Spatial, temporal, and intensive determinants of dopamine release in the chick retina
Bibliographic record
Abstract
The retinal dopaminergic system is a global regulator of retinal function. Apart from the fact that the rates of dopamine synthesis and release are increased by increasing illumination, the visual image parameters that influence dopaminergic function are mostly unknown. Roles for spatial and temporal frequency and image contrast are suggested by the effects of form-deprivation with a diffusing goggle. Form-deprivation reduces the rates of dopamine synthesis and release, and induces myopia, which is prevented by dopamine agonists. Our purpose here was to identify visual stimulus parameters that activate dopaminergic amacrine cells and elicit dopamine release. White Leghorn cockerels 4-7 days old were exposed to 2 h of form-deprivation, reduced light intensity, or stimuli of varied temporal or spatial frequency. Activation of dopaminergic neurons, labeled for tyrosine hydroxylase (TH), was assessed with immunocytochemistry for c-Fos, and dopamine release was measured by HPLC analysis of dopamine metabolite accumulation in the vitreous body. Form-deprivation did not reduce TH+ cell activation or vitreal dopamine metabolite accumulation any more than did neutral-density filters of approximately equal transmittance. TH+ cell activation and vitreal metabolite accumulation were not affected significantly by exposure to 2, 5, 10, 15, or 20 Hz stroboscopic stimulation on a dark background, or by sine-wave gratings of 0.089, 0.44, 0.89, 1.04, or 3.13 cycles/deg compared to a uniform gray target of equal mean luminance. These data indicate that the retinal dopaminergic system does not respond readily to short-term changes in visual stimulus parameters, other than light intensity, under the conditions of these experiments.
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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) | 0.001 | 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".