Prefrontal dopamine D4 receptors are involved in encoding fear extinction.

The medial prefrontal cortex is known to be crucially involved in the memory for fear extinction. It has been shown that the dopamine D4 receptor is abundantly localized in the medial prefrontal cortex of rodents and that this receptor subtype is involved in the mediation of fear-related behaviour. In the present study, we tested whether dopamine D4 receptors within the medial prefrontal cortex are involved in the learning and encoding of fear extinction. Infusions of the specific dopamine D4 receptor antagonist L-741,741 into the medial prefrontal cortex immediately before fear extinction did not affect fear extinction learning but attenuated the memory on fear extinction on the following day. These results suggest that medial prefrontal cortex dopamine D4 receptors are involved in the consolidation of fear extinction memory.