Adult rat ultrasonic vocalizations and reward: Effects of propranolol and repeated cocaine administration
Bibliographic record
Abstract
BACKGROUND: Mechanisms underlying psychostimulant euphoria remain poorly understood. In adult rats, positive emotional states are associated with alterations in 50-kHz ultrasonic vocalizations (USVs): specifically, "trill" calls are promoted over "flat" calls. Here, we investigated the effects of acute and repeated cocaine administration, and-based on previous findings with amphetamine-their possible dependence on beta-adrenergic receptors. METHODS: Adult male Long-Evans rats received intraperitoneal drug or saline injections before daily USV recording. Fourteen 50-kHz call subtypes were analyzed. In Experiments 1 and 2, cocaine (1-10 mg/kg) and propranolol (10 mg/kg) were tested alone. In Experiment 3, propranolol/cocaine interactions were sought within a conditioned place preference (CPP) procedure. Experiment 4 investigated acute and chronic cocaine effects (Phase 1), and propranolol/cocaine interactions either in an open field (Phase 2) or within a CPP procedure (Phase 3). RESULTS: In drug-naïve animals, cocaine increased the 50-kHz call rate, with sensitization developing rapidly. After more extended exposure, cocaine now also increased the relative prevalence of trill versus flat calls; effects on other subtypes were also revealed. The beta-blocker propranolol prevented neither cocaine CPP nor cocaine effects on USV emission or locomotion but exerted significant USV-related effects when given alone. CPP magnitude and USV-related measures were uncorrelated. CONCLUSIONS: With long-term intraperitoneal administration, cocaine can alter the relative prevalence of several 50-kHz call subtypes; its ability to promote trill versus flat calls, in particular, is consistent with a positive affect interpretation. Cocaine's behavioral effects (i.e., USV-related, locomotor, CPP) appear independent of beta-adrenergic receptor activity.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".