On the light dark discrimination, older treated mice learned the task more slowly, made fewer errors on the first-response choice of a trial but more perseverative errors after an initial error, and had lower latencies to respond compared with controls.
However, we found no evidence that more stereotypic birds were more perseverative, as measured by an extinction task and a two-choice guessing task.
Exposed mice exhibited a greater degree of accuracy on the first response of a trial (fewer first-choice errors) than did their controls, but they emitted more perseverative errors (repeated errors on the same incorrect lever after an initial incorrect response).
We began this project with the hypothesis that hand-reared starlings would be more stereotypic, and that birds with stereotypies would be more perseverative, resulting in prolonged pecking in the extinction task, greater sequential dependency in the two-choice guessing task and less accurate and less precise interval timing functions (Garner et al. 2003a, b).
While lowering the Hamming distance in the Hamming block gave rise to progressively more perseverative responses, changing the threshold vector of the Hopfield network resulted in more set maintenance failures.
A Group (lower-, higher-SPS) by Condition (WCST, EFCST) by Sorting Rule (color, form, number) interaction was expected in which the higher-SPS EFCST group would have worse overall performance and make more perseverative errors than the other groups.
After controlling for these compared to controls marijuana-using participants made significantly more perseverative and total errors on the WCST and showed significantly impaired (e.g., less adaptive) response allocation to the changing reinforcement contingencies on the concurrent-reinforcement task.
Patients, particularly those who made more perseverative errors, demonstrated amphetamine-associated improvement on WCST performance.
The instrument has been shown to be sensitive to frontal lobe damage; people with frontal lobe damage tend to make more perseverative errors.
This task demands cognitive flexibility and strategies to deal with the environmental contingence (Nyhus and Barceló 2009), and the extra-frontal lesion group needed more cards to complete the task, as well as making many more perseverative errors.
