First- and second-order contrast sensitivity functions reveal disrupted visual processing following mild traumatic brain injury
Bibliographic record
Abstract
• TBI patients have increased sensitivity for 1 st order motion stimuli. • TBI patients have decreased sensitivity to contrast-defined 2 nd order stimuli. • TBI patients have decreased sensitivity to orientation-defined 2 nd order stimuli. • CSFs are shifted towards higher spatial frequencies in TBI patients. Vision is disrupted by traumatic brain injury (TBI), with vision-related complaints being amongst the most common in this population. Based on the neural responses of early visual cortical areas, injury to the visual cortex would be predicted to affect both 1 st order and 2 nd order contrast sensitivity functions (CSFs)—the height and/or the cut-off of the CSF are expected to be affected by TBI. Previous studies have reported disruptions only in 2 nd order contrast sensitivity, but using a narrow range of parameters and divergent methodologies—no study has characterized the effect of TBI on the full CSF for both 1 st and 2 nd order stimuli. Such information is needed to properly understand the effect of TBI on contrast perception, which underlies all visual processing. Using a unified framework based on the quick contrast sensitivity function, we measured full CSFs for static and dynamic 1 st and 2 nd order stimuli. Our results provide a unique dataset showing alterations in sensitivity for both 1 st and 2 nd order visual stimuli. In particular, we show that TBI patients have increased sensitivity for 1 st order motion stimuli and decreased sensitivity to orientation-defined and contrast-defined 2 nd order stimuli. In addition, our data suggest that TBI patients’ sensitivity for both 1 st order stimuli and 2 nd order contrast-defined stimuli is shifted towards higher spatial frequencies.
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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 | 0.001 | 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".