Testing the effect of dichoptic luminance masking on monocular visual function with functional magnetic resonance imaging (fMRI)
Bibliographic record
Abstract
Functional magnetic resonance imaging (fMRI) methods are now an important tool for characterization of human visual cortex, in healthy participants as well as those with visual disorders.A wide range of serious ophthalmological diseases manifest in one eye only, or asymmetrically between each eye.Accordingly, evaluating each eye separately (i.e., monocular testing) is necessary.However, a lack of standardization exists regarding the status of the nontested eye during monocular visual assessments, and this is particularly acute for fMRI experiments that use modern advanced equipment for (dichoptic) stimulation of each eye separately.To address this knowledge gap, we conducted an experiment to identify the viewing condition of the fellow/non-tested eye (i.e., closed, black screen, gray screen or same stimulus as tested eye) that produces the least interocular inhibition on responses to a battery of stimuli presented to the other (i.e., tested) eye in cortical visual areas.Overall, binocular stimulation elicited the highest brain activity in all regions of interest (ROIs), early visual cortices and MT+, in comparison to dichoptic viewing conditions.ROIs showed differential preferences for the presented stimuli, with MT+ and peripheral eccentricities of early visual areas strongly activated for fast moving stimuli, whereas vast majority of early visual areas respond maximally to flickering stimuli.A strong trend for dichoptic luminance masking (higher brain activity for black screen (i.e., low luminance stimulus) compared to gray screen) was evident, especially in early visual areas, for moving low spatial frequency magnocellular-biased stimuli.The dichoptic luminance masking effect was not significantly enhanced by imbalances in sensory eye dominance, although a trend for higher masking was observed for non-dominant eye than dominant eye.The closed-eye condition produces a slightly different activation pattern for the cortical visual areas than all the other fellow eye viewing conditions, including a black screen.In general, our results are consistent with the binocular contrast normalization model of vision and the low pass nature of the masking effect.Previous studies also predominantly report lower interocular inhibition on tested eye, and therefore higher activity in brain areas, when between-eye luminance difference increases.Our findings suggest that the black screen condition in the fellow eye produces the least interocular inhibition and closely resembles binocular stimulation.As such, we have identified the monocular fMRI visual function testing protocol that maximizes the brain responses to monocular visual stimulation using dichoptic presentation system, and reduces the potential confounding effect the luminance masking effect may have for identifying the dysfunction of magnocellular pathways in patients with visual deficits in future studies.
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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 | 0.002 |
| 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) | 0.007 | 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".