Abstract: The prefrontal cortex (PFC) and striatum are two important regions in the brain, which involves in many higher cognitive processes, e.g., learning, memory, information processing, and inference, decision-making, and so on. Reward prediction is essential for learning behavior and decision-making process in the brain. It is well-known that the neurons in both PFC and striatum are responsible for encoding reward information, and the interplay between the PFC and striatum plays an important role in cognitive processes. However, the specific ways of information exchange between these two brain regions and the interaction between PFC and striatum are still not clearly known. To this end, we records in this work the local field potentials (LFPs) in the lateral PFC and the striatum of two male monkeys, while these monkeys are experimentally performed the sequential paired-association task with the asymmetric reward scheme. And then, the nonlinear interdependence (NLI) measure is computed to quantify the strength of functional connectivity between the PFC and striatum. It is found that the functional connectivity strength between these two brain regions is significantly higher in small reward conditions than that in big ones, which mainly happens in β frequency band. Besides, it is also found via results that there exists significantly greater functional connectivity from the PFC to the striatum than that in opposite direction. This result is consistent with the fact that PFC neurons have direct projections to striatal neurons, while striatal neurons do not project to LPFC neurons directly. This means that PFC neurons could regulate the striatum neurons’ activity to some extent.