate nucleus and primary visual cortex. In humans, psychophysical and neurophysiological data indicate that darks are better detected than brights, suggesting that the dark bias found in early visual areas is transmitted across the cortical hierarchy. Here, we tested this assumption by investigating the spatiotemporal features of responses to brights and darks in area 21a, a gateway area of the cat ventral stream, using reverse correlation analysis of a sparse noise stimulus. The receptive field of most 21a neurons exhibited larger dark subfields. Additionally, the amplitude of the responses to darks was considerably greater than those evoked by brights. In the temporal domain, no differences were found between the response peak latency. Thus, the present study supports the notion that bright/dark asymmetries are transmitted throughout the cortical hierarchy and further, that the luminance processing varies as a function of the position in the cortical hierarchy, dark preference being strongly enhanced (in the spatial domain and response amplitude) along the ventral 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 | 0.000 |
| 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 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| 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 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".