The dorsolateral striatum (DLS) is frequently implicated in sensory-motor integration, including the performance of sensory orienting responses and learned stimulus-response habits. Our laboratory previously identified a role for the DLS in rats' performance of conditioned orienting responses (ORs) to Pavlovian cues for food delivery. Here, we considered whether DLS is also critical to another aspect of attention in associative learning, the surprise-induced enhancement of cue associability. A large behavioral literature shows that a cue present when an expected event is omitted enters into new associations more rapidly, when that cue is subsequently paired with food. Research from our laboratory has shown that both cue associability enhancements and conditioned ORs depend on the function of a circuit that includes the amygdala central nucleus and the substantia nigra pars compacta. In three experiments, we explored the involvement of DLS in surprise-induced associability enhancements, using a three-stage serial prediction task that permitted separation of DLS function in registering surprise (prediction error) and enhancing cue associability, and in using that increased associability to learn more rapidly about that cue later. The results showed that DLS is critical to the expression, but not the establishment, of the enhanced cue associability normally produced by surprise in this task. They extend the role of DLS and the amygdalo-nigro-striatal circuit underlying learned orienting to more subtle aspects of attention in associative learning, but are consistent with the general notion that DLS is more important in the expression of previously-acquired tendencies than in their acquisition.
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