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The mysterious a‐wave

2009· article· en· W2068708646 on OpenAlexaff
Pierre Lachapelle, ML GARON, Anna Polosa, E. Zimak

Bibliographic record

VenueActa Ophthalmologica · 2009
Typearticle
Languageen
FieldBiochemistry, Genetics and Molecular Biology
TopicRetinal Development and Disorders
Canadian institutionsMcGill UniversityMontreal Children's Hospital
Fundersnot available
KeywordsScotopic visionPhotopic visionLuminanceErgPhysicsFlash (photography)DiabaticOpticsAdiabatic processRetinaQuantum mechanics

Abstract

fetched live from OpenAlex

Abstract Purpose The electroretinogram (ERG) waveform usually consists of two major components, the a‐ and b‐waves. Exceptions to the above rule are scotopic ERGs evoked to dim flashes, where only b‐waves are recorded. The aim of this study was to examine if the no a‐wave ERG was a feature of scotopic ERG only and try to explain why it occurs. Methods Photopic (background: 30 cd.s.m‐2; flash:‐1.81 to 2.84 log cd.s.m‐2 in 0.2 log unit steps) and scotopic (‐5.01 to ‐0.96 log cd.s.m‐2 in 0.4 log unit steps) ERG luminance‐response functions were obtained from normal human subjects (n=30) and Long‐Evans (n=8) and Sprague‐Dawley (n=8) rats (scotopic ERGs only). Results Human photopic ERG waveform always included an a‐wave. With flash luminance, its peak time first increased, reached a maximal value and then decreased progressively and could be fitted to a fourth order polynomial function. In contrast, scotopic a‐waves appeared only in ERGs evoked to flashes equal to or brighter than ‐3.01 log cd.s.m‐2. With increasing intensity, the peak time of the a‐wave shortened following a linear model.On average, for each log‐unit of flash attenuation, the scotopic a‐wave shortened by more than 10 ms compared to 1.4 ms for the photopic one. Of interest, in rat scotopic ERGs evoked to the dimmest intensities the a‐wave appeared to be replaced by a group of short latency oscillations that were best seen in recordings where the low frequency cut‐off had been raised to 100 Hz. Conclusion The a‐b‐wave rule seems to apply only to photopic ERGs where an a‐wave was still identifiable in ERGs smaller than 1% of maximal amplitude. One wonders if the submicrovolt oscillations occurring prior to the onset of the b‐wave of rat scotopic ERGs evoked to dim flashes could represent remnant of the original a‐wave. Funded by CIHR

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not 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.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.003
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Not applicable · Consensus signal: none
GenreCandidate signal: Commentary · Consensus signal: none
Teacher disagreement score0.004
Threshold uncertainty score0.014

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0010.003
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0010.000
Science and technology studies0.0010.002
Scholarly communication0.0020.003
Open science0.0010.001
Research integrity0.0010.003
Insufficient payload (model declined to judge)0.0040.002

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.

Opus teacher head0.017
GPT teacher head0.257
Teacher spread0.240 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designNot applicable
Domainnot available
GenreCommentary

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".

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Citations0
Published2009
Admission routes1
Has abstractyes

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