A Role for Medial Prefrontal Dopaminergic Innervation in Instrumental Conditioning
Journal of Neuroscience. 2009-05-20; 29(20): 6599-6606
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1. J Neurosci. 2009 May 20;29(20):6599-606. doi: 10.1523/JNEUROSCI.1234-09.2009.
A role for medial prefrontal dopaminergic innervation in instrumental
Naneix F(1), Marchand AR, Di Scala G, Pape JR, Coutureau E.
(1)Centre National de la Recherche Scientifique and Université de Bordeaux, Unité
Mixte de Recherche 5228, Talence F-33405, France.
To investigate the involvement of dopaminergic projections to the prelimbic and
infralimbic cortex in the control of goal-directed responses, a first experiment
examined the effect of pretraining 6-OHDA lesions of these cortices. We used
outcome devaluation and contingency degradation procedures to separately assess
the representation of the outcome as a goal or the encoding of the contingency
between the action and its outcome. All groups acquired the instrumental response
at a normal rate, indicating that dopaminergic activity in the medial prefrontal
cortex is not necessary for the acquisition of instrumental learning.
Sham-operated animals showed sensitivity to both outcome devaluation and
contingency degradation. Animals with dopaminergic lesions of the prelimbic
cortex, but not the infralimbic cortex, failed to adapt their instrumental
response to changes in contingency, whereas their response remained sensitive to
outcome devaluation. In a second experiment, aimed at determining whether
dopamine was specifically needed during contingency changes, we performed
microinfusions of the dopamine D(1)/D(2) receptor antagonist flupenthixol in the
prelimbic cortex only before contingency degradation sessions. Animals with
infusions of flupenthixol failed to adapt their response to changes in
contingency, thus replicating the deficit of animals with dopaminergic lesions in
Experiment 1. These results demonstrate that dissociable neurobiological
mechanisms support action-outcome relationships and goal representation, dopamine
signaling in the prelimbic cortex being necessary for the former but not the
PMID: 19458230 [Indexed for MEDLINE]