Dopamine activity in the nucleus accumbens modulates blocking in fear conditioning.
Associative learning depends on the discrepancy between actual and predicted outcomes. The neurochemical mechanisms involved in regulating this discrepancy in Pavlovian fear conditioning in rats are unknown. We employed the blocking paradigm to show that this learning discrepancy is decreased by heightened activation of dopamine following an accumbal infusion of d-amphetamine, and increased by dopaminegic blockade following an accumbal infusion of cis-(z)-flupenthixol or by combined infusions of the D1 (SCH23390) and D2 (sulpiride) antagonists but not by infusion of either alone.
Iordanova
Mihaela D
MD
School of Psychology, The University of New South Wales, Sydney, Australia. iordanovamd@cardiff.ac.uk
Westbrook
R Frederick
RF
Killcross
A Simon
AS
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology*; D003213:Conditioning, Psychological / Q000187:drug effects / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism*; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D065127:Dopamine D2 Receptor Antagonists; D004347:Drug Interactions / Q000502:physiology; D005239:Fear / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology; D009434:Neural Pathways / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D017447:Receptors, Dopamine D1 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000819:agonists / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*
D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D065127:Dopamine D2 Receptor Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D004298:Dopamine