Dissociable Roles for the Nucleus Accumbens Core and Shell in Regulating Set Shifting
Bibliographic record
Abstract
The ability to behave in a flexible manner is an executive function mediated in part by different regions of the prefrontal cortex. The present study investigated the role of two major efferents of the prefrontal cortex, the nucleus accumbens (NAc) core and shell, in behavioral flexibility using a maze-based strategy set-shifting task. During initial discrimination training, rats learned to use either an egocentric response or a visual-cue discrimination strategy to obtain food reward. During the set shift, animals had to shift from the previously acquired response or visual-cue-based strategy and learn the alternate discrimination. Inactivation of the NAc core, induced by infusion of the GABA agonists baclofen and muscimol, did not impair initial acquisition of either a response or visual-cue discrimination but severely disrupted shifting from one strategy to another. Analysis of the type of errors revealed that impairments in set shifting were not attributable to increased perseveration but to a disruption of the acquisition and maintenance of a new strategy. In contrast, inactivation of the NAc shell did not impair acquisition of either a response or a visual-cue discrimination, or shifting from one strategy to another. However, inactivation of the NAc shell before initial discrimination training improved performance during the set shift relative to control animals. These data indicate that the NAc core and shell make dissociable contributions to behavioral flexibility during set shifting. The NAc core facilitates the acquisition and maintenance of novel behavioral strategies and elimination of inappropriate response options, whereas the shell may mediate learning about irrelevant stimuli.
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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 | 0.001 |
| 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".