Speaker 4: Marco Leyton, Canada
Bibliographic record
Abstract
Cocaine addiction is increasingly considered to stem from the development of maladaptive, stimulus bound, drug seeking habits that both contribute to the maintenance of drug use despite aversive consequences, and also to high rates of relapse.However because relapse by definition occurs only after a period of abstinence, the relative contribution of habits and pharmacological withdrawal from the drug to relapse is unknown.In this study we demonstrate that preventing rats from expressing their drug seeking habits after forced abstinence results in aberrant, compulsive drug seeking behaviour at relapse.Thus, Lister-Hooded rats were trained under a fixed-interval (FI) 15-min schedule or a FI 15 (FR10:S) second order schedule of reinforcement, the latter having been shown to recruit stimulus bound, dorsolateral striatum-dependent, maladaptive habits.Indeed, in this procedure every ten active lever presses produces the presentation of a 1s (CS) so that rats respond more vigorously for the drug in the presence, than in the absence, of the drug CS.The results showed that a 3-day forced abstinence period increased cocaine seeking responses only in the group trained under second-order schedule of reinforcement, while cocaine abstinence had no effect in the FI 15 group who responded for cocaine but without earned drug cue presentations.In order to test if this increase in responding depended on the motivational effect of pharmacological withdrawal from cocaine, rats then received non contingent cocaine injections while being prevented from responding for the drug for a 3-day "instrumental seeking abstinence" period.The results showed that despite receiving the same amount of cocaine as during the self-administration sessions, only the rats with a history of CS-dependent cocaine seeking habits displayed the robust increase in cocaine seeking after abstinence.These results strongly suggests that the expression of maladaptive seeking habits, rather than pharmacological drug withdrawal itself, contribute to addiction by invigorating drug seeking behaviour in individuals under abstinence, indicating a core psychological component of the addiction cycle.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.004 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.794 | 0.459 |
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; the direct Gemma label and the distilled Codex classifier agree on what is shown here.
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".