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Dissociation of prefrontal cortex and nucleus accumbens dopaminergic systems in conditional learning in rats

George, David N.; Jenkins, Trisha A.; Killcross, Simon

Authors

Trisha A. Jenkins

Simon Killcross



Abstract

There is converging evidence that the prefrontal and mesolimbic dopaminergic (DAergic) systems are involved in the performance of a variety of tasks that require the use of contextual, or task-setting, information to select an appropriate response from a number of candidate responses. Performance on tasks of this nature are impaired in schizophrenia and in rats exposed to psychotomimetics; impairments that are often attenuated by administration of dopamine (DA) antagonists. Rats were trained on either a complex instrumental discrimination task, that required the use of task-setting cues, or a simple discrimination task that did not. Following training, microdialysis probes were implanted unilaterally in either the medial prefrontal cortex (mPFC) or nucleus accumbens (NAc) and samples were collected in freely moving animals during a behavioural test session. In Experiment 1, we found no difference in levels of DA in the mPFC of rats while they were performing the two discrimination tasks. Rats that performed the complex task did, however, show significantly higher mPFC DA levels relative to rats in the simple discrimination condition following the end of the behavioural test session. In Experiment 2, rats performing the conditional discrimination showed lower levels of DA in the NAc compared to the simple discrimination group both during the test session and after it. These results provide direct evidence that conditional discrimination tasks engage frontal and mesolimbic DAergic systems and are consistent with the proposal that regulation of fronto-striatal DA is involved in aspects of cognitive control that are known to be impaired in individuals with schizophrenia.

Citation

George, D. N., Jenkins, T. A., & Killcross, S. (2011). Dissociation of prefrontal cortex and nucleus accumbens dopaminergic systems in conditional learning in rats. Behavioural Brain Research, 225(1), 47-55. https://doi.org/10.1016/j.bbr.2011.06.028

Journal Article Type Article
Acceptance Date Jun 22, 2011
Online Publication Date Jun 30, 2011
Publication Date Nov 20, 2011
Deposit Date Nov 13, 2014
Publicly Available Date Mar 29, 2024
Journal Behavioural Brain Research
Print ISSN 1872-7549
Electronic ISSN 1872-7549
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 225
Issue 1
Pages 47-55
DOI https://doi.org/10.1016/j.bbr.2011.06.028
Keywords Conditional learning; Dopamine; Prefrontal cortex; Nucleus accumbens; Schizophrenia; Microdialysis
Public URL https://hull-repository.worktribe.com/output/462479
Publisher URL https://www.sciencedirect.com/science/article/pii/S0166432811004918?via%3Dihub