Modulation of memory consolidation by heroin and heroin conditioned stimuli: roles of expectation and dopamine D1 receptor?
Bibliographic record
Abstract
Abstract It has been theorized that drugs of abuse have enhancing effects on memory consolidation, but recent evidence suggests that this cognitive effect may be mediated by mode of drug administration (i.e., passive vs active). Hence, two studies were designed to test the hypothesis that modulation of memory consolidation by heroin, and by a heroin conditioned stimulus (CS), may be mediated by a dopamine D1 receptor dependent mechanism of prediction error. Using male Sprague-Dawley rats and the object location memory task, Study 1 employed the D1 antagonist SCH23390 (0, 0.05, 0.10 mg/kg, subcutaneous, SC) to modulate enhancement of memory consolidation induced by post-training passive injections of heroin (1 mg/kg, SC) as well as by exposure to the environment paired with heroin injections (6 pairings, 1 h each, 1 mg/kg). Study 2 investigated the same hypothesis but in animals that could learn to predict heroin because the drug was self-administered (0.05 mg/kg/infusion, intravenous), and further explored whether SCH23390 (0 and 0.1 mg/kg) could prevent memory modulation induced by a change in schedule of self-administration (from fixed to variable ratio). It was found that while repeated passive injections of heroin retained their modulatory effect on memory, when self-administered, heroin enhanced consolidation of object location only at the beginning of self-administration and after a change in schedule. Importantly, SCH23390 blocked memory modulation by heroin when passively administered and when the drug was self-administered on a novel schedule. SCH23390 also blocked conditioned memory modulation induced by post-training exposure to the heroin-paired CS. Taken together, these results suggest that modulation of memory consolidation by unconditioned and conditioned opiate reinforcers may involve a DA D1-dependent mechanism that could be encoding the anticipation of drug effects.
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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".