Frequency responses of human magnetophosphene perception thresholds during dark adaptation point to rod modulation
Bibliographic record
Abstract
Magnetophosphenes are flickering lights perceived when an extremely low frequency magnetic field generates a sufficiently strong electric field in the head. Understanding how phosphenes are produced is crucial, as they form the basis for international safety standards and guidelines for both workers and the general population. However, there is still ongoing debate about whether this phenomenon originates in the retina, the cortex, or involves both. Investigating magnetophosphenes at various frequencies during dark adaptation provides deeper physiological insights into this process. Forty-one participants were exposed to varying levels of magnetic stimulation using a custom global transcranial alternative magnetic stimulation system that provided full-head exposure. Participants were divided into four groups: one light-exposed group and three dark-adapted groups, each assigned a different frequency (20, 50 and 60 Hz). Every 3 min during a 42-min dark adaptation period, participants reported their threshold for magnetophosphene perception. Flux density thresholds were then compared across groups using repeated measures ANOVAs. The data acquired showed a significant (F(15, 270) = 3.637, P < 0.001) increase in the magnetophosphene threshold throughout the 42-min darkness adaptation period. An inversed exponential decay regression was used to model the time course of the magnetophosphene threshold for each frequency. The rising magnetophosphene threshold during dark adaptation is likely linked to retinal phototransduction mechanisms, suggesting that magnetophosphene perception originates from rod cells in the retina. In addition to their significance for establishing new international guidelines and safety standards for workers and the public, our findings could also pave the way for new research into non-invasive assessments of retinal dysfunction.
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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 | 0.000 |
| 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".