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In this study, the functional properties of the medial prefrontal cortex (mPFC) of the rat were examined in a task for spatial navigation. The dorsomedial (dmPFC) and ventromedial (vmPFC) parts of the PFC differ in their connectivity with the hippocampus, vmPFC being the main recipient of hippocampal input. Therefore, it is hypothesized that in a spatial(More)
Chronic neonatal treatment with the non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 from postnatal day 8 through 19 has been shown to affect hippocampal NMDA receptor function of adult rats. Since many studies have shown that NMDA receptors play a crucial role in learning and memory, and since one of the hippocampal functions is(More)
Performance in food hoarding, a species-typical task, and spatial delayed alternation, a learning task, was investigated in male rats with bilateral medial prefrontal cortex (mPFC) lesions sustained in adulthood or at the age of 6 days. Animals with adult mPFC lesions hoarded significantly fewer food pellets than their controls. The mPFC lesion effect on(More)
The question examined in this study is concerned with a possible functional dissociation between the hippocampal formation and the prefrontal cortex in spatial navigation. Wistar rats with hippocampal damage (inflicted by a bilateral lesion of the fimbria fornix), rats with damage to the medial prefrontal cortex, and control-operated rats were examined for(More)
Dopamine transmission within the nucleus accumbens has been implicated in associative reinforcement learning. We investigated the effect of appetitive classical conditioning on dopamine efflux in the rat nucleus accumbens shell and core, as dopamine may be differentially activated by conditioned and unconditioned stimuli (CS, US) in these subregions. After(More)
We tested the hypothesis that inhibition of NMDA-receptors in rats would lead to a selective impairment of reversal learning in a serial reversal task in the Skinner box. Low doses of MK-801 (0.025 and 0.05 mg/kg) did not affect acquisition of the two-lever discrimination, but impaired performance during the first reversal more than during the third(More)
This study is concerned with the question whether the medial prefrontal cortex mediates spatial navigation requiring the expression of response learning. It consists of two parts. In the first experiment it was investigated whether intact male Wistar rats can learn a spatial response task in a Morris water maze, and, if so, how the learning of this task(More)
The prefrontal cortex (PFC) of the rat supports cognitive flexibility, the ability to spontaneously adapt goal-directed behavior in response to radically changing situational demands. We have shown previously that transient inactivation of the rat medial PFC (mPFC) impairs initial reversal learning in a spatial 2-lever discrimination task. Given the(More)
The putative involvement of the dopaminergic innervation of the medial part of the prefrontal cortex (PFC) in short-term memory functioning was investigated by evaluating the effects of local infusions of dopaminergic drugs into the ventral part of the medial PFC of rats in an operant delayed-matching-to-position (DMTP) task. Two separate groups of rats(More)
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(More)