Embryonic exposure to environmentally relevant concentrations of a brominated flame retardant reduces the size of song‐control nuclei in a songbird
Bibliographic record
Abstract
Environmental contaminants have the potential to act as developmental stressors and impair development of song and the brain of songbirds, but they have been largely unstudied in this context. 2,2',4,4',5-Pentabromodiphenyl ether (BDE-99) is a brominated flame retardant congener that has demonstrated endocrine disrupting effects, and has pervaded the global environment. We assessed the effects of in ovo exposure to environmentally relevant levels of BDE-99 on the neuroanatomy of the song-control system in a model songbird species, the zebra finch (Taeniopygia guttata). Embryos were exposed via egg injection to a vehicle control (DMSO), 10, 100, or 1000 ng BDE-99/g egg on the day the egg was laid. Chicks were raised to sexual maturity to investigate long-term effects of BDE-99 on the adult male brain. Three key song-control nuclei (Area X, HVC, RA) all showed a dose-dependent trend toward decreasing volume as BDE-99 concentration increased, and birds exposed to 1000 ng/g in ovo BDE-99 had significantly smaller song-control nuclei volume compared to control birds. High environmental concentrations of BDE-99 in avian tissues can be within that range and thus could affect development of the song-control system in birds, and potentially other processes. We previously found that BDE-99 exposure during the nestling period had no effect of on the song-control system, although it did have significant effects on some behaviural endpoints. Taken together, these results suggest that exposure to polybrominated diphenyl ether (PBDEs) during critical developmental windows can significantly alter neurological development. © 2018 Wiley Periodicals, Inc. Develop Neurobiol, 2018.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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 teacher head, 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".