<i>Drosophila</i> mutants lacking octopamine exhibit impairment in aversive olfactory associative learning
Bibliographic record
Abstract
Octopamine is a biogenic amine in invertebrates that is considered a functional homolog of vertebrate norepinephrine, acting as a neurotransmitter, neuromodulator and neurohormone. Octopamine regulates many physiological processes such as metabolism, reproduction and different types of behaviour including learning and memory. Previous studies in insects led to the notion that acquisition of an olfactory memory depends on the octopaminergic system during appetitive (reward-based) learning, but not in the case of aversive (punishment-based) learning. Here, we provide several lines of evidence demonstrating that aversive associative olfactory learning in Drosophila is also dependent on octopamine signalling. Specifically, we used Drosophila Tβh (tyramine-β-hydroxylase) mutants, which lack octopamine and are female sterile, to determine whether octopamine plays a role in aversive learning. We show that Tβh mutant flies exhibit a significant reduction in learning compared to control lines that is independent of either genetic background or the methods used to induce aversive olfactory memory. We also show that the learning deficits observed in Tβh mutants are not due to defects in sensorimotor behaviours. Finally, to unambiguously demonstrate that octopamine synthesis plays a role in aversive olfactory learning, we performed rescue experiments using the Gal4/UAS system. We show that expression of UAS-Tβh in octopamine/tyraminergic neurons using Tdc2-Gal4 in Tβh null mutant flies fully rescued both the aversive learning defects and female sterility observed in Tβh mutants.
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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) | 0.001 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".