Bistable percepts in the brain: fMRI contrasts monocular pattern rivalry and binocular rivalry
Bibliographic record
Abstract
INTRODUCTION. In monocular rivalry, the observer experiences alternations between different perceptual representations of the same image, in which different components alternate in visibility, but without complete suppression as in binocular rivalry. Surprisingly, no previous fMRI studies have directly compared binocular and monocular rivalry. METHODS. Here we used fMRI at 3T to image activity in visual cortex while subjects perceived either monocular or binocular rivalry. The stimulus patterns were colored gratings (left & right oblique orientations) or face/house composites. The stimulus components (red or green) were either presented dichoptically for binocular rivalry or as a (monoptic) composite image with both components shown to each eye. Linear polarizers were used for dichoptic presentation. Six subjects performed either a binocular or monocular rivalry report task with the face/house or grating stimuli by indicating alternating percepts with button presses to measure alternation rates. The luminance contrasts were 9%, 18% or 36%. RESULTS. The cortical activation for monocular rivalry included occipital pole, ventral temporal, and superior parietal cortex, while the areas for binocular rivalry also prominently included lateral occipital regions including MT+ as well as inferior parietal cortex near the TPJ. Both binocular rivalry and monocular rivalry showed a U-shaped function of activation as a function of contrast, i.e. higher activity for most areas at 9% and 36%. The increase in activation at higher contrast can be explained by an increase in neuronal response gain reflected in faster alternation rates, while that at low contrast can be explained by disinhibition (Wilson, 2007). CONCLUSIONS. Overall, our results call into question models that distinguish binocular from monocular rivalry solely on the basis of V1 interocular competition. Rather our results indicate that binocular rivalry invokes binocular competition and suppression in higher-tier levels, whereas competition in monocular rivalry is relatively focused in early visual areas, with less inhibition.
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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 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".