Role of the prefrontal cortex of the rat in learning and decision making: effects of transient inactivation.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
J P De Bruin
Publications and source records attributed to J P De Bruin.
Dopamine and noradrenaline release in the prefrontal cortex of rats during classical aversive and appetitive conditioning to a contextual stimulus: interference by novelty effects.
Extracellular dopamine and noradrenaline concentrations in the medial prefrontal cortex were determined using online microdialysis in freely moving rats during classical appetitive or aversive conditioning to a contextual conditioned stimulus (CS). As CS we used placement in a Skinner box where either foot shocks or food pellets were delivered as unconditioned stimuli. In the aversive conditioning group we observed a conditioned increase in noradrenaline, but not in dopamine release, upon a final exposure to CS-alone. Other conditioned effects were possibly masked by the continued presence of novelty and handling effects of the transfer to the Skinner box.
Animals↗
Ineffectiveness of GM1 and ORG2766 on behavioural recovery after prefrontal cortical lesions in adult rats.
This study examines whether treatment with GM1 ganglioside or the corticotropin (ACTH)(4-9) analogue ORG2766 can facilitate the behavioural recovery of adult rats with medial prefrontal cortex (mPFC) lesions, as animals are impaired in their food hoarding and spatial delayed alternation performance following mPFC lesions. No ameliorating effects of GM1 treatment on performance of these behaviours were observed. Although treatment with ORG2766 somewhat improved the hoarding performance of lesioned animals, the intermediate amount of pellets hoarded was not significantly different from that of either sham-operated or vehicle-treated lesioned rats. No effect of ORG2766 treatment was observed in the spatial delayed alternation test. Further, no changes were detected in the mesocortical dopamine innervation, presumed to be involved in the neural mechanism of behavioural sparing, in response to either treatment.
Adrenocorticotropic Hormone↗
Age-dependent effects of lesioning the mesocortical dopamine system upon prefrontal cortex morphometry and PFC-related behaviors.
Explore the source record for details and available documents.
Aging↗
Neonatal thermal lesions of the mesolimbocortical dopaminergic projection decrease food-hoarding behavior.
In order to examine the effect of neonatal depletion of the dopaminergic mesocortical projection on the development of prefrontal cortex-mediated behaviors, male and female adult rats with neonatally applied thermal lesions of the dopaminergic A10 cell group in the ventral tegmental area were studied in a food-hoarding situation. Control male animals hoarded significantly more pellets than females. Neonatal depletion of dopamine in the prefrontal cortex strongly decreased food-hoarding activity in contrast with previous studies by others which have shown that neonatal lesions of the prefrontal cortex allow sparing of food-hoarding activity. Biochemical analysis demonstrated an approximately 50% depletion of both dopamine and serotonin in the prefrontal cortex of males, whereas noradrenaline levels were unchanged. The brains of the female rats were used to visualize the decreased dopaminergic and serotonergic innervation of the forebrain. Hoarding scores showed a significant positive correlation with the measured dopamine content of the medial prefrontal cortex, and not with the serotonin content. These results imply that the integrity of the dopaminergic projection to the prefrontal cortex is essential for food-hoarding behavior to occur and that food-hoarding activity is not spared after neonatal depletion of dopamine.
Animals↗
Sex, age and shock-intensity as factors in passive avoidance.
Sex, age and shock-intensity were studied in a step-through passive avoidance test. In adult rats (140 days) males showed more inhibition of a previously punished approach response. No sex differences were observed in young adult animals (60 days). In prepuberal animals (30 days), on the other hand, it was the females which showed more response inhibition. In prebuberty females showed far more response inhibition than in adulthood. Even when using 1.6 mA as a reinforcer, only 17% of the adult females showed inhibition after punishment of the entering response.
Age Factors↗
Delayed spatial response alternation: effects of delay-interval duration and lesions of the medial prefrontal cortex on response accuracy of male and female Wistar rats.
A delayed spatial response alternation procedure was used to assess behavioural differences between male and female Wistar rats, assumed to involve memory functioning. In Expt. I, subjects were required to alternate responses between two levers in an operant environment. The delay between response opportunities was varied between 1, 3, 7.5 and 15 s in different experimental conditions. Incorrect responses produced a time-out from experimental contingencies for the duration of the currently active delay interval. Response accuracy decreased for males as well as females as the duration of the delay interval was increased. Performance improved as subjects were exposed to the different delay interval durations during consecutive trials. Sex differences in behavioural accuracy were not observed. In Expt. II, some subjects who participated in Expt. I received lesions of the medial prefrontal cortex, while others were control-operated. When re-exposed to the 1 and 7.5 s delay conditions of the first experiment, lesioned subjects at first behaved less accurately than control-operated subjects. Accuracy, however, improved after prolonged exposure to the experimental conditions. Sex differences in behaviour after surgery could not be observed.
Analysis of Variance↗